Having a nightmare bleeding up rear brakes on an 1100 GS after swapping out a hose

[shaunclark]

Hi All,

As the title suggests I'm struggling big time with the bleeding up of the rear brakes on my 1100.

I've read various forum posts on brake bleeding on this and other forums and I've tried traditional pedal bleeding and also syringe backwards bleeding from the brake to the ABS nipple then from the ABS to the reserviour. I even tried unscrewing the bipe from the top of the master cylinder and bleeding that line up then refitting it!

It's worth me letting you know that if I disconnect the pipe at the top of the master cylinder/brake pedal then then put my finger over the hole and pump a few times then it does build pressure so I'm convinced the master cylinder is not faulty.

when I connect everything back I simply can not get any pressure at the peddle - it drops as low as possible to the floor and has nothing there!

All Help/advice is welcome... I'm willing to try anything as I need to get the bike in for re-test ASAP as it had failed MOT on the pipe which I replaced.

Thanks!
Shaun

 

[ThreeDawg]

Hmm, finger over the pipe might not be an accurate indicator of the state of the m/c. I had this with my front brake some time ago - only fixed with new seals.

 

[Mzokk]

Take off the boot on the rear master cylinder and if the washer/circlip is corroded its probably goosed. Had similar on my r1150gs recently. Couldn't find a seal kit for the 13mm FTE master cylinder on the 1150 and went for a good used master cylinder. Not sure if the 1100 has a brembo one (which refurb kits are avaliable for) or not. Good Luck.

 

[Two wheels good]

Performoto on ebay should have a master cyl to suit.
Otherwise the usual tricks. A block of wood to keep pistons fully retracted; hang the calipers upright overnight; cable tie the brake lever to apply brake overnight.

 

[(RIP) digger37]

Remember having same problem years ago with an 1100. Had the gearbox out for repair and once reinstalled and brake lines reconnected couldn't get any pressure. Ended up cracking open a tad all the joints in the system in turn and pressurising with a syringe. Wrap a cloth round the open joints while you do it.

 

[squibb34]

Weird how this happens so often when messing with an old braking system; I guess crap in the MC ports or a failing seal. Hopefully a replacement or rebuild will solve the problem.

 

[Nick591]

Only to highlight that the problem is likely not with the bleeding procedures. I fitted a new Goodrich rear hose on my 1100 over a year ago and as far as I can recall I had no problems at all getting normal brake function using conventional bleeding from the caliper. It sounds like there may be a problem with the rear master cylinder.

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