rear brake locked up - '96R1100RS

[Dewey]

I hope someone can shed some light on this. I have a 96 R1100RS that's been locking up the rear brake. The ABS has been bypassed a long time ago. It builds up so much pressure in the system that the rear brake pedal feels solid. There's no give whatsoever. Once it cools down, it frees up again. I need to know if this sounds like the caliper or the master cylinder. I don't understand why that pressure doesn't bleed back into the reservoir. HELP!!!!!

 

 

[dirtrider]

Morning Dewey

 

No way to really tell from this far away but your lock-up problem has all the ear marks of a mis-adjusted rear master cylinder push rod.

 

(IF), the rear master cylinder piston can't return ALL the way out then it blocks the fluid return port so any brake heating expands the brake fluid & prevents brake release.

 

So, at least start at the rear master cylinder push rod adjustment.

 

If nothing found with that then look into seized rear caliper pins, or an inner rear brake hose delamination causing a sort of fluid check valve.

[Jim Moore]

Are the hoses original? If so, I'd start there.

[Dewey]

Rear brake line is 6 months old.

 

@dirtrider, I will check that. That makes sense to me.

[dirtrider]

Afternoon Dewey

 

One other thing to check-- If you (or someone) has removed the rear wheel spacer & you installed new rear brake pads then the rear brake rotor might be too far to the right & causing a brake pad drag. (only happens on some bikes, not all)

 

If you suspect this just install a used brake pad to give more clearance.