Model S Technical / Mechanical Issues

[ajbessinger]

A quick update to that seized up motor that I posted some pictures of earlier. We managed to get the rotor pressed out today, and it looks pretty nasty... We'll try to clean it all up as best we can with the hopes of salvaging this drive unit.

 

[2101Guy]

@ajbessinger This is great work that you are doing, and sharing. Wanted to let you know that your posts/photos are extremely appreciated over here across the country. Helps some of us who are used to working on ICE cars only, have a better understanding of some of the innerworkings of these EV's

 

[Palmtree]

@ajbessinger This is great work that you are doing, and sharing. Wanted to let you know that your posts/photos are extremely appreciated over here across the country. Helps some of us who are used to working on ICE cars only, have a better understanding of some of the innerworkings of these EV's

What he said.

 

[ajbessinger]

@ajbessinger This is great work that you are doing, and sharing. Wanted to let you know that your posts/photos are extremely appreciated over here across the country. Helps some of us who are used to working on ICE cars only, have a better understanding of some of the innerworkings of these EV's

What he said.

Thanks guys!

I started a thread on the site feedback page to see about creating a dedicated sub-forum for repairing/maintaining Teslas (as opposed to just these super long "Technical/Mechanical Issues" threads for each model). I think it would be really helpful to folks to have a dedicated place to go on the site here in order to ask questions or provide helpful information to keep these cars on the road, especially once they are out of the warranty period!

BTW, I got another motor apart today, and I'm working on replacing bearings and a putting in a new coolant seal. On this one the seal was just starting to leak coolant into the motor, and it had started to form some rust on the rotor and steel bars in the windings. Luckily the owner of the car caught it in time when they were replacing a bad motor speed sensor, and saw evidence of coolant leakage.

 

[ajbessinger]

Here's the motor I was working on today. As you can see, the steel bars in the windings and the rotor were both starting to rust from exposure to coolant. Got it all cleaned up and started putting it back together with new hybrid ceramic bearings and a new/improved PTFE seal!

 

[hpartsch]

I don't want it to seem like I'm hijacking this thread, but here's one more post on the coolant leakage issue to just to help drive home the point of how important it is to check for coolant leakage, especially if you are out of warranty. Here's an example of what can happen when the coolant leaks into the motor:

This particular large drive unit (or LDU) is seized up solid; meaning the rotor is stuck and can no longer spin. It was a replacement drive unit, and only had about 20-30k miles on it. As you can see, there's lots of crud built up in there, which is a result of the rotor and copper windings corroding, and then grinding on one another until it got to a point where the rotor could no longer turn anymore. We can try to press the rotor out, but this motor is most likely going to be a total loss, and the customer will need a new one (which is of course quite expensive).

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Based on my experience, later LDUs (typically those that were new or replaced in 2016-2018) are the most prone to this seizing issue when coolant leaks in. Earlier drive units (2012-2015) don't usually seem to seize like this, but the coolant will still cause plenty of damage, and eventually migrates all the way through to the inverter and destroys it (also a very expensive repair). I've been rebuilding these things in increasing numbers over the past 3 years, and I can tell you that these days I have usually at least one or two torn apart every week out of just the Toyota Rav4 EV and Mercedes B250e alone (both of which were built under partnerships with Tesla, and use the same LDU as the Model S), and only about 10k were built between them. There are a lot more Model S's out there...

If caught in time, the motor can be taken apart to replace the bearings and the coolant seal. We can do all this at the shop where I work, and we always use an upgraded PTFE triple lip seal, and new hybrid-ceramic bearings that should last much longer than the originals.

All that being said, a quick, simple check of the speed sensor could literally save you thousands of dollars, and a lot of headache. Also, like I said before in an earlier post, we can check your speed sensor for free at QC Charge in Vista California.



Note: Small drive units (front and rear) are not affected by this issue, only the large drive units are.

Am I correct to assume ASY,PTRAIN,RMN,MDLS,BASE,CMC,HS,FA2+ (1025276-00-Q) is a large drive unit? I checked on the tesla parts page -- and I clicked large drive unit. But under large drive units it looks like there is even more and mine is not labelled large... So even more confusing...

Lastly, I've not yet jacked up my Tesla yet. Got a jack pad. Can I check this by jacking up one side only or do both sides need to be jacked up?

 

[ajbessinger]

Am I correct to assume ASY,PTRAIN,RMN,MDLS,BASE,CMC,HS,FA2+ (1025276-00-Q) is a large drive unit? I checked on the tesla parts page -- and I clicked large drive unit. But under large drive units it looks like there is even more and mine is not labelled large... So even more confusing...

Lastly, I've not yet jacked up my Tesla yet. Got a jack pad. Can I check this by jacking up one side only or do both sides need to be jacked up?
View attachment 627691

Both of those are large drive units. The highlighted one is the "base" large drive unit, and the other is the "sport" (otherwise known as performance) large drive unit. There are a multitude of different part numbers for them as there have been several revisions. But essentially, if your car is RWD only, or is a Pre-2017 AWD performance model; e.g., P85D or P90D, then it has a large drive unit (as far as I'm aware, P100D and of course the newer Raven performance models do not have a large drive unit).

You might be able do it by jacking up just the left side, but it may be difficult to remove the splash shield. An alternative to jacking it up would be to use ramps instead (as long as they'll fit under the bumper without scraping).

 

[Palmtree]

That's a great idea to ask for a sub forum here since there's already a lot of eyes on this site. I hope we can get it done. We are definitely on the cusp of high demand for diy repairs as model s cars come out of warranty coverage. I certainly hope to keep mine going as long as you have.

 

[LTUAE42]

Help for no reason my passenger side of the car went dead yesterday. The doors wont present or open from the outside and the windows will not function. The side mirror is also not functioning with no door lights too. Tesla suggested it could be the ground stud. I pulled the frunk and the ground stud looks fine. The headlights work too. The only thing dead is from the passenger door to the back door on the passenger side. When I open the door from the inside the window drops like its suppose to and goes back up when the door is shut so there is power . I am so confused what it could be. I looked at the wiring going to the door and I dont see any damage from mice etc. any idea ?? i cant afford an expensive diagnostics and the first opening at Tesla is the end of the month and I drive my car every day. Thanks for any help.

 

[LTUAE42]

Help for no reason my passenger side of the car went dead yesterday. The doors wont present or open from the outside and the windows will not function. The side mirror is also not functioning with no door lights too. Tesla suggested it could be the ground stud. I pulled the frunk and the ground stud looks fine. The headlights work too. The only thing dead is from the passenger door to the back door on the passenger side. When I open the door from the inside the window drops like its suppose to and goes back up when the door is shut so there is power . I am so confused what it could be. I looked at the wiring going to the door and I dont see any damage from mice etc. any idea ?? i cant afford an expensive diagnostics and the first opening at Tesla is the end of the month and I drive my car every day. Thanks for any help.

2015 model s 85 d

 

[Luv2preech]

Here's the motor I was working on today. As you can see, the steel bars in the windings and the rotor were both starting to rust from exposure to coolant. Got it all cleaned up and started putting it back together with new hybrid ceramic bearings and a new/improved PTFE seal!

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[Gtech]

Help for no reason my passenger side of the car went dead yesterday. The doors wont present or open from the outside and the windows will not function. The side mirror is also not functioning with no door lights too. Tesla suggested it could be the ground stud. I pulled the frunk and the ground stud looks fine. The headlights work too. The only thing dead is from the passenger door to the back door on the passenger side. When I open the door from the inside the window drops like its suppose to and goes back up when the door is shut so there is power . I am so confused what it could be. I looked at the wiring going to the door and I dont see any damage from mice etc. any idea ?? i cant afford an expensive diagnostics and the first opening at Tesla is the end of the month and I drive my car every day. Thanks for any help.

Side mirror and door lights are connected to the door module. This module is grounded on the A pillar and not the frunk. (For 10 dollar on Ebay you can get the whole Model S wiring diagram and that is very helpful with this sort of cases)

You know how to measure a faulty ground point?

You could also check if your LIN network isn't shorted but for that you need a scope. (door handle right front, left front, window switch all connected with LIN bus so if one component is shorted nothing works.

Good luck

 

[LTUAE42]

Side mirror and door lights are connected to the door module. This module is grounded on the A pillar and not the frunk. (For 10 dollar on Ebay you can get the whole Model S wiring diagram and that is very helpful with this sort of cases)

View attachment 628634

You know how to measure a faulty ground point?

You could also check if your LIN network isn't shorted but for that you need a scope. (door handle right front, left front, window switch all connected with LIN bus so if one component is shorted nothing works.

Good luck

Thank you I have a meter but never did faulty ground before. dont know how.

 

[LTUAE42]

Side mirror and door lights are connected to the door module. This module is grounded on the A pillar and not the frunk. (For 10 dollar on Ebay you can get the whole Model S wiring diagram and that is very helpful with this sort of cases)

View attachment 628634

You know how to measure a faulty ground point?

You could also check if your LIN network isn't shorted but for that you need a scope. (door handle right front, left front, window switch all connected with LIN bus so if one component is shorted nothing works.

Good luck

how do I get into the pillar to check the ground. Couldnt from Frunk

 

[Gtech]

how do I get into the pillar to check the ground. Couldnt from Frunk

Think your ground point is behind some trim panels in the passenger footwell near the a pillar.

Bad ground can be measured with a voltmeter, I'll try to explain.

One pin into the ground wire you want to test, other pin goes to a 100% ground point. If you measure more than 0.1 volt then there is a resistance in the circuit you are testing. Hope this helps.

 

[LTUAE42]

Think your ground point is behind some trim panels in the passenger footwell near the a pillar.

Bad ground can be measured with a voltmeter, I'll try to explain.

One pin into the ground wire you want to test, other pin goes to a 100% ground point. If you measure more than 0.1 volt then there is a resistance in the circuit you are testing. Hope this helps.

Thank You ! now to figure out the trim piece lol you have been very helpful

 

[LTUAE42]

Think your ground point is behind some trim panels in the passenger footwell near the a pillar.

Bad ground can be measured with a voltmeter, I'll try to explain.

One pin into the ground wire you want to test, other pin goes to a 100% ground point. If you measure more than 0.1 volt then there is a resistance in the circuit you are testing. Hope this helps.

i Am downloading the wire diagram etc right now from ebay !

 

[Gtech]

You could also check if your LIN network isn't shorted but for that you need a scope. (door handle right front, left front, window switch all connected with LIN bus

Cannot edit anymore but it is door handle RF, door handle RR and window motor RF and RR are all connected together with the same LIN bus.

 

[Luv2preech]

@jbbessinger
Great posts! I am going to tackle my 2015 p85 this week as I suspect the problems you have mentioned are happening to my DU.
Do you mind sharing the bearing and seal numbers and source?
Thank you

 

[ajbessinger]

@jbbessinger
Great posts! I am going to tackle my 2015 p85 this week as I suspect the problems you have mentioned are happening to my DU.
Do you mind sharing the bearing and seal numbers and source?
Thank you

The seal we use is custom built for us to our specifications. As far as I know, there is no source for a suitable off the shelf replacement, trust me, I searched for a long time to find one.

The hybrid ceramic bearings for the rotor are a special order item that comes from Germany, and retail for about ~$400 ea. There are also two other bearings in the gearbox that we replace as well whenever we have a motor torn apart.

If you want to call our shop tomorrow, we may be able to sell you a set of new bearings and a seal (that's up to my boss Tony though, and he might not want to do that). I do know that if you wanted to ship the car, or just the drive unit itself to our shop, we'd be happy to do a full rebuild for you.

There are quite a few specialized and expensive tools required to tear down a drive unit properly without damaging it, and a fair bit of expertise that goes along with doing so as well.

since you say that you are having issues with the car, it would be best to have the whole thing torn down and closely examined in order to repvent a catastrophic failure. There are a multitude of other issues to check for while the motor is out of the car, besides just the seal, so its best to tear the whole thing down to make sure everything is in good order. We have rebuild dozens of these drive units, and as far as I know we are the only shop in the world that is doing so, so I think its pretty safe to say we are the world wide experts.

If you want to get in touch here's the contact info for our shop:
QC Charge
Vista California, USA
+1 (760) 798-0342
+1 (844) EV-Parts
[email protected]