Problem Rear Brakes

[RockyDave]

After sorting out blown bulbs and re-painting wing mirror bases (amongst many other jobs ) I am after a bit of advice about my rear brakes...

When I bought the car in September it hadn't been used much in the preceding 6 months and although It had passed its MOT OK the brake discs, particularly the rears were pretty corroded. Prior to using the car regularly I had all the brakes apart and cleaned off the rust so all the calipers were "floating" freely, lubricating them using copper slip.
After a few miles the disc rotors on the front had cleaned up nicely but the rears were still looking pretty rusty.

So, do I persevere and hope the rear rotors will clean up when the car starts doing more miles in the summer or do I cut my losses and bin the original rotors and treat the Zed to new pads and discs? Or is it worth taking the disc rotors off and getting them skimmed?

Have a look at the pictures and tell me what you think...

[Del]

Hi Rockydave
The discs look in a bad state in my view, what is usually just a rusty outer edge seems to have spread inwards. They also look scored.

Edit - With regard to skimming, I've seen it done lightly to very expensive discs but Z3 rear discs are not that expensive - mine are under £30 each from carparts4less.co.uk.

[Zed Carer]

The rear brakes don't look that good!!!! It's not just doing more miles as the brakes are biased towards the front (as most cars are) therefore the rear brakes quite often do very little braking. It looks as if some after market pads have been fitted and they look to be much smaller than OEM judging by the gap between the swept area and the outer edge of the disc- normally the pads come to within a couple of mm of the edge of the disc.

As above the discs are not an expensive item particularly as Eurocarparts are currently doing 25% discount on brakes. There is a good write up in the Knowledgbase that many of us have used when changing brakes.

[Mr Silver]

I have to say that those brakes are in a seriously bad condition. I would suggest that if you were unlucky enough to be involved in an accident that you may find the insurance company dodging a payout with brakes in such poor condition. It appears that the calipers have been seized for some time causing the pad surfaces to become degraded which has allowed the discs to rust into the state they are now. I would be surprised if the rear brakes are working at all.

You are probably aware that the hand brake hub is inside the disc and that may be more expense.

Discs and pads are relatively cheap but a pair of calipers will set you back some - but you have to sort this!


Regards

[Rafolian]

Don't know about rear calipers, but new front ones from 40 quid!

[Brian H]

I refreshed my rear brakes a while back and they looked pretty similar, problem was the caliper was not applying equal pressure across the disc. As others have said it is cheap enough to replace discs and pads but I would also address the calipers otherwise you will be in the same position a little further down the road.

[TitanTim]

The discs are cheap to buy, its the calipers that can be a pain, I've had calipers refurbed before not on a Z3 and somehow they just seem to gum up again a seize after 6 months, but it might be worth getting the calipers professionally refurbed or source a pair of refurbed ones, I think the E46 calipers (3 Series are the same but worth checking). You will get a shock if you buy the calipers from BMW . I had my front brakes done by BMW last year as one of the calipers seized and it was a tad eye watering

34.11.6.761.242 Front brake pad set 32 @ £67.50
34.35.1.181.338 Front pad sensor @ £11.68
34.11.1.165.559 Brake caliper @ £210.84
34.11.1.165.560 Brake caliper @ £210.84
34.11.6.757.750 Front brake disc set @ £46.25
Bleeding ABS brake system with ASC+T @ £10.00

When I checked out of interest how much the rear calipers are they're about the same cost as the fronts

Tim.

[Mike Fishwick]

Rusty discs are not a problem as after all they are only made of cast iron and your discs are only slightly rusted anyway.

Even new discs will corode if the car is not used much, and like scoring it is not a problem - just use the car properly, and stop finding things to spend money on! If the calipers are able to move freely, and the pads are in good condition things will look after themselves, and even if an MoT tester issues an advisory they are only looking to take money off the ignorant.

My rears became very ridged/grooved a few years ago, but after a change of pads from Pagid to EBC they wore themselves flat again.

PS - could we please agree to call a brake disc a 'disc' and not a 'rotor,' which is a nonsense . . . we do not talk about 'Rotor brakes.'

[roadvoyager1]

Just a comment on language.
Brake Rotor is American English for Brake Disc, much like fender = wing, hood = bonnet, rocker box = sill etc. We remain two nation divided by a common language and long may it remain that way. Wave the flag by all means and lets accept that "Johnny foreigner" has his own funny habits (including strange spellings), but lets try to keep true to our own version of the language (whatever that may be) when posting on the forum. It all adds colour (or color for our friends in the US) to our ramblings.

[bertiejaffa]

maybe we need a translation thread on the knowledge forum

[Mr Silver]

** Rusty discs are not a problem...**

Did you actually take the trouble to look at the pics the OP provided above??

The brakes on this vehicle are not functioning properly period - nothing to do with rusty discs. Any experienced engineer can diagnose the problems with these brakes from the photos easily. Only a fool would continue to use a vehicle in this condition and only a bigger fool would advise otherwise.

When safety is an issue is is essential that the professionals on a forum advise correctly for obvious reasons. I find comments like 'Find something else to waste your money on' when a poster has asked for help with the problem that exists here is of no value whatsoever! Was it ever taken into consideration that the vehicle is capable of well over 100mph when this banal comment was made or was it of far more importance to berate a poster for use of 'your' English?

I sometimes despair of the stupidity of grown men.


I'm done


Regards

[Rafolian]

While we are on the subject of disc's/rotors, can we also refrain from curb (as in my wheels are curbed) as this is also American for KERB. In "English" English curb means restrain and nothing to do with footpath edgings!

[Koolflyer]

This forum is normally full of really useful help for us with genuine questions, but I have to say reading certain replies on this post are far from helpful, and I'd consider somewhat offensive too! The original OP clearly has a problem with the rear brakes not working as they should, therefore all he appears to be wanting is to correct the problem. None my BMW's have ever looked like that, and if they did I would want it sorted. Perhaps there are those who are quite happy to press on and accept things which are not working correctly, and who are more concerned about lesser things.
I'm quite sure the majority of people on this forum are more interested in the mechanics and well being of their cherished 'Zed's', rather than worrying about what the 'Corrective Police' think and what berating they are going to get in public!

Lets get back to the original post and the real issue....... frustrating

[gookah]

rear discs here for £20 each:

eBay link


From Euro Car Parts and free postage, It is worth changing them and pads now that the callipers are done.
Disc edges as rusty as that would tend to wear down the pads first before they would repair the disc.
Getting them turned down would just reduce the thickness needing earlier replacement when the money would be better put towards new ones.

[TitanTim]

There are rusty discs then rusty discs Brand new discs will oxidise when they come into contact with water which is only very light surface rust which will disappear with braking. However coroded dics are more likely to be pitted which will be an MOT failure and grooved or scored discs will be an MOT advisory to get them replaced. For what they cost simply replace them, I don't see the point really in skimming them etc.

Realised were only discussing the discs lol when rotors were mentioned I was guessing the calipers

Tim.