Urgent help needed... warping brake discs

Discuss Suspension, Brakes, Wheels and Tyres
Post Reply
Erika GTi
New
Posts: 9
Joined: Sat May 20, 2006 7:24 pm
Location: The sunny South East!!

Urgent help needed... warping brake discs

Post by Erika GTi »

May as well start from the beginning... my polo gti had new discs and pads fitted shortly before i bought it as the old ones were warped. A few months after i bought it i noticed the steering shuddering when i braked and it turned out that the discs had warped. The garage put it down to my heavy foot and i got them replaced.
Here's where the problem sarted. A few months after getting the discs replaced i notice a judder in the steering again. It only seems to happen when driving over 50mph and is smooth as silk under 40mph. Garage checked it out and the discs aren't warped yet. They couldn't find anything wrong with the braking system but said that the judder could be what's causing the discs to warp so quickly cause let's face it... who drives under 40mph all the time. I have had a couple of guys look at the car including my local VW dealer and no one can find anything wrong. Has anyone had or heard of anyone else with similar problems? if so, i would love to hear from you. This has me climbing the walls :cry: [/list]
ModifiedMadness
Sponsor
Posts: 6769
Joined: Tue Jun 14, 2005 8:38 pm
Location: Bedford Drives: MK5 Golf R32

Post by ModifiedMadness »

May sound silly but have you had the tracking checked?
Erika GTi
New
Posts: 9
Joined: Sat May 20, 2006 7:24 pm
Location: The sunny South East!!

Post by Erika GTi »

Yeah, tracking... camber... wheels balanced etc. Checked everything i can think of. Completely out of ideas...
This is the 3rd set on the car since i bought it less than two years ago. I'm completely out of ideas and the mechanics who have looked at the car are baffled.
Rob123
Getting There!
Posts: 51
Joined: Mon Apr 10, 2006 12:25 pm
Location: South Machester Drives: Po-slow mk6

Post by Rob123 »

if they say you get the juddering even thought the brakes arent warped this obv. doesnt apply to you, but the main cause for warped brakes it people not using the handbrake and sitting at a standstill with their foot on the brakes, especially when you have braked hard and the brakes are very hot, the pressure causes them to be crushed by the pads and they come out of shape. thought i'd just ge that in there, :lol: :lol:

could be unbalanced wheels, just get everything checked, could be problem with a wishbone or a top mount, anything really! probably a bit extreme and unlikely, but ti may have been in a crash and have a twisted chasis or something, i only say this because its a new car to you and you may not know its history.
warrmr
Silver Member
Posts: 335
Joined: Thu Aug 11, 2005 10:02 pm

Post by warrmr »

Rob123 wrote:if they say you get the juddering even thought the brakes arent warped this obv. doesnt apply to you, but the main cause for warped brakes it people not using the handbrake and sitting at a standstill with their foot on the brakes, especially when you have braked hard and the brakes are very hot, the pressure causes them to be crushed by the pads and they come out of shape. thought i'd just ge that in there, :lol: :lol:

could be unbalanced wheels, just get everything checked, could be problem with a wishbone or a top mount, anything really! probably a bit extreme and unlikely, but ti may have been in a crash and have a twisted chasis or something, i only say this because its a new car to you and you may not know its history.

i dont like to be pedantic but thats not 100% true.

ok a brief how brakes work tutorial.

when brakes bed in ( new disks and pads) the brake pad rubs off a small layer of pad material onto the disk and it fuses to the disk and makes the disk "sticky" so now when you brake you have 2 surfaces coated with the same matiral meaning you will have efficiant braking. ok there is the how they work


this is a track situation ( not as extrame as on teh street but principal is the same)
you have had a ragging session and you have come into the pit lanes for a cool down and something to eat your brakes are glowing so you stop in the pits and wack your handbrake on your pads hit the rotor and start cooling down through dissapation hot rotor hits cooler pads and transfers heat to caliper and brake fluid and anything it can get to. meanwhile the pad material is fuseing to the layer of pad material on the disk.

so you now release the brakes and goto move off they release but leave a pad imprint on the disks causing a high spot on the perfectly balenced rotor. so now your braking again and you feel a pulsing sensation similar to warped rotors. but its the pads hitting the high spots and moving trying to erode the high spot down to level with the rest of the disk but it wont work as it builds higher with each application of the brake as it removes more pad material.

moral of the story in pit stops leave the car in gear engine off handbrake off.

at traffic lights put handbrake on and take foot off brake. ( rear drums/disks stay cooler thus meaning you can have them engaged and not leave an imprint.

( i wish i had have taken a photo of my rear disks before i had them resurfaced you would have seen a pad high spot.
ccjjGTI
New
Posts: 37
Joined: Wed Jul 19, 2006 3:39 pm

Post by ccjjGTI »

Erika, I have the exact same problem you are having. Replaced the discs and pads with EBC in Jan, fine for a while then the judder comes back. Bled the whole system and replaced with new fluid after rebuilding both front calipers, still judders! In my gti, if I do an emergency stop the ABS kicks in on the front right and at the same time the car pulls to the right. This says to me that the right calliper is applying more force to the disc .. OR the left calliper is not applying as much force to the disc as I believe the warp/fault is on the front left. Hopefully makes sense! I live in a house of motorsport engineering students and its got us baffled too.

Did you manage to find out what it was? Would appreciate any help, I may drive it into the scrappy next time I see one! :shock:
Bryony84
Sponsor
Posts: 1049
Joined: Sat Sep 30, 2006 3:37 pm
Location: Portsmouth
Contact:

Post by Bryony84 »

I have a juddering problem too, however it only started when I changed my wheels. I've had the new wheels balanced, but its still there. Hopefully I'm getting it checked out later this week to see if the garage can work out what it is.
Erika GTi
New
Posts: 9
Joined: Sat May 20, 2006 7:24 pm
Location: The sunny South East!!

Post by Erika GTi »

Hi guys... I'm afraid I can't help. I was advised my local stealers to change the calipers, carriers, hubs and barings on both sides at the front but this was going to cost me the bones of €2k :roll: I gave up in the end and sold the car on. I hated passing the problem on to someone else but i was left with no choice... i just couldn't afford to keep throwing money at it. Hope you have more luck than i did
User avatar
Josh_PoloGTi
Site Admin
Posts: 2782
Joined: Wed Oct 09, 2002 8:32 pm
Drives: BMW E85 Z4 3.0i
Location: Sheffield, UK
Contact:

Post by Josh_PoloGTi »

Damn

I only just saw this thread.

If this happens to anyone else (ie discs warping very quickly after fitting <2 months etc), then get your hub runout checked, and have your hubs replaced if necessary.

It happened to me on my old MK4 years ago, and it's recently happened to someone on the Skoda forum too.
User avatar
J+silva
Bronze Member
Posts: 110
Joined: Fri Aug 09, 2019 5:53 pm
Drives: polo conf.
Location: Lisboa

Re: Urgent help needed... warping brake discs

Post by J+silva »

It happened to me in December 2023, I changed the rims and tires of my polo, everything was calibrated and the steering was aligned, in February of this year the car only trembles when braking after 60/70km, I changed pads and discs, all new, in April now it started shaking again braking, from 60/70km onwards, below that speed it doesn't seem to shake, I don't know what could be
Post Reply