New MR Owner / Brakes Question

G

GNH

Member
Hi this is my first post after a few months of “lurking and learning” both pre and post purchase. Firstly thanks to everyone for posting such a mine of useful information and experiences on this excellent forum, it certainly helps to be in the know when you’re contemplating splashing the cash or justifying to the OH

Anyhow six weeks into ownership these are just my first impressions and one question which I’d like some informed opinion on please.

My new baby is a Sept 06 registered Z4M Roadster with just 15000 miles on it. The spec is nothing special, (eg no nav or cruise) but it was the colour combo, (Sapphire Black / Imola Red interior) mileage and condition I was after.

First impressions are interesting especially when referenced against some of the recurring “shortcomings” that have been flagged up on this forum. If you think the ride is harsh and the gearbox is a swine you should try tooling around in a 20 year old Ferrari on old tyre technology and no second gear until the gearbox oil is warm. If you think “kangaroo” starts are confined to this motor, I’ve just put 100k miles on a Merc C200K manual in 3 years and man, does that take some getting away smoothly.

So big ticks for performance, (sport button is a hoot but I wonder if its novelty value will fade), noise (still getting used to not having the engine right behind my earhole though), creamy power delivery, and a surprisingly civilised composed ride / handling balance..

Which brings me to my question. The only gripe I have is a small but persistent vibration through the steering wheel (but not the brake pedal) under braking. I’ve done numerous searches on this and other forums. If I look at the discs I can’t see any brake pad deposits or imprints, neither can I detect any uneven rotation either visually or by the sound of the pad chafing on the disc. I’ve used a brake cleaner all round. Of course I can’t see the reverse side of the discs without removing them. Has anyone had this problem and cured it, and if so how? I’d really rather not just bang new discs on if I don’t have to (£600 quote from my local dealer). No BMW warranty so no chance of discs being covered there, gotta sort it myself. Any help gratefully accepted.

Anyway what a great car, even made my bro-in law squeal like a girl the other day!

Oh by the way no pics right now cos I can't be messing around with Photobucket/Flickr/bla bla bla...might try some later. Anyway you must know what black with red looks like by now :)
 
Have you had the tracking done? Also check bushings.

The brakes are rumbly though, especially when warmed up - i think a certain amount of grumble is a case of "they all do that sir" (although someone might correct me).
 
No vibration for me either.

If you have to go down the new discs route, the OEM items can be had for £343.63 delivered from bmminiparts which is a bit more palatable than your BMW quote :o
 
Thanks guys for replies.

It's just been MOT's so I'd hope bushes are in OK nick but I could get a geometry check done.

The brakes don't really rumble or squeal audibly just the vibration, which itself is by no means horrendous (at the mo)

Dealer price of £600 was fitted inc VAT including new pads, consumables etc. Discs supply only were £165 each + VAT. bmwminiparts plus Indy may be the way if I have to do it.

Ok and I give in here are few pics taken at the dealer before I picked it up as I managed to get them on Photobucket. Hope this works!

bmw-z4-convertible-petrol_2442001-1.jpg

bmw-z4-convertible-petrol_2442011-1.jpg

bmw-z4-convertible-petrol_2442007.jpg

bmw-z4-convertible-petrol_24420091.jpg
 
dgm said:
No vibration for me either.

If you have to go down the new discs route, the OEM items can be had for £343.63 delivered from bmminiparts which is a bit more palatable than your BMW quote :o
Click to expand...

343 for all four? Because i just priced a set of front and rear disks on http://www.bmminiparts.com and it came out at 460 without shipping....
 
Just looking at bmminiparts website the price with VAT and lowest carriage option for two front discs is £325ish, whereas main dealer price is £396 with VAT and you have to collect, so it's not a bad saving. Of course I'm hoping for a fix that doesn't involve changing them but if worst comes to the worst.........
 
I had all 4 discs changed on my SLK, the rears were worst and you steering hardly juddered when braking, just the pedal. Would it be worth you taking the front discs off and pads out for cleaning?
 
Having just replaced my suspension at 22k I can tell you my FCAB were both completely shot. The front end shimmy on braking has gone away after replacement...I would check these first
 
Hi congratulation's on the purchase z4m :D
I too get vibration from braking and currently on my 4th set of brake disc's
(all replaced by BMW under warranty) in only 16000 miles
I think the problem is the brake pads glazing the disc's with something
If they aren't used hard enough!

If u check my first post,it will tell u a I have a leaflet from BMW advising heavier braking
If u find a solution then let me know ( my change my pads yet)
Otherwise a fantastic car !!!!!!!!!!
 
congrats on a great car, same colour combo as mine. all we need is a bit of consistent sunshine for topdown driving and listen to the engine.
 
Budgie 195 thanks for your comments which led me to some new posts on here which I hadn't found when I searched before.

Looks like I'm not alone, whether the problem is pad deposits or warped discs. It's not that I have any reason to mistrust my local main dealer but I'm sure they'd prefer to sell me new discs than fanny around all day investigating the problem and possibly selling me just some new pads.

I think I'll probably get a BMW Indy or brake specialist to put a dial guage on them and take a look myself when he does it so I know I'm not being BS'd. Other than that it looks worth changing pads and doing some of that bedding in stuff to see if I can get rid of deposits. I'd actually be happier if I could see my discs were covered in marks, crud or rust; then I'd have a clue.

I find it a bit disturbing if the only way to avoid the problem is to hoon around and brake quite heavily, we all have to use town centres roundabouts and junctions in heavy traffic at some point and we all have people driving close behind us. It almost seems as if the brakes struggle to cope with it. The pad deposit theory does play up to a pet hate of mine though, people who just sit stationary with their foot planted on the brake for ages' maybe I can just smugly say to myself "You're only wrecking your brakes you know"
 
My car lives in London and is well versed in town driving, no vibration under braking here so definitely something awry somewhere...I should add I don't hoon everywhere just to ensure this. My car is on 37k and as far as I'm aware the discs are original...slightly grooved now though!
 
If there's been a pad deposition problem in the past that hasn't been cleared with some heavy braking you can get uneven wear on the disc that gives the same effect even though the pad deposition has long worn away.

Dial test indicator which show that though, as it will warped discs.
 
GNH said:
Budgie 195 thanks for your comments which led me to some new posts on here which I hadn't found when I searched before.

Looks like I'm not alone, whether the problem is pad deposits or warped discs. It's not that I have any reason to mistrust my local main dealer but I'm sure they'd prefer to sell me new discs than fanny around all day investigating the problem and possibly selling me just some new pads.

I think I'll probably get a BMW Indy or brake specialist to put a dial guage on them and take a look myself when he does it so I know I'm not being BS'd. Other than that it looks worth changing pads and doing some of that bedding in stuff to see if I can get rid of deposits. I'd actually be happier if I could see my discs were covered in marks, crud or rust; then I'd have a clue.

I find it a bit disturbing if the only way to avoid the problem is to hoon around and brake quite heavily, we all have to use town centres roundabouts and junctions in heavy traffic at some point and we all have people driving close behind us. It almost seems as if the brakes struggle to cope with it. The pad deposit theory does play up to a pet hate of mine though, people who just sit stationary with their foot planted on the brake for ages' maybe I can just smugly say to myself "You're only wrecking your brakes you know"
Click to expand...

Hello GNH. Lovely car, very smart 8)

Pilchardthecat has a good point. I've had similar problems with other fast beemers. My advice is to go by a process of elimination:
Before you go to the expense of new disks etc its well worth going to a specialist and get the tracking done. This is where I like BMW dealerships as they have the exact spec depending on your wheel size / model year combo.

Once I had this done, it cleared it and I can't tell you the relief, especially after having seen all the forums talking about the potential cause being every suspension component (arm, bearings, calipers, pads, disks, bushes...)

Also the ridiculously fat M rim has a fairly communicative and will have sometimes vibrations depending on the surface and break pressure. Sometimes nothing. So long as you don't get any "tugging" as such, you should be in the clear.

Bonne chance. :thumbsup:
 
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