Warped front discs with R32/S3 setup

[lamas]

My first post so, hi everybody!

I'm Lawrence from Barcelona. I've got an ED30 APR Stage 2+ (325bhp) with complete S3/R32 setup (front and rear with Goodridge lines and RBF600 fluid) with BBS CH 8x18 ET50.

The problem is that, without tracking my car (only fast road use), I always end warping my discs. I have proven OEM discs, Zimmerman discs, OEM pads, DS2500 and DSPerformance pads... In less than a thousand km, my steering wheel starts juddering and I also note the vibration through the brake pedal and the seat. What "part" could be the responsible of?

A couple of ideas:

Broken bushes
Deformed Wishbones
Deformed Hubs
Sticky calipers piston
Bad Bearings

I'm totally exhausted and I'm afraid that if I go to a BBK like AP, that "bad part" warped my new discs (much more expensive than the ones I have).

Thank you all for you help!

P.S: Excuse me for my english

[Beddie]

Hi mate  

Sounds very much like your problem is the pad transfer that happens with all pads to some extent but is more common especially with the ferodo ds performance and ds2500 pads, it's surprisingly hard to actually physically warp the disc..

Problem is that when they get hot they spread a load of uneven pad material over the disc surface which is felt as a judder through the steering wheel and the car, this is a common problem with these pads and can be lessened by following a strict bedding in procedure to transfer an even pad layer onto the discs first, problem with the ferodos though is the high rubber content which leeches out
I'd clean your discs and maybe try a change to some carbotech xp8 or pagid blue pads and see how you get on with those 

[danishmkvgti]

same as above, i have same brakes with DS2500 and after hard use twice i have had judder, but it har dissapeared after the "sediment" left on the discs has benn warn down 

[chungster]

Hmmm currently have DS2500s in my AP set up - hope they don't bloody judder this weekend!

Last set of non OE 345s with OE Pagids warped inside 3 conservative laps.....

Original set took a lot of abuse though.

[lamas]

the thing is that I'm tired of R32 setup and I wan't to upgrade to AP Racing kit 330mm 4 pots... As the kits comes with DS2500, will the grooves of the disc reduce the load of uneven pad material?

@Beddie: Could you please explain how to do a proper bedding in procedure? Thanks!

[rich83]

What i want to know is... how blooming fast are you driving on the roads?  

Ive got OEM r32 pads in mine and although they are not very 'bitey' Ive not managed to get them to a point where they start to go off and leave material behind. Although they are starting to cut grooves in my discs where the drill holes are.

[the bruce]

In less than a thousand km, my steering wheel starts juddering and I also note the vibration
through the brake pedal and the seat. What "part" could be the responsible of?

A couple of ideas:

Broken bushes
Deformed Wishbones
Deformed Hubs
Sticky calipers piston
Bad Bearings

Just my thoughts:

- wheel bolts fastened too strong (first by hand, then 120 Nm)
- warped hubs
- pad deposits on disc surface after braking to zero speed


Worn bushes and/or bearings just amplify existing vibrations.

 

[john_o]

Hi,

have you got any pictures of the discs youve replaced?
Did you actually prove they were warped(dial out guage), or was it just the vibration that makes you think they are warped?

Have the brakes worked ok since fitted? have they warped from day one?
is it both front discs?

[Beddie]

@Beddie: Could you please explain how to do a proper bedding in procedure? Thanks!

Here you go mate, try this link and then at the bottom you will see a couple more on how to bed the pads in 

http://www.stoptech.com/tech_info/wp_bedintheory.shtml

[Top Cat]

I am with Beddie, it will just be contaminated disc's, in my experience they only way to cure it properly is getting them skimmed. It is possible to drive through the vibration and try and clean them that way but it takes some doing. I fitted a B5 RS 4 front brake kit to mine, worked fine then changed the pads for a track day and followed the bedding in procedure to the letter. Drove all the way to germany with the brakes working fine got near the Nurburgring and they started to vibrate really bad Took the wheels off twice and cleaned the discs, also drove the hell out of it with lots of heavy braking,  still vibrated like hell.    Came home 2 weeks later the vibration went. 
I would get the discs lightly skimmed, fit some decent pads then go and bed them in hard. find somewhere to get your speed into 3 figures then apply a hard brake application right down to 30 MPH then keep repeating the process a good few times. 

[QD MBE]

The solution is to buy a set of discs for track use, and only use them with your track pads, and a set of road discs, and use them only with road pads.

Remove them after the track, with the pads, store them together marked up as to which side, and which pad they are so you can refit them in exactly the same orientation.

as said above, you have cross contaminated discs in my opinion.

[Carrera2RS]

I had a similar exercise with an AP kit after 3 years of trouble free running with DS11 Ferodo's and brand new discs on am M5. All great 500 miles later bad judder, then ridiculous judder I ......

Had everything dialled for true and wear, replaced all front bushes anyway, refaced disc, spoke to AP, ran different pads, replaced the AP's again. Had the the discs inspected and refaced. Eventually I had the calipers stripped and all seals replaced. One piston was a little slow/sticky.

After 3m and well over £1k, it seemed to go away following rebuilding calipers. My guess is the pad build up was because of the sticky piston allowing the disc to drag a little on the pad and this allowed pad deposits. Never had it before or since. Currently running VWR's with 2500's no judder but only completed 150 miles since fitting

[Tfsi_Mike]

Little off topic so PM reply if you want.  Im interested in what performance hardware you have you have on your APR St2+  

As above a set of track discs and pads and a set of road discs and pads is a good routine!  Probably savea few quid in the long run too 

[lamas]

Just my thoughts:

- wheel bolts fastened too strong (first by hand, then 120 Nm)
- warped hubs
- pad deposits on disc surface after braking to zero speed


Worn bushes and/or bearings just amplify existing vibrations.

 

Related to warped hubs or discs, which is the max. inch or mm of tolerance with the dial gauge?

[lamas]

Hi,

have you got any pictures of the discs youve replaced?
Did you actually prove they were warped(dial out guage), or was it just the vibration that makes you think they are warped?

Have the brakes worked ok since fitted? have they warped from day one?
is it both front discs?

In fact, I haven't checked it with the gauge... Each time I have put new discs in, they have worked well... this makes me think that the issue is related to brakes and not the chasis (hubs, bearings, etc).

I am with Beddie, it will just be contaminated disc's, in my experience they only way to cure it properly is getting them skimmed. It is possible to drive through the vibration and try and clean them that way but it takes some doing. I fitted a B5 RS 4 front brake kit to mine, worked fine then changed the pads for a track day and followed the bedding in procedure to the letter. Drove all the way to germany with the brakes working fine got near the Nurburgring and they started to vibrate really bad Took the wheels off twice and cleaned the discs, also drove the hell out of it with lots of heavy braking,  still vibrated like hell.    Came home 2 weeks later the vibration went. 
I would get the discs lightly skimmed, fit some decent pads then go and bed them in hard. find somewhere to get your speed into 3 figures then apply a hard brake application right down to 30 MPH then keep repeating the process a good few times. 

How do you clean the discs? With a brakecleaner spray?

The solution is to buy a set of discs for track use, and only use them with your track pads, and a set of road discs, and use them only with road pads.

Remove them after the track, with the pads, store them together marked up as to which side, and which pad they are so you can refit them in exactly the same orientation.

as said above, you have cross contaminated discs in my opinion.

I do not track my car at all...

I had a similar exercise with an AP kit after 3 years of trouble free running with DS11 Ferodo's and brand new discs on am M5. All great 500 miles later bad judder, then ridiculous judder I ......

Had everything dialled for true and wear, replaced all front bushes anyway, refaced disc, spoke to AP, ran different pads, replaced the AP's again. Had the the discs inspected and refaced. Eventually I had the calipers stripped and all seals replaced. One piston was a little slow/sticky.

After 3m and well over £1k, it seemed to go away following rebuilding calipers. My guess is the pad build up was because of the sticky piston allowing the disc to drag a little on the pad and this allowed pad deposits. Never had it before or since. Currently running VWR's with 2500's no judder but only completed 150 miles since fitting

I think that I have the same problem than you: sticky piston... However, as I only have 1 piston, it makes the issue to become earlier.

I am looking at diferent AP distributors (with online store), wich do you think is the cheapest (and "safer") to buy online? I have looked at Demon Tweeks and Balance Motorspots...