[AndyVR]

Tonight when driving home from work, I slowed up into some traffic after about 20 mins steady driving and noticed that the car wasn't rolling to a stop normally, it slowed more quickly than normal and wasn't rolling back on the slight incline. No noise could be heard so carried on another two miles slowly to my destination, it felt ok when driving at 30mph but still braking itself when down to about 5mph, I checked the handbrake - it felt normal.

I got out of the car and could smell overheated brakes - the offside rear brake disc was blue and pretty hot, as was the wheel. I went to collect my son which took about 5 minutes, I then got back in the car and drove away slowly, let off the accelerator, and the car rolled for ages as it normally would do, it seemed to have freed itself off. Drove a couple of miles home, still no dragging/binding.

What do you guys think? I suspect the caliper but seems odd for it to happen so suddenly, then be free again after just 5 minutes cooling? how common are seized calipers on these cars?

I should mention that the offending wheel has had a 17" space saver on it for the last week or so (due to a cracked alloy) could it be related somehow? not had any problems so far, and i'm only doing 50 mph max.

Also just before I noticed the binding, I had accelerated slightly off a roundabout in the wet, and the DSC or some other light flickered on the dash for a second, I assumed it was just because the spare tyre had lost grip slightly on the rough/wet surface.

I guess it could all be coincidence - but are there any causes of brake binding
other than seized calipers/stuck caliper sliders? like DSC/ABS unit faults?

It's a 2010 E91 on 78k miles (I think it had new pads in previous ownership at around 70k) I won't be driving it for the rest of the week now in case it happens again, and will have a look at it this weekend.

[ChawenHalo]

It should not happen if the brakes have been maintained regularly IMO. Some air in the system could cause it but its more likely the calliper seals. Have you checked the colour of your brake fluid? Bet its dark brown. However if you've been on a hard run using the brakes a lot or lots of DST/ ESP activated then just parked with the handbrake on then yes the callipers can stick. But we're talking just coming off a track day session here. I suspect something's a bit wrong. Coud be the rear pads were never changed.

[bishbosh]

I had a binding caliper last summer which overheated the disc, although it didn't warp it. The culprit was the piston seal in the caliper. Got a new one fitted and all was fine.

However upon checking I noticed that although the disc was OK the brake pads didn't stand up well to the heat and they were quite crumbly. Ended up swapping the disc and pad on that wheel. Didn't bother with the other side as the pads had only been replaced a couple of months before.

[AndyVR]

Originally Posted by ChawenHalo

It should not happen if the brakes have been maintained regularly IMO. Some air in the system could cause it but its more likely the calliper seals. Have you checked the colour of your brake fluid? Bet its dark brown. However if you've been on a hard run using the brakes a lot or lots of DST/ ESP activated then just parked with the handbrake on then yes the callipers can stick. But we're talking just coming off a track day session here. I suspect something's a bit wrong. Coud be the rear pads were never changed.

What is the prescribed 'regular maintenance' though? BMW would just say replace pads when worn, discs when worn, brake fluid every two years.

The brake fluid was replaced about 20 months ago so not overdue yet.
I don't think there is air in the system, I would feel that at the pedal.

Guess I need to start with checking the caliper slide pins, thinking back now I had a car once that wore down the inner pad to nothing because the slide pins were seized(rubber boots had split, pins rusted)

After that i'll check the caliper piston/seal, guess it's that age/mileage now where it could be seizing up.

[blueh88]

Check the complete suspension strut assembly out. If something has failed on that one strut, that could put the disc/hub section out of alignment and hence cause touching/sticking/binding or whatever.

[ChawenHalo]

Originally Posted by AndyVR

What is the prescribed 'regular maintenance' though? BMW would just say replace pads when worn, discs when worn, brake fluid every two years.

The brake fluid was replaced about 20 months ago so not overdue yet.
I don't think there is air in the system, I would feel that at the pedal.

Guess I need to start with checking the caliper slide pins, thinking back now I had a car once that wore down the inner pad to nothing because the slide pins were seized(rubber boots had split, pins rusted)

After that i'll check the caliper piston/seal, guess it's that age/mileage now where it could be seizing up.

You are correct in your description TBH. Just be aware that sometimes dealerships write on the service book they've done something while they have not (brake fluid on my wife's Z3 Coupe). Never had the fluid changed despite having a perfect service book.

Let us know.

[AndyVR]

I took the wheel off, something was binding as the disc would barely turn - loosened the caliper then pulled it towards me, the piston retracted easily enough so I could slide it away from the disc, then the disc turned freely.

I cleaned everything up, carriers were a bit dry and rusty where the pad sits/slides so used emery then re-assembled with a dab of copperslip on the contact points. Caliper slide pins in the rubber bushings were perfect so left alone. There was a twist in the flexi brake line so corrected that.

Put it all back together and that disc still gets warm on a slow drive, while all the rest are stone cold. So maybe the caliper is binding even though the piston pushed back easily. I have ordered a new caliper and will do a full brake fluid change.

[bishbosh]

Originally Posted by AndyVR

I took the wheel off, something was binding as the disc would barely turn - loosened the caliper then pulled it towards me, the piston retracted easily enough so I could slide it away from the disc, then the disc turned freely.

I cleaned everything up, carriers were a bit dry and rusty where the pad sits/slides so used emery then re-assembled with a dab of copperslip on the contact points. Caliper slide pins in the rubber bushings were perfect so left alone. There was a twist in the flexi brake line so corrected that.

Put it all back together and that disc still gets warm on a slow drive, while all the rest are stone cold. So maybe the caliper is binding even though the piston pushed back easily. I have ordered a new caliper and will do a full brake fluid change.

That's what happened to my caliper, although I retracted the piston it still stuck and overheated the disc. A new caliper fixed it.

[Big13]

Where did you get the caliper from also how much cheers

[bishbosh]

It was done at a garage in an emergency while on holiday so I don't know the exact price, maybe £80 or so, I expect that was the marked up price.

Try autodoc / onlinecarparts. They sell genuine stuff and cheaper than ecp.

[rasa bmw]

carparts forless,,around £100 when surcharge is redeemed,,around £20 to fit..although it may be dearer to fit depending where you get it done..but its only a 30 min job

[sirleeofroy]

Originally Posted by bishbosh

It was done at a garage in an emergency while on holiday so I don't know the exact price, maybe £80 or so, I expect that was the marked up price.

Try autodoc / onlinecarparts. They sell genuine stuff and cheaper than ecp.

+1

I've been buying most of my parts from Autodoc recently..... Their communications could do with a bit of improvement but all bar one item has been spot on and a good bit cheaper than anywhere else.

[rasa bmw]

Originally Posted by sirleeofroy

+1

I've been buying most of my parts from Autodoc recently..... Their communications could do with a bit of improvement but all bar one item has been spot on and a good bit cheaper than anywhere else.

are the calipers bmw original(refurbed)? the ones from cpfl and ecp are,,they are stamped as so..

[sirleeofroy]

Originally Posted by rasa bmw

are the calipers bmw original(refurbed)? the ones from cpfl and ecp are,,they are stamped as so..

I don't know about the calipers I'm afraid, I recently bought discs, pads, top and bottom strut/spring mounts for all four corners, DMF and some other misc service items.

[bishbosh]

It depends on who the oem manufacturer is, for example my front control arms are made by TRW. You can buy TRW arms from autodoc for a fraction of the price that bmw charge. In fact the arms are identical except for the BMW logo being ground off. This is because trw can't sell the part with the BMW logo to the end consumer.