Brake shudder - SOLVED!

[FST4RD]

Hi all having an issue...
On my Legacy the front outer CV's were knackered so got a mate whose a mechanic to replace them. Whilst he was at it he swapped the inner CV's from side to side. Ever since then if your doing more then 50kmph and put your foot on the brakes you get a shudder through the steering wheel. There's no shudder or anything through the pedal.
Since the CV's were replaced all 4 suspension struts have been replaced, also wheel alignment done and car has been run with 2 difference sets of wheels, so that pretty much rules out all those things.

1 other important thing to note is that the CV's are about 6 weeks old, brand new and brand new boots as well. 2 days ago I took the car into get a WOF and 1 of the CV boots is completely split, the other one doesn't look good and it looks like they are both perishing pretty bad! (going to get them replaced under warrenty).

Would a faulty outer CV cause a brake shudder through the steering wheel and not through the pedal?

[Mr Ree]

Were they genuine parts, or supershitauto aftermarket options?

I wonder if the tolerances are ever so slightly different and could cause the issues you are having

[Girvs]

I've experienced really bad shuddering through my steering wheel of my old shitbaru due to a bad CV joint. It was fine when you drove the car initially, but the more you drove it - as the CV heated up - it started affecting the steering and it got really violent to the point where the car was trying to throw me into the other lane. I don't recall the brakes affecting the shuddering however.

[FST4RD]

Acceleration is fine and cornering seems to be fine, it's only under braking I get the shuddering through the steering wheel.
I don't think that they are genuine, although he said that he's used them heaps before with no issues. Perhaps these are just 2 faulty CV's and boots?

[RedMist]

I'd never switch a CV from side to side. They wear and are stressed to a certain rotation.
I would however rotate your wheels first. Just to see if it's not something like a bent rim, tyre not on the bead correctly.

[FST4RD]

I'd never switch a CV from side to side. They wear and are stressed to a certain rotation.
I would however rotate your wheels first. Just to see if it's not something like a bent rim, tyre not on the bead correctly.

I've had 2 completely different sets of wheels on the car, also have changed front to back and back to front. Still does it.

It's literally only happened since the cv's were changed. Seems to be an odd thing that's happened. Talked to my mate and hopefully will be getting 2 new cv's and boots under warranty, going to switch the inner cv's back to their original sides.

[BattleSnayke]

Warped rotors?

[FST4RD]

Warped rotors?

I thought this, but wouldn't I feel it through the brake pedal?
Plus the rotors and pads all round would only be about 3000k's old.

[sergei]

I had a bad case of brake shudder on almost brand new rotors.

What happened was very silly: Rotors had smaller diameter centre hole (54mm vs 55mm) and were force bolted when the wheels were put on. This caused major warping of the whole rotor (and cracking in the centre).

[FST4RD]

I'll check that out...

Other thing I was thinking... If one of the CV's is a bit sloppy or something it would be fine under power as it's loaded up. As soon as I'm braking the load comes off, the slop causes the CV to become unbalanced and cause the vibration?

[sergei]

I'll check that out...

Other thing I was thinking... If one of the CV's is a bit sloppy or something it would be fine under power as it's loaded up. As soon as I'm braking the load comes off, the slop causes the CV to become unbalanced and cause the vibration?

I don't think it will do it due to free play, it does vibrate because it binds (seizes in some spots). If CV completely seizes you will be thrown into a side fairly quick.

[allencr]

2 bad boots!!
Very unlikely.. Figure out what's wrong before you have 2 more.
Switching the CV's sides/directions doesn't sound like a good idea at all, was it accidental or intentional?

[FST4RD]

2 bad boots!!
Very unlikely.. Figure out what's wrong before you have 2 more.
Switching the CV's sides/directions doesn't sound like a good idea at all, was it accidental or intentional?

Yeah, seriously I watched him put the boots on and they were definately new when put on. Perhaps a faulty batch of boots? There's nothing rubbing on them or anything, nothing that has dripped or leaked onto them, nothing that would suggest anything but faulty boots to be honest. My other mechanic mate that did the WOF could believe how quickly they had gone like that. He thought they were a few years old.

Apprently switching the inner cv's from side to side is a standard thing, perhaps it's different from workshop to work shop?

I noticed today that when I accelerate from a stand still I can hear a couple of clicks coming from the front hub area, sounds like a semi quiet CV click as if they were worn out.

I have a feeling that I have just got 2 bad CV's and boots.

[DeeCee]

do you have any play in the bearings? or are they brand new as well?

[FST4RD]

Nah bearings are quite new as well...
Lol I have replced so many things on this car to new! Not selling it for a long time!

[DeeCee]

what were the conditions of the hubs? No damage from the old bearings?

wheels balanced?

[Crucible]

What was the reason for switching inners? seems odd.As suggested above they would be worn one way and now being driven in the opposite direction which maybe causing them to bind.

Were the cv nuts done up with a gun? are they tight? A loose wheel bearing can cause the same symptoms also as the flange/rotor/wheel will float off centre but generally you will get brake pulse also.

Ive never come across new cvs that give that problem, you never know though. wont be boots.

[AE82 FXGT]

1) Seems random to swap inner CVs, I wouldn't do it myself
2) Have you told the guy that did the work?

[FST4RD]

What was the reason for switching inners? seems odd.As suggested above they would be worn one way and now being driven in the opposite direction which maybe causing them to bind.

Were the cv nuts done up with a gun? are they tight? A loose wheel bearing can cause the same symptoms also as the flange/rotor/wheel will float off centre but generally you will get brake pulse also.

Ive never come across new cvs that give that problem, you never know though. wont be boots.

Yeah everything was done us with a rattle gun.
No brake pulse at all.
The inner cv's were/are in really good nick, think he said something about making them last longer, although i would doubt that would be the issue?
He has got 2 new boots, will probably sort it next week, going to pull everything apart and have a good look...

[FST4RD]

Well it seems that the surface on one of the front hubs which butts up against the brake rotor had a little bit of corrosion. When the new brake rotors were put on we didn't realise this and the brake rotor mustn't have been on perfectly straight, so everytime I put my foot on the brake pedal at higher speeds the brake caliper would have been shuddering side to side slightly causing the steering wheel to shake. This would also explain why there was no feeling in the pedal.
So did a little sanding on the hub surface and brake rotor surface to clean up and now the problem has gone!