How to stop my discs warping again?

[Synchromesh]

I'll give the back story first. Bought an E36 328i saloon in September. It needed new discs and pads all round so got Pagid parts from ECP and had my local garage fit them.

Did a few thousand miles without issue (wasn't harsh on them for the first few hundred), did a track day without issue, did further few thousand miles without issue, then started to feel a wobble through the steering wheel when braking from high speeds. Carried on driving it as it was rarely an issue on the road, did another track day (where the wobble was pretty annoying), now I'm continuing to drive it on the road where it doesn't bother me too much.

At first I thought it was the control arm bushes (common cause of this symptom on E36s), but more recently I've started feeling a slight pulsing through the pedal when braking firmly from speed (not ABS, more gentle and low frequency than that). When braking from about 10-0mph the braking feels uneven. So I'm 99% sure it's warped discs.

So I'll get some new front discs on it, but I'm worried this scenario will keep repeating. What I found quite odd was that I started feeling it after 1000+ miles of road driving, not straight after a track day. My garage thinks it's the track days which caused it though. Given that I do quite a lot of track days (at least one a month), is there any way I can prevent it from happening again? Would better discs (or pads) reduce the likelihood?

TIA
Synchro

[HustleRussell]

I had this on my E34. Ditching the pattern pads and fitting OEM ones from BMW seemed to have solved it. I've used Pagid before, was not impressed (except their Motorsport products)

[derin100]

Synchromesh said:

I'll give the back story first. Bought an E36 328i saloon in September. It needed new discs and pads all round so got Pagid parts from ECP and had my local garage fit them.

Did a few thousand miles without issue (wasn't harsh on them for the first few hundred), did a track day without issue, did further few thousand miles without issue, then started to feel a wobble through the steering wheel when braking from high speeds. Carried on driving it as it was rarely an issue on the road, did another track day (where the wobble was pretty annoying), now I'm continuing to drive it on the road where it doesn't bother me too much.

At first I thought it was the control arm bushes (common cause of this symptom on E36s), but more recently I've started feeling a slight pulsing through the pedal when braking firmly from speed (not ABS, more gentle and low frequency than that). When braking from about 10-0mph the braking feels uneven. So I'm 99% sure it's warped discs.

So I'll get some new front discs on it, but I'm worried this scenario will keep repeating. What I found quite odd was that I started feeling it after 1000+ miles of road driving, not straight after a track day. My garage thinks it's the track days which caused it though. Given that I do quite a lot of track days (at least one a month), is there any way I can prevent it from happening again? Would better discs (or pads) reduce the likelihood?

TIA
Synchro

"Warped discs" is a myth. I can't find the original tech article but here it is repeated and explained:

http://www.examiner.com/article/there-s-no-such-th...

[VinceFox]

derin100 said:

"Warped discs" is a myth. I can't find the original tech article but here it is repeated and explained:

http://www.examiner.com/article/there-s-no-such-th...

Utter bks. All those cases happen as well but to say there's no such thing is nonsense.

[crossy67]

DTI to check run out. Stopping with your foot on the brake can heat discs locally, not good. Also make sure your hubs are spotless before fitting new discs.

Personally I would prefer a set of resurfaced discs as they have been heat treated. Discs are cast and as such will be prone to moving after cooling then re-heating if they're not heat treated after manufacture.

[Liquid Tuna]

derin100 said:

"Warped discs" is a myth. I can't find the original tech article but here it is repeated and explained:

http://www.examiner.com/article/there-s-no-such-th...

Oh come on!!

[egor110]

crossy67 said:

DTI to check run out. Stopping with your foot on the brake can heat discs locally, not good. Also make sure your hubs are spotless before fitting new discs.

Personally I would prefer a set of resurfaced discs as they have been heat treated. Discs are cast and as such will be prone to moving after cooling then re-heating if they're not heat treated after manufacture.

How come all automatics don't suffer from warped discs then?

[MarJay]

Warped discs are something that affect motorcycles with very very thin brake discs. Large vented car brake discs simply don't warp. The issue is that pad material welds itself to the surface of the disc.

Apparently the best way to stop this is to correctly bed the brake discs in by braking from 60-30 then allowing the discs to cool with gentle driving, and then repeating a few times.

I tried this on my car and it seems to make the brakes work well, although it's never had a problem with brake pedal pulsing... I did also do this on my old MR2 which did have pedal pulsing and it went away with the new discs. Not scientific results, but might tell you something.

[FourWheelDrift]

derin100 said:

"Warped discs" is a myth. I can't find the original tech article but here it is repeated and explained:

This is what you are looking for I think http://www.supramania.com/forums/content.php?125-T...

[CrutyRammers]

It would certainly seem unlikely that cast iron would warp, without getting to orange heat or so.

[TA14]

FourWheelDrift said:

derin100 said:

"Warped discs" is a myth. I can't find the original tech article but here it is repeated and explained:

This is what you are looking for I think http://www.supramania.com/forums/content.php?125-T...

I thought that that was standard reading for membership here.

[Rickyy]

Cheap discs do seem prone to warping. When I was 17 I seriously cooked the brakes on my 306. The brakes got so hot that smoke poured off them and the wheels trims went soft! I think the warping occurred because I kept my foot on the brake after I'd stopped.

Replaced them with cheap discs and warped them again within a few thousand miles, replaced them AGAIN with Brembo discs (OE Spec, nothing special) and never had the issue again. Infact, that was the only car I ever had that issue with.

[sparkyhx]

local pad transfer is the usual culprit - hot spots of pad material on the disc. Its much worse when the brakes get hot.

[996TT02]

Warped or not, wtf, the OP wants an answer to help prevent this happening again, whatever it is.

Let's just say it's simpler to condense all that tech info into one term "warped discs".

Anyone who disagrees is of course welcome to copy-paste the entire tech article each time they wish to refer to "warped discs".

[leem5]

The hub cleaning is a good piece of advice.

Edited by leem5 on Monday 2nd December 22:35

[FourWheelDrift]

996TT02 said:

Warped or not, wtf, the OP wants an answer to help prevent this happening again, whatever it is.

Let's just say it's simpler to condense all that tech info into one term "warped discs".

Anyone who disagrees is of course welcome to copy-paste the entire tech article each time they wish to refer to "warped discs".

The OP is spending unnecessary money changing the discs thinking they are warping and might be doing it again.

syncromesh said:

So I'll get some new front discs on it, but I'm worried this scenario will keep repeating.

when what he needs to do is bed them in properly and make sure the hub and wheel flange are in good condition and flat when fitting, by reading the tech notes posted. In stead of changing and throwing away the current discs if they aren't too bad he could get them skimmed as well.

[derin100]

TA14 said:

FourWheelDrift said:

derin100 said:

"Warped discs" is a myth. I can't find the original tech article but here it is repeated and explained:

This is what you are looking for I think http://www.supramania.com/forums/content.php?125-T...

I thought that that was standard reading for membership here.

So did I. The people who say "utter bks" can present their own evidence against this based on their "engineering expertise" (which they can't because all they can say is, "utter bks"...yet offer nothing else).

Anyway...can't be bothered with this 'debate' myself anymore.

Bye!

[Synchromesh]

FourWheelDrift said:

In stead of changing and throwing away the current discs if they aren't too bad he could get them skimmed as well.

The discs only cost £60 for a pair, would getting them skimmed really be much cheaper?

And is the general consensus to just get better quality discs, and go through a proper bedding-in procedure next time?

[mygoldfishbowl]

My opinion..Disks don't warp. Buy Bosch not Pagid.

Edited by mygoldfishbowl on Tuesday 3rd December 00:09

[VinceFox]

derin100 said:

TA14 said:

FourWheelDrift said:

derin100 said:

"Warped discs" is a myth. I can't find the original tech article but here it is repeated and explained:

This is what you are looking for I think http://www.supramania.com/forums/content.php?125-T...

I thought that that was standard reading for membership here.

So did I. The people who say "utter bks" can present their own evidence against this based on their "engineering expertise" (which they can't because all they can say is, "utter bks"...yet offer nothing else).

Anyway...can't be bothered with this 'debate' myself anymore.

Bye!

Ive just had a set of discs refinished in the past month due to heat warping.