my back brake was seazing on so stripped it out, freed the pistons and found the piston in the master cylinder stuck, I freed it off but i noticed there was no spring behind the piston in the master cylinder and corrspndingly it doesnt return when you press the brake, is this correct?

bikes a JTX250 97

Doesn't sound right most master cylinders have a spring behind the piston.

Doesn't sound right most master cylinders have a spring behind the piston.

That's my experience also. The piston return spring is designed to push the piston assembly back to its stop

at the circlip in order to uncover the bleed hole to the reservoir and allow the system to equalize pressure.

Sometimes, in older systems, water will rust the spring to the point where it breaks, but you should have

found the spring parts. The rear hydraulic system is "closed" and usually does not ingest air above the bladder

which is why the reservoir should be filled about 2/3rds full at max.

You will need to carefully check the M/C bore for any pits or scratches. If any are present, I'd replace the M/C.

Edited May 12, 201016 yr by JSE

cheers guys I thought there should be a spring soI'll have another look tomorrow night, am I right in thinking the master cylinder off the TXT is the same?

cheers guys I thought there should be a spring soI'll have another look tomorrow night, am I right in thinking the master cylinder off the TXT is the same?

I might be wrong, but as I remember, the TXT and Pro are different as the TXT takes #R350004 rebuild kit and the Pro takes #BT280222220.

Jon

Doh!

there is a spring, just hidden right in the bottom, no service kit available for this according to GasGas Uk managed to free the piston off and get it moving but it sticks deep on the bore despite much skidin it in and out (oo-err missus!) so think it will have to be a new one.

I was also told this week that no piston / seal kit available anymore.

Saving grace is that I as also told that 'pro' type replacement cylinder unit bolts straight on and is cheaper than TXT type.

I refering to 2001 TXT 200 - no idea what frame is like on yours