Front Brakes Seized..

[spookytooth]

When I got my bike the front brakes came with it in a separate box. The guy I bought it from had no explanation as to why they had been removed... Now I found out.. When I installed them I cleaned them and put new pads on. Bled them for freaking ever... Now, brakes apply nicely but do not release. When I put c-clamps on the caliper pistons they won't go back unless I loosen the bleeder. I let them soak in penetrating oil overnight to no avail. Is there any magic fix for this or do I just need to get a different set? If I do need to replace them is there a source for aftermarket or do I just take my chances with eBay?

Thanks in advance fellas!

[Calzone]

You need to rebuild them or if you feel confident about a seller then buy known good used ones. They aren't that difficult to rebuild if you go that way, It`s a fine line for the piston to engage and release without leaking, it sounds like your Orings are slightly swelled so they stick.

[spookytooth]

Looks like two rebuild kits will run me about $90... I'm looking at a set from a reputable seller for $70 with shipping...

Decisions..

[Fred Camper]

Does not seem like the seals should cost that much. By polishing the pistons you will get some better return effort. The seals are not leaking, so maybe they are okay. Might just take one apart and see what you think.

[spookytooth]

That's the quoted price from Randakk... I may be able to get them cheaper elsewhere.

[plumbermullins]

seems to me that if you have to release the bleeder to compress the piston the problem is not the piston but the master cylinder is clogged at the relief hole. a friend had the same problem w/rear brakes not releasing found the mc clogged.
look for a very small hole closest to the outlet hose on the master cyl we used a small guitar string and then flushed the lines w/new fluid.
this happens when you compress the pistons without releasing the bleeder you force contaminated (small rubber particles and gelled fluid) back into the master cyl.
lesson learned the hard way.
good luck

[spookytooth]

seems to me that if you have to release the bleeder to compress the piston the problem is not the piston but the master cylinder is clogged at the relief hole. a friend had the same problem w/rear brakes not releasing found the mc clogged.
look for a very small hole closest to the outlet hose on the master cyl we used a small guitar string and then flushed the lines w/new fluid.
this happens when you compress the pistons without releasing the bleeder you force contaminated (small rubber particles and gelled fluid) back into the master cyl.
lesson learned the hard way.
good luck

Good info. It's a brand new master cylinder. I sure did bleed it a long time but I admit I reused some of the fluid...

[Placerville]

Plumbermullins is 100% correct. The little hole, sometimes called a 'relief' or 'spooge' hole is smaller in diameter then a pin and must be clear in order for your pads to return. It can be found under the reservoir. Clean it out with a very small wire. Below are a series of photos showing that hole being reviled in a '79 reservoir. It's the hole on the left. My advice would be to clean it out and bleed your breaks again. (Photo credit to Njbeacher at the NGW.)

[spookytooth]

So... I bought the set of calipers online AND replaced the master cylinder (the one I had wouldn't pump I think I ruined it by recycling fluid) and the brakes STILL won't release. I can put a c-clamp on them and push them back now but they will not release on their own. What am I doing wrong??

[Fred Camper]

Runout in the rotor retracts the pads, they do not get sucked back in on their own. You are just releasing the force, and the out of round rotor pushes them just far enough back. So have you rode the bike yet? If they drag heavy, let us know as that would suggest something is not right.

[spookytooth]

Runout in the rotor retracts the pads, they do not get sucked back in on their own. You are just releasing the force, and the out of round rotor pushes them just far enough back. So have you rode the bike yet? If they drag heavy, let us know as that would suggest something is not right.

Yes they drag heavy.

[Fred Camper]

So the pressure is not being released. Seems that it must be a master cylinder issue. We know you replaced it, but since you can push the pistons back in without too much effort the master cylinder seems most likely.

[Placerville]

So, it's back to square one. If they're dragging heavy, open the bleeder valve as you're turning the tire. If they release; it's your master cylinder.

[WingAdmin]

So, it's back to square one. If they're dragging heavy, open the bleeder valve as you're turning the tire. If they release; it's your master cylinder.

Correct. And if they don't, it's a bound up caliper.

[spookytooth]

Bound up caliper. Traded it out with another and it works fine. It was just the right one..