BLEEDING CLUTCH GG 280 TXT

[arden]

HELP. USED VACUM METHOD HELD 25 INCHES COULD NOT DRAIN MASTER CYCLINDER

TRIED PUMPING FROM THE BOTTOM UP..NO RESULT. ANY SUGGESTIONS

[lemur]

Adjust, repair or unplug the master cylinder so it lets fluid up into the reservoir when the pads are pushed apart, no flow back means you have a problem.

[RonH]

It could be also that you need to adjust the screw on the lever that presses on the master cylinder piston. If the piston is not in the correct position, when pressed or opened, it effectively blocks fluid flow and won’t drain and it won’t allow fluid to flow from the bottom up either. Screw it out a turn and try again. Turn the screw, little by little, until you can pump fluid.

Another possibility is that one of the ports inside the cylinder could be blocked by debris. Use a very fine sewing needle to clear it out.

Edited Monday at 01:50 AM by RonH

[arden]

On 7/6/2025 at 4:44 PM, lemur said:

Adjust, repair or unplug the master cylinder so it lets fluid up into the reservoir when the pads are pushed apart, no flow back means you have a problem.

THANKS FOR RESPONDING, ILL GIVE IT A SHOT

CANNOT FIND ANYBODY IN B'HAM THAT WILL LOOK AT A 2001

[arden]

On 7/7/2025 at 4:25 PM, RonH said:

It could be also that you need to adjust the screw on the lever that presses on the master cylinder piston. If the piston is not in the correct position, when pressed or opened, it effectively blocks fluid flow and won’t drain and it won’t allow fluid to flow from the bottom up either. Screw it out a turn and try again. Turn the screw, little by little, until you can pump fluid.

THANKS FOR RESPONDING, IT IS HARD TO BLEED W/MY HARBOR FT PUMP WHICH MAKES SENSE IF THE PLUNGER IS NOT ADJUSED RITE

[lineaway]

Let"s back up a little bit. Did you have the clutch apart?

[lemur]

I posted how to push fluid back up into a brake reservoir, but the clutch hydraulics are virtually identical with the clutch piston being synonymous to the pistons on the brakes, it's all just simple hydraulics with the biggest difference being it uses DOT fluid or it uses Mineral Oil.  There are very few high spots in a clutch hydraulic system where air can be trapped, so bleeding a trials bike clutch is Not generally a significantly difficult task unless you encounter a mechanical problem such as deteriorated rubber bits at either end of the system.  

Add: parts diagrams show your clutch master to be an AJP model that uses DOT fluid and not Mineral Oil, for a shop to not want to service an AJP clutch they must be a little bit clueless or simply don't want your business, the same parts were commonly used on additional bike makes and models.  The Slave cylinder and piston is unique for your bike but the 2 o-rings inside it are nothing special, the rubber o-rings simply need to be compatible with the hydraulic fluids you are using and you can source appropriate o-rings from anywhere that sells o-rings and or hydraulic service supplies.