2 replies to this topic

[scraggydog64]

Hello all,

I apologise in advance because brake bleeding has been discussed to death on the forums.

My lad rode my 4RT the other week and burnt the back brake out. Don't know how. The disc was warped and the cylinder seals were melted. New disc, seals and copper washers were fitted. I've bled a few brakes in my time and thought I had the knack. Pays not to be cocky because I have been on night after night trying to get this one bled.

Did AJP design the rear caliper to trap air? Why is accessing the fluid reservoir like keyhole surgery? I think I am getting bitter.

Anyway, I have constantly bled the thing. I remove the rear brake lever and use an allan key to get enough stroke on the cylinder to push the fluid through. I have tried back bleeding, I have tried bleeding with the caliper at all different positions to displace any air but still no joy.

When I removed dust cover from the cylinder and there was a very slight trace of fluid beside the circlip.

My question is do you think its possible to damage the cylinder seals using an allan key to pump the brakes when bleeding? After all it was damage to the caliper that caused the problem.

Any advice would be welcome. If you lot can't help I am on the phone to the Samaritans. Will they have anyone who knows how to fix brakes?

Thanks in advance, Scragg

[thedishes]

scraggydog64, on Nov 9 2009, 08:48 PM, said:

Hello all,

I apologise in advance because brake bleeding has been discussed to death on the forums.

My lad rode my 4RT the other week and burnt the back brake out. Don't know how. The disc was warped and the cylinder seals were melted. New disc, seals and copper washers were fitted. I've bled a few brakes in my time and thought I had the knack. Pays not to be cocky because I have been on night after night trying to get this one bled.

Did AJP design the rear caliper to trap air? Why is accessing the fluid reservoir like keyhole surgery? I think I am getting bitter.

Anyway, I have constantly bled the thing. I remove the rear brake lever and use an allan key to get enough stroke on the cylinder to push the fluid through. I have tried back bleeding, I have tried bleeding with the caliper at all different positions to displace any air but still no joy.

When I removed dust cover from the cylinder and there was a very slight trace of fluid beside the circlip.

My question is do you think its possible to damage the cylinder seals using an allan key to pump the brakes when bleeding? After all it was damage to the caliper that caused the problem.

Any advice would be welcome. If you lot can't help I am on the phone to the Samaritans. Will they have anyone who knows how to fix brakes?

Thanks in advance, Scragg

bleed it at the banjo bolt on master cylinder first where the rear brake hose joins cylinder. have found air always gets trapped there, then bleed out the rest of the system as normal. hope that helps

[GII]

They're a complete pain

I gave up on the normal methods, like you I've done plenty of GasGas Sherco and Beta rear brakes and thought I was reasonably competent but the Mont can be in a different league, made worse by the inaccessible reservoir.

I do mine using a pressure bleeder but the aforementioned reservoir can make it messy.