Bleeding Rear Brake on RS driving me crazy!!!!

[Darryl Flynn]

I have now been trying to bleed the rear brake on my 1980 RS for 3 days and am getting absolutely NOWHERE

I have searched on this site and as a result have tried the methods mentioned still no luck.

If i use a large syringe and try to force fluid back through the system via the open bleed nipple all i get is an impossible amount of resistance and the pipe often starts to come off the syringe.

If i try to suck it through via the bleed nipple with the syringe it feels as if there is a vaccum.

The normal method of pumping the pedal whilst opening and closing the nipple with a tube into a jar of fluid ( always worked on other bikes for me ) does diddle squat.

I have swapped ALL parts with known good spares that i have in an attempt to sort this and am at a loss.

Any assistance would be greatly appreciated.

Darryl

[Major Softie]

If your rear brake lever is misadjusted, it could cause this problem by never getting the reservoir open to the line.

[Darryl Flynn]

Hi and thanks. The lever is attached correctly and certainly seems to be travelling throughout it's full throw as i can see the arm on the master cylinder being moved

[Kurt in S.A.]

IIRC, you need to remove the caliper to get the bleed nipple at the most top position.

Kurt in S.A.

[Darryl Flynn]

If your rear brake lever is misadjusted, it could cause this problem by never getting the reservoir open to the line.

Thanks my friend i think you are on the money !


I bought my RS after it had undregone a complete restoration ie engine out, frame stove enamelled and full respray.

That took place 10 years ago and the bike was never used on reassembly as the guy also owns 13 classic bikes .

Taking on board Major Softies opinion i went and checked the rear brake lever stop nut that sits against the brake light switch.

This was well extended and after screwing it fully in, the lever is sitting much higher and in cosequence the position of the piston in the master cylinder is different. As a result i can now easily push fluid from the syringe through the caliper bleed nipple into the resevoir.

I have done this twice now and have quite a decent pedal but have decided to wedge the brake lever down overnight and see if this gets the last of the air out.

Absolutely certain i can sort it now but was stumped so a VERY BIG THANKYOU Major Softie.

Cheers Darryl. If you lived closer i would buy you a Pint.

[Major Softie]

I'll have one anyway to celebrate the success of my diagnosis and your bleeding.

[Darryl Flynn]

Cheers

Darryl

[SteveD]

A small trick to get the bleed nipples at 12 o'clock on the rear caliper.
1. Disconnect the torque arm from the caliper.
2. Loosen the axle clamp nut at the end of the swing-arm brake side.
3. Caliper should now swing to where the nipple is highest.
4. Proceed with bleed.

[ME 109]

Jolly good show Major! Well considered.

[Major Softie]

I had one of these:




A fine little 9.4% local area brew (from Petaluma).