Rear brake failure on the road today..

[LCBIKEMAN]

Background: Dealer serviced rear brake, bleeding line while installing brake pads one week ago.
Fresh oil. R1100RT 2000, rides well. Rear brake fluid reservoir is full to max line.

Today's adventure: on the road for what would have been a great ride to W.VA. Bike running fine. Rear brake pads have about 140 miles on them and were doing fine.
Slowed on road using rear brake to find no stopping power at all on rear. About 1/4 mile later the rear brake seized (I was moving slowly) and the engine nearly stalled. At the side of the road, bike would not roll forward or back due to rear brake. About less than 10 mins later the rear wheel was free to roll, rode it to a parking spot, had breakfast, and called dealer. Tech suspected piston failure. Got it home using front brake only. That alone took a good amount of habit breaking.

Have Clymer manual and am willing to tackle something doable without special tools (have none). Have previously only done oil changes and battery change via left side of Tupperware et al. New battery PCM680 Odyssey is great and solved starting and ABS lights hiccoughs.

Thoughts on what the brake challenge might be and where to start in troubleshooting or repair are very welcome. I checked the MOA forum from a friend's phone while stopped and read of brake bleeding etc.

Thanks, ladies and gentlemen - it pains me to see the bike ailing in the driveway.
Larry in VA.

 

[bc1100s]

Couple questions:

1. Have you ever replaced your brake hoses? At 10 years, they would be way overdue.

2. I suspect you don't have linked brake system. Or do you?

Wild ass guesses on your problem:

1. Could be you have an internal separation of the brake hose which isn't allowing fluid to return thereby keeping brake on.
2. If you do have a seized caliper piston(s), make sure you're confident before tackling the job. After all - its your brakes! (not calling your competence into question, btw)

Others more knowledgeable will chime in soon.

Oh, and lastly, using your front brake in the absence of using the rear is not necessarily a bad habit to get into!

Best o' luck!

 

[happy wanderer]

There have been reports of failed rubber brake hoses on these bikes. The inner lining rots and bits break off or fold up in such a way as to block fluid flow. If you take a look at the caliper and pads and see nothing obviously wrong (like a missing pin or something)
Suggestions:
- stomp on the rear brake and lock it up
- suck up the fluid in the reservoir since you'll be replacing it anyway
- get lots of rags and paper towels and cover the areas below the front and rear brake line connectors
- loosen the front brake line connector to release line pressure (does fluid come out? does brake release?) If fluid comes out, good. If the break releases the problem might be the master cylinder. If not, still could be the hose or caliper.

If wheel still locked up:
- loosen rear brake line connector. If brake releases the line was holding back pressure and is probably blocked up. Replace it.
If not problem is likely the caliper. Loosen brake bleed screw to release and remove the caliper. Fix whatever is wrong. (sticking pistons or ???)

And go buy some Spiegler brake lines regardless. Your brake lines are most likely too old anyway if they are original.

 

[LCBIKEMAN]

thank you

Appreciate the information / your advice. Will get to wrenching and see what develops. Many thanks. I appreciate the comments on brake line replacement as well. On to price lines on the web.

 

[m_stock10506]

It's possible that when installing new pads, the dealer didn't remove excess brake fluid from the M/C. Too much fluid could have caused pressure on the calipers and pads causing them to rub and heat up which could have heated and expanded the fluid even more locking up the pads on the rotor. When the fluid cooled the pressure eased and you could roll the wheel. Just a guess.

+1 on partial collapse of the hose too. Replace it.

 

[LCBIKEMAN]

thanks

That was my thinking at the time as well, as the failure, then the lockup, then the release all happened within a fairly short time. Copy brake line renewal. Thank you!

 

[AntonLargiader]

It's possible that when installing new pads, the dealer didn't remove excess brake fluid from the M/C... .... Just a guess.

A pretty wild one, at that. That could be enough to cause some drag, but stopping the bike dead in its tracks against engine power would take more pressure than the reservoir can handle.

It's almost certainly a brake line or MC problem. Did anyone recently adjust the height of the brake pedal? If you do it wrong you get EXACTLY that outcome, and it can look like this:

http://www.largiader.com/shop/gallery/caliper.jpg

 

[kconant]

Buddy of mine had same thing happen on his 04 K1200rs.It was a failed rubber brake line.Replaced with Speiglers,problem solved.He had to have the dealer bleed the brakes because of it being an integrated system.
I put Speigler lines on my 01 1150 GS after blowing a line bleeding the rears.I dealt directly with Speigler and got great service.

 

[henzilla]

Did anyone recently adjust the height of the brake pedal? If you do it wrong you get EXACTLY that outcome, and it can look like this:

http://www.largiader.com/shop/gallery/caliper.jpg

Was riding near a bud on his K 12RS on the freeway...he was pointing to the back of his bike as I saw smoke and a small flame... he had adjusted his pedal that morning...same result you pictured. Luckily we pulled over and put the fire out! He said it was needing a whole lot of throttle

 

[Bobmws]

Brake Pedal Adjustment

There are 2 adjustment points that need to be modified if you wish to change pedal height. The obvious one actually adjusts the height of the pedal where it contacts the brake switch. The one that causes the problem is the push rod that activates the master cylinder. Changing only the pedal height will cause the MC piston to move, applying brake pressure to the rear caliper.

 

[BMW Triumphant]

Thank you for this info

There are 2 adjustment points that need to be modified if you wish to change pedal height. The obvious one actually adjusts the height of the pedal where it contacts the brake switch. The one that causes the problem is the push rod that activates the master cylinder. Changing only the pedal height will cause the MC piston to move, applying brake pressure to the rear caliper.

I believe this adjustment is needed if peg lowering blocks are installed. This is something i have been considering.

I have now been given fair warning!

Is there a procedure for this adjustment? Such as: loosen both, adjust height, adjust push rod? Can you feel when the push rod is in place, or watch for caliper movement or something else?

 

[Bobmws]

I believe this adjustment is needed if peg lowering blocks are installed. This is something i have been considering.

I have now been given fair warning!

Is there a procedure for this adjustment? Such as: loosen both, adjust height, adjust push rod? Can you feel when the push rod is in place, or watch for caliper movement or something else?

It's been quite a few years since I adjusted mine, but I believe you can feel/see there is some freeplay in the MC pushrod when the pedal is at the top of it's travel in the stock position. I believe I adjusted/lowered the pedal and than adjusted the pushrod to get the same freeplay. Knowing this it will be more recognizable when you are looking at the unit.

 

[LCBIKEMAN]

the continuing saga

trouble-shooting this morning was my first opportunity since the failure last weekend.
1. pedal has not been adjusted but thanks for the idea to check it
2. I thought the MC may have been overfilled and removed some fluid from the reservoir to just above midpoint on min/max.
3. wheel on center stand was able to easily and freely rotate.
4. no abs lights when riding after 3mph
5. brake light only on when brake pedal/lever applied

Still have zero braking from rear brake. ABSII brakes. I cannot feel that the rear brake is being applied while riding and using the front brake lever.

I read about small stones sometimes getting into the rear brake mechanism and will check that out next.

appreciate the ideas. I'm about ready to get it to the dealer who last did the new pads/bleed/etc. Thanks, Larry

 

[m_stock10506]

trouble-shooting this morning was my first opportunity since the failure last weekend.
Still have zero braking from rear brake. ABSII brakes. I cannot feel that the rear brake is being applied while riding and using the front brake lever.

You have an R1100RT with an ABS-II system. The front and rear brake lines are separate and only operate each system separately - they are not linked.

 

[LCBIKEMAN]

Resolution and thanks

To all: Failed rubber brake line in rear was the culprit. Brake lines replaced with stainless from Bobs BMW in Jessup, MD (I"m not associated with them in any way other than satisfied customer). Problems solved with brakes.
86 degree day in early May in Northern Virginia....anyone have a spare room in a cooler climate for July/August?
Thanks for all the advice and your correct diagnoses.
Safe riding.