Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

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

Post by johu »

Hoping I don't disturb the discussion too much. Just watched a video about the 1000000 mile/1600000 km Tesla. It has eaten up 13 drive units! The best one lasted 760000 km but many didn't even last 100000 km. Batteries lasted much longer on average, he's on the third.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Boxster EV »

I’d be really interested to know if anyone has a lead on a good quality 30x55x8 seal. After a 1000 miles my drive unit is leaking again with Ceimin seal.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Johan »

@Boxster EV: O no! Thanks for the update!

Guess what: SKF actually showcases "SLX"(?) PTFE seals with concentric cuts (as in my Tesla DU, see my previous msg) here on their website, repeated here:
SKF seal.PNG
So maybe SKF is the supplier after all. Or not, who knows. Also: "The majority of PTFE radial shaft seals from SKF are made to order to meet the demands of each application." - Source p.98.
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 Boxster EV »

Sounds very promising. Figured out a part number?
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Johan »

I think that most of SKF's PTFE seals are custom made to order. The closest SKF off-the-shelf catalogue seal that matches the desired dimensions and is able to run at 12,420RPM is the rubber(!) seal model HMS5 V, but that one is "designed for oil or grease lubricated applications" (source). The problem is that the viscosity ("thickness") of coolant is much lower than oil/grease so the seal and shaft surface roughness asperities may contact each other, leading to fast seal wear. However if the shaft is smooth enough, it may work "for a while". Anybody wants to test this out, or does anybody have a reference with info that dismisses this proposal?
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 Boxster EV »

Johan wrote: Sun Jul 10, 2022 7:51 pm I think that most of SKF's PTFE seals are custom made to order. The closest SKF off-the-shelf catalogue seal that matches the desired dimensions and is able to run at 12,420RPM is the rubber(!) seal model HMS5 V, but that one is "designed for oil or grease lubricated applications" (source). The problem is that the viscosity ("thickness") of coolant is much lower than oil/grease so the seal and shaft surface roughness asperities may contact each other, leading to fast seal wear. However if the shaft is smooth enough, it may work "for a while". Anybody wants to test this out, or does anybody have a reference with info that dismisses this proposal?
Thanks for the ongoing contribution. I’m happy to test it out. Nothing to lose and I’ll be running it on a speedi sleeve so if there is shaft or seal wear I can replace the parts and try something else..

Just to check this is the part:

https://simplybearings.co.uk/shop/produ ... CCEALw_wcB
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Johan »

This guy bought a replacement seal from HybridRevolt. I contacted both the youtuber and HR, but no reply yet.
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 »

Boxster EV wrote: Sun Jul 10, 2022 8:00 pm
Johan wrote: Sun Jul 10, 2022 7:51 pm I think that most of SKF's PTFE seals are custom made to order. The closest SKF off-the-shelf catalogue seal that matches the desired dimensions and is able to run at 12,420RPM is the rubber(!) seal model HMS5 V, but that one is "designed for oil or grease lubricated applications" (source). The problem is that the viscosity ("thickness") of coolant is much lower than oil/grease so the seal and shaft surface roughness asperities may contact each other, leading to fast seal wear. However if the shaft is smooth enough, it may work "for a while". Anybody wants to test this out, or does anybody have a reference with info that dismisses this proposal?
Thanks for the ongoing contribution. I’m happy to test it out. Nothing to lose and I’ll be running it on a speedi sleeve so if there is shaft or seal wear I can replace the parts and try something else..

Just to check this is the part:

https://simplybearings.co.uk/shop/produ ... CCEALw_wcB
Have you watched saint gobain? Judging by their catalogs, they may have worked or are working with Tesla.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Johan »

Boxster EV wrote: Sun Jul 10, 2022 8:00 pm Just to check this is the part:
https://simplybearings.co.uk/shop/produ ... CCEALw_wcB
The model number matches, but I could not find Simply Bearings in the SKF distributor list, so I "safely assume" that it is counterfeit. You could buy it nonetheless and contact genuine@skf.com to verify (or use their authenticate app), usually they respond in 24h.
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 Johan »

Vsevolod wrote: Sun Jul 10, 2022 8:08 pm Have you watched saint gobain? Judging by their catalogs, they may have worked or are working with Tesla.
I reached out by webform, email and phone, but no response so far.
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 Boxster EV »

Johan wrote: Sun Jul 10, 2022 8:17 pm
Vsevolod wrote: Sun Jul 10, 2022 8:08 pm Have you watched saint gobain? Judging by their catalogs, they may have worked or are working with Tesla.
I reached out by webform, email and phone, but no response so far.
I did the same. They didn’t respond.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Boxster EV »

Johan wrote: Sun Jul 10, 2022 8:15 pm
Boxster EV wrote: Sun Jul 10, 2022 8:00 pm Just to check this is the part:
https://simplybearings.co.uk/shop/produ ... CCEALw_wcB
The model number matches, but I could not find Simply Bearings in the SKF distributor list, so I "safely assume" that it is counterfeit. You could buy it nonetheless and contact genuine@skf.com to verify (or use their authenticate app), usually they respond in 24h.

Thanks! I’ve ordered one and will inspect upon arrival.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Vsevolod »

Boxster EV wrote: Sun Jul 10, 2022 5:59 pm I’d be really interested to know if anyone has a lead on a good quality 30x55x8 seal. After a 1000 miles my drive unit is leaking again with Ceimin seal.
And the one that dripped after 1000 soaps, is it still the same or was it 1000 miles, then a new oil seal and again after 1000 miles? And was there a rough (uneven surface) on the rotor? Usually the stuffing box leaks if the rotor surface is not restored
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Boxster EV »

Vsevolod wrote: Sun Jul 10, 2022 9:03 pm
Boxster EV wrote: Sun Jul 10, 2022 5:59 pm I’d be really interested to know if anyone has a lead on a good quality 30x55x8 seal. After a 1000 miles my drive unit is leaking again with Ceimin seal.
And the one that dripped after 1000 soaps, is it still the same or was it 1000 miles, then a new oil seal and again after 1000 miles? And was there a rough (uneven surface) on the rotor? Usually the stuffing box leaks if the rotor surface is not restored
First test with a Ceimin on original shaft: drove the car for 1000 miles it was wet.

Second test with another new Ceimin (same part number) AND speedi sleeve fitted. Drove car for 1000 miles and it was wet again, albeit much less compared with the first test.

The Ceimin seal quality isn’t good enough.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Vsevolod »

Boxster EV wrote: Sun Jul 10, 2022 9:09 pm
Vsevolod wrote: Sun Jul 10, 2022 9:03 pm
Boxster EV wrote: Sun Jul 10, 2022 5:59 pm I’d be really interested to know if anyone has a lead on a good quality 30x55x8 seal. After a 1000 miles my drive unit is leaking again with Ceimin seal.
And the one that dripped after 1000 soaps, is it still the same or was it 1000 miles, then a new oil seal and again after 1000 miles? And was there a rough (uneven surface) on the rotor? Usually the stuffing box leaks if the rotor surface is not restored
First test with a Ceimin on original shaft: drove the car for 1000 miles it was wet.

Second test with another new Ceimin (same part number) AND speedi sleeve fitted. Drove car for 1000 miles and it was wet again, albeit much less compared with the first test.

The Ceimin seal quality isn’t good enough.
And the surface of the rotor itself was checked for runout? It happens that the neck (where the seal is put on) wears out and therefore a new one flows quickly. There are people who make a new surface with the help of spraying.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Johan »

Maybe we just have to live with a bit of a leak and install a drain and 12V pump it back to the coolant reservoir (drill small hole next to reluctor wheel etc etc).

Also check a good related thread on ENG-TIPS.com. From this thread (FWIW):
"Bear in mind that PTFE is a sintered product, inherently porous, and that reinforcement makes it more porous. So the glycol will eventually reach whatever the reinforcement is, and whatever is behind the seal also."
"For glycoel [...], this paper recommends for dynamic sealing elements [...] FKM, EPDM, Kalrez and PTFE. [...]"
We have seen this before!: FKM is a fluoro rubber, and the SKF seal "HMS5 V" lip is actually made of this. This gives some hope that this seal may work. An advantage of a rubber may be that it is more forgiving for small shaft eccentricities w.r.t. PTFE.
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 Johan »

Vsevolod wrote: Sun Jul 10, 2022 10:26 pm There are people who make a new surface with the help of spraying.
Yes: example of spray welding of tesla rotor on Youtube
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 »

Johan wrote: Sun Jul 10, 2022 10:42 pm
Vsevolod wrote: Sun Jul 10, 2022 10:26 pm There are people who make a new surface with the help of spraying.
Yes: example of spray welding of tesla rotor on Youtube
Yes, that's what I'm talking about. In order for the new seal to last longer, it is necessary that the surface of the rotor be in a normal state, and if there are grooves and irregularities, then the new seal will quickly fail
I made a drainage hole with a tube (screwed in) to make it harder for debris and moisture to get in from the outside, and the antifreeze itself is quite fluid and will have to come out (in theory)
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Boxster EV »

It's all good feedback, Folks.

The SKF 30x55x7 HMS5 V is designed to work with the SKF speedi sleeve 99114. If it works, it'll be a far easier solution to repair than having the rotor re-machined.

I'm happy to be the guinea pig. I am however away on business for a week so wont be able to install until I return.

Edit: spec sheet here:
30X55X7 HMS5 V_20220711.pdf
(2.99 MiB) Downloaded 39 times
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Vsevolod »

Boxster EV wrote: Mon Jul 11, 2022 12:20 pm It's all good feedback, Folks.

The SKF 30x55x7 HMS5 V is designed to work with the SKF speedi sleeve 99114. If it works, it'll be a far easier solution to repair than having the rotor re-machined.

I'm happy to be the guinea pig. I am however away on business for a week so wont be able to install until I return.
Okay, have a good trip!
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by OlyThoreau »

Johan wrote: Sun Jul 10, 2022 6:11 pm @Boxster EV: O no! Thanks for the update!

Guess what: SKF actually showcases "SLX"(?) PTFE seals with concentric cuts (as in my Tesla DU, see my previous msg) here on their website, repeated here:

SKF seal.PNG

So maybe SKF is the supplier after all. Or not, who knows. Also: "The majority of PTFE radial shaft seals from SKF are made to order to meet the demands of each application." - Source p.98.
Threaded sealing lip which pumps the media away from the seal:
https://www.omniseal-solutions.com/comp ... lip-seals
As noted in the specifications, this should only be used in lubricating media. It looks like this could be a big reason that the original seals fail consistently. If a seal was used that was designed only for lubricating media, it makes perfect sense that it would not last long.


Higher speed seal with better leak-proofing:
https://www.omniseal-solutions.com/comp ... lip-seals
This part of the line appears to be for higher speeds (although the speed listed looks about the same) and is described as being long-life, low maintenance, and super leak resistant.

All of these product lines (10 to 90) are listed as "catalog" products not custom solutions, so there should be some way to get a hold of a distributor. However, it does not appear that any of these are made for bi-directional operation.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by OlyThoreau »

Found the Holy Grail... this might be exactly what we all need to get our hands on:

https://www.trelleborg.com/en/seals/pro ... in-pdr-rt
Screenshot (111).png
Screenshot (112).png
https://www.trelleborg.com/en/seals/pro ... spin-hs40
Screenshot (114).png
Screenshot (113).png
You all would know more than I would about the specific needs of the application though, as to which one would suit the needs better between these two. I haven't taken my motor apart yet.
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by SuperV8 »

Johan wrote: Sun Jul 10, 2022 10:38 pm Maybe we just have to live with a bit of a leak and install a drain and 12V pump it back to the coolant reservoir (drill small hole next to reluctor wheel etc etc).

Also check a good related thread on ENG-TIPS.com. From this thread (FWIW):
"Bear in mind that PTFE is a sintered product, inherently porous, and that reinforcement makes it more porous. So the glycol will eventually reach whatever the reinforcement is, and whatever is behind the seal also."
"For glycoel [...], this paper recommends for dynamic sealing elements [...] FKM, EPDM, Kalrez and PTFE. [...]"
We have seen this before!: FKM is a fluoro rubber, and the SKF seal "HMS5 V" lip is actually made of this. This gives some hope that this seal may work. An advantage of a rubber may be that it is more forgiving for small shaft eccentricities w.r.t. PTFE.
This is my thought. I think I would be looking at drilling a weep hole with suction pump, or pipe and suction pump - so when this seal leaks again it doesn't matter and cause catastrophic damage.

I re-built my centrifugal supercharger (basically a belt driven turbo) which destroyed its high speed bearing - 80,000max RPM! (though I found the bearing they used only had a 20,000max rating!! :x ) I was able to eventually find a ceramic balled very high speed bearing from Barden which I could buy individually - though rather expensive (£100 each)! but I could not find a seal for sale anywhere (PTFE high speed rating) which I suspect you will find here with this Tesla DU. You can find the seal's in catalogues BUT they (SKF/Saint Gobin/Trelleborg etc..) are not interested in selling 1 to an end user - the best I found was an MOQ of something like 100! at £10 piece price!
I had to use an off the self rubber type seal - and just increase my maintenance checks on the oil. So far its holding up well - though it doesn't spend much time at 80000 if ever!
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by Vsevolod »

SuperV8 wrote: Tue Jul 12, 2022 6:19 pm
Johan wrote: Sun Jul 10, 2022 10:38 pm Maybe we just have to live with a bit of a leak and install a drain and 12V pump it back to the coolant reservoir (drill small hole next to reluctor wheel etc etc).

Also check a good related thread on ENG-TIPS.com. From this thread (FWIW):
"Bear in mind that PTFE is a sintered product, inherently porous, and that reinforcement makes it more porous. So the glycol will eventually reach whatever the reinforcement is, and whatever is behind the seal also."
"For glycoel [...], this paper recommends for dynamic sealing elements [...] FKM, EPDM, Kalrez and PTFE. [...]"
We have seen this before!: FKM is a fluoro rubber, and the SKF seal "HMS5 V" lip is actually made of this. This gives some hope that this seal may work. An advantage of a rubber may be that it is more forgiving for small shaft eccentricities w.r.t. PTFE.
This is my thought. I think I would be looking at drilling a weep hole with suction pump, or pipe and suction pump - so when this seal leaks again it doesn't matter and cause catastrophic damage.

I re-built my centrifugal supercharger (basically a belt driven turbo) which destroyed its high speed bearing - 80,000max RPM! (though I found the bearing they used only had a 20,000max rating!! :x ) I was able to eventually find a ceramic balled very high speed bearing from Barden which I could buy individually - though rather expensive (£100 each)! but I could not find a seal for sale anywhere (PTFE high speed rating) which I suspect you will find here with this Tesla DU. You can find the seal's in catalogues BUT they (SKF/Saint Gobin/Trelleborg etc..) are not interested in selling 1 to an end user - the best I found was an MOQ of something like 100! at £10 piece price!
I had to use an off the self rubber type seal - and just increase my maintenance checks on the oil. So far its holding up well - though it doesn't spend much time at 80000 if ever!
What seal are you using?
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Re: Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

Post by SuperV8 »

Vsevolod wrote: Tue Jul 12, 2022 7:30 pm
SuperV8 wrote: Tue Jul 12, 2022 6:19 pm
Johan wrote: Sun Jul 10, 2022 10:38 pm Maybe we just have to live with a bit of a leak and install a drain and 12V pump it back to the coolant reservoir (drill small hole next to reluctor wheel etc etc).

Also check a good related thread on ENG-TIPS.com. From this thread (FWIW):





We have seen this before!: FKM is a fluoro rubber, and the SKF seal "HMS5 V" lip is actually made of this. This gives some hope that this seal may work. An advantage of a rubber may be that it is more forgiving for small shaft eccentricities w.r.t. PTFE.
This is my thought. I think I would be looking at drilling a weep hole with suction pump, or pipe and suction pump - so when this seal leaks again it doesn't matter and cause catastrophic damage.

I re-built my centrifugal supercharger (basically a belt driven turbo) which destroyed its high speed bearing - 80,000max RPM! (though I found the bearing they used only had a 20,000max rating!! :x ) I was able to eventually find a ceramic balled very high speed bearing from Barden which I could buy individually - though rather expensive (£100 each)! but I could not find a seal for sale anywhere (PTFE high speed rating) which I suspect you will find here with this Tesla DU. You can find the seal's in catalogues BUT they (SKF/Saint Gobin/Trelleborg etc..) are not interested in selling 1 to an end user - the best I found was an MOQ of something like 100! at £10 piece price!
I had to use an off the self rubber type seal - and just increase my maintenance checks on the oil. So far its holding up well - though it doesn't spend much time at 80000 if ever!
What seal are you using?
Got my Barden ceramic bearing from:
https://alpinebearing.com/

And got the seal from
https://928motorsports.com/ (- they specialise in superchargers so probably have a limited sizes.)

The seal was a GST seal
https://www.gstracing.co.uk/bearing-seals/
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