Topic: 1972 CB500F Master Cylinder?!

[GUSter920]

Hey everyone this is my first post and i need a little help. i just bought a 72 cb500 and the master cylinder is frozen. i have been searching the web but havent found a rebuilt kit for this year and model. are the ones for a 72 cb750 that same? also would i be able to use any master cylinder? i read a post on here that said any one would work. im not looking to completely restore the bike i want to make it a cafe racer. any help would be greatly appreciated.

[Chachi]

A rebuild didn't work for mine so I replaced with one from Northeast Vintage Cycle on Ebay:
http://www.ebay.com/itm/Honda-CB450-CB500-CB550-CB750-CB750F-Front-Master-Cylinder-Assy-NIB-/360437939034?pt=Motorcycles_Parts_Accessories&hash=item53ebc67b5a&vxp=mtr

It looks to be the same as the one available from David Silver spares:
http://www.davidsilverspares.co.uk/CB500K1-FOUR-1972/part_123893/

[GUSter920]

i pulled apart the whole front brake and found out that the caliper is frozen and the master cylinder is actually free. how come the rebuild didn't work? are there any tricks to free up the caliper? i soaked it with liquid wrench hoping maybe that may help. also could someone recommend some good websites to get parts.

[bandit1]

Just rebuilt mine today with an OEM kit from classic cycle depot off ebay.  The thing was nasty and leaking, reason for the rebuild.  So far looks like it's working.  I believe I read somewhere here that a grease gun could be used to free a stuck caliper piston, just fill till it pops would be my guess.

[GUSter920]

thanks for the info. i looked up the grease gun method and my question is do i need to use a pneumatic gun or and i use just a regular gun?

[krusty]

This topic was covered elsewhere but I can't remember where I found it. It works a treat. Use an ordinary shop grease gun (you should have one as part of your servicing kit), remove the end nozzle, wrap the thread with some plumbers tape and gently screw it into the hole where the brake line fits in. A few gentle pumps and the piston eases out.

[GUSter920]

thanks for the info. good news i did in fact get the pad and piston out using the grease method but the bad news is that the previous owner must have beat on the thing and cracked the aluminum casing where the piston seats. it doesn't look safe at all and i want to get a new or rebuilt caliper. does anyone know where to get one or is anyone selling one?