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For my sins, I still ride a bike with 2002 Mini Master Cylinder kit -
I have recently noticed that the RHS lever has play in it - i can push it away from me when before i couldn't. This isn't the case with the LHS lever. The LHS lever has a stop point and then when its pulled towards me the brakes start to engage. My understanding is that i can move this bite point (reach?) by adjusting the Mini Adjuster screw. The end of the RHS lever is also further away from the bar than the LHS.
I removed the RHS lever by unscrewing the lever pivot screw (HBSP18) and locknut (HBSP19). Unscrewing the Mini adjuster screw (HBSP105) allows the lever blade to be removed. Everything looks to be intact behind the dust cover (HBSP102).
However, i can move the Mini adjuster screw (HBSP105) in and out quite a bit which probably accounts for the play i am seeing in the lever? I wasn't expecting to see this movement.
How is the Mini adjuster screw held in place to remove the play i am seeing? Or, what do i need to do to fix this? The brakes still work, but the free play in the lever annoys me!
Thanks
Bite point is different to reach. When did you last bleed the brake?
By mini adjustor screw do you mean the one that threads through the brass pivot? If so that is held in by the circlip and brass washer iirc.
I m guessing the piston is not returning fully. Its a fiddly rebuild but not that hard
Is that the piston in the Lever or the caliper that you think isnt returning fully?
Last year i changed the caliper pistons and the brake fluid but didnt touch the master cylinder other than for the oil.
lever piston - its the only reason I can think of for this
My best guess is that the piston spring hbsp110 has broken and the master cylinder is not returning. Remove the spring clip and dust seal from both levers and compare how far they return. The ball end of the adjuster screw should be pushed out until it stops against the bevelled brass washer.
It sounds like one of yours doesn't.
So the question becomes, "what is stopping it returning fully?"
It's either seal friction in the caliper, seal friction in the lever. Both of these would leave the brakes dragging. The third option is that the piston return spring has failed which is what this sounds like to me.
Have you disassembled the adjuster/actuator to rule out a blown retaining washer? You just need to remove the circlip where the bit you adjust enters the master cylinder, once you've done that the copper retaining washer and the ball end of the actuator can be pulled out. If your washer is blown then the lever will easily move beyond it's outer travel limit. Simple fix.
That's a good point. I've seen where a crash has caused the lever to pull the adjuster pin almost through the bevelled brass washer. That will cause the lever to have a floppy initial feel. If you're cunning, that brass washer can be changed without having to rebleed
I didnt want to disassemble until i had a better idea of what might be the culprit and what parts i would need.
Im going to go with squirrelkings suggestion first. Just need to get some parts in.
Onzadog : How cunning? "As cunning as a fox who's just been appointed Professor of Cunning at Oxford University?" Or is there a trick you can suggest?
Onzadog : How cunning? “As cunning as a fox who’s just been appointed Professor of Cunning at Oxford University?” Or is there a trick you can suggest?
I can’t really help beyond musing that you’re in the stickiest situation since Sticky the stick insect got stuck on a sticky bun!
So cunning you could pin a tail on it and call it a weasel.
Compress the master piston with the adjuster pin, lift the damaged washer with a pick. Hold the rod from underneath, replace washer, push the rod from the end again and replace the circlip.
Comparing the two sides should make it pretty clear of its the bore of the washer that's been blown out.