Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

[Vsevolod]

I could be wrong but I think 56 is the coolant outlet seal.

How is your car and seal?

[Boxster EV]

I could be wrong but I think 56 is the coolant outlet seal.

How is your car and seal?

It’s no longer leaking with the speedi sleeve fitted. However I don’t think it will last long-term.

[Vsevolod]

I could be wrong but I think 56 is the coolant outlet seal.

How is your car and seal?

It’s no longer leaking with the speedi sleeve fitted. However I don’t think it will last long-term.

Understood, you'll be fine. Today I installed the motor, but I had to pay $ 50 to an electrician to reset the BMS error (remained in my memory), after the reset I went, I will have to pump the antifreeze and I think what equipment to buy for diagnostics and calibration ....

[SuperV8]

I'm not aware of any OE suppliers of that seal. Please post here if you find one!

The Merc B250E uses a Tesla motor, and there are seal's available which you should be able to order/by from any Merc dealer.

I can let you know the part number for each from the drawing below - let me know if any look close? Looks like they are £3-£10 so not expensive.

B Class 246 B250E motor

Maybe 40 and 42 to see? Item 40 is similar to where the tube is in the Boxster EV photo

Number 40 is a PARK PAWL = A242270 00 00 - This is on the gear reduction/diff section of the motor, not on the rotor. You're discussing the rotor seal aren't you?
Number 42 is = A 099 997 03 45 SEALING RING. Same part number as 44.
Number 50 is the position sensor - which looks like it is next to the rotor seal from the photos.
Number 58 is an o-ring A 027 997 71 45

[Vsevolod]

The Merc B250E uses a Tesla motor, and there are seal's available which you should be able to order/by from any Merc dealer.

I can let you know the part number for each from the drawing below - let me know if any look close? Looks like they are £3-£10 so not expensive.

B Class 246 B250E motor

Maybe 40 and 42 to see? Item 40 is similar to where the tube is in the Boxster EV photo

Number 40 is a PARK PAWL = A242270 00 00 - This is on the gear reduction/diff section of the motor, not on the rotor. You're discussing the rotor seal aren't you?
Number 42 is = A 099 997 03 45 SEALING RING. Same part number as 44.
Number 50 is the position sensor - which looks like it is next to the rotor seal from the photos.
Number 58 is an o-ring A 027 997 71 45

Yes, apparently, they do not have a coolant tube in the diagram (inside which the 30x55x8 oil seal is located), sensor 50 is really located inside the place where the oil seal is installed nearby. I understand that tesla does not openly sell the 30x55x8 oil seal, including for Toyota and Mercedes, or can you check with your local dealership? Do you think it makes sense to make some kind of petition for access to purchase the original oil seal? After all, otherwise Tesla forces (according to its logic) to buy the entire motor assembly, and not to carry out a routine replacement of the sealing element

[SuperV8]

According to the seller, BK means "oil flooded" and should have a longer life. I don't know what they exactly mean with oil flooded. PTFE often has certain additives to improve friction and dry run, so maybe they mean an additive.

Have a look here for the actual spec for the Ceimin seals they are selling.

https://www.chenmingseal.com/seals-guid ... ml?lang=en
https://www.chenmingseal.com/product/tr ... al?lang=en

Ceimin® PTFE sealing lips are PTFE compound discs that are mechanically formed to a diameter slightly smaller than the shaft. The forming of the lip creats a shape that takes advantage of the hoop strength of the PTFE compound discs. This hoop strength provides the load that is critical for low or no pressure applications to obtain a positive seal.

Compound Description:
CM-1760 PTFE – virgin, white, FDA approved; Good for gases, slow-dynamic, light-duty and cryogenic application in food and pharmaceutical equipments. Major in food mixers.
CM-1775 PTFE with Carbon Fiber and Graphite, black; Excellent wear resistance and reduced creep. Major in water filters.
CM-1865 PTFE with Glass Fiber and Molybdenum Disulfide, black; Excellent for extreme conditions such as high pressure & temperature and for longer wear life on hardened dynamic surfaces. Major in screw air compressors.
CM-2160 PTFE with special filler, black; Excellent elongation performance. high pressure & temperature and for longer wear life on hardened dynamic surfaces. Major in gear boxes.
CM-3965 PTFE with special filler, yellow; Highly wear resistant in fast-rotary service and on unhardened shafts in low-lube, oil-free rotary service. Major in vacuum pumps.

The CTLBDYW = triple seal, both directions & yellow - which must be CM-3965 above.
The CTLBDBK = triple seal, both directions & black. From above there are 3x black options. from the comment from the seller about 'oil flooded' I would 'guess' that is referring to CM-1895 with moly disulfate.

Looking at the state of the pitted surface in the previous photos I would defiantly be using something like an SKF speedi-sleeve.

[Vsevolod]

According to the seller, BK means "oil flooded" and should have a longer life. I don't know what they exactly mean with oil flooded. PTFE often has certain additives to improve friction and dry run, so maybe they mean an additive.

Have a look here for the actual spec for the Ceimin seals they are selling.

https://www.chenmingseal.com/seals-guid ... ml?lang=en
https://www.chenmingseal.com/product/tr ... al?lang=en

Ceimin® PTFE sealing lips are PTFE compound discs that are mechanically formed to a diameter slightly smaller than the shaft. The forming of the lip creats a shape that takes advantage of the hoop strength of the PTFE compound discs. This hoop strength provides the load that is critical for low or no pressure applications to obtain a positive seal.

Compound Description:
CM-1760 PTFE – virgin, white, FDA approved; Good for gases, slow-dynamic, light-duty and cryogenic application in food and pharmaceutical equipments. Major in food mixers.
CM-1775 PTFE with Carbon Fiber and Graphite, black; Excellent wear resistance and reduced creep. Major in water filters.
CM-1865 PTFE with Glass Fiber and Molybdenum Disulfide, black; Excellent for extreme conditions such as high pressure & temperature and for longer wear life on hardened dynamic surfaces. Major in screw air compressors.
CM-2160 PTFE with special filler, black; Excellent elongation performance. high pressure & temperature and for longer wear life on hardened dynamic surfaces. Major in gear boxes.
CM-3965 PTFE with special filler, yellow; Highly wear resistant in fast-rotary service and on unhardened shafts in low-lube, oil-free rotary service. Major in vacuum pumps.

The CTLBDYW = triple seal, both directions & yellow - which must be CM-3965 above.
The CTLBDBK = triple seal, both directions & black. From above there are 3x black options. from the comment from the seller about 'oil flooded' I would 'guess' that is referring to CM-1895 with moly disulfate.

Looking at the state of the pitted surface in the previous photos I would defiantly be using something like an SKF speedi-sleeve.

Maybe someone on the forum can ask SKF about the presence of such an oil seal?

[Johan]

SKF does not offer a seal with dimensions 30 x 55 x 8mm (d1 x D x b, using SKF symbols). I just received this info from SKF USA by email.

[Vsevolod]

I could be wrong but I think 56 is the coolant outlet seal.

How is your car and seal?

It’s no longer leaking with the speedi sleeve fitted. However I don’t think it will last long-term.

Hi ! How are you?

[Vsevolod]

SKF does not offer a seal with dimensions 30 x 55 x 8mm (d1 x D x b, using SKF symbols). I just received this info from SKF USA by email.

Hello, thanks a lot for the info. Who do you think we can turn to? After all, someone makes these seals for Tesla, it is unlikely that they themselves

[SuperV8]

SKF does not offer a seal with dimensions 30 x 55 x 8mm (d1 x D x b, using SKF symbols). I just received this info from SKF USA by email.

Hello, thanks a lot for the info. Who do you think we can turn to? After all, someone makes these seals for Tesla, it is unlikely that they themselves

Ceimin seals as I posted previously has this size:
This is the one from aliexpress I beileve.

https://www.chenmingseal.com/seals-guid ... ml?lang=en
https://www.chenmingseal.com/product/tr ... al?lang=en

[Vsevolod]

SKF does not offer a seal with dimensions 30 x 55 x 8mm (d1 x D x b, using SKF symbols). I just received this info from SKF USA by email.

Hello, thanks a lot for the info. Who do you think we can turn to? After all, someone makes these seals for Tesla, it is unlikely that they themselves

Ceimin seals as I posted previously has this size:
This is the one from aliexpress I beileve.

https://www.chenmingseal.com/seals-guid ... ml?lang=en
https://www.chenmingseal.com/product/tr ... al?lang=en

Thank you!

[Boxster EV]

In my opinion these seals are of inferior quality compared with OE and have not been tested long term.

[EV_Builder]

In my opinion these seals are of inferior quality compared with OE and have not been tested long term.

Since Tesla doesn't make seals who makes them for them?

[Boxster EV]

In my opinion these seals are of inferior quality compared with OE and have not been tested long term.

Since Tesla doesn't make seals who makes them for them?

That is the question. Somebody must know.

[Johan]

Being an "outsider", it is extremely tough to find Tesla's suppliers. My next guess after SKF is the giant Saint-Gobain because they mention Tesla here and there on their website and they are large enough to serve Tesla in the long term. See also this presentation showing a Model 3 on the cover page. I called them and they referred me to Tesla for the purchase of seals . I think that a seal of their OmniLip product line is a good candidate for being the original. See here and here for some very brief test data.

However my fear is that rotor eccentricity and -runout at high RPM and sharp turns, caused by gyroscopic effects and impacts due to e.g. road bumps, will cause any replacement seal to leak quickly because PTFE (low friction; needed for high RPM) is far more prone to creep compared to elastomers (like rubbers), so it does not "follow" the shaft movements as well as elastomers. Small rotor movements (w.r.t. the housing) in radial direction are possible because there is (or seems to be) an elastomer O-ring between the rotor bearings' outer race and the housing (why?). See also the attachment. I said "small", but my guess is that this play is large enough for leaks, see also Figure 2-24 in Parker's Rotary Seal Design Guide for a coarse idea about acceptable misalignment (yes, this is yet another seal manufacturer). Can anybody show that this should not be a concern?

[Boxster EV]

Being an "outsider", it is extremely tough to find Tesla's suppliers. My next guess after SKF is the giant Saint-Gobain because they mention Tesla here and there on their website and they are large enough to serve Tesla in the long term. See also this presentation showing a Model 3 on the cover page. I called them and they referred me to Tesla for the purchase of seals . I think that a seal of their OmniLip product line is a good candidate for being the original. See here and here for some very brief test data.

However my fear is that rotor eccentricity and -runout at high RPM and sharp turns, caused by gyroscopic effects and impacts due to e.g. road bumps, will cause any replacement seal to leak quickly because PTFE (low friction; needed for high RPM) is far more prone to creep compared to elastomers (like rubbers), so it does not "follow" the shaft movements as well as elastomers. Small rotor movements (w.r.t. the housing) in radial direction are possible because there is (or seems to be) an elastomer O-ring between the rotor bearings' outer race and the housing (why?). See also the attachment. I said "small", but my guess is that this play is large enough for leaks, see also Figure 2-24 in Parker's Rotary Seal Design Guide for a coarse idea about acceptable misalignment (yes, this is yet another seal manufacturer). Can anybody show that this should not be a concern?

drawing.png

Good post - very informative. Thanks for contributing.

From my limited experience I don’t feel the eccentricity and gyroscopic concern of the shaft would be an issue providing the bearings are in good health. What’s likely to be more of an issue is the shaft finish where it contacts the seal. If you zoom in on my earlier pictures in this thread of the seal to shaft contact area, you’ll see the pitting is so bad it looks like the surface of the moon, which is likely to be the biggest variable.

Regarding the Saint-Gobain company, it’s highly plausible they’re the OE supplier.

In terms of longevity and the report that LDU experience issues at 60k miles, I suspect bad maintenance is a big factor. IE change coolant frequently, check for bearing wear and inspect for leaks.

[Vsevolod]

I think you should try to contact them or browse the catalogs of available oil seals on third-party sites.
You have given good information, thanks!

[Vsevolod]

https://www.omniseal-solutions.com/components
I also found such an oil seal on aliexpress, to the previously found ceimin
https://aliexpress.ru/item/100500421953 ... 7f81UlGdux

[Vsevolod]

I got this response from them:
"We do not sell to the public. Is this for personal use, or for a commercial application? How many pieces are you after?

Please let me know and I can direct you from there."
best regards,
Aaron Friedmann


It may be asked if there are those who sell their products to ordinary people?

[Vsevolod]

Here is what the staff member told me:
Hello,



Please try McMasterCarr for an off the shelf item.



If you don’t have luck with them, please try one of the following.



Windy City Seals, Inc. Chicago area

510 N Main Street Suite 2

Sycamore, IL 60178

Ken Reinert

815-895-4205 Main

815-895-9705 Fax

847-514-5351 Cell



VB Seals Midwest VB Seals- A Trelleborg Company

1107 Airport Road | Ames | IA | 50010 | United States

T 515-292-6065 | F 515-292-6250



Niantic Seals east coast

Niantic Seal, Inc.

17 Powder Hill Rd.

Lincoln, RI 02865

Cell: 508.942.4244

Office: 401.334.6829

Fax: 401.334.6871

web: http://www.nianticseal.com


Best Regards

[Johan]

Another data point: I just removed the leaky PTFE seal with brute force from my rev. G Tesla drive unit:

Note the cuts in circumferential direction around the hole: These reduce the effective PTFE bending stiffness. Consequently, (maybe) there is less pressure from the seal on the shaft as compared to a seal without cuts. I say "maybe" because PTFE is known for its creep, reducing stresses in the long term, partially depending on the additives. I have never seen this feature in any catalogue (but I am a novice so that sais nothing). The Ceimin seals that I purchased (a brand owned by the factory Chenming in Ningbo, China) do not have cuts. So the presence of these cuts may be unique way to identify the manufacturer.

See also for the painful details: Removing rotor and leaking seal from Tesla LDU

@Boxter EV: do you have a photo of your old seal?

[Vsevolod]

Try searching here?
https://www.mcmaster.com/o-rings/

[muehlpower]

Another data point: I just removed the leaky PTFE seal with brute force from my rev. G Tesla drive unit:

PXL_20220707_011354799_close_up.jpg

Note the cuts in circumferential direction around the hole: These reduce the effective PTFE bending stiffness. Consequently, (maybe) there is less pressure from the seal on the shaft as compared to a seal without cuts. I say "maybe" because PTFE is known for its creep, reducing stresses in the long term, partially depending on the additives. I have never seen this feature in any catalogue (but I am a novice so that sais nothing). The Ceimin seals that I purchased (a brand owned by the factory Chenming in Ningbo, China) do not have cuts. So the presence of these cuts may be unique way to identify the manufacturer.

See also for the painful details: Removing rotor and leaking seal from Tesla LDU

@Boxter EV: do you have a photo of your old seal?

what you call cuts is a kind of thread. There are these seals with a twist to improve the sealing effect.Thay then have a given direction of rotation. This causes problems for the people who let the motor run backwards!

[Johan]

@muehlpower: Thanks, it could indeed be a thread/helix/spiral to "drag" the fluid back to where it came from. I took some measurements (click to enlarge):

So I think that the cuts are concentric, primarily for structural instead of hydrodynamic purposes. It would be nice if someone would repeat this measurement on his own seal to verify. Note that I bought another seal from Ceimin (separates rotor cavity from gear box) with helix/spiral protrusions in both directions for forward and reverse driving:

Note that the latter seal is from Chenming and looks a lot like Tesla's original seal. After less than 42k miles, this Tesla Seal failed too, allowing Dexron VI (from gear box) into the rotor cavity AND subsequently into the inverter :
https://youtu.be/bnhOt1i0vpo?t=770