Electric Power Steering (EPS) noisy

[Ultramaroon]

May we see a couple full-size closeups of that psu?

[Ultramaroon]

I think the worm gear is binding by being wedged crooked.

[ermax]

Originally Posted by Ultramaroon

I think the worm gear is binding by being wedged crooked.

I agree which I think is also removing the gear lash. I’m afraid that simply cramming a bigger o-ring in here isn’t going to be the fix. Ultimately the plastic gear is worn out and I think pushing the worm gear off center is compensating for the worn gear. I’ve seen another fix where you put a washer on the end of the main gear which sort of changes the thrust. I’m trying to wrap my head around why that would fix it.

[Ultramaroon]

I don't think the ring and pinion are worn. I think the flexible mount for the end bearing wore out, allowing it to flex out of alignment.

[ermax]

I found the perfect o-ring at Hime Depot that tapers down nicely so the more you push it in the fatter it gets but it has no impact on the rattle. It seems pushing it off to the side is the only thing that works from this easy to access plate. I give up for the day. The next attempt will be to completely remove the unit and see what else I can come up with. I may buy a used one off eBay and use that one as my guinea pig.

Kind of bummed it wasn’t easy to fix.

[ermax]

Originally Posted by Ultramaroon

I don't think the ring and pinion are worn. I think the flexible mount for the end bearing wore out, allowing it to flex out of alignment.

Could be. It’s kind of hard to tell without removing the whole thing and taking it apart. When I get to a computer I will dig up some of the links to the Russian solutions.

[ermax]

So to summarize, wedging something on one side of the bearing so that the worm presses tighter to the main gear makes the noise go away. But then it causes binding and the wheel will not self center anymore. There is another Russian guy that found a better solution. He claims that wedging the bearing will only last so long before the main (plastic) gear continues to wear and the sound comes back. His solution involves adding a thrust washer at the end of the main shaft which causes the worm to ride on a new surface of the big gear. IMO this will also be a temporary fix. Seems the only real fix would be to replace the big plastic gear. Actually that isn't even a permanent fix. I am used to putting 250k on a car and the plastic gear didn't even make it 100k. A better fix would be to replace the plastic gear with a metal one. I did actually see another Russian claim he had an metal gear made.

The Russian guy completely removed the EPS unit to add the thrust washer but looking at this thing I think you could get away with simply removing the lower part of the steering shaft, remove the 27mm nut at the end of the shaft and then pull the cover off, add the washer and then reassemble.

If I get some time this weekend I may attempt this.

Here is a link to the Russian page explaining the process:
https://www.drive2.ru/l/3207770/

[Ultramaroon]

If this is the case, then the wear will be concentrated in the area where the steering wheel is centered. If the worm gear is also worn then you might be SOL.

Might it be possible to just rotate the spur gear a half turn and reassemble? Just spitballing here.

[ermax]

Originally Posted by Ultramaroon

If this is the case, then the wear will be concentrated in the area where the steering wheel is centered. If the worm gear is also worn then you might be SOL.

Might it be possible to just rotate the spur gear a half turn and reassemble? Just spitballing here.

Freaking great idea! I kind of doubt the worm gear is worn much seeing as it's made of steel and meshing with plastic. It would probably take more work to rotate it than simply adding a thrust washer but I think I like this idea better.

I would probably need to reset the clock spring and there is some calibration stuff in Techstream that I'd probably have to do. No big deal though.

[ermax]

I'd still love to know what this "rubber coupler" is that @

click the link so it goes to the correct timecode) you will see a little rubber gear that goes between the motor and the worm. I could see this being referred to as a coupler. Maybe this is what he was referring to. I know Hyundai has had EPS problems related to a rubber gear that sits between the motor and the worm. Hyundai was nice enough to produce a TSB and sell the gear individually.

[Ultramaroon]

Originally Posted by ermax

I'd still love to know what this "rubber coupler" is that @gt86gh was referring to.

There will always be some sort of flexible coupling between the motor shaft and whatever it drives. For the lexus video, that little rubber piece is only the center part which gives a little bit of force to push the two halves apart. It takes up the axial play in the motor.

[ermax]

Originally Posted by Ultramaroon

There will always be some sort of flexible coupling between the motor shaft and whatever it drives. For the lexus video, that little rubber piece is only the center part which gives a little bit of force to push the two halves apart. It takes up the axial play in the motor.

Yeah but if it is decentigrated then the worm would be thrusting in and out and I could see that making a bunch of noise. Two other people have reported a "rubber" piece being the problem. Other than the rubber part that wraps around the bearing at the end of the worm It's the only rubber part I've seen.

[Ultramaroon]

Originally Posted by ermax

Yeah but if it is decentigrated then the worm would be thrusting in and out and I could see that making a bunch of noise. Two other people have reported a "rubber" piece being the problem. Other than the rubber part that wraps around the bearing at the end of the worm It's the only rubber part I've seen.

No, the worm gear will be captivated tightly by some other means. For instance, this is the moment when the worm shaft is loosened on the lexus vid.


edit: for some reason, # is the magical prefix that works for applying the start time argument inline.



[ame]https://www.youtube.com/watch?v=fsP_qDCmxQ8#t=189[/ame]

[ermax]

Originally Posted by Ultramaroon

No, the worm gear will be captivated tightly by some other means. For instance, this is the moment when the worm shaft is loosened on the lexus vid.

Yeah I guess so. When I had the cap off the end of the worm you could see it moving around a lot but I guess it isn't really thrusting, it's just moving off center.

After taking the spring out of it a few times I seem to have made it worse. Tonight I am going to pull the spring back out and bend it so it's more springy and put it back in to see if it cuts the noise at least back to where it was before. The way that spring sits in there it presses the worm against the ring gear.

The spring I am referring to is also in the Lexus unit. It looks identical actually.

[ame]https://www.youtube.com/watch?v=fsP_qDCmxQ8#t=155[/ame]

Edit: Thanks for the timecode tip!