Help with steering vibration

[QBee]

Incognegro said:

QBee said:

Have you still got your original Tuscan disks and pads?
If you do, perhaps that would be the best test to try?
Perhaps controversially, in the absence of track days and track day speeds, i wonder whether you really needed the big brake upgrade anyway?

If that was for me mate, Im a Cerbie... the big brakes were done in anticipation of going on to enjoy the car at track days etc. After hearing all views Im leaning the squeak towards the lack of some sticky pads applied to the back of pad (I was told they were built into the AP branded ferodos Im running on the front). The slight wobble may have been caused by a slight 'moment' I had of energy stopping?

No, it was for Mr Chips, but I see these forums as an experience sharing opportunity anyway. I have learnt so much from fellow owners.

[Incognegro]

Totally right mate. I learn lots on here, thanks to the more in the know and experienced guys (like yourself). Sorry if I confused or crossed wires.

Have a great Xmas

[ukkid35]

QBee said:

Have you still got your original Tuscan disks and pads?
If you do, perhaps that would be the best test to try?

That's the mistake I made too.

I disposed of the old discs as soon as I fitted the replacements. But the vibration (not even under braking) started from fitting the new discs - but surely there was no way they could be the culprits.

Only when I was given some used discs was I able to confirm that the brand new discs were at fault.

[QBee]

Chilliwhizz had this happen with a brand new set of bells and rotors a couple of years ago. Spent loads upgrading the front brakes on his 360 bhp Chimaera for his first track day, and promptly suffered terminal brake judder as soon as he got near a braking zone.
Had the disks checked and even skimmed on the car, but I don't know if he ever cured it with those disks.

[MrChips]

Just a quick update (or lack of) for this one. I'm bringing the car back home for a few weeks so i can take some pics.

In an ideal world i'd fine someone with some 322mm fronts and just swap over to check it is actually the brakes causing the issue, however having changed the entire steering system, and the car driving fine when on throttle then it looks the most likely.

At least it's winter so i'm not missing using the car.. just getting fed up with it but will keep going trying to diagnose

[m4tti]

Maybe the brakes are fine.

Sounds rotational. Have you examined the wheel bearing assemblies closely.

Edited by m4tti on Wednesday 28th December 13:31

[MrChips]

m4tti said:

Maybe the brakes are fine.

Sounds rotational. Have you examined the wheel bearing assemblies closely.

Edited by m4tti on Wednesday 28th December 13:31

Everything has been checked as much as can be (without replacing) by the garage yep.
I've had wheel bearing issues on a previous car and they showed symptoms during acceleration as well as braking. Last time i drove the Tuscan, it was silky smooth to drive unless on the brakes. Obviously it could be that the braking force is simply highlighting an issue elsewhere as the forces are obviously different to those under coasting/acceleration.

My logic says to exclude the brakes first before going to the next step as there's a decent size list of what it "could be" so it's just a matter of figuring out what's best to start with, hopefully without just emptying my pockets needlessly.

Should pick up the car tomorrow night so i'll take it for a spin to check the symptoms are exactly as they were a couple of months ago before it went it for repair.

[m4tti]

I'd probably check it with your own eyes and hands in this instance. Won't take a huge amount of time.

I'd also look at the bottom ball joint which clamps through the steering arm and into the upright.

Shame if I had seen this a few weeks back I had a completely serviceable front end everything, but replaced the lot with clean and rust free components when polybushing and powder coating the suspension.

[Incognegro]

Need to bring this back. Bells and rotors off car. Outer face clean but the inner face of disc has 3 pad patches? Is this a warped pad? It's the same on both front discs.

I see contact but only on 3 areas what is cause and any fix ideas?

[QBee]

You need an expert, but if the discs are slightly out of true, you can get them skimmed in the car.

[MrChips]

Just to conclude it from my side... new discs solved the issue completely. I've sent the older ones back to see if anything can be found as they were straight on a dti machine. I can only guess really but maybe there was a lip on one/some of the grooves. I'd definitely be interested to know but the seller dealt with the exchange without issue.

[Incognegro]

Thanks guys. With the discs being straight according to machine can issues be caused by a faulty bell? (Just a question as mine are yet to be checked) gonna drop to my Range Rover guys today

[portzi]

Incognegro said:

Thanks guys. With the discs being straight according to machine can issues be caused by a faulty bell? (Just a question as mine are yet to be checked) gonna drop to my Range Rover guys today

Put the bell on a surface plate first to check it's completely flat, if not run a DTI over it whilst on the surface plate to check how far out it is and whether it can be skimmed down on a lathe, l believe most bells are made of aluminium?

[Outl4w]

Incognegro]lassiChimi said:

.

Do you get any brake squeal when there hot and coming to a gentle stop?


What does that imply. This has been annoying me for years. First on my 304mm CL pads upgrade and now on my 350mm upgrade and on the cp6600 calipers

I had this on my Cerb and Aide suggested I used Anti Squeal shims, which I did and instantly solved the problem.

[Incognegro]

Thanks on the comments above guys. Its appreciated.

[gruffalo]

portzi said:

Incognegro said:

Thanks guys. With the discs being straight according to machine can issues be caused by a faulty bell? (Just a question as mine are yet to be checked) gonna drop to my Range Rover guys today

Put the bell on a surface plate first to check it's completely flat, if not run a DTI over it whilst on the surface plate to check how far out it is and whether it can be skimmed down on a lathe, l believe most bells are made of aluminium?

Certainly dirt between the hub and bell can stop it sitting flat and thus cause a vibration.

[Incognegro]

This really has me puzzled as it's on both inner faces of the front discs where as the outer faces are completely swept by the pads?

[s p a c e m a n]

gruffalo said:

Certainly dirt between the hub and bell can stop it sitting flat and thus cause a vibration.

That. Is the mating surface clean? Only takes a little bit of crud to knock the disk way out making it feel warped, had to do the disks twice on my runaround because I rushed it.