Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Topics concerning the Tesla front and rear drive unit drop-in board
howardc64
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

Ceimin triple lip seal cage is a lot stronger than original Tesla's single lip seal cage. Multiple stainless ring blocks pressed together and a lot heavier. Removal is much greater challenge than original seal but pretty easy this way (thanks to @Boxster EV)

- drill pilot hole through top stainless steel layer (closer to the outer edge as interior rings have larger ID and can be missed drilling at an angle), maybe 1/2 way through the 2nd layer of steel (slow speed with oil to cool, getting stainless hot only gets it harder) Drilling will be at a slight angle since the manifold pipe is in the way.
- screw in self tapping screw. Preferably one can turn and lock in tight with ratchet
- bite screw head on a vice, lever out the seal

Came out pretty easy. Ability to apply high leverage properly makes it easy.
IMG_0659.jpeg
Here is a better look at the seal interior. All PTFE seal lips intact, rust packed in between.
IMG_0660.jpeg
My best guess now is prior reman removed the protective plating and didn't reapply. My light sanding probably wouldn't have taken off the plating (unless of course I did take off whatever surface finish protectant). Fresh O2 is introduced via drain port. Cooling contracting volume coolant probably vacuum pulls air into the seal lip chamber from dry side sucking in fresh air. Can't prove any of this but seems most likely
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

Made some calls to inquire about possible rotor shaft repair. Here is first pass info

Electric Motor Repair Business

These business exist in more industrialized regions. Fixing industrial motors. But non of them do shaft repair.

Flame Spray Repair Service

Got a referral from a couple of electric motor repair shop on a flame spray repair service when I mentioned shaft repair + sprayed metal. Here is the business

https://www.flamespray.us/abouta/

Looks like speciality is shaft repair. Spoke with 2 different knowledgeable techs for about 10min each at different times (everyone gives me 10min when hearing interesting Tesla application). I provided the application, geometry, and problem. Tech(s) suggested the following

Ceramic

Both's first thought was ceramic for anti-corrosion properties and they do a lot of them. But its a heat barrier rather than transfer. They didn't think it would be a problem but certainly hasn't done any deep analysis on seal heat density. Ceramic starts as a powder and applied by a plasma gun.

Inconel

A nickle chrome + a little moly alloy. ( https://en.wikipedia.org/wiki/Inconel Used in first jet engines haha) Applied with a twin wire spray gun. He said this avoids transferring heat to the shaft like welding. Probably this? ( https://www.youtube.com/watch?v=eE4QmRn ... oShotBlast )

Stoddy 133

Chrome carbide (welding wire). Also applied with a twin wire spray gun.

In all cases, he would machine off about 25/1000 (less for ceramic), apply the material (along with any bonding agent), finished to desire roughness (say 20 Ra), maintain and polish the bevel lip for PTFE seal insertion. For a 12" long rotor, 70lb, 7" diamater copper, bearings removed, 15mm length of hallow 30mm shaft with about 2+mm thickness. One said < $300.

If only Tesla LDU removal.+ install is easier haha... Lift + scissor table makes it easier but I have no access.

Porosity

@asavage noted spray metal layer will be porous based on 40yo experience. Shop said this is still the situation after attempt improvement (higher velocity, oxygenated fuel etc). However, once finished to say 20-30Ra, not an issue according to the shop.

Based on Seattle, they do a lot of ship based equipment. When I mentioned speedi-sleeve, tech said great solution if out at sea but spray metal repair is more robust once back at port :)

Automotive Liability

Tech did say owner generally avoid automotive application due to liability. Maybe a bigger issue here in USA.

Finish

Based on my understanding of PTFE seal sealing mechanism (depend on proper surface roughness to transfer small amount of PTFE material onto the shaft to seal against the PTFE seal) I'd imagine the bevel shaft entry should be super smooth to avoid transferring PTFE during initial insertion. Looking at the rotor shaft bevel lip carefully, it seems to even coated with something that smooth out the machining grooves.

Spline Grease

Anyone know what this stuff is? Saving it 2x now means I have less and less of it on the spline coupling. It looks like really thick grease. Perhaps electric insolation property too? No idea.

====

Anyway, way beyond my knowledge domain but posting it for reference. But I'd imagine the proper material choice would be a more robust solution than sleeve and even chrome plating.

Another interesting thing is all these electric motor and shaft repair companies are multi-decade old family type businesses. Father passing the trade to the son like the old days.
2oldteslas
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by 2oldteslas »

I'm going to try this 2 lip PTFE seal for my 2012 P85. It took 8 days to come in the US mail from New Jersey to the Chicago area. It ships with an internal collar spacer fitted to keep the seals oriented and stretched until installation.
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2012 P85, 2013 85, 2013 85 parts car.
2oldteslas
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by 2oldteslas »

Howardc64 RE: Spline grease.
A good sticky grease used for propellor shafts is made by Overall Supply Inc from New Jersey. It is called "super grease" and is very sticky. It worked well on tug boat prop shaft bearings and seals. A couple other synthetic greases are made by Hydrotex and Certified Laboratories. I used the super grease on my rotor splines.
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howardc64
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

2oldteslas wrote: Thu Aug 03, 2023 12:45 am I'm going to try this 2 lip PTFE seal for my 2012 P85. It took 8 days to come in the US mail from New Jersey to the Chicago area. It ships with an internal collar spacer fitted to keep the seals oriented and stretched until installation.
Another PTFE seal from China. Interesting. Pic shows both lips face coolant side (no excluder) so much easier to install over the beveled shaft opening without risk of folding the lips.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by jrbe »

Has anyone looked at making a new coolant extension tube (blue) an adapter lip / flange (aqua green - black is an o-ring) that extends into an internal seal (red) in the motor shaft?
The coolant extension tube could be 2 pieces (at the dashes) to be a bit more cost effective.

Anyone have the shaft ID where the red is?
Screenshot_20230802_213732_YouTube.jpg
This would cut down on coolant flow somewhat. It would also give a smaller seal diameter / surface speed. Might give a bunch of seal options flipping it like this. The wear item would be the adapter lip / flange and should be easy to replace if needed.
Could also be a solution for motors with mangled sealing surfaces.

*edit, the seal lip would probably open from centrifugal force if one tried to use a seal pressed into the motor shaft as I drew. Probably would have to flip it to an external lip seal.*
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by jrbe »

This is generic info but worth a read for people considering multi-lip seals. PTFE might be allowed to run dry but I wouldn't expect that to be the case at the speeds that these are spinning.
https://www.skf.com/us/products/industrial-seals/power-transmission-seals/radial-shaft-seals/technical-specification wrote: For a radial shaft seal to seal efficiently over a long period, the sealing lip must be lubricated. This reduces friction and wear to the sealing lip and shaft. Dry running of sealing lips made of standard materials should always be avoided. To prevent dry running, coat the counterface surface with a suitable lubricant prior to seal installation.

The lubricant must not only lubricate the sealing lip to reduce friction and wear, but also dissipate heat generated by the seal. To promote heat dissipation, a sufficient quantity of lubricant must be able to reach the sealing lip from start-up.

Some rolling bearings, such as angular contact ball bearings, tapered roller bearings and spherical roller thrust bearings, as well as gears, create a pumping action by virtue of their design. This means that the sealing lip can either be starved of lubricant, or subjected to excessive quantities of lubricant. In either case, steps must be taken during the design stage to make sure that the proper amount of lubricant reaches the sealing lip, as too much or too little can affect seal performance.

To prevent lubricant starvation, lubrication ducts can be provided. If the seal is subjected to excessive amounts of lubricant, a flinger can be installed between the bearing and seal.

In applications where the sealing lip is not exposed to a lubricant, for example when two seals are installed in tandem, grease or oil must be supplied separately to provide lip lubrication. In some cases, it may be sufficient to provide an initial grease fill between the two lips.
under lubrication.
Trick would be to find a PTFE compatible lubricant that doesn't gum up when expose to g48.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

jrbe wrote: Thu Aug 03, 2023 2:03 am Has anyone looked at making a new coolant extension tube (blue) an adapter lip / flange (aqua green - black is an o-ring) that extends into an internal seal (red) in the motor shaft?
The coolant extension tube could be 2 pieces (at the dashes) to be a bit more cost effective.

Anyone have the shaft ID where the red is?

Screenshot_20230802_213732_YouTube.jpg

This would cut down on coolant flow somewhat. It would also give a smaller seal diameter / surface speed. Might give a bunch of seal options flipping it like this. The wear item would be the adapter lip / flange and should be easy to replace if needed.
Could also be a solution for motors with mangled sealing surfaces.
Shaft ID at just behind the beveled (beveled on ID as well as OD) edge is 25.5mm +- 0.1mm. Hard to measure precisely.

One challenge to seal on the ID is potential lack of surface treatment. If these shafts were plated, probably OD and only where the seal contacts.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

While looking inside rotor coolant shaft to see if any channels to route coolant into the copper block (none, just a straight hollow tube) Saw something. Poked at it with a borescope and separated into pieces. trying to get it out but sticky to the walls.

Looks like gel formation? Not sure anything to worry about.

Sorry for the poor pic, cheap Aliexpress borescope.
S20230802_002.jpg
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

2oldteslas wrote: Thu Aug 03, 2023 1:04 am Howardc64 RE: Spline grease.
A good sticky grease used for propellor shafts is made by Overall Supply Inc from New Jersey. It is called "super grease" and is very sticky. It worked well on tug boat prop shaft bearings and seals. A couple other synthetic greases are made by Hydrotex and Certified Laboratories. I used the super grease on my rotor splines.
Thanks, that grease looks thick! haha

Few questions

- Did you mix it with the original grease?
- Any longevity data? I guess need to pull again to see for sure.. PITA haha
- Any thoughts on electrical conductivity characteristics?

Thanks
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by 2oldteslas »

howardc64 wrote: Thu Aug 03, 2023 6:25 pm Thanks, that grease looks thick! haha

Few questions

- Did you mix it with the original grease?
- Any longevity data? I guess need to pull again to see for sure.. PITA haha
- Any thoughts on electrical conductivity characteristics?

Thanks

-I cleaned off most of the old grease but not all so a small amount is mixed in with the super grease.
-no information on longevity or conductivity. Judging by experience it is a good heavy duty grease.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by 2oldteslas »

These are the 3 coolant seals I bought. Single lip, double lip and triple lip. Time will tell which works best.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

2oldteslas wrote: Thu Aug 03, 2023 10:32 pm These are the 3 coolant seals I bought. Single lip, double lip and triple lip. Time will tell which works best.
For the FKM seal, you can get better qualify SKF with and without excluder lip. ~$5 each at Acorn in UK (but $30 international 2 day DHL ship) so best to combine with bearing purchase.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

Spline Coupler Grease

Found some info on the spline coupler grease. Tesla use to sell it but no more :( Unfortunately no brand or spec. Tesla has a lot of parts including oil products made by South Korean companies (gearbox ATF for example) All with Tesla labels and no specs. Maybe this spline coupler grease is same.

Tesla PN Is 2004942

Listed in catalogs of various eastern european outfits. For example : https://tsk.ua/en/parts-catalogue/motor ... er=2004942

This part is no longer available in current US online part listing. The line where it appears amongst other products is gone. Maybe the eastern European outfit's catalogs are older catalog download.
no spline coupler grease.png
Like to find the grease Tesla used because the inner primary (pinion) shaft where the spline is has a 3mm+ opening exposed to the gearbox ATF on the counter bore side. So ATF can possibly get inside although I've never seen this grease getting washed out by ATF in 2 times I've opened the gearbox.
IMG_0666.jpeg
Here is a engineering thread discussing EV motor coupling to the pinion shaft.

https://www.eng-tips.com/viewthread.cfm?qid=464172

Mid way down this short thread shows a motor with spline coupling grease spec (CASMOLY L9508 https://www.gobizkorea.com/user/goods/f ... 0110298787 ) Yet another South Korean company product. Don't know what car this motor is for or whether this spline has potential exposure to ATF.

Rest of the thread discusses the robustness of the pinion gear spline and bearings (beyond my knowledge) but also hints at South Korean design.

Given all the SK products in Model S HV+drive train (ATF is SK Lubricant, DCDC1 HV connectors are KET (Korea Electric Terminal), curious how much of it was designed by SK firms.

UPDATE : Got a tip from Alex at QC Charge any high quality high temp grease will work.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

Coolant Manifold with rotor cooling "DELETE"

While searching for spline coupler grease, found this newish PN on Tesla LDU catalog
rotor coolant delete manifold.png
For reference, most Tesla LDU PNs are ~1M. Model 3 LDU PNs are ~1.2M. MY's refurb drive unit PN Is ~1.5M. 2021+ MS drive unit PNs are ~1.7M. Judging by PN, this manifold PN (~1.5M) is fairly recent.

No other coolant manifold is listed in the parts catalog (ie with lower PN which would be presumably the original design)

It says ROTOR COOLING DELETE and triggered my curiosity. Unfortunately googling the PN yields nothing. I guess have to probe Tesla parts ordering process to see about cost and getting one of these... If Tesla figured out rotor cooling is unnecessary, it'd more than than silly haha.

UPDATE : Someone has a parts catalog with price list show this item is $0.01 and over the counter item. So looks like unlikely available. And nothing like this has been seen by LDU rebuilders. So what this is is really unknown.

UPDATE 2 (8/29/23) : Tesla eventually replied to my parts request and said not available for sale. So the mystery coolant DELETE manifold continues...
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

How Much Cooling Does Rotor Get Anyway?

Here is the LDU coolant circuit diagram. Most of the flow rate is from Stator -> Inverter IGBTs/ATF heat exchanger. Flow rate on output of rotor coolant circuit has a 4.5mm restriction. Schematic here



So I wonder how much cooling does rotor require given this flow rate restriction?

For additional info, there are track guys that don't like the fact that cold coolant goes through the stator before IGBTs. Stator runs hotting than IGBTs are happier running cooler so they split the inverter and motor loop.

https://www.diyelectriccar.com/threads/ ... ost-991426

There are recent research papers outlining how to computer rotor temperature of induction motor as direct measurement is not possible. Research goal is seeking more accurate estimates. I guess motor control needs this estimate to make decisions. So not sure its possible to change cooling characteristics without proper Tesla firmware changes.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by muehlpower »

So you assume that the Tesla solution is to omit the rotor cooling, because it doesn't do anything anyway?
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by jrbe »

Has anyone reached out to Parker Hannifin for a 19657H1L5PTFE seal?
Screenshot_20230805_071529_Adobe Acrobat.jpg
I'm not sure why they couldn't list that as a metric seal.
Might be worth trying through motion industries or other reseller if they don't want to be bothered directly.

It's an ss style lip,
Screenshot_20230805_072510_Adobe Acrobat.jpg
Screenshot_20230805_072510_Adobe Acrobat.jpg (9.88 KiB) Viewed 30163 times
My previous scribbles on this might not work out well as I first thought. I added an edit note to my post on that. With a seal in the shaft spinning, centrifugal force will probably open the seal lip. But they have a bunch of external lip seals if someone wants to experiment with flipping the sealing method inside out. With a sleeve pressed (and sealed) inside the hollow shaft it could give a decent surface for an external lip seal.
Screenshot_20230805_073540_Adobe Acrobat.jpg
They also have FKM seals with a bonded PTFE section to have the flexibility of rubber and a sealing edge / wear / friction surface of PTFE. Click on the image and zoom in, white rectangle is PTFE,
Screenshot_20230805_065947_Adobe Acrobat.jpg
But no off the shelf offerings for this that I saw in their design guide / catalog.

They also have seal designs with a molded in spring like section to allow for greater misalignment (some shown in the design style image above.) I don't think it's needed here though. Lots of interesting things in their 400 page design guide,
https://www.parker.com/content/dam/Park ... s/5350.pdf
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

muehlpower wrote: Sat Aug 05, 2023 8:55 am So you assume that the Tesla solution is to omit the rotor cooling, because it doesn't do anything anyway?
I think can not make such conclusion without detailed analysis. I was just curious based on the new rotor cooling delete manifold part number in Tesla's parts catalog. But it seem no one has seen this manifold or can purchase.

Here is a 2020 research paper (Renault EV power train) on how to estimate induction motor (IM) rotor temperature (can not directly measure in mass production) They are using a fan cooled motor (TEFC : Totally Enclosed Fan Cooled) TEFC motor has fan blade externally to cool the stator and internally to cool the rotor ( https://www.mdpi.com/2079-9292/9/7/1096 ) The rotor is aluminum cage (LDU is copper cage rotor)

https://www.mdpi.com/2079-9292/9/7/1096

Figure 8 & 9 shows rotor temp is higher than stator. Up to 200C with 30kW power. They measure rotor temp directly (infrared pyrometer) and compare with their estimation calculation.

Here is a paper comparing Tesla IM vs Audi etron IM. It doesn't have temperature measurements. Just noting Tesla IM is copper rotor cage (more expensive, lower resistance = lower rotor temp) vs etron's aluminum rotor cage.

https://hal.science/hal-03304650/document

Anyhow, have not found enough data analysis yet to conclude can omit LDU rotor cooling. Someone with mechanical engineering background might be able to calculate heat removal capacity with LDU's 4.5mm rotor cooling output restriction and incoming coolant inlet size and pressure (20psi?)
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

jrbe wrote: Sat Aug 05, 2023 11:57 am Has anyone reached out to Parker Hannifin for a 19657H1L5PTFE seal?
Screenshot_20230805_071529_Adobe Acrobat.jpg
I'm not sure why they couldn't list that as a metric seal.
Might be worth trying through motion industries or other reseller if they don't want to be bothered directly.

It's an ss style lip,
Screenshot_20230805_072510_Adobe Acrobat.jpg

My previous scribbles on this might not work out well as I first thought. I added an edit note to my post on that. With a seal in the shaft spinning, centrifugal force will probably open the seal lip. But they have a bunch of external lip seals if someone wants to experiment with flipping the sealing method inside out. With a sleeve pressed (and sealed) inside the hollow shaft it could give a decent surface for an external lip seal.
Screenshot_20230805_073540_Adobe Acrobat.jpg

They also have FKM seals with a bonded PTFE section to have the flexibility of rubber and a sealing edge / wear / friction surface of PTFE. Click on the image and zoom in, white rectangle is PTFE,
Screenshot_20230805_065947_Adobe Acrobat.jpg
But no off the shelf offerings for this that I saw in their design guide / catalog.

They also have seal designs with a molded in spring like section to allow for greater misalignment (some shown in the design style image above.) I don't think it's needed here though. Lots of interesting things in their 400 page design guide,
https://www.parker.com/content/dam/Park ... s/5350.pdf
Yes, I reached out to Parker and Saint Gobain custom seal divisions. Neither wanted to engage. Saint Gobain said the seal was proprietary in nature so didn't want to provide services. I'm guessing all these big manufactures already contacted by Tesla/Tier 1 supplier. Maybe some are past/current LDU seal manufacturers.

viewtopic.php?p=49553#p49553
viewtopic.php?p=46858#p46858

SKF also have similar custom PTFE seal division but contact requires business emails. SLX profile (single lipped, concentric ribs to aid bending) in the link below is nearly identical to the Tesla sourced single lip seal found in LDUs.

https://www.skf.com/us/products/industr ... tions/ptfe

Someone is welcome to attempt contact again. Search the thread for Parker and Saint Gobain and can find all my summaries from contact attempts. Also included many summaries from contacting smaller PTFE seal companies. All without success but gathered many info. Posts all towards end of 2022.

I also had no luck with motion industries and other distributors. $$$ and no one wants to deal with DIYer quantities.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by jrbe »

howardc64 wrote: Sat Aug 05, 2023 12:26 pm Yes, I reached out to Parker and Saint Gobain custom seal divisions. Neither wanted to engage. Saint Gobain said the seal was proprietary in nature so didn't want to provide services. I'm guessing all these big manufactures already contacted by Tesla/Tier 1 supplier. Maybe some are past/current LDU seal manufacturers.
...
viewtopic.php?p=49553#p49553
viewtopic.php?p=46858#p46858
Sorry I missed those posts.

I find it strange that potential OEM suppliers are not willing to sell parts. I could see them not using a Tesla logo or the Tesla part # on it. Maybe they know it's a bad design, they might just see it as a liability that they know will fail and shut it down asap. Maybe that's Tesla's refusal to sell seals too.

For clarity, 19657H1L5PTFE should be an off the shelf part. No need to go the custom route or even mention Tesla while trying to order some. It doesn't seem to be a thick sealing surface but that could be a good thing given the speed it can run at.

For the rotor cooling temperature reference, using an IR sensor should get the rotor temp without complications or assumptions. They should be pretty immune to electromagnetic environments. There are also temp recording paints that could be manually checked for testing / verification.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

jrbe wrote: Sat Aug 05, 2023 1:18 pm Sorry I missed those posts.

I find it strange that potential OEM suppliers are not willing to sell parts. I could see them not using a Tesla logo or the Tesla part # on it. Maybe they know it's a bad design, they might just see it as a liability that they know will fail and shut it down asap. Maybe that's Tesla's refusal to sell seals too.
All I can tell you is its pretty clear Tesla is anti aftermarket therefore DIY. Most of the 5-10 seal makers I've contacted told of prior engagement with Tesla/Tier1 supplier on the coolant seal. One told me they stopped after finding out was in some kind of design competition to make one that doesn't have prominent leak problem. Tesla is a big gorilla in relation to these seal makers (large/small) in terms of business and PR leverage. By contrast, other car manufacturers don't really police parts manufacturers selling aftermarket. I've done much DIY on Volvo+VW/Audi repairs, OEM manufacturers grinding off car manufacturer logo and sell aftermarket is common place. So my guess is Tesla is pushing legal restrictions to their manufacturers.

Tesla's SC policy is also anti in-field end point learning, modding, enhancement. Tesla provide no solutions for their SC to service LDU+battery pack at SC (I think finally enabling contactor repairs etc) So its ship to repair center and back. Huge downside of this policy is the constriction of design improvement (many brains working at the end point rather than few (if any on last gen car) at HQ) and the core cost of such integrated and expensive item. Currently port warranty customer is paying for the expensive core. If you want an LDU+battery pack, need to turn in your old one and pay for the rebuilt one ($~7.5k for LDU, ~$15k+ for battery pack)

With off the shelf Parker parts, its basically going through distributor (if call seal manufacturer, they just point you to distributor) I've had no luck with distributors (Motion Industry + others) on DIY effort/1x volume. EU's much stronger right to repair laws seems to have a much more robust aftermarket DNA. Silicon Valley companies like Apple+Tesla is amongst the worst in aftermarket enablement. If you try to get the SKF ceramic bearing for the LDU in US, its basically impossible. But through EU, distributors are even willing to ship SKF bearings to US which is basically grey market. Talking with bearing distributors, they've also used Canada's more EU business relations as a grey market sourcing for US buyers for decades haha. US trade laws seems much more restrictive here.

Anyhow, tons of business mechanics, right to repair laws, and international trade laws are probably involved. Apple's anti-right to repair results in expensive battery+screen service cost (by them, even batteries are married to logic board these days and aftermarket methods and programmers become more and more challenging/less cost effective) but its still just a $1k asset. Tesla disabling right-to-repair for post warranty repair on a premium car asset is much more painful financially. Car value will drop like a rock post warranty. Probably same or worse than European premium cars (20%+ original price post warranty). Add in the periodically gov financial incentives on EVs that depresses used EV prices, post warranty price shoots below cheap subcompacts of the same vintage haha.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

SKF PTFE Seal Installation Direction

https://www.skf.com/us/products/industr ... tions/ptfe

Reviewing SKF's PTFE seal installation. They clearly state PTFE seal is not an elastomer material (NBR, FKM) and easily damaged by any sharp edge. Since PTFE's material property is like a hard plastic rather than an elastomer, the sealing mechanism therefore is different. Thus the more precise requirement on shaft surface, installation method etc.

In LDU's blind seal install, it is not possible to use a tool to avoid sharp edges. Instead, the shaft and its chamfered edge has to function as an installation tool. The chamfered edge has to be smooth.

Using SKF's speedi-sleeve on LDU rotor coolant shaft is probably incompatible with ANY PTFE seal. Its not possible to avoid sharped edges during install no matter how well the sleeve's sharp edge is machined/dremeled. Elastomer seal can survive sleeve's micro sharp edge but any scratches on PTFE hard plastic like sealing lip will become a leak channel.

A custom sleeve with chamfered edge over the existing shaft edge will probably work. But of course require yet another custom fabricated item to source and manufacturer. Without this, a damaged shaft's surface has to be spray metal repaired and chamfered edge carefully polished if want to use a PTFE seal.

Very much a decision I'm faced with 1) spray metal repair + PTFE seal 2) speedi-sleeve + Elastomer seal. I have a NBR seal with PTFE coated lip. Probably also can not be used with speedi-sleeve.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by SuperV8 »

howardc64 wrote: Sat Aug 05, 2023 2:35 pm All I can tell you is its pretty clear Tesla is anti aftermarket therefore DIY. Most of the 5-10 seal makers I've contacted told of prior engagement with Tesla/Tier1 supplier on the coolant seal. One told me they stopped after finding out was in some kind of design competition to make one that doesn't have prominent leak problem. Tesla is a big gorilla in relation to these seal makers (large/small) in terms of business and PR leverage. By contrast, other car manufacturers don't really police parts manufacturers selling aftermarket. I've done much DIY on Volvo+VW/Audi repairs, OEM manufacturers grinding off car manufacturer logo and sell aftermarket is common place. So my guess is Tesla is pushing legal restrictions to their manufacturers.

Tesla's SC policy is also anti in-field end point learning, modding, enhancement. Tesla provide no solutions for their SC to service LDU+battery pack at SC (I think finally enabling contactor repairs etc) So its ship to repair center and back. Huge downside of this policy is the constriction of design improvement (many brains working at the end point rather than few (if any on last gen car) at HQ) and the core cost of such integrated and expensive item. Currently port warranty customer is paying for the expensive core. If you want an LDU+battery pack, need to turn in your old one and pay for the rebuilt one ($~7.5k for LDU, ~$15k+ for battery pack)

With off the shelf Parker parts, its basically going through distributor (if call seal manufacturer, they just point you to distributor) I've had no luck with distributors (Motion Industry + others) on DIY effort/1x volume. EU's much stronger right to repair laws seems to have a much more robust aftermarket DNA. Silicon Valley companies like Apple+Tesla is amongst the worst in aftermarket enablement. If you try to get the SKF ceramic bearing for the LDU in US, its basically impossible. But through EU, distributors are even willing to ship SKF bearings to US which is basically grey market. Talking with bearing distributors, they've also used Canada's more EU business relations as a grey market sourcing for US buyers for decades haha. US trade laws seems much more restrictive here.

Anyhow, tons of business mechanics, right to repair laws, and international trade laws are probably involved. Apple's anti-right to repair results in expensive battery+screen service cost (by them, even batteries are married to logic board these days and aftermarket methods and programmers become more and more challenging/less cost effective) but its still just a $1k asset. Tesla disabling right-to-repair for post warranty repair on a premium car asset is much more painful financially. Car value will drop like a rock post warranty. Probably same or worse than European premium cars (20%+ original price post warranty). Add in the periodically gov financial incentives on EVs that depresses used EV prices, post warranty price shoots below cheap subcompacts of the same vintage haha.
Usually depends on who owns the tooling along with master supply contract agrements.
If the OEM owns/paid for the tooling they usually dictate where the parts go. If the tier one supplier owns/paid for the tooling they have more flexibility on selling versions in different/aftermarket sales channels. Obviously usually without OEM branding - which is why you sometimes see aftermarket parts with OEM branding ground off.

Some OEM's like to pay for all their tooling - keeping the supply chain locked down, others are more open - and let the tier one supplier take the upfront costs, with the benefit of some aftermarket sales revenue.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

Got rotor back from flame spray shop today.

Spec

I provided the following spec

~50Rc shaft hardness. Based on PTFE seal shaft hardness research
~0.2um surface finish (or N4 or 8uin) Based on PTFE seal shaft surface preparation research.

They did the following

- machined down 25/1000
- Arc twin wire sprayed Stoddy 133 (chrome carbide) They said basically stainless steel. Inconel could only achieve 20Rc so not a candidate. Just going by what they tell me. Keep in mind these are flame sprayed on with porosity rather than melted metal crystals. I asked what was done to solve the porous surface, they mentioned filler of some kind. All non sprayed areas are masked off.
- Polished to 0.2um spec. It appears polish is all the way to the chamfered edge enabling this built-in PTFE seal install structure.
- Cost $300
IMG_0762.jpg
Misc

This shop has 6-7 large machine lathe stations. Handles shaft repair for marine (I'm in Seattle), building equipment, and public busses with 12k RPM shafts (presumably hybrid bus) My $300 private consumer job is tiny compared to their other businesses so very much depending on their good will.

Next

Now onto LDU reassembly AND coolant seal lottery :) Have SKF FKM, NBR+PTFE coated, GFD single lip PTFE, Ceimin dual lip + excluder (commonly referred to as triple lip) Probably using a single lip this time.

IMG_0760.jpg
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