Front brake problems - HELP !!!

[Animal]

Hi Guys.


The front brakes on my 12,000m GSa were sticking far too much for my liking, but I assumed they just needed a clean after a winter of (mis)use, so left it to the 12k service.

At the service, the callipers were cleaned thouroughly. No change.

The bike has since been back to the dealer 3 times, and the following has been tried:

Full strip and rebuild of Callipers, incl new seals
New Master Cyl
Alternative Front Wheel
Alternative Front Axle

However the brakes are still rubbing.

It's OK in normal use, but after an hour at 70(ahem) the front wheel will hardly move due to the discs getting very hot and expanding.



The dealer is stumped (but is gonna fit new lines next week) and so are BMW.
They're asking Q's about accident damage, but the bike has never been crashed, and has only been jumped/wheelied a few times, nothing major.



Any ideas ??

 

[Professional Boxer]

With the adventure you get evo brakes ( the caliper should have BMW on it) The brake pads corrode & stick in the caliper, try asking them to chamfer the backing of the pads ( the metal bit ) & to lubricate all the surfaces where the brake pads contact the caliper with Never-seez(TM) BM part no 83.23.9.407.830.

Works every time for us


Who ever we are!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Adrian B]

Warped discs ?

 

[Captain Beaky]

Could be a bent/twisted brake caliper mounting on the fork leg (Seen it before on a GSXR1000).

This fault can only be solved by replacing the fork bottoms.

Can be caused by leaving the disc lock on and trying to ride away.

 

[Squidbrain]

the front wheel will hardly move due to the discs getting very hot and expanding.

Animal

The pads are supposed to float on the discs, so in theory the discs can get as hot and expanded as they want without binding. Does the wheel spin freely with the bike on the centre stand with the brakes cold both before and after giving the lever a decent squeeze? If it does then the hydraulic system is unlikely to be at fault, if not, look no further Did the alternative wheel include alternative discs? If not it sounds as though Adrian B or Captain Beaky has the solution.

Good luck.

Mick

 

[Animal]

With a cold bike, the wheel will spin 1/2 a turn, max.
Pulling and releasing the brake makes no difference.

The callipers have been cleaned lubed and copper paste put on the back of the pads... which have also been replaced just in case.


I've haven't done the disk-lock thing (touch wood) - but then I use a U-Lock which won't even reach the callipers should I forget.



I've had warped disks on previous BMWs, and it's quite noticable when riding. As I've said, they've tried a new wheel anyway...

 

[Animal]

PS

The bike Hasn't got ABS.

 

[MikeO]

Does the wheel have a tight spot when cold? I've had 2 sets of replacement discs & pads on my bike (under warranty) in 20k miles as a result of warping. Strangely, the pads don't show undue wear .The dealer & I are both at a loss as to how it's happening.

I've just started noticing the tell-tale 'pulsing' feel from the rear brake again......


MikeO

 

[John Armstrong]

I had a Peugot 205 where the rubber looking flexible pipe that went to the caliper collapsed inwards. Feet on the brake managed to get pressure past the blockage and put the brakes on, but then the brakes wouldn't release properly. The wheel also got a "little" warm. Bleeding made no difference at all, of course if I'd tried to move the wheel after opening the bleed nipple I'd have saved myself a lot of agro.

BTW you couldn't tell from looking at the pipe that it had collapsed.

 

[Fanum]

Animal....I was reading the ADVRider forum and came across this posted by Guzzler.....could it be your problem too?

I would recommend looking at the brake pad retaining pin (the big pin that you have to push out to remove the pads). And making sure that it is smooth and that the pads do not get hung up on them.

I had my rear brake pads prematurely wear out because the pin was corroded. The pads were binding on the disc. You may have this happen, not sure.

I found a site once that explained that most Brembo brakes have an issue with this.

My new normal routine is when I change my oil, I take out the retaining pins, clean them up with a scotch bright pad and lube them.

the whole thread is here......

http://www.advrider.com/forums/showthread.php?s=&threadid=8609&highlight=brakes+binding

 

[Jimb]

Fanum

That is a very usefull link, I noticed in winter that the salt would bulid up and do exactly that even when it was religiously washed out there was still a buildup and only removing the pads and cleaning them stopped it, eventually I did it once a week and it stopped it.

 

[MikeO]

I wonder if replacing the pin with a stainless one would help?

MikeO

 

[Professional Boxer]

nowt to do with the pin try taking the brake pads out & i'm sure they will be seized in

 

[kcain]

How freely should the front wheel spin on an Adv when turned by hand with the bike on the centre stand? How many revolutions?
Thanks in advance.