cb 500 brake caliper problem

M

Mowillie

Been Around the Block
i think i posted this issue that i am having in the wrong section...first i put it in the brake section...go figure...ill try it here!
i am trying to clean up an old 72 cb500 and keeping the front end (ie shocks, wheel, fender, brake, etc.) stock. the brake is frozen and i am trying to get the pads off and the piston out, clean it up and replace the pads. how the hell do you get the pads out. looks like some kind of hollow pin or something holding it in on the top....piston side. my shop book doesnt specify. thanks for any advice... i will post pics of the bike shortly.
 
If its like a cb750 caliper (I think its pretty much the same) that hollow pin is a roll pin and just keeps the puck in place. You should be able to just pull it out by hand. It must be jammed with dirt. Since your going to clean out the caliper just pump the piston and the puck out at the same time. Or maybe not.
 
ya, the rolled pin you see is just to stop the pad rotating. it doesn't hold it in at all. the non-piston side pad is held in with a little cotter pin. if the pads aren't coming out it's cuz of years of gunky neglect and rust because (other than the cotter pin) nothing holds them in... so it sounds like they're gooped in there somehow. the piston can also freeze over time. there's a number of threads on getting the piston out, most of them involving hooking up the brake master and pumping fluid into it until it pops out, or other people have also forced it out using a grease gun attached to the bleed nipple. remembering to block off the line in hole obvy. good luck!
 
thanks for the insight...i got the non piston side out with out a problem. the piston side was more of a challenge. i put the disassembled unit into my wood workers vice and slowing compressed the piston, pad and all, just to see movement. i had previously lubed it with deep creep. then with the bleeder valve in and tight i held the piston side down into a 5 gal. bucket with old towels and used my air compressor blower into the inlet where the rigid fluid line goes in and blew. after several attempts...it shot out. not something that you want to watch happen, or you could have the mark of the piston on your head. i cleaned it up and got it back together...i will try bleeding it down in the next few days...after i replace the tire. thanks for the input.
 
i am having the same issues with my CB500 i popped out the piston and pad with no problem... just pumped it till it popped out the piston... i cleaned it all really well and put it back together... same brake drag as before! sucks... i ordered a rebuild kit so we will see what happens after that... my master cylinder is new... i bet it may be my brake line
 
hey now! please do tell... are you talking about under the seal? cool i will do that, what about this pivot you speak of? clearance to 6,000? Pj you have any more info or where i can snag some pics of what you are speaking? my new gasket kit for it should be here today and i want to knock it out real fast... for cleaning the corrosion do you sugest just sand paper? i cleaned up the pads really well (they where corroded on the back but the actuall pad looks brand new) i want to try and salvage them, but they stop me so if they are trash i will replace them. thanks man!
 
I agree.
You must take the seal out and clean the grove out with picks and toothbrush. After time and moisture that old fluid starts to brak down and turn into a browinsh grainy goo. When it get under your piston seal the stuff cant get out so it pushes your seal tighter than what it should be against your caliper piston. Wouldnt be a bad idea to use a brake hone with some 1500 grit wet dry under the stones. If your doing it by hand use very fine wet dry sandpaper with water and only sand enough to make it feel right. It doesnt have to look like chrome.
 
PJ that was awesome! thank you man... ill have this sucker rocking tongiht! i am sure it is the pivot that is my problem... ill keep you posted... thank you for explaing that to me... ha ha ha sad to say on CB's i have always used a piece of printer paper or consruction paper to gap my pads :( shhhhhh i know i know
thanks again that was a HUGE help! hell the way it is going she may be riding this weekend!
 
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