Author Topic: Bleeding, not breaking (Read 1656 times)

thelowmax · « **on:** June 26, 2013, 05:21:47 AM »

Anybody have a suggestion for getting my front brake bleeder valve to open without completely stripping or breaking off? I'm at the breaking off point.

Kenzo1979 · « **Reply #1 on:** June 26, 2013, 05:34:07 AM »

Heat it up, soak it in PB Blaster for hours, work it a little bit at a time.

Or do what I did, Break it off, drill it out and tap it to fit this:

Most autoparts stores carry a brake bleeder repair valve that you can put in there, go to the store, you'll find it.

Did this to 3 bikes, works great, antisieze on the new one and a vac cap on the valve to keep dirt out.

good luck.

flybox1 · « **Reply #2 on:** June 26, 2013, 06:44:43 AM »

PB Blaster/hot/cold cycles really help. so does a hammer, so you can gently tap it to break it away.
replace it with a speed bleeder.

John Eberly · « **Reply #3 on:** June 26, 2013, 07:10:52 AM »

I boiled my caliper in vinegar overnight, the bleeder screw will erode awa and eventually screw out. You'll need a new bleeder fitting, and you'll lose the paint on the caliper.

thelowmax · « **Reply #4 on:** June 26, 2013, 08:03:13 AM »

I'm off to get some PB Blaster and a new valve. Maybe a couple.

evanphi · « **Reply #5 on:** June 28, 2013, 08:50:13 AM »

I asked this question only a short while ago. I sprayed PB Blaster on it about once an hour for 5 hours, then let it sit over night, then one more spray in the morning. Turned no problem when I got home from work that afternoon.

thelowmax · « **Reply #6 on:** June 28, 2013, 09:31:29 AM »

This one is giving me the business. I have Pb'd it, heated it, tapped it, stripped it, hammered it. It is now round. I forge on. I may try the vinegar route, as the paint is mostly gone on the caliper anyway.

flybox1 · « **Reply #7 on:** June 28, 2013, 09:38:39 AM »

$18bucks....done.

http://forums.sohc4.net/index.php?topic=104370.0

Henning · « **Reply #8 on:** June 28, 2013, 11:55:43 AM »

Popular topic. I put the heat gun on the caliper for 30 minutes until it was nice and warm. I also put the T-bar, extension and socket in the freezer until they were good and cold. With the T-bar I then applied steady and increasing pressure to the bleeder bolt, maybe over five to ten seconds, giving time to cool and shrink the bolt down. It let go; I was happy.

thelowmax · « **Reply #9 on:** June 29, 2013, 03:22:17 AM »

Quote from: flybox1 on June 28, 2013, 09:38:39 AM

$18bucks....done.

http://forums.sohc4.net/index.php?topic=104370.0

And done.

thelowmax · « **Reply #10 on:** June 29, 2013, 06:45:29 AM »

OK. I finally got the bleeder open. Fluid was black. Ran fresh fluid through. Bled for air. Closed valve.

Now I seem to be having the same problem I had when I started. When I apply the brake, it doesn't release. It gets tighter and tighter.

Kenzo1979 · « **Reply #11 on:** June 29, 2013, 08:30:49 AM »

Sounds like you need to clean out the caliper. Remove the caliper bolts, hold the caliper with the piston facing down into a catch pan. Pump the brake until the piston pops out and all the brake fluid oozes out. If the piston doesn't pop all the way out (sometimes it just makes it to the edge), grab it with vice grips over a rag as to not damage the piston, and pull it the rest of the way. Now unscrew the brake line so you can work on the caliper on the bench.

Look inside, it's probably gunked up and scaly in places. Clen it out with brake cleaner, hit the outer ring with a wire brush and some sandpaper while being careful the whole time not to mess up the gasket that's inside the piston hole. Clean inside the piston whole with PB blaster, wire brush, whatever you can get in there. Now clean the piston itself, steel wool and PB blaster work well. Finally clean the Brake Pad paying special attention to the sides so it can move freely back and forth into its housing (little sandpaper should do it.

Clean everything with brake cleaner, reassemble, refill, re-bleed. Done.

flybox1 · « **Reply #12 on:** June 29, 2013, 09:15:14 AM »

+1 to cleaning the caliper.
-1 to doing it with steel wool unless you can be sure there are no tiny filings hanging on to the piston. They'll ufk up your piston seal
Also drain and clean your mastecylinder. Pay attention to the tiny holes in the bottom of the cup. There are two. Run a wire in them to clear any debris.

thelowmax · « **Reply #13 on:** June 30, 2013, 10:27:23 AM »

All the lines are clean and clear. Can't get the piston out. And now I get no pressure when I pump brake. The piston is in there pretty tight. I finally opened the valve and blew some compressed air in. The piston moved halfway out but even pulling with needle nose vice grips, I can't get it to budge further.

Kenzo1979 · « **Reply #14 on:** June 30, 2013, 12:01:49 PM »

Spray PB Blaster into the caliper behind the piston. Sit the caliper pisto side down and let it sit for hours or overnight. Now grab that piston with the vgrips and rock it, twist it, turn it and pull it until it pops out. Don't give up, it will come out. Been there before. Shoot more air into it too after it soaks, that might work as well.

Bootlegger56 · « **Reply #15 on:** June 30, 2013, 12:34:14 PM »

+1 for the grease gun method of pumping the piston out. My ElCheapo version has a flex hose with a brass that sort of screws right into the hard line fitting. It leaves a little grease to clean up but....you have to clean it meticulously anyway.

thelowmax · « **Reply #16 on:** June 30, 2013, 07:25:16 PM »

Once I get the piston out and clean it, it seems even harder to get it back in and once back
in, it seems even more stuck than before. This is most frustrating.

Dave Voss · « **Reply #17 on:** June 30, 2013, 07:41:24 PM »

Quote from: thelowmax on June 30, 2013, 07:25:16 PM

Once I get the piston out and clean it, it seems even harder to get it back in and once back
in, it seems even more stuck than before. This is most frustrating.

In order for the piston to move in the caliper correctly, it is very important that the sides of the piston are smooth and corrosion free, the inside bore of the caliper is also smooth and corrosion free, the piston seal is new or in otherwise excellent condition, and probably most important, that the groove inside the caliper that the piston seal sits in, be clear of all debris, corrosion, etc. that might cause that seal to grip the piston too tightly, as this will create excessive drag on the piston.

Cleaning the piston seal groove in the caliper can be tedious, sometimes it requires a small pick of sorts to reach up under the near (top) side to scrap away built-up corrosion. If the caliper body is especially corroded such that the groove is no longer square shaped, then it may be time for a replacement.

thelowmax · « **Reply #18 on:** July 01, 2013, 07:50:52 AM »

The piston and the inside the caliper has been cleaned pretty well, though I didn't remove the seal gasket. I'm going to remove the seal and see what happens.

As a side question... The piston is supposed to move freely in the caliper, but how freely? A subjective question but considering that I can't get it to move at all, any info will be helpful.

flybox1 · « **Reply #19 on:** July 01, 2013, 08:14:31 AM »

replace your piston seal with a new one.
dry, it wont slide in easily

if you put a real light brake parts lube on the piston and seal, it should slide in with some pressure. once its in, it shouldnt move except with brake fluid pressure.
if you have a hollow piston, it should face outward.

Shane72 · « **Reply #20 on:** July 01, 2013, 09:40:03 AM »

Quote from: thelowmax on June 29, 2013, 06:45:29 AM

OK. I finally got the bleeder open. Fluid was black. Ran fresh fluid through. Bled for air. Closed valve.

Now I seem to be having the same problem I had when I started. When I apply the brake, it doesn't release. It gets tighter and tighter.

I would also have a look at the master cylinder--my guess is that the condition of the fluid-moving parts (below the reservoir) is no better than the caliper. I've rebuild two, and consider this to be a mandatory repair in combination with the caliper rebuild/cleaning.

All the best,

Shane

thelowmax · « **Reply #21 on:** July 01, 2013, 12:02:57 PM »

Through this whole process I have been canabalizing my other bikes and thus have taken apart 3 calipers. Got two pistons out. One seal is pretty rough and has become calcified in conjunction to the build up and corrosion in the seal groove. The other cleaned up pretty good and the seal looks great but I can't get the seal back in. It seems to have grown since I took it out. I put it in the cooler to see if it shrinks a little. In the meantime, I took the first seal, cleaned it up and used that in the clean caliper. Piston slid in very smooth and even. Filled master cylinder but don't have time to address it yet. I'll post my progress, if any

Thanks for the help.

I'll be ordering new seals but I need to get my bike going (and stopping) for now.

thelowmax · « **Reply #22 on:** July 01, 2013, 12:05:20 PM »

Quote from: Shane72 on July 01, 2013, 09:40:03 AM

Quote from: thelowmax on June 29, 2013, 06:45:29 AM
OK. I finally got the bleeder open. Fluid was black. Ran fresh fluid through. Bled for air. Closed valve.

Now I seem to be having the same problem I had when I started. When I apply the brake, it doesn't release. It gets tighter and tighter.

I have thoroughly cleaned everything else and I do seem to be getting no pressure response.

I would also have a look at the master cylinder--my guess is that the condition of the fluid-moving parts (below the reservoir) is no better than the caliper. I've rebuild two, and consider this to be a mandatory repair in combination with the caliper rebuild/cleaning.

All the best,

Shane

flybox1 · « **Reply #23 on:** July 01, 2013, 12:07:25 PM »

The seal shouldnt swell, unless it came into contact with gas

Try fitting it again. It might just fall into place with a little finessing.

thelowmax · « **Reply #24 on:** July 01, 2013, 09:33:22 PM »

The seal I took out is soft and pliable but now almost doesn't fit in the caliper never mind the actual seal groove. If I hadn't taken it out, I never would have believed that was where it came from. I can put the other seal inside this seal. Weird.

Still no pressure.

News:

Author Topic: Bleeding, not breaking (Read 1656 times)