after bleeding, brake won't return???

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

Hi eveyone, I'm new here, got a '83 xs 650 from my brother for 100$. Was sitting for a few years, so I got all the fluids replaced/checked, new battery, Bendix gear (yet to be installed), clubman bars from Mikes xs, (yet to be installed), new spark plugs, and a few other little things here and there. The other day I was returning from work and the front brakes were seized tight, so I pulled off the road into the clossest parkinglot... unfortunetly it was gravel... crash!!!
But not too bad, bent the shift lever and broke a turn signal lense...

Anyways... The brakes would lock up tight when it was warm out and loosen at night. From reading the posts on here, I figured I'd take apart the whole brake set-up and clean it out, top to bottom. Which I did. After putting it all back together, and bleeding it several times over, I can't seem to get the break pads to butt-up against the disk anymore. I squeeze on the brake lever and I can see the pads are going in and releasing properly, but it's about 1/8 inch away from the disk when released, and barely touching when engaged. Is there an adjusting knob for this? Or did I just not bleed the brake well enough? I did notice on 650 wiki they suggest to keep the coffee cup that the bleed hose goes into OVER the caliper, which I didn't do (I had it under, something about trusting gravity). The Master cylinder was draining though.

Any advice?
Thank you very much... I'm not yet decided on what I'll do with the bike... Bobber or Cafe... or a new beast all-together. But I'm loving the cafe/clubman bars from Mike's and can't wait to install them.

Cheers,
XSDAD from Winnipeg.
(funny story, XSDAD was the name I used on a different forum meant to be X's Dad, my son's name is Xavier...)

yamaman

Old brake hoses can cause this! They might look ok on the outside but the inside is probably shagged. Sounds like yours have been around a while. Would be the first thing I'd do anyway, dont want that happening again! Good luck

jayel

yes bad hoses are probably part of the problem also the puck isn't pumping out properly when you say it would lock up when warm and loosen overnight makes me think your bleed back hole in the master cylinder is plugged if you look in the resevior there is a small tab that covers the bleed back hole you can twist the plastic cup to the side to uncover it a fine wire bristle from a wire brush will fit the hole there is a larger hole that feeds fluid into the system but you need to clear that bleed back hole and replace those old hoses

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

Thanks, I'll be replacing the hoses for sure, and I cleaned up the bleed back hole pretty well, I think. I beleive I solved the original problem of the brakes sticking, I think it was in fact the bleed back hole... the problem now is getting the pads back to being pressed against the disk... the right hand pad doesn't touch anymore and only barely reaches it when the brakes are fully engaged.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

Well, old hoses can be a problem but usually they just give a spongy feel to the lever. It sounds like your caliper piston is hanging somehow. It should just pump right out and hit the disc. If the disc wasn't there, it should keep on moving out until it pops right out of the caliper. When you say you took everything apart and cleaned it, did you remove the piston from the caliper? Did you thoroughly clean the groove for the square sectioned o-ring seal?

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

Yeah, I did take the piston out and cleaned it. As far as the inside of the caliper, I cleaned it out "gently" by spraying some brake cleaner in there and lightly wipeing it out. Not sure what you mean by square sectioned o-ring seal?

If I understand correctly, there should be constant pressure on the piston/brake pad to push it right up to the disk, but that's not happening. Would an air bubble do that?

yamaman

sounds like you did what you could, cool.
They can be tricky to get all the air out, I'd have another go at bleeding it for sure. You could try (with a hose off the bleeder nipple into a jar of brake fluid) crack the bleeder nipple and tape brake lever back to the bar over night, can help rid you of recalcitrant air bubbles!

yamaman

square section "O" ring, if you were to cut the "O" ring and look from the side, you would see it is a square shape, "O" rings come in many diferent section shapes, round, square and X amongst others!

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

yamaman wrote:

sounds like you did what you could, cool.
They can be tricky to get all the air out, I'd have another go at bleeding it for sure. You could try (with a hose off the bleeder nipple into a jar of brake fluid) crack the bleeder nipple and tape brake lever back to the bar over night, can help rid you of recalcitrant air bubbles!

Thanks! A few more questions now...
It sounds like the brade fluid should be on a constant flow, which would help get the air out, but mine wasn't. I would open the valve, squeeze the lever, close the valve, release the leaver, and repeat. It would push out the fluid a bit at a time. Is this because I had the hose/reservoir below the caliper? Also, as for leaving it overnight, if it does do a constant flow, would that not drain the master and bring me back having air in the lines?

Thanks for all the help, super appreciated.

yamaman

Ahh I see, you had the master cylinder below the calliper, correct?
Keep it on the bars where it belongs.
It wont drain out all the fluid, it will enable any air bubbles to make there way out through the top.
You definately either have air in there, a blockage or perished hoses, some bike shops can take a couple of days to fully bleed some systems!
Have another go or 2 at bleeding it conventionly.
If you are getting new hoses, and you can wait, then I'd start again then.

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

No no, I had the master where it belonged, on the bars, but the bleed hose connected to the bleed valve went into a cup that had fluid in it, to submerge the hose, but the cup was on the ground, not above the caliper. 650wiki mentioned having it over the caliper, so I'm not sure if it's important, it's not mentioned elswhere.

As for the air bubbles going out the top, that does make sense, I should try that. Thanks.

yamaman

Ok, I've always done it your way so I cant see the drama, have fun!

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

Ah yes, fun will be had. Thanks for the help.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

Well, if you don't know what I mean by the square sectioned o-ring seal and it's groove, then it doesn't sound like you cleaned them. Old dried up brake fluid builds up in the groove and forces the seal out more. This binds the piston and causes all sorts of problems. Either it freezes right up, or sticks on and fails to return. In your case, it may be keeping the piston from moving out far enough. Cleaning that seal groove is the most important part of cleaning out a caliper.

New lines aren't a bad idea on a bike this old. Most need them by now but if they don't fix the problem, I would revisit the caliper and clean out that seal groove. In fact, I'd do that first.

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

So is this the o-ring built right into the caliper, halfway down, and keeps the piston sealed? If so, I did not remove it, just sprayed break cleaner on it and wiped it clean. How is it removed? Should I just replace it?

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

I'm looking on Mike's XS and I don't see any square O-rings... do you know the part #?

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

It's not sold by itself, it comes in the caliper rebuild kit. You may not need to replace it. As long as it's in good shape and not ripped or broken, you can usually re-use it. It's easily removed from the groove with a small screwdriver or pocket knife. Just pry it out in one spot and the whole thing will pull out. The important thing is to clean all the crud out of the groove it rides in. You'll probably need to scrape it out as the crud gets pretty hard. I finish with the wire wheel bit in a Dremel.

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

Thanks 5twins, I defenetly didn't do that, but I know which part you're refering to now. I'll look into that tonight, hopefully.

sschering

Quick question..
Did you clean 1 or 2 ports out?

I don't know about the front but my rear MC has 2 ports.. a feed/return and an equalization port. It drove me nuts trying to find out why my rear MC wouldn't bleed till I found and cleaned the feed/return port.

If the feed/return port is clean you should be able to open the bleed valve on the caliper and have fluid flow out from the MC reservoir without touching the lever.

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

Yeah, there's the two holes in the master, one of them is hidden under a tab. I had a hard time getting in there, so I might not have cleaned it enough, what type of wire would you recommend?

sschering

I used pipe cleaners from a craft store.. The kids had a pile so I grabbed a few. I pushed out the major junk with a 1/16 drill bit then ran the pipe cleaner through.

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

pipe cleaner for the bleed hole? the hole seems so small, I don't think it would fit. Are you talking about the rear master?

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

One of the holes is bigger and a pipe cleaner would probably work on that one. The other is very small though. I use an old dental pick and then blow compressed air and brake cleaner through. I use either the tapered rubber tip or a needle point tip on my blow gun, whatever will fit down into the hole best .....

XSDAD · Full Member Joined: Sep 03, 2008 Posts: 176

I used the dental pick first, sprayed lots of cleaner in, and tried to clean it with a strand from an electrical wire (car wire). But I don't know if the wire was strong enough. I read on here somewhere someone mention a guitar string, which would in theory be strong enough... anyone try that? I don't have access to an air compressor.

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