New brake discs warped???

Bradmax57 · 29 May 2013 at 10:47

So I fitted new front discs and pads to my E90 recently as they were worn and there was some vibration coming from the front under braking from speed. I got Pagid discs and pads so not the cheapest stuff you can buy and supposedly oem spec.

I made sure I cleaned the face of the hub, firstly with a wire brush then with some sandpaper so it was all good and smooth, cleaned up the caliper holder with the wire brush again, and cleaned up the slider pins and re-greased them up. The caliper pistons themselves pushed back in with no effort at all and looked fairly clean (not sure if they have been replaced at sometime as they still look newish, car is 2006). Put it all back together and went for a drive and to my joy the vibration had gone

now a couple k later its back, under normal speeds its hardly noticble but at motorway speeds etc you can definately feel it, they certainly work well as i tried them out yesterday thinking it might be a build up brake dust etc and tbh ive not had a car that stops aswell as this.

So i stripped them back down, cleaned everything up again, pistons again pushed back in with little effort so im sure its not a sticking caliper, cant see any noticible warp on the disc but thats all I can think it would be, if it was just a wheel balance issue surely i would notice it all the time?

Both discs are still smooth with no scores in them, the backs are going to need doing soon but that wouldnt come through as vibration on the steering wheel under braking would it?

Anyone had anything similar or any advice to give?

paradigm · 29 May 2013 at 10:55

This happened to my E46, it was a sticky caliper, even though I could push them back in no problem when changing the pads.

Bradmax57 · 29 May 2013 at 10:59

Right, so im guessing if that is the cause the new discs will be buggered too, damn cars

wonder if its worthwhile getting a caliper repair kit and having a go at doing that, im not afraid to have a go myself

Nightglow · 29 May 2013 at 11:02

Binding brake calipers would be top of my list.

Have you also checked bushings, upper control arm, lower ball joints,etc for movement.

Havana_UK · 29 May 2013 at 11:04

There's some sort of funky micrometer gauge you can get to check for disc warp (I've seen Edd use it on Wheeler Dealers!). Disc warp is rarely visible to the eye, but it only takes <0.5mm or so for it to be noticeable through the pedal.

Having said that, the fact that you've stripped and replaced a couple of times, each time temporarily solving the issue would seem to point to it being the caliper and not the discs themselves.

Bradmax57 · 29 May 2013 at 11:25

Just looking at repair kits now

Rybo89 · 29 May 2013 at 11:29

Is it only doing it under braking? If not it will be unbalanced wheels, especially with it only doing it at motorway speeds.

I would get them tracked up and balanced and then go from there.

Also... When you did the disks, you didn't just wollop a load of copper grease on did you? Too much can boil n go solid which makes the disk go off balance (causing quite an aggressive shake in the steering wheel under high speed braking).

Bradmax57 · 29 May 2013 at 11:33

Rybo89 said:
Is it only doing it under braking? If not it will be unbalanced wheels, especially with it only doing it at motorway speeds.

I would get them tracked up and balanced and then go from there.

Also... When you did the disks, you didn't just wollop a load of copper grease on did you? Too much can boil n go solid which makes the disk go off balance (causing quite an aggressive shake in the steering wheel under high speed braking).

Yeah its only really noticable when under higher speed braking, i'm sure the wheels could do be with balancing and tracking so will get them done asap, you can feel a tiny little judder at normal urban speeds but nothing worrying. It had a brake fluid change last year at BMW if thats going to make any odds?

With regards to the copper grease I didn't put much on at all tbh, i've put far more on in the past on other cars and not noticed the same effects.

Regarding the balancing tho, the judder/wobble/ vibration whatever you want to call it went away after the initial fitting of the new parts so if it had been the balancing it wouldn't have gone... found the repair kits for £14 so might just go with them, will give me something to do at the weekend anyway

Concrete · 29 May 2013 at 13:41

You can get the disks skimmed on the car for less than the cost of a new set. Worth doing if they are pretty much new.

Also check that the pads can move freely in their grooves. I recently had a problem on my IS300 where the inside pad was getting stuck on the disk due to it getting gunked up.

Matt82 · 29 May 2013 at 14:22

I have pagid discs/pads on the front of my Golf, been there for 30k miles now, maybe more

From day one they juddered when used hard. Nowadays the car only gets thrashed once in a blue moon, but as soon as you thrash it the juddering comes back.

I think its down to pagid components not being as good as theyd like you to beleive

Gaygle · 30 May 2013 at 18:07

I too am having this exact problem with my E92. With the exact same components.

Everything you've written in your post, i've done. I have seen others mention this exact problem on E90post using....yep....Pagid discs and pads. I did 8-9 heavy stops from 60-10mph the other day to see if i can reset the pads/discs, and i am yet to see if this has worked - i will check tonight to see if the juddering is still there.

I've got mine booked in on Tuesday next week to check run out of all the discs - i'll keep you updated.

If it does turn out to be the Pagid discs that have been destroyed, i'll be PO'd as they were £140 IIRC. But i will be sure never to use them again and just get some normal ones from eBay.

Matt82 · 30 May 2013 at 18:09

i dont think its the discs. i bet if you put a set of ate or textar pads on it would go away, the problem will be the pads leaving deposits on the discs

Gaygle · 30 May 2013 at 18:10

Havana_UK said:
but it only takes <0.5mm or so for it to be noticeable through the pedal.

Ha. The tolerance for most cars is about 0.003in or 0.0762mm.

In the last month or so, I think i've learnt pretty much all there is to know about brake judder and disc brakes.

Just for reference - i had new brake pads on BMW discs. Judder started some months later. Thought it was rear discs as they were scored and rusted around the outside - so replaced rear discs and pads. Judder went away a small amount. Judder still present, so fitted new Pagid discs and pads. Judder present after a couple of thousand miles. So that's:

1 x Rear pads
1 x Rear discs
2 x Front pads
1 x Front discs

and probably soon to be another front pads and discs. Oh joy.

The judder gets much worse when the brakes get hot and at about 60-80mph under light-medium braking when hot is when it is worst.

Tom_ed1987 · 30 May 2013 at 18:45

If it's a sticking piston/slider the brakes will be overheating at speed when causing the judder, have a feel of the wheel in a motorway services to see if it's hot.

If it's not the caliper and you are sure the disc is sitting true to the hub with no rust or grit sandwiched inbetween, the hub/stub axle could be warped slightly. Get the disc machined true while it is mounted to the hub, which will remove any runout:

http://www.skimmydiscs.co.uk/

Howard · 30 May 2013 at 18:55

Gaygle said:
Ha. The tolerance for most cars is about 0.003in or 0.0762mm.

In the last month or so, I think i've learnt pretty much all there is to know about brake judder and disc brakes.

Just for reference - i had new brake pads on BMW discs. Judder started some months later. Thought it was rear discs as they were scored and rusted around the outside - so replaced rear discs and pads. Judder went away a small amount. Judder still present, so fitted new Pagid discs and pads. Judder present after a couple of thousand miles. So that's:

1 x Rear pads
1 x Rear discs
2 x Front pads
1 x Front discs

and probably soon to be another front pads and discs. Oh joy.

The judder gets much worse when the brakes get hot and at about 60-80mph under light-medium braking when hot is when it is worst.

It's not a worn bushing somewhere is it? I'm sure they can "oscillate" with varying loads and give a juddering effect

Gaygle · 30 May 2013 at 20:02

Howard said:
It's not a worn bushing somewhere is it? I'm sure they can "oscillate" with varying loads and give a juddering effect

It might well be, but it wouldn't explain why the problem gets 100x worse when the discs get hot.

Just gone on a drive to see if my 10 60-0mph stops did anything and for the first 5-10 miles it seemed to have worked and the juddering was completely gone at 60-70mph. However, what i discovered is that all it did was that i takes more heat in the brakes before the juddering appears. After a few decent slow downs from 90kph - 50mph the juddering is back until the discs cool off.

It's driving me mad. I really really suspect it is something to do with Pagid discs and pads as there was a thread on E90post with some guy complaining about this exact problem - and more and more people kept saying it had happened to them with Pagid disc and pads.

Gonna see what the mechanic man makes of it on Tuesday. He'll do a run out check on all discs and check all bushes, however, from seeing how bad the juddering is when the discs are hot - my money is on the front Pagid discs/pads.

Fuzz · 30 May 2013 at 20:26

You hooned it too early I'd say

Bradmax57 · 30 May 2013 at 20:36

Fuzz said:
You hooned it too early I'd say

I made sure I was very carefull on mine for the first 500 miles or so, even then i dont recall any heavy braking incidents, i'm generally quite light on my brakes as I often flick it over into DS and use the gears to slow down

Bradmax57 · 30 May 2013 at 20:39

Howard said:
It's not a worn bushing somewhere is it? I'm sure they can "oscillate" with varying loads and give a juddering effect

I'm beginning to think something along those lines too as i do have a bit of a weird noise from the front suspension when going over low speed bumps etc, I can't put my finger on what tho as the car still feels extremely tight especially the steering, time to get it up on some ramps I think.

Bradmax57 · 30 May 2013 at 20:40

Gaygle said:
I too am having this exact problem with my E92. With the exact same components.

Everything you've written in your post, i've done. I have seen others mention this exact problem on E90post using....yep....Pagid discs and pads. I did 8-9 heavy stops from 60-10mph the other day to see if i can reset the pads/discs, and i am yet to see if this has worked - i will check tonight to see if the juddering is still there.

I've got mine booked in on Tuesday next week to check run out of all the discs - i'll keep you updated.

If it does turn out to be the Pagid discs that have been destroyed, i'll be PO'd as they were £140 IIRC. But i will be sure never to use them again and just get some normal ones from eBay.

I'd appreciate it if you would let us know what they find.