Z4M Front disc wear

tomscott · Post by **tomscott** » Mon Sep 18, 2023 12:33 am

Hi guys,

I need a bit of advice.

When I bought the car 4 years ago there was a vibration through the steering wheel. On my old Mcoupe I had the same issue and found it to be warped discs. No need to panic, I had the discs replaced on the MR all sorted.

I have done 12k miles since that time and most of my driving is unfortunately motorways I have only really been out hooning a dozen or so times. So they aren’t getting much hammer at all.

I went down to Beaulieu for Simply BMW this weekend and did 535 miles and I noticed I again have a small vibration through the steering wheel under breaking. It’s by no means bad but it’s there and it’s annoying.

I thought surely can’t be warped discs again! I decided to check the paperwork for the car and its first set of front discs was 42k second set was 12k later at 54k and then myself when I bought the car again at 66k and the car has just rolled over 77k

The only common denominator is both sets of discs are ATE. I thought BMW used ATE anyway?

I don’t know if this is coincidence but is the car running through these at a bit of a rate? Or am I worrying unnecessarily? I’m just wondering whether I need to get the brake system looked at not just replace again because it seems premature considering a front disc and pad kit is in the £600 range.

I pulled over at the service 200 miles in and both discs were hot to touch which I would expect anyway.

If it was a sticky calliper the vibration would be much worse and not just braking as I’ve experienced this before too. If it was a wheel weight the vibration would be worse as the speed increased? All is well there.

Anyone any ideas or is 12k about right for the discs.
I had a quick look at the E46 M4 forums and I read a thread where the synopsis is - if you’re tracking they go through quicker but most were quoting depending on driving 20-30k.

Cheers

Tom

plenty · Post by **plenty** » Mon Sep 18, 2023 1:14 am

I had a vibration under braking from 60 mph that was a sticky caliper.

flimper · Post by **flimper** » Mon Sep 18, 2023 11:18 am

I can't be having 12k as right for the discs, I'm no Ayrton Senna at all but I just replaced my first set at 67k

pvr · Post by **pvr** » Mon Sep 18, 2023 11:31 am

How many pad sets on the discs? Usually I expect 2 sets of pads versus 1 disc replacement.

Interestingly enough, TVR drove my old M that Bing is borrowing a couple of weeks ago, and the same is the case on that one.

Ed Doe · Post by **Ed Doe** » Mon Sep 18, 2023 12:25 pm

Tom, have you tried to use them hard for several applications - ie almost like a pad bedding in procedure - to get them roasting hot and clear any crap off the disc faces? Often that resolves it.

For info I had second hand z4m discs on my old 3.0si with performance calipers and I did 10k miles easily and several trackdays and had zero wobbliness/vibration on the road under normal use. I did however often find that the first few laps of a trackday the brakes were a bit wobbly or grumbly as the shite from light road use burned off the disc faces with some 'proper' use!

tomscott · Post by **tomscott** » Mon Sep 18, 2023 1:12 pm

Thanks for the replies everyone!

I had the pads done at the same time as the discs, guessing if the pads were low the wear sensor would throw and error?

I have done a couple of emergency stops to see if that helps, maybe they do need a good run out! Its just such a horrible feeling the wobble through the steering wheel.

Glad its not just me 12k, well 11 in this case, seems very low for a set of discs.

pvr · Post by **pvr** » Mon Sep 18, 2023 1:19 pm

I followed this procedure:

https://www.zeckhausen.com/catalog/inde ... =6446_6443

Post by **srhutch** » Mon Sep 18, 2023 1:54 pm

flimper wrote: ↑Mon Sep 18, 2023 11:18 am I can't be having 12k as right for the discs, I'm no Ayrton Senna at all but I just replaced my first set at 67k

I've just replaced mine all round at 54K, pretty sure they were original.

Mr Tidy · Post by **Mr Tidy** » Mon Sep 18, 2023 8:29 pm

I tend to be pretty gentle on brakes (my 1 Series got past 80K miles on the original pads and discs) and I had a similar problem with my 330i a couple of years ago.

Like Ed suggested using them hard a few times sorted things out.

Although I have done 12K in my MC now I've never had that issue, probably because I use the brakes harder as it is usually travelling much faster.

I certainly hope to get many more miles out of them as I can't see any scoring or lipping on them.

-Tom- · Post by **-Tom-** » Mon Sep 18, 2023 8:47 pm

Yes Tom, no way should that mileage be a factor with this. Any visible rust build up or pad deposit from harsh stops and suddenly letting off the brakes?

Otherwise I’d be leaning towards sticking calliper. That can come and go, I had it on mine.

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