Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

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

Post by muehlpower »

In my unit I found a 3 lip seal with an aluminum body. The seals from the ukraine look like the ones from china with a stainless steel housing and laser marking. On aliexpress the 3 lip seals can be found in black and light yellow, just like the two offered on ebay. I have two more units here and will see what is installed there.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by TastyGuac »

Skudak wrote: Thu Jul 28, 2022 5:36 pm
Which one did you order? Did it come in the manufacturers box with a part #? I have been eyeing these two. Both ship from Ukraine but different sellers and different cities

https://www.ebay.com/itm/255414332627?h ... Sw06dh~sJH
https://www.ebay.com/itm/363912238070?h ... Swg0Bi1C5k
This is the listing I bought: https://www.ebay.com/itm/255414345077 (Edit 8/31: See comment below about this seal leaking)

I wanted output shaft seals too as I think I nicked one of them when pulling the axles out.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by asavage »

On the Tesla LRU, the axle adapter seals are a high-failure item (they leak frequently).
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by muehlpower »

I use BMW parts for the axle adapters


https://www.ebay.de/itm/133413837269

Breite [mm]: 10
Breite [mm]: 15,5
Innendurchmesser [mm]: 44
Außendurchmesser [mm]: 67
Einbauposition: Hinterachse beidseitig
Gewicht [kg]: 0,032
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by TastyGuac »

Does anyone know the size of the O-ring on the drive unit speed sensor? I don't see the ring itself listed in the Tesla or MB parts diagrams. Mine was torn when removed.

Edit - it appears to be a 24mm ID, 2mm thick O-ring.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Vsevolod »

TastyGuac wrote: Wed Aug 10, 2022 7:13 pm Does anyone know the size of the O-ring on the drive unit speed sensor? I don't see the ring itself listed in the Tesla or MB parts diagrams. Mine was torn when removed.

Edit - it appears to be a 24mm ID, 2mm thick O-ring.
It is necessary that someone measure what was taken, try to approach the car market with a torn ring, it may turn out to pick up or cut another
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Johan »

@TastyGuac:
O-ring.PNG
The maximum inner diameter should be 24.25mm in order to fit snugly around the speed sensor ("circuit assembly switch").
Mine measured 23.85mm after taking it off the sensor.

The minimum outer diameter should (after assembly and straining) be 27.00mm in order to fit snugly in the aluminium manifold.
Mine measured 27.25mm after taking it off the sensor.

Measured thickness: 2.00mm (assuming a circular cross-section)

I know that 23.85mm + 2 x 2.00mm ≠ 27.25mm because the cross-section has become oval in the course of time.

My measurement accuracy estimation: 0.1mm.

You can also buy a new "circuit assembly switch" for $245.57 :o at at Toyota
Disclaimer: Despite all efforts, all (which I write) should be conservatively interpreted as a poorly informed, error-prone, non-expert opinion that is subject to continuous change, especially in this age of hyper-specialization and newly gained insights.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by TastyGuac »

I can confirm my new Chenming seal is leaking. Sensor is wet after about 300 miles but doesn't seem to be leaking at a high volume. No fluid in the motor or inverter, and nothing came out of the drain bolt I drilled next to the sensor.

The search for a better seal continues. @Boxster EV - Any update on the SKF seal?
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Boxster EV »

TastyGuac wrote: Wed Aug 31, 2022 5:41 pm I can confirm my new Chenming seal is leaking. Sensor is wet after about 300 miles but doesn't seem to be leaking at a high volume. No fluid in the motor or inverter, and nothing came out of the drain bolt I drilled next to the sensor.

The search for a better seal continues. @Boxster EV - Any update on the SKF seal?
I’ve done about 800 miles on the SKF seal / speedi sleeve combo and it’s completely dry. Not one single sign of residue.

@johan how are you getting on with the Toyota?
Porsche 986 powered by a Tesla large drive unit. Backwards. Build documented here and Instagram @tesla_porsche here.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by SuperV8 »

Johan wrote: Thu Aug 11, 2022 10:02 pm You can also buy a new "circuit assembly switch" for $245.57 :o at at Toyota
Who'd have thought Mercedes parts prices might be 'reasonable'!
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Vsevolod »

TastyGuac wrote: Wed Aug 31, 2022 5:41 pm I can confirm my new Chenming seal is leaking. Sensor is wet after about 300 miles but doesn't seem to be leaking at a high volume. No fluid in the motor or inverter, and nothing came out of the drain bolt I drilled next to the sensor.

The search for a better seal continues. @Boxster EV - Any update on the SKF seal?

Chenming seal Walks usually about 60,000-100,000 km
In the USA and Ukraine, they put it at service stations and give a guarantee of 60,000, the main thing is to put the rotor on a flat surface and not break the cut of the stuffing box during installation
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by asavage »

Hey! If it wasn't for us Toyota RAV4 EV and Mercedes B250e owners, you probably wouldn't be able to buy that sensor at all!
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Vsevolod »

asavage wrote: Thu Sep 01, 2022 4:06 pm Hey! If it wasn't for us Toyota RAV4 EV and Mercedes B250e owners, you probably wouldn't be able to buy that sensor at all!
Probably yes :)
By the way, do you think it makes no sense to contact Tesla so that they start selling these oil seals or give the contact of the factory that made them
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by asavage »

From what I've read, Tesla seems to have no interest in selling parts to end-users (and few parts to professionals), which is discouraging.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Vsevolod »

asavage wrote: Thu Sep 01, 2022 4:11 pm From what I've read, Tesla seems to have no interest in selling parts to end-users (and few parts to professionals), which is discouraging.
Yes, they sell engines and batteries only if they install them, but it seems to me that with the right to repair, the sale of the oil seal is really necessary, because it's just wrecking, changing the whole engine instead of replacing the rubber according to the regulations
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by asavage »

Oh, I agree with what Tesla should do, but I'm not holding my breath for it to happen. Look at all the other stupid things Tesla has done and continues to do.

We sold our M3 last month. I'm keeping the RAV4 EV.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by SuperV8 »

Vsevolod wrote: Thu Sep 01, 2022 5:25 pm Yes, they sell engines and batteries only if they install them, but it seems to me that with the right to repair, the sale of the oil seal is really necessary, because it's just wrecking, changing the whole engine instead of replacing the rubber according to the regulations
To give them their due :o - the encoder/sensor is listed in their catalogue - with a comment "Over-the-Counter(No VIN)" so in 'theory' it should be available? RRP in UK is £90 - which is a bit steep if you just need the o-ring!.

They list an inlet manifold o-ring separately - 11 INLET MANIFOLD FITTING O-RING 1008806-00-A why not the sensor o-ring! would be nice if they were the same size?
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Johan »

Boxster EV wrote: Wed Aug 31, 2022 6:35 pm @johan how are you getting on with the Toyota?
After some error message trouble (see here for a video log), I was able to put the car back together correctly. So far, the Chenming seals have run 80mi without leaks. I could not drive much yet, partially bc I was overseas :( .
Disclaimer: Despite all efforts, all (which I write) should be conservatively interpreted as a poorly informed, error-prone, non-expert opinion that is subject to continuous change, especially in this age of hyper-specialization and newly gained insights.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Vsevolod »

Maybe anyone can ask SKF about the dimensions of such an oil seal? It seems to be for electric motors, it would be interesting to know what sizes are available
https://www.skf.com/group/products/auto ... for-edrive
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

New member here. 2013 Tesla MS85 3rd RevQ reman LDU. Discovered coolant seal leaking (coolant on speed sensor) recently at 72k miles (installed 3/2017 at 40k miles). Had an engine break like whine since install at 40k. Most notable under 30kW regen load going down hill (going slow, no wind noise, noise frequency most prominent under this condition). Tesla has been "its acceptable noise" punt mode. Out of DU warranty now. Recently hear more higher pitched faint noises at all speeds. Thus checked the speed sensor and discovered the leak.

Reviewed many rebuild sources and contacted few folks (Johan, asavage, QC Charge tech in another forum) Seems sourcing the seal is quite the challenge. Furthermore, nothing suggest Tesla's OEM seal is any good.

Reached out to a US PTFE seal manufacturer (google PTFE seal supplier, probably same as some tesla designer did years ago haha). Smallish company but list many industrial application customers. Looks like mostly high end high grade stuff. They are familiar with Tesla LDU seals for a few years now. Got the following info in a brief phone call

- This application (Coolant seal on a 10k RPM shaft) likely will leak after some period due to amount of surface that is engage per time period (I forgot the term he used) with water/coolant media. Basically 10k RPM = a lot of surface is engaged in unit time.
- Use lipped PTFE seals. As the seal material wears down, the tension of the lip will maintain contact.
- Use low wear PTFE seal material. This also depend on shaft material.
- They build seals to spec, can make triple/quad lip etc. Seal cage in stainless in current supply chain situation.
- Minimum order of $500 which is about 4-5 seals.
- Can't warranty of course (same as any other seal purchased)

Anyone interested in developing our own seal? For $1k, maybe we can get 15? seals. Anyway, say $75-$100/seal shipped. I'll would need to coordinate spec, purchase, and not sure all thats involved yet. Probably need to get Johan's CAD, maybe ship a rotor and coolant tube assembly to them? Don't know yet but thought I check interest. PM me.

On seal design, I was wondering if don't need the extruding lip on the dry side to keep oil/dirt out would make install much easier. Need to consult with seal designer of course.
Tesla LDU rebuild website https://sites.google.com/view/teslaldu
2013 Model S85 3rd (Reman RevQ) LDU on 2017 @40k. Coolant seal leak discovered in 8/2022 @ 72k miles
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by WimV »

Very interesting! I'm also looking for a quality seal. QC Charge claims to have them, but they ignore me if I ask if they're willing to sell them.
howardc64 wrote: Wed Sep 07, 2022 4:50 am They are familiar with Tesla LDU seals for a few years now.
Do you mean that they have produced them before? Did they say for which company?

Anyway, I'm interested!
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by howardc64 »

WimV wrote: Thu Sep 08, 2022 8:15 pm Very interesting! I'm also looking for a quality seal. QC Charge claims to have them, but they ignore me if I ask if they're willing to sell them.

Do you mean that they have produced them before? Did they say for which company?

Anyway, I'm interested!
Ok let me see if more interest. They were engaged on LDU seal. Prefer not to disclose more without their permission. Anyway, their website shows Tesla logo haha. I'll be glad to share company name once I get more interest and their permission.

One note is we don't know if quality will be better or worse than Chenming seal. We are just unable to draw confidence through contact and evaluate expertise. Anyway, doesn't sound like any seal is going to last much more than 30-50k miles and can start leaking in much sooner.

I am in need to rebuild the LDU in same situation as you. I can't see how working with a vendor that isn't making the seal now meet our time schedule. Anyway, My 13 MS85 is parked with insurance turned off for now so could stay that way for few months haha.
Tesla LDU rebuild website https://sites.google.com/view/teslaldu
2013 Model S85 3rd (Reman RevQ) LDU on 2017 @40k. Coolant seal leak discovered in 8/2022 @ 72k miles
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by beastman »

I'm interested in the custom seal too. 2013 model S P85 here that has 20k on the model q DU from 2020. I have been pondering Tesla's the use of the coolant in the DU's instead of traditional hydraulic fluid or oils, which have much higher viscosity and would likely leak less on a seal in this situation. Also, if electrolysis is occuring due to conductivity and causing high voltage arcing/damage to the seal area, we might be better off running a hybrid coolant with very low conductivity (e.g. distilled water). A company called evans has some low conductivity coolant but reviews of it on traditional cars is a mixed bag due to it not performing as well as traditional coolant and cars running a bit hotter. There is an acquaintance of mine on the tesla forums who lives in Wisconsin who I have talked to over chat - he has 353k on his 2014 model S, original battery and about 250k miles on the current drive unit which was put into the car around 2017. (not sure what drive unit rev he has). These are the anecdotal cases we should focus on to see possibly what seals and revisions were done to get these things to last 150k with the right seals. I am sure without an aegis ring or similar voltage buildup and discharge will continue to be a problem now that the hybrid ceramic bearings aren't the preferred path for this discharge- I would suspect the seal and coolant would have possibly low enough resistance that electrolysis might possibly be damaging it. My past work as an engineer is primarily electrical and software where I designed outdoor wireless systems for last mile internet access and came up with solutions to channel esd away from sensitive radio chips, electronics, etc for 16 years; I currently design and sell automotive electronics for a living for the past 5 years. There are a ton of automotive transients on a traditional vehicle, but an EV is on a whole new level @ 400v w/tons of current.

My $.02.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Vsevolod »

howardc64 wrote: Fri Sep 09, 2022 2:20 am Ok let me see if more interest. They were engaged on LDU seal. Prefer not to disclose more without their permission. Anyway, their website shows Tesla logo haha. I'll be glad to share company name once I get more interest and their permission.

One note is we don't know if quality will be better or worse than Chenming seal. We are just unable to draw confidence through contact and evaluate expertise. Anyway, doesn't sound like any seal is going to last much more than 30-50k miles and can start leaking in much sooner.

I am in need to rebuild the LDU in same situation as you. I can't see how working with a vendor that isn't making the seal now meet our time schedule. Anyway, My 13 MS85 is parked with insurance turned off for now so could stay that way for few months haha.
Have you talked to Saint Gobain?
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Skudak »

I would also be interested in doing a group buy of custom seals. I'd be in for at least 2
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