Sever pull to the left when braking

[tsviatko]

That problem has been there for a couple of months now. Here's what I've done about it so far:

- Brake test. Showed some problems that I fixed. No stuck pins or calipers now and all new pads. Did another brake test after that and everything was green, i.e. there was no significant difference between the braking force applied to each pair of wheels.
- Changed lower wishbone bushings. These looked bad. The problem got somewhat worse after that.
- Changed upper and lower balljoints (their time had come anyways). No change after that.
- Changed rear axle arms bushes (these had gone bad too). The problem got somewhat worse after that.
- Tried rotating tires. No effect.

So I pretty much cannot think of anything else to check up now and I cannot get rid of this problem. Can any of you guys think of something else I could do?

 

[Doodle]

You've not mentioned it, so perhaps a geometry/alignment check is due?

 

[Shayne]

Swap the discs and pads over see if it pulls to the right instead ?

 

[AndyCook]

what are the steering rack track-rod ends like? loose?
and the steering rack bushings?

 

[tsviatko]

Yep, I forgot to mention this. Alignment has been done after the bushings/ball joints replacement. Then I did another one after a couple of weeks to make sure nothing changed.

I have swapped the brake pads. I have not swapped the discs but the brake test shows equal braking forces on both sides.

I've checked tie rod ends and steering rack have no apparent slack. Alignment wouldn't have persisted if they did anyways.

 

[Shayne]

Front ends under compression while breaking so maybe if you winch it down it will reveal something you can't see otherwise ?

 

[Chris Green90]

Had a similar problem recently and it turned out to be mr rear prop UJ. Sounds daft i know but changing that stopped it.

 

[tsviatko]

Did you have some play in that UJ? What made you change it?

 

[Chris Green90]

TBH Yes Quite a lot.

 

[tsviatko]

No play in the UJs on my side. The only thing I can think of now is double-checking brake test and alignment at some other shop. Can you guys think of anything else that I can do?

 

[grantw]

What have you checked suspension side? A shot shock absorber on one side wouldn't help things at all.

 

[fridayman]

A severe pull to one side is almost always a sticky calliper piston (usually a front one). I would check them myself by taking the callipers off (one at a time), pads out and getting someone to very slowly press the brake pedal. Try not to let any of the pistons pop right out (not a big deal if one does though). You will soon see if there is one piston that won't come out.

 

[fridayman]

Also check your steering rack bushes.

 

[tsviatko]

The shock absorbers make no weird noises or anything and I see no leaks on them so I assume they are still good. Is there anything more specific I can do to test them?

I've personally checked the caliper pistons when I replaced the brake pads. All of them were moving just fine. Also, the brake test would show any difference in the braking force applied to each of the front wheels so I am pretty sure pistons and calipers are fine.

 

[fridayman]

Then there is an outside chance it is a steering rack bush, but they usually give vague steering rather than pulling to one side.

 

[grantw]

How severe is severe? Can you give us a description?

I'm kind of with everyone else in the ense that if it really severe (i.e quite significant pull on the steering wheel) there is little else it can be. Perhaps it's worth a recheck?

 

[tsviatko]

Yep I did check the steering rack bushes. I used a breaker bar and tried to move the steering rack using the frame as a pivot. No play detected. Sorry about forgetting to mention that.

By severe I mean like 60 degrees rotation of the steering wheel when braking at 50kmh and not holding on the steering wheel. At higher speeds it gets much worse than that.

 

[tsviatko]

Yep I am just gonna start rechecking everything unless something I have not thought about comes up.

 

[grantw]

As you say though ... if the break balance keeps coming back it really can't be the pistons/calipers. But with it pulling that severely what else can it be?

 

[Shayne]

A warped brake disc is my guess .