Rear Brake Seizure

[clivewhilde]

Rear brake seized on going through the Black Forest on holiday earlier this month. No rear wheel lock up or anything, just felt like I was losing power. I pushed the pads back and stopped using the rear brake for the rest of the trip.
I thought it might have been because it was over used from riding the Stelvio pass the day before but as I was ordering new pads and seals etc the nice man at Motorworks said it could be the servo/ABS unit
I've searched servoectomy threads for the last 45mins and all those problems seem to coincide with warning lights etc which I didn't have.

Is it time for a servoectomy I do I rebuild the caliper and wait for it to happen again?

2002 R1150GS with ABS (stupid question - does ABS automatically mean you have a servo?)

 

[NeilDD]

Rear brake seized on going through the Black Forest on holiday earlier this month. No rear wheel lock up or anything, just felt like I was losing power. I pushed the pads back and stopped using the rear brake for the rest of the trip.
I thought it might have been because it was over used from riding the Stelvio pass the day before but as I was ordering new pads and seals etc the nice man at Motorworks said it could be the servo/ABS unit
I've searched servoectomy threads for the last 45mins and all those problems seem to coincide with warning lights etc which I didn't have.

Is it time for a servoectomy I do I rebuild the caliper and wait for it to happen again?

2002 R1150GS with ABS (stupid question - does ABS automatically mean you have a servo?)

2002
Non Servo conventional ABS

HTH
Neil

 

[MattW]

I'd rebuild the caliper. I did mine last year - made a big difference.

If a normal sliding pin clean and lube etc doesn't do the trick (use red rubber grease on the caliper slide pins - not copperslip), be prepared to pop the pistons and change the piston seals too (after cleaning out the seal recesses). The seal groove can corrode underneath the seal causing the seal to squeeze too hard on the piston.

 

[Grizzly]

Free Play at Master Cylinder Rod??

Could be the master cylinder piston not getting fully back to the "rest" position - where it should uncover the bleed hole to the reservoir. If it's not uncovering this hole, then when the fluid expands as you use the brake and it heats up it cannot escape to the reservoir & will push the pads out & gradually apply the brake more & more - when everything cools down again the brake would free off again.
This could be caused by the pushrod at the mastercylinder being badly adjusted or the brake pedal stop being badly adjusted - or just loose & now in the wrong position.
Also a small stone etc jammed in somewhere around the brake pedal holding it down slightly so the bleed hole is covered would also cause the same problem - I had this many years ago on a Honda VF100FF - loss of power etc, stopped & found back disc smoking & brake on - eventually traced to small bit of road gravel lodged in pedal stop.
To check for any of above make sure you can bleed the brake - ie, can you pump fluid out of the bleed nipple & the reservoir level drops??

Cheers.......Grizzly

 

[taz]

Happend to me earlier this year the caliper and final drive rubbers were on fire when i stopped it was the master corroded around the pushrod under the rubber.

Dave.

 

[clivewhilde]

Thanks all, this should set me up for the weekend. At least nobody suggested removing the ABS!

 

[AndrewD]

Had similar on our trip to France with a K1100LT earlier this year, problem was not the caliper but the fluid was old and had moisture in it. Quick bleed with fresh fluid and all was well (I bloody hope so I'm off at 4am to Holland with him!).

Worth a try to diagnose, but your probably due a rebuild from the heat issues binding has caused....

 

[duckspeed]

Mine was the sliding pins mounting the caliper to the bracket. Motorworks sell a kit consisting of new pins, rubber dust covers and correct grease. made a huge difference to my bike and also saved fuel as a result

 

[clivewhilde]

New pistons as well? There was a baked crust on top of the pistons that was very brittle. Are the pistons lined with something? There are markings on the inside that look like they should be there....... circumferential rings.

 

[(RIP) Mark H]

Agree with the above suggestions to overhaul your rear brake caliper, the broken areas of the caliper pistons are a plug in each piston, I believe to stop squealing and minimise heat transfer from pad, don't forget to check you brake pipe as well, after 10 years they can disintegrate inside causing sticky brakes and difficulty bleeding see pic of mine, best not use pipe clamps to prevent fluid loss whilst removing caliper this can damage rubber pipe internally.

The damage you see to the plugs is often caused by levering the pistons back with a screwdriver or similar between the pad and piston.

If you order a caliper overhaul kit the plugs in the pistons come with the kit (At least they do from motobins, but do ask )

 

[clivewhilde]

Rear Caliper Pistons

No one makes rear caliper pistons for the 1150GS, not Motorworks, Motobins or BMW. BMW will charge you £300 for a new caliper.

So I rang the nice people at Wemoto, sent them my old pistons and they now make new ones. I also sent them my rear brake line and they had HEL make me up a new one to match. The charge - £23 including postage.

So if you need new pistons Wemoto have them but it sounds like they'll make stuff if they think there's a demand.

Just need some garage time now, the bike's only been in bits since the end of September!

 

[clivewhilde]

Rear Caliper Rubbing?

Can anyone see what I'm doing wrong?

R1150GS 02 with ABS. New rear disk and pads, new rear brake line, new seals and pistons.

As soon as I start to tighten the caliper bolts the rear wheel starts to lock up. I thought it was just that everything was at top tolerance so I started the bike and ran it in gear but ended up with little aluminium shavings. The front edge of the sliding aluminium arm seems to be interfering with the disk (see picture). Its almost like it needs the washers for the caliper bolts on the caliper side to space it out a bit. I've looked at the manual exploded view, can't figure out what's wrong unless it's something to do with the caliper being distorted from overheating (see beginning of thread).

 

[clivewhilde]

Please go to last post for latest problem.........

 

[aspiring]

never owned a bmw mate but i know thats wrong,dont ride the bike or even run it in gear again cos it will only cause more damage

 

[aspiring]

probably a daft question but are the new sliding pins the same length as the ones you took out? can you post a picture from a little further back and down the line of the disc? if you see what i mean

 

[AndrewD]

Hard to see but is the disk on backwards?

 

[clivewhilde]

The sliding pins haven't changed, they're the same as before and I had the same problem with the old disk, figured it was warped. The new disk is slightly better, at least the wheel turned a little bit. Thought that was it but no.......

 

[clivewhilde]

Hard to see but is the disk on backwards?

Even though it happened with the old disk I had removed it to check if it was straight....... You might be right! The recesses in the disk seemed to fit nicely over the lugs on the wheel. I'll turn it around and try it.

 

[*DAVE*]

This helped me last year with similar problems
Hope you find it of some use.