Jump to content
The mkiv Supra Owners Club

Warping brake discs


Paul372
 Share

Recommended Posts

Hi, I’m running uk spec four pot calipers on my jap spec tt auto with Oem discs and pads but the problem is that I keep warping the discs I’ve been through two sets now. So what make discs and pads are you guys using and what’s the best set up for discs and pads for uk spec calipers

Link to comment
Share on other sites

If you hammer the brakes and come to a stop , put the car in N and use hand brake , coming to a stop and leaving your foot on the brake to stop the car creeping forwards could cause warpage as the pads pull heat out of the disc on contact area and disc cools unevenly .

You would have to hammer the brakes to do this though , sure your pistons are moving evenly ?

Link to comment
Share on other sites

If you hammer the brakes and come to a stop , put the car in N and use hand brake , coming to a stop and leaving your foot on the brake to stop the car creeping forwards could cause warpage as the pads pull heat out of the disc on contact area and disc cools unevenly .

You would have to hammer the brakes to do this though , sure your pistons are moving evenly ?

 

This...or maybe a wheel bearing?

Link to comment
Share on other sites

I’ve got no noises at all coming from the brakes the discs are just warped, it’s horrible when braking you can feel it through the brake pedal and the steering when braking, I just don’t think that the Oem discs can take a lot of heavy braking

Link to comment
Share on other sites

I’ve got no noises at all coming from the brakes the discs are just warped, it’s horrible when braking you can feel it through the brake pedal and the steering when braking, I just don’t think that the Oem discs can take a lot of heavy braking

 

I remember someone saying either front or rears have been known to come warped from toyota! Bloody shame toyota brakes and discs actually arnt that good

Link to comment
Share on other sites

I have never warped any UK sized stock Toyota discs, and I really hammer the brakes hard. I feel you have an underlying problem that's causing you to warp discs, wheel bearing perhaps?

 

For years now there's been a problem with facelift Supra's warping disc's over and over again, Pete, Branners are two members that have/had this problem. We've never gotten to the bottom of it.

Link to comment
Share on other sites

Are you sure it's warpage? Pad deposits can create the same shuddering feeling. Having said that I (thought I) warped lots of sets of stock disks on my facelift model. Eventually fitted APs and never looked back.

Link to comment
Share on other sites

Sounds like front wheel bearing, or the hub faces aren’t clean when you put the discs on.

 

Possibly this, if you can get one of those 'dial gauges' I think it's called.......think of like an old vinyl record stylus, you fit the disc with all 5 wheel nuts and then rotate it with this gauge contacting the disk face and you will see the dial fluctuating, sometimes a reclean and rotating the disc one stud round etc can even it out, at least then you are starting from as true as possible.

Link to comment
Share on other sites

I see hub flanges warped from ill fitting wheels being overtightened. If the hub flange has run out then so has the disc. As stated above, a DTI on the disc and then on the flange will tell the tale. The hub flange can be trued uo in a lathe, but it's a bit of a PITA, i would recommend getting a new one if one or more have warped. Discs can be surface ground back to true.

Link to comment
Share on other sites

Another thing that can cause front brake judder is tired inner wishbone bushes or a tired bottom ball joint. Mainly the former.

 

Im replacing my front upper and lower wishbones because I'm struggling with high speed vibration and brake vibration. Even after replacing the discs, brake pedal vibrations happened with new discs and a loud knock when braking hard.

Link to comment
Share on other sites

Check the caliper pistons are retracting after a hard brake application with the engine running to give servo assist, with the front wheels off the ground. If the wheels do not rotate very freely due to brake bind the pistons are not free enough for the deliberately shaped seal recesses in the caliper bores to retract the pistons from the pads a few thousandths of an inch. This will cause uneven piston pressures on the disc which in turn causes "strange things" to occur. The seal grooves DO NOT have a flat bottom, the bottom of the grooves are chamfered at an angle to deform the seals in brake application and their hysteresis should retract the pistons a tad when the brakes are released. Get someone to watch the front tyres and wheels within the front arches when you hit the brakes hard at a fast walking pace. If they move back more than a bit in the arches the wishbone bushes are shot, and any brake imbalance or slight (and normal...) frictional changes between pads and discs will start an oscillation (judder) at certain speeds. Older BMW's were notorious for this due to bush wear.

Edited by Chris Wilson
Typos, senility (see edit history)
Link to comment
Share on other sites

Check the caliper pistons are retracting after a hard brake application with the engine running to give servo assist. If the wheels do not rotate very freely due to brake bind the pistons are noty free enough for the deliberately shaped seal recesses in the caliper bores to retract the pistons from the pads a few thousandths of an inch. this will cause uneven piston pressures on the disc which in turn causes "strange things" to occur. The seal grooves DO NOT have a flat bottom, the bottom of the grooves are chamfered at an angle to deform the seals in brake application and their hysteresis should retract the pistons a tad when the brakes are released. get someone to with the front tyres and wheels within the front arches when you hit the brakes hard at a fast walking pace. if they move back more than a bit in the arches the wishbone bushes are shot, any brake imbalance or slight (and normal...) frictional changes between pads and discs will start an oscillation at certain speeds. Older BMW's were notorious for this due to bush wear.

 

I'll give that a go thanks chris

Link to comment
Share on other sites

Get the discs skimmed on the car using 1 of these,https://brakelathe.co.uk/ if you search on their site it will show garages local to you that can do it, problem with new discs is that once you put a few heat cycles through them the discs harden , i get mine machined after a couple of trackdays then they don`t warp again.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.