Warped disc feeling under braking that isnt warped discs?

[VinceFox]

I get an intermittent wobble under braking that's really annoying. I replaced my discs a while back and tbh it's been there pretty much the whole time since, on and off.

What else can cause this?

[Apache]

knackered bushes or ball joints?

[VinceFox]

How do i isolate/ test these?

It's an e36 evo btw.

[Apache]

Best take it to your friendly local spannerman and he'll check all the wobbly bits, shouldn't be expensive

[VinceFox]

Added wrinkle to the diagnosis, the nsf wheel is at 28 psi, osf is at 34.

If one is that much lower than the other, would a symptom be wobbling under braking?

[Apache]

Best take it to your friendly local spannerman and he'll check all the wobbly bits, shouldn't be expensive

[VinceFox]

Up on ramps job, you think?

I love the car but little things like this don't half sour the taste of owning it. Non specific, vague symptoms are a pita.

[Apache]

VinceFox said:

Up on ramps job, you think?

I love the car but little things like this don't half sour the taste of owning it. Non specific, vague symptoms are a pita.

Yup

They are standard wear items, Ebay has all the stuff you'll need at pretty low prices

[VinceFox]

Cheers Apache, think i'll have to bite the bullet and book it in somewhere.

[Gruber]

Could be all sorts:

Control arm / brake reaction bushes? (whatever they're called on an e36)
A wheel bearing on its way out? (this is what caused the recent wobble under braking on my M5)
Top mounts
Shocks on their way out
Etc etc etc

As above, best to get it to someone who can get it in the air and have a good look under / around it.

[nottyash]

Balancing?

[ecain63]

That feeling is normally due to the disc being worn out. The tolerance between OK and dead are very fine. M-discs are very hard to warp. When worn too far the discs will expand unevenly, giving that warped or buckled feel.

[VinceFox]

Balancing and tracking have been done and rechecked and discs were brand new 18 months ago. I do very low mileage in it.

[ecain63]

Are the pads seated correctly? Also, take the wheels off and clean the hubs.

[VinceFox]

ecain63 said:

Are the pads seated correctly? Also, take the wheels off and clean the hubs.

I've got a bit of time next week so i'll be checking those myself first, but i suspect it'll still need to go up.

[stevesingo]

Brake pad transfer! The pads work by transferring material to the disc under high loads (temps). This aids friction.

So, you get the brakes nice and hot, come to a stop and hold your foot on the brake. The point where the pad is held against the disc by the foot brake receives a large amount of pad transfer and therefore, when ever you brake, this high friction point grabs more than the rest of the disc surface. And, because it grabs more than the rest surface, it generates more heat and therefore more pad transfer.

It won't show up on measuring equipment as this is occurring at a molecular level.

Get the discs skimmed and it will be fixed.

Steve

[benm3evo]

Hi.
I have the same problem on my car.
I have had the disks & pads out & gave them a good rub down (by hand) but this made no difference at all so put it down to the disks being on their way out, although they aren't worn too much thickness wise.
I was going to buy new disks & pads thinking this would be the solution but now I'm not so sure!
Cheers, Ben.

[VinceFox]

Ben, is your brake wobble intermittent or there all the time?

[benm3evo]

Hi, sorry I took a while to reply....

It's only when the brakes are hot. I.e. during hard braking from a high speed it will shake the wheel quite a bit. If I then drive 'normally' for a while, letting them cool down I guess, with light braking it will be ok.

I can do a normaly journey through town etc & you would never know there's anything wrong.

Cheers, Ben

[RVVUNM]

I had this problem on my 911, turned out to be the EBC red stuff brake pads. Put a set of standard pads on and sorted it.