Brake bleeding help 91 EGC
Thread Starter
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Cruiser
Joined: Apr 2009
Posts: 149
Likes: 6
From: wichita, ks
Brake bleeding help 91 EGC
Hey guys, tried to change my front brake fluid last night and I'm having some trouble. I've got a vacuum bleeder. Hooked it up to the bleeder valve just like I have many times before. Only got a few ounces of fluid out then nothing. Tried the other side, same result. The bike still has the factory rubber lines and I'm guessing it's collapsed. Wanted to get some other opinions before I tear the bike apart. I had the lid off the master cylinder and both holes in the bottom are clean. We tried pumping the lever to get the fluid moving, still nothing. Bleeder screws and calipers are clean and clear. I can put 25" of vacuum on it and it will hold, so there's no leaks, but no fluid movement either. Am I missing something? Any ideas?
Thanks in advance.
Thanks in advance.
Thread Starter
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Cruiser
Joined: Apr 2009
Posts: 149
Likes: 6
From: wichita, ks
That I do not know. I believe it may need some attention though. The brakes worked ok until I tried to change the fluid. Go figure!
I think this is what I'm going to do. After working on it for a few hours again this evening, I think I've got an obstruction somewhere in the system. We were able to get some fluid through, but it would stop intermittently. Then stopped altogether. I can't make any sense of it.
Thanks for the input!
Thanks for the input!
Seasoned HDF Member
Joined: Apr 2011
Posts: 6,183
Likes: 2,131
From: W. Texas
This is just my experience in dealing with auto brake systems and some bikes.
Trace any hard lines (piping) and ck for any crimps or flattened out area's.
Take the line off at the M/cyl, use a pair of needle nose vice grips and pinch the rubber line going to a caliper. It wont. take much pressure on the grips to pinch the line closed. Wrap a bunch of rags around the fitting that goes to the M/cyl. Remove a bleeder screw and with compressed air blow back into the caliper. Not a 100 psi about 30-40 more than enough. Repeat with other caliper.
Do be aware that this will blow brake fluid back out of the fitting at the master cylinder. Dot 3or 4 eats paint Dot 5 not so much BUT if someone in the past has added dot3 or 4 to the system you need to cover and protect yourself and the bike. Big sheet of painters plastic comes to mind.
If you can get a fair amount air from each side I'd rebuild the master cylinder. DO NOT put compressed air back through the M/cyl while still together They don't like it. Once M/cly is disassembled ok to blow out passages, again not a 100 psi.
If you feel you want to flush the system out you can use Denatured Alcohol from a paint supply store or Home Depot or such. done it many times
Good Luck
WP
Trace any hard lines (piping) and ck for any crimps or flattened out area's.
Take the line off at the M/cyl, use a pair of needle nose vice grips and pinch the rubber line going to a caliper. It wont. take much pressure on the grips to pinch the line closed. Wrap a bunch of rags around the fitting that goes to the M/cyl. Remove a bleeder screw and with compressed air blow back into the caliper. Not a 100 psi about 30-40 more than enough. Repeat with other caliper.
Do be aware that this will blow brake fluid back out of the fitting at the master cylinder. Dot 3or 4 eats paint Dot 5 not so much BUT if someone in the past has added dot3 or 4 to the system you need to cover and protect yourself and the bike. Big sheet of painters plastic comes to mind.
If you can get a fair amount air from each side I'd rebuild the master cylinder. DO NOT put compressed air back through the M/cyl while still together They don't like it. Once M/cly is disassembled ok to blow out passages, again not a 100 psi.
If you feel you want to flush the system out you can use Denatured Alcohol from a paint supply store or Home Depot or such. done it many times
Good Luck
WP
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Road Captain
Joined: Jul 2014
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From: Galesville, WI
https://www.hdforums.com/forum/evo-c...991-flhtc.html
Maybe this will help out some? Looks like I went through the same kind of thing when I upgraded my bars a while back.
Maybe this will help out some? Looks like I went through the same kind of thing when I upgraded my bars a while back.
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Thread Starter
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Cruiser
Joined: Apr 2009
Posts: 149
Likes: 6
From: wichita, ks
Thanks for all the input guys! I decided over the weekend that I'm just going to rebuild the entire brake system and install new braided lines. There's something screwy with the master cylinder and/or I've got an obstruction in the line somewhere. I'll let you know how it turns out. Thanks again!
Seasoned HDF Member
Joined: Oct 2005
Posts: 7,481
Likes: 3,677
From: Santa Klaus County, Cali
You might consider Speed Bleeders as well. Used them on the drum brakes for my 64 El Camino and just installed them on a friend's 75 FLH. Works great on both. Cheap investment on a great return IMO.