Txt Pro Rear Brake Will Not Hold Pressure

[mccarro]

I can get a brake by back bleeding with a syringe but after a few minutes it fades and I'm back to square one !

Curiously to get any pressure, I have to unbolt the m/cylinder and bleed with it as near to upside down as I can get it. Without doing so I get nothing at all.

I've tried a different m/cylinder but with the same result.

Could it be the seals in the caliper?

Any sugestions ?

Also as you can't get replacement seal kits the AJP m/cylinder what option are there for replacements ?

Thanks in advance for any help

[dadof2]

You don't say what age your bike is.

It could be the caliper seals. It is likely not the seals semselves but corrosion in their grooves. It has to be scraped out carefully then finally poished out with fine steel wool.

Is the few minutes you mention riding the bike - if so a bent disc could be pushing the pads too far back.

Can air get into the top of your rservoir - see if leaving the cap loose cures the problem

Master cylinder - make sure the free play has not been adjusted so that the feed hole is not being properly uncovered when pedal is released. It is possible the master cylinder piston is partially seizing due to sludge and corrosion and not returning fully when pedal is released.

Use a good brake fluid such as castrol motorcycle brake fluid, not a universal car type fluid.

Cheers

[mccarro]

It's a 2006

The pressure goes on the stand. I've had m/cylinder apart and it look fine

Thanks for reply - I'll try what u suggest tonight (loose cap)

[neilh]

is there any external leaks at all?

when u lose pedal pressure does the level drop in the reservoir?

[jse]

It's a 2006

The pressure goes on the stand. I've had m/cylinder apart and it look fine

Thanks for reply - I'll try what u suggest tonight (loose cap)

You really can't tell by looking at the o-ring and seal. M/C repair kits are still available

and theres a good chance that would fix your problem. If the o-ring on the plunger

is worn (easily done if the rubber boot is compromised) it will allow air to enter the

system, which will gravitate to the upper fitting area of the M/C. A large syringe

attached to the reservoir line will often flow enough fluid to move the bubble out of the

top of the M/C to the caliper (sometimes laying the bike on the left side will help).

Usually air leaks in the system fittings will show by fluid leaking out under pressure.

There is a temporary pressure depression in the system when the pedal is released,

which can draw air past the M/C o-ring (at the other end of the plunger rod that the

seal is attached to), which otherwise is not under pressure.

Jon

[scraggydog64]

I was on an age try to bleed the rear brake on my last Mont. I tried everything, syringes, caliper up in the air etc.. I had spent hours in the garage.

I was told to get an eezibleed kit from Halfords or similar, you have to get a spare cap for the fluid reservoir to drill or drill the original and fit the nipple supplied with the kit. The eezibleed uses air pressure from a tyre to push the fluid through the brake from the reservoir.

It took minutes to get the brake bled.

[mccarro]

"is there any external leaks at all?

when u lose pedal pressure does the level drop in the reservoir? "

No leaks thats I can detect and the level doesn't drop. I tried again last night with the cap off and the same result

It takes about 5 - 10 pushes on the brake pedal to go from solid resistance to nothing.

Does anyone know where to get AJP M/C kits in the UK ?

Cheers

[bmseven]

Not sure if its right 1

http://www.splatshop.co.uk/ajp-clutch-m-c-kit-small-cyl.html

[arnoux]

The Master cylinder kits are available again. We are in Australia and we have got bags and bags of the things, so I'm sure you will be able to find them locally.