Help with Brake Judder

[cmcm789]

Discs were changed on the front at about 115k miles for the first time, pads renewed also. Within 5k miles there was constant and very obvious judder under any sort of braking. Mechanic had discs replaced at next service (10k miles). I now have about 7k miles since then and the brake judder has come back as bad. Now under any sort of heavy braking the whole steering wheel shakes its that bad.

I will be phoning the mechanic this week, but is there any common reason why this would happen? I have read that the hub should be cleaned to make sure the new discs are aligned.

My normal journey is a 70mile round trip to work on decent roads with only light braking, so i don't think brake dust build up at this stage is a problem.

Thanks

[Volvomeg]

What make of discs and pads are they as i've never had a problem with my bosch discs warping even when totally cooked and smoldering

[PropWarp]

Have you had the new brake pads & disks put on and within 400 miles come off a motorway and sat with your foot on the brakes for a long time whilst the brakes have been toasty warm???

[stig1]

might be cheapo disks i put oem on mine and been fine and had a very hard time

[David 8]

I had this with a set of TPS supplied discs, they wouldn't warranty them either !!

Put pagids on and no problem since

[PropWarp]

Yea if the garage is using the awesome Eicher brand that sound German but are forged in India and are super super cheap then that will also be the source of the issue.

Remember you buy cheap you buy twice

[cmcm789]

Mechanic usually uses OEM for all parts. He returned the last ones as warranty to the supplier, but i don't want to just do the same thing again and have the same issue.

[cmcm789]

Have you had the new brake pads & disks put on and within 400 miles come off a motorway and sat with your foot on the brakes for a long time whilst the brakes have been toasty warm???

Not that i recall, although i never went through any "running in" driving, should i? and it's strange that both sets of discs have developed same fault at same miles?

[PropWarp]

Yea defo you should always run them in in the first 200 & 400 miles. Its matures the metal and hardens the structure of the metal through constant heating and cooling. It eventually forges to be much stronger. However if you have not done the run in then at high temps the metal will be soft (so to speak) and your pad sitting on the disk with lots of heat and lots of pressure will pit the disk. or if you dab the brakes suddenly and very very hard that will also cause them to pit so under normal braking you shall feel the juddering.

Its on odd feeling , its like the brake is rapidly applying on and off very very quickly and giving the effect of a judder..

[cmcm789]

Yea defo you should always run them in in the first 200 & 400 miles. Its matures the metal and hardens the structure of the metal through constant heating and cooling. It eventually forges to be much stronger. However if you have not done the run in then at high temps the metal will be soft (so to speak) and your pad sitting on the disk with lots of heat and lots of pressure will pit the disk. or if you dab the brakes suddenly and very very hard that will also cause them to pit so under normal braking you shall feel the juddering.

Its on odd feeling , its like the brake is rapidly applying on and off very very quickly and giving the effect of a judder..

That's exactly how mine feels. Feedback through the pedal is almost like ABS kicking in and the steering wheel feedback/ shake when braking hard is getting very annoying.

[vRSsunroof]

Bed them in.....

also get your mechanic to check the hubs.

[PropWarp]

Best course of action at this stage is to change the pads and disks again but drive like a priest and be gentle on your brakes. use your handbrake even in stop start. Only for 400 miles, I know it sounds a lot but it will pass very quickly.

Some may say just change the disks but its better to change both so that pads and disks mate to each other. Keep the brands the same and never go budget on them, remember they are your brakes and will have to save you one day, so bedding them in is absolute. So when you do slam the anchors on at speed and the heat is awesome then they will stop you well

[vRSsunroof]

i agree with propwarp, the octy i bought had warped discs, plenty of life in them but had to change them. i followed some of the guides online on the best bedding in proccess and they have been spot on since.

[chrisevans]

Alternatively really hammer the brakes for 10 successive 80 to 30 mph decelerations (where safe) then drive round for 15 mins without applying the brakes(tricky I know). This has vastly improved mine(still noticeable at v slow speed). Have also read that light sanding with garnet paper can be effective at removing the deposits which are most likely to be causing this. Brake discs are VERY difficult to warp even under race conditions. Only use garnet paper as sand paper or wet and dry will cause more issues .

[PropWarp]

Ermmm when brakes are brand new and fresh out of the kiln warping is easier than you think.

If you brake, the disk is rotating thus equal pressure and heat is caused however when the car eventualy does stop and your foot it still placed on the brake and pressure is squeezing the disk it will pit. It really is near impossible to see the damage but all you need is a fraction just so the pitted section looses friction against the pad.

Brake disks can be skimmed to remove and resurface the disk but it costs as much as a new disk and its rare that people do it.

The successive method works to a degree, as you say you can still feel it under braking at low speeds. Best course of action however is to scrap the fitted brakes, run the news ones in correctly. For the few milliseconds the disk doesnt have traction against the pad that significantly reduces braking power and increased overall brake distance.

Pads and disks, like a fine wine have a maturity period and that is measure in distance I.E. 300 / 400 miles. They get better will age and mileage.

Ive managed to warp disks and boil fluid on a track (TVR Tuscan) and that was fitted with very large, vented HONEYWELL JURIDS that I can assure you arent cheap.

If I remember rightly the old Skyline used to overheat the disk, warp and then shatter......

Using Garnet paper is more used to isolate the squeel from pads, minor minor particles creating ultrasonic noise. Give it a go though, I could be proven wrong............. havent been wrong since 1997 ha