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Slow Slave Cylinder


Bionic Balls

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I went for a particularly muddy and wet ride on sunday and my bike turned into a big brown cake. Of course, my brakes went terrible....

Cleaned the mud off and regreased some bearings but my rear brake (magura hs33) moves really slowly and is almost always on (because the slave comes out but doesn't move back!

I've tried putting bike spray all over the piston, and i've rebled it, but the slave is still really slow. I've taken the slaves off and filled them with bikespray to try and loosen them up a bit....but when i pull the piston out with pliers it is still really stiff and moves back pretty slowly.

I've been running it on water and its been fine for about a year....the brake is about 3 years old in total- is it knackered? I wondered if i can actually take the piston out to give it a right good cleaning up? Can i do that? how?

any other ideas?

cheers,

adam

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thanks for the replies......"Re-bleeding dosn't do anything. (Or it shouldnt). Have no TPA, and set the brakes up again."

that doesn't help- TPA or not...pistons move (in) real slowly.

hopefully when i get home tonight the bike spray will have worked some magic...it's been in it since this morning.

adam

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Quick guide - this never fails when done correctly.

Attach a bleed pipe to the slave cylinder, and put the pipe into the presta fitment of a track pump, or an air line. Remove bleed screw from the lever.

This bit can get messy, go slow at first, and then use a rag to catch all the flying fluid/water: blast air through the system to clean it all out nicely.

When this is done, put a couple of drops of chain lube on the seals in your lever, pull it a few times to work the lube around, and then wipe off the excess.

Turn all TPA off.

Re-bleed with water/water-antifreeze mix.

When its all bled correctly, put the TPA fully on and depress the lever (elastic band (Y)" ).

Push one of the slave pistons in by hand, and put a few drops of lube on the other one (WD40 also works ok). Then repeat for the other cylinder. Take the TPA off, remove elastic band, and pull the lever a few times to work the lube in. Wipe off the excess.

If all done correctly, this will have your brake feeling better than new (Y)

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Thanks for the guide adam....i've already tried most of that (connected a pump and rebled + lubed pistons....the problem is the pistons.

if i depress the lever, it is really hard to push one piston in if i wanted to get the other piston right out... (Y) they are just really stiff.

the pump thing is fun!

adam

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Thanks for the guide adam....i've already tried most of that (connected a pump and rebled + lubed pistons....the problem is the pistons.

if i depress the lever, it is really hard to push one piston in if i wanted to get the other piston right out... :)  they are just really stiff.

the pump thing is fun!

adam

You think using a pump is fun? Try using an air compressor on it, and pulsing the trigger on it (Y) Probably not vry healthy for it thouh (Y)

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sorry but hey??? water in magura?????? water is less dens than oil isnt it? does it work??? (Y)

Some people say it works better. I think its a bit odd. But its suposed to feel different, and it dosn't cost anything! (Y)

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Water is alot better than standard Magura Blood. Stiffer and much easier to pull. Seems to return quicker too. Make sure if you ever use it use deionised water from most car type shops. Or if your clever like me get it out of your tumble drier.

Edited by Trials Punk
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Agreed.

Re-bleeding dosn't do anything. (Or it shouldnt). Have no TPA, and set the brakes up again.

(Y)  (Y)

Mine did.

Although I gave mine a proper good blow down with the Airline. made it work all time 'cos I always had to re-bleed it every day or so 'cos it kept going back to how it was before.

corish

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