Tesla Large Drive Unit (LDU) Motor Teardown and maintenance

[howardc64]

DELETED

[asavage]

Hmmm, I'm disappointed; my expensive (like $500 new/$350 for mine) Snap-On CG40CB blind bearing puller set, which has actually been expanded upward a bit, currently only handles 1/4" thru 1-1/4"; 35mm is almost exactly 1-3/8", which requires one more collet that I don't have (and which is apparently unavailable in easy-for-me supply chains).

However, Snap-On-level tools aren't required; the Motion Pro is $38 and its poor stars rating is due to the ad's photos having showed for years a set rather than a single collet; nobody has complained in the ratings about a deficiency in the collet itself.

You'll need a slide-hammer to go with it. Unfortunately, it's reported to not use the industry-standard 5/8"-11 thread. OK, maybe this tool wouldn't be a good choice. I'm just bummed I can't lend you my set and get hero points.

---

It's an aluminum casting, so another method I've used would be to oven the case half to, say, 350°F for 20 mins., then remove, suspend over a pair of blocks, and squirt "canned air" at the bearing with the can inverted, putting the cold liquid on the bearing. It'll shrink fast and sometimes the bearing will fall right out. Tapping the other side (ie the "top" or "outside" of the inverted casting) can help. It's cheap.

In the field, we would sometimes weld a 5/8"-11 nut to the inner race any way we could, and use a slide hammer. We're replacing the bearing, so no loss by welding to the inner race. The issue with that is you'd need to weld the nut to a piece of plate, then weld that to the race, or you'd be pulling off to the side and it would likely jam.

[howardc64]

DELETED

[asavage]

Too much play? 6207 C3 bearing 35mm ID 72mm OD 17mm wide. Long moment arm with the primary shaft fitted of course.

https://photos.app.goo.gl/z2yhPZ5FpXc5bKh3A

Probably should just change since gearbox open? Need a blind bearing puller. FAG 6207 C3 ~$25.

Vertical (12/6 o'clock) radial play seems worse than horizontal (9/3 o'clock) radial play for some reason.. hmmm.

Standard ball bearings in general don't control angular or thrust loads well, so "testing" via the method you use in the video doesn't reveal how much wear the bearing has experienced, because the bearing assy. is not designed to control motion in that direction, and the tracks in the races that have wear you should be concerned with are not in play when you are testing with a cantilever load on a single bearing.

I mean, sure, if the bearing is really toast, the balls are bad and that will show in that test, but race wear will not, because testing like that puts the load on the sides of the race, which is not where a typical ball bearing would be be loaded in a well-engineered design.

There are ball bearing designs that have more axial control that standard, and even some with limited thrust control (think angular contact ball bearings in bicycle steering tubes, for example), and this bearing might be a deep groove style for some axial/thrust load control due to the helical gear involved, but measuring the movement that way will be inconclusive unless you've got more experience than most people have. It's not really even a "rough test", and I wouldn't place much stock in the results.

The bearing is cheap, your labor is not, and I'll be replacing it in my box, when the time comes.

[howardc64]

DELETED

[howardc64]

DELETED

[dzolotnyuk]

Plan is to run in on a speedy sleeve I did get two of then 30x52x7 ordered smaller on purpose so there is enough clearance to make a press fit case for it

[howardc64]

DELETED

[asavage]

Yes, through the bearing must be the coolant path in that case.

If enough coolant made it though, it'd get to the inverter -- there's that huge tunnel!

[howardc64]

DELETED

[howardc64]

DELETED

[WimV]

I took apart mine yesterday. Bought the car in the beginning of this year, checked the speed sensor and noticed some condensation. Had no time to do the repair until now, so kept driving. Still drives fine without bearing noice or errors.

The drive unit is a rev Q. Replaced under warranty in 2017 at 70.000 km. The car has 145.000 km at the moment.

Although i've driven at least 10 months with a small leak, the DU is perfectly clean and dry (besides some coolant drops around the seal.

The seal surface on the rotor is pretty rough. Maybe it wasn't in great condition when the DU was remanufactured?

The grease of the rotor bearings is at the outside of the seals. They are perfectly clean and dry, so it's not washed out by coolant.

I'm going to use a speedi sleeve, Ceimin seal and new bearings. Potting the phase wire tunnel and add a few vents and drains.

[howardc64]

DELETED

[WimV]

On speedi sleeve + Ceimin seal combo, did you see Boxster EV's leak experience and Johan's analysis? The main lip sealing off the coolant rides on the end of the speedi sleeve and probably compromised it. The sleeve is not wide enough for that seal.

viewtopic.php?p=42967#p42967

On bearing, will follow with a post as I'm looking for match and USA source now.

I'm going to try to install 2 speedi sleeves.

I bought the bearings here:
https://shop.eriks.be/nl/lagers-kogella ... -24002310/

[howardc64]

DELETED

[WimV]

A few photo's of the rotor before and after cleaning and the seal.

The rotor has way to much wear to use without sleeve or welding and grinding.

The seal is a tripple lip. It's disintegrated pretty bad. Maybe the rotor already was rough when they rebuild it? I'm suprised there wasn't more leaked coolant.

[howardc64]

DELETED

[WimV]

Which lips were most damaged?

Theoretically the lip in contact with coolant will run a flim of coolant between lip and shaft for hydrodynamic effect to avoid burning up the seal. Since the other 2 lips has no hydrodynamic effect from coolant, I wonder how they survive?

I'll try to make a good picture, but all of them looked pretty bad.

Fresh bearings and two sleeves fitted. The sleeve is grinded flush with the rotor.

[WimV]

I'll try to make a good picture, but all of them looked pretty bad.

Fresh bearings and two sleeves fitted. The sleeve is grinded flush with the rotor.

The phase tunnel is potted.

[howardc64]

DELETED

[WimV]

Yes, remanufactered

[WimV]

Which lips were most damaged?

Theoretically the lip in contact with coolant will run a flim of coolant between lip and shaft for hydrodynamic effect to avoid burning up the seal. Since the other 2 lips has no hydrodynamic effect from coolant, I wonder how they survive?

I just removed the seal. Started cutting it, but then I noticed the steel was pretty thic. Tapped two holes in it and pushed it out with two bolts. Works perfectly, seal is removed within 5 minutes.

The lip at coolant side was, as expected in best shape. Other two rings were very worn and had a lot of black sticky mess on them (probably ptfe dust mixed with coolant).

[WimV]

Plugged the hole between reluctor wheel and stator, added vents and drains to reluctor housing and stator housing.

Now cleaning everything and reassemble (and adding a drain to inverter housing).

[asavage]

Good work, thanks for the pics.

[WimV]

I used a wiring harness sleeve to pull the temp sensor wires through the tunnel, worked very well.

The motor is assembled. Going to put it in the subframe now.

How do you guys purge the cooling system? Is it necessary to fill the motor before connecting the cooling system in the car? Or will it purge itself while driving?