Power steering rack slip

[Turbolab]

Wanted to add to the pool that I recently was diagnosed with a slipped Steering rack belt. 2020 with 9,200 miles. My abs ecu failed when I unsuccessfully tried launch control. I believe we slipped the belt trying to man handle the steering pulling it in shop. Talked with the Supra tech for quite awhile and he was told in training that they have seen this failure a few times. Most notably was when securing car on Dyno and trying to center car with steering when roller turning . Part numbers for rack attached

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[Turbolab]

Ok, since I haven't seen a write up I'll give basic info. First off the rack has a small Gilmer belt inside it that assists the manual rack. They are independent if each other so if belt fails you still have unassisted steering, not death. The large brushless motor has a position sensor in it(verified it has over 900 degrees readable travel) that is used for various things including lane control and assists. What I think happened on my car was we pushed it into shop for abs dme failure and I turned key on while cranking on wheel. This caused the pinion angle to slip to -200. Dealer said I needed new rack but decided I'd try to repair. The repair is simple if you have a lift and you need a scan tool that will read pinion angle. View pinion live data to see where it at first(should be significantly off) With vehicle in air Pull lower aluminum panel. Locate 3 torx holding in electrical unit and remove them. Ignition on and with wheels straight , pull unit out while looking at scanner and reinstall as close to zero as you can. Tighten screws and you should be good to go. The whole process took me 1.3 hours . My car required a dealer trip because we cleared ps data that reset the zero point reference . Hopefully this helps someone from spending 3k for a slipped belt.

 

[razorlab]

All that because you moved the steering wheel while pushing the car? I've done that in almost every single car I have owned with zero issues.

Why is it so fragile? Seems odd.

 

[Turbolab]

That's the only thing we can come up with. Was working normally with no steering fault till we pushed it in . Perhaps something else but the bmw...er Toyota tech said these racks are a known problem at time of his training. Fragile was the word he used.

 

[mokleen]

@SD_MK

 

[NickGreyA90]

Hey man can you describe the symptoms of the slipped eps belt? I'm having a hell of figuring out what's up with my car. Had full spl put on and springs. 1st shop screwed it up, second shop fixed it all but ever since play at dead center on the wheel. So when I'm driving the car wanders a bit, and when the tyranny shifts it likes to veer off. Also car is unstable at higher speeds. I also have a vibration that comes in at 55ish, peaks at 63ish and back to smooth as glass by 70. Any info would be greatly appreciated!

 

[Narquis]

Hey man can you describe the symptoms of the slipped eps belt? I'm having a hell of figuring out what's up with my car. Had full spl put on and springs. 1st shop screwed it up, second shop fixed it all but ever since play at dead center on the wheel. So when I'm driving the car wanders a bit, and when the tyranny shifts it likes to veer off. Also car is unstable at higher speeds. I also have a vibration that comes in at 55ish, peaks at 63ish and back to smooth as glass by 70. Any info would be greatly appreciated!

Hey Nick, were you able to find what’s up with it?

 

[freeform911]

Hey Nick, were you able to find what’s up with it?

most of that seems like a front toe issue!

Steve

 

[NickGreyA90]

Hey Nick, were you able to find what’s up with it?

I have not. Can't afford to throw money at it when they don't seem to think there's a problem

 

[NickGreyA90]

most of that seems like a front toe issue!

Steve

What do you think the toe should be? This is the last alignment. While it is better than when I 1st posted, it's still not great

 

[NickGreyA90]

What do you think the toe should be? This is the last alignment. While it is better than when I 1st posted, it's still not great

Don't know what happened there. Won't load it properly
So.. Also corner balanced

LF
camber -2.53
Caster. 8.23
Toe. -0.10
RF
Camber.-2.75
Caster. 8.11
Toe. -0.10
Front toe. - 0.20
Thrust angle 0.00
LR
Camber. -2.25
Toe. 0.14
RR
Camber. - 2.25
Toe. 0.18
Total toe. 0.32
Thrist angle. - 0.02

 

[JimboSlice]

Hey man can you describe the symptoms of the slipped eps belt? I'm having a hell of figuring out what's up with my car. Had full spl put on and springs. 1st shop screwed it up, second shop fixed it all but ever since play at dead center on the wheel. So when I'm driving the car wanders a bit, and when the tyranny shifts it likes to veer off. Also car is unstable at higher speeds. I also have a vibration that comes in at 55ish, peaks at 63ish and back to smooth as glass by 70. Any info would be greatly appreciated!

Hey Nick. I have the same vibration issue at literally the same exact speeds.
I’m bringing mine into the shop today for my window not rolling ? and will try to have them diagnose the vibration as well.

As for the floatiness and instability at higher speeds…I agree with freeform911 that the toe could be the main culprit as these alignments are out of spec even from the factory, but what kind of tire are you running?

I know it sounds crazy simple, but if you’re running mismatched tires or cheap rubber this could likely be the culprit.

 

[NickGreyA90]

Hey Nick. I have the same vibration issue at literally the same exact speeds.
I’m bringing mine into the shop today for my window not rolling ? and will try to have them diagnose the vibration as well.

As for the floatiness and instability at higher speeds…I agree with freeform911 that the toe could be the main culprit as these alignments are out of spec even from the factory, but what kind of tire are you running?

I know it sounds crazy simple, but if you’re running mismatched tires or cheap rubber this could likely be the culprit.

Good tires here. 275s and 305s rear michellin ps 4s. Alignment was perfect for me from stock and tracked the car with good results. All the issues came after spl, springs, alignment and new wheels and tires

 

[Narquis]

That front toe should be positive (toe in)... 0.05 toe in both sides should work (Total 0.10)

If it is toe out 0.10 no wonder it wanders around.

Don't know what happened there. Won't load it properly
So.. Also corner balanced

LF
camber -2.53
Caster. 8.23
Toe. -0.10
RF
Camber.-2.75
Caster. 8.11
Toe. -0.10
Front toe. - 0.20
Thrust angle 0.00
LR
Camber. -2.25
Toe. 0.14
RR
Camber. - 2.25
Toe. 0.18
Total toe. 0.32
Thrist angle. - 0.02

 

[NickGreyA90]

That front toe should be positive (toe in)... 0.05 toe in both sides should work (Total 0.10)

If it is toe out 0.10 no wonder it wanders around.

They said it was for better turn in. But it also is super sensitive to steering input, perhaps to much.
Alot of people seem to go 0 toe. What do you think about that?

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