how to clean a master cylinder.

[beef]

this is a how to clean a master cylinder.

firstly protect the bike with a rag, in case of spillage.

empty the M/C. I use a syringe.

then remove the banjo bolt, note the washers.

the undo the handle bar clamp and carefully remove from the bike.

now this is where things will vary, get yourself the correct haynes manual for your bike and follow the instructions.

now remove the brake lever. mine had a nut underneath. red arrow.

and one on top, red arrow

next step for me was to remove the top half of the M/C.

undo the two screws, arrowed with the green arrows.

this took some pulling and a little gentle prying but it did come off.

now its time to remove the slide assembly.

remove the rubber dust cover/ boot. mine wasnt there as it had rotted,

if you are not replacing the parts carefully remove it, if you are replacing the parts then just grip it with some pliers and pull it out ensuring that you get the wire ring that is at the bottom of it.

remove the circlip, red arrows show the ends, for this you will need some long nosed circlip pliers.

then with a little pull of the end of the assembly it should come out

[beef]

there is another rubber cap over the end ot the spring

to get this out i put a long allen key in the far end of the slide and gently tap it until the cap pops out. watch out for the spring.

and as you can see its all a little bit crusty and rotten.

now you can clean these parts, i use brake cleaner and a tooth brush and a rag. give it a good spray and brush and wipe.

i also cleaned inside the M/C and the slide husing. note the holes at the bottom of the M/C. dont stick a nail or pin or what ever in there. use the straw that goes with the cleaner to blast the crap out of there. along with the tooth brush.

and yes i noticed the spring was the wrong way around. thats why i take step by step photo's. it went back in the right way though.

now you can re assemble the slider. dip the parts in a little clean brake fluid prior to reinstalling them.

put them back in the right order and then as you put the circlip on you will need to push the bits in as the spring will push them back out.

then put the top half of the master cylinder on and then put it back on the bike and then bleed the brakes..

[Speedshop]

Nice write up. For safety critical systems such as brakes, the seals etc should be replaced as a matter of course - particularly when they look like those - all the sealing lips are worn. I'd check that spring too the metal pad often goes up against the rubber seal, it could be different on your bike which is why the parts book is useful - to check if someone else put it back together wrong - so you don't copy their mistake. Most bike parts books are on line at CMSL

[beef]

to be honest i have not refitted this master cylinder. i have fitted a brand new unit i got of ebay. but the rebuild kit is £18 delivered, it contains all the bits needed to replace the internals. this master cylinder was off my cx500. and i needed a new brake light switch, couldnt find the one i need and found the replacement cylinder for £20 delivered.

[Preload]

If you can get use of one, drop it in an ultrasonic bath for an hour and watch the sh*t come off then wire brush and paint job done.

[Speedshop]

I found out by accident that the plasticote 'project' paint in blue arsehole cans you can buy in places like B&Q is actually completely brake fluid resistant! They even do a heat proof one (sold for bbqs). I use the satin black for brake parts. let it dry and harden off for a day or two then its not affected by brake fluid.

It seems that you can get the old fashioned planet killer paint that actually protects and stays on the thing you want to paint - so long as its not sold for automotive use, hence this stuff is sold as hobby paint I guess.

[Preload]

Thats right I used it on my brake housing as well and its not effectived by brake fluid.