15 S85D intermittent steering assist

[livesmith]

So my 85D is currently giving me intermittent steering assist. Like I'll drive for a while as normal, then turn at an intersection and steering will stiffen up, then go easy again, sometimes repeatedly. Feels like switching from comfort to sport steering settings.

This what happens when the grounding stud starts to go bad? Or is there some other stiffening in the steering mechanicals that's happening that the motor is trying to compensate for? Although I can't hear or feel anything that makes me feel like there's binding going on other than the resistance in the steering wheel which still feels rather smooth. But I suppose that could just be the motor assist covering something up? Seems to really only be when I'm turning slightly more significantly like at least a half turn or something.

 

[David Harvey]

Whenever you have the frunk removed, squirt the steering universal joint with lithium grease or failing that a lubricant which goes on thin and stringy but solidifies such as motorcycle chain or chainsaw lubricant. https://photos.app.goo.gl/J2h52gdq2NG9KzCZA

 

[islandbayy]

Same for S & X for the most part. Slightly easier to hit it with the frunk removed though for the Model S. Links to lubricant that should be used in video description box.

 

[livesmith]

Whenever you have the frunk removed, squirt the steering universal joint with lithium grease or failing that a lubricant which goes on thin and stringy but solidifies such as motorcycle chain or chainsaw lubricant. https://photos.app.goo.gl/J2h52gdq2NG9KzCZA

Do you have a dual motor? I pulled the frunk and had my mechanic who takes care of the larger jobs look as well. There didn't seem to be any actual place to see the joint from frunk, wheel well or underneath. He did manage to somewhat blindly get some ATF drizzled on it and the next day it started acting a lot nicer.

I stopped at Tesla to get a replacement, but the one they showed up with was the old style with no boot so they have the correct one on order. Just wondering if I should go ahead and get it replaced or if it will last if I just hit it once in a while with lube somehow...

 

[islandbayy]

Do you have a dual motor? I pulled the frunk and had my mechanic who takes care of the larger jobs look as well. There didn't seem to be any actual place to see the joint from frunk, wheel well or underneath. He did manage to somewhat blindly get some ATF drizzled on it and the next day it started acting a lot nicer.

I stopped at Tesla to get a replacement, but the one they showed up with was the old style with no boot so they have the correct one on order. Just wondering if I should go ahead and get it replaced or if it will last if I just hit it once in a while with lube somehow...

Mine before doing it for the video was so bad, autopilot wouldn't even work, as it thought I was taking over the steering wheel, as well as my wife could no longer turn the wheel. Did it like shown in the video, sprayed it once more since, and still smooth as butter. That was 3 years ago.

 

[David Harvey]

Do you have a dual motor? I pulled the frunk and had my mechanic who takes care of the larger jobs look as well. There didn't seem to be any actual place to see the joint from frunk, wheel well or underneath. He did manage to somewhat blindly get some ATF drizzled on it and the next day it started acting a lot nicer.

I stopped at Tesla to get a replacement, but the one they showed up with was the old style with no boot so they have the correct one on order. Just wondering if I should go ahead and get it replaced or if it will last if I just hit it once in a while with lube somehow...

My S75 is rear wheel drive.

 

[livesmith]

My S75 is rear wheel drive.

Yeah, sounds like it's a lot easier to get to that joint without the front motor and drive shafts

 

[Decibelle]

I had the exact same issue, plus I also had a small 1/4” play when turning the steering wheel back and forth. My Universal Joint was seized up and since I have the dual motors, I opted to check with Tesla to see how much they would charge. To my surprise they only charge for a little more than half an hour of labor so I had them do it. The SC said it would take them about 2-3 hours to do the job, so I waited while they did the work. They claim only the old version of the u-joint, without the cover, would fit in my car (2015 P85D). Now the steering wheel returns to center easily after each turn, and the play in the steering wheel is gone. Happy customer.

 

[islandbayy]

I had the exact same issue, plus I also had a small 1/4” play when turning the steering wheel back and forth. My Universal Joint was seized up and since I have the dual motors, I opted to check with Tesla to see how much they would charge. To my surprise they only charge for a little more than half an hour of labor so I had them do it. The SC said it would take them about 2-3 hours to do the job, so I waited while they did the work. They claim only the old version of the u-joint, without the cover, would fit in my car (2015 P85D). Now the steering wheel returns to center easily after each turn, and the play in the steering wheel is gone. Happy customer.

Can you post a redacted copy of the invoice? The quote I got was a bit nuts at the time. Hopefully that price has come down some.

 

[Decibelle]

Sorry, don't really know how to redact an invoice, but here is a link to an earlier post where the poster attached some really good information including the shop time for fixing this issue.

2015 Model S lower ishaft (u-joint) replacement with pictures, Stiff joint, Stiff steering, protective boot installed

I managed to replaced my lower I-shaft on my 2015 Model S 85D, custom job adding the protective boot. My steering was stiff and while I was on auto-pilot it had a play in the steering, about 5 degrees. The play turned out to be that the lower bolt on the lower i-shaft loosened. The stiffness was...

teslamotorsclub.com

Here is another link with two invoices from other members (go to post #14 and #16)

Steering U-Joint Lower Shaft Issue and my Solution so far.

Lesser known issue that is more common in the snow belt area is the Lower Steering I-Shaft U-Joint. Problem is that it is more exposed to the elements, and subject to Water, Snow, Salt, Sand, Dirt, and anything else that can be kicked up by the drivers side tire while driving. What ends up...

teslamotorsclub.com