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Brake Lines

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I filled the master with fluid, jiggled air out of it, sucked air and fluid out of each caliper. Back to where I was weeks ago: no leaks that I see or hear, no resistance at the brake handle other the spring.
 
Manfred said:
I filled the master with fluid, jiggled air out of it, sucked air and fluid out of each caliper. Back to where I was weeks ago: no leaks that I see or hear, no resistance at the brake handle other the spring.
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can you actuate the master cylinder apart from the brake lever? Is something missing on the brake lever that actuates the master cylinder?
 
Tracker said:
can you actuate the master cylinder apart from the brake lever? Is something missing on the brake lever that actuates the master cylinder?
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No - there's nothing other than the handle. It's a new master cylinder that works fine.
 
Have you tried just putting a simple piece of brake line between the master and the caliper, bypassing whatever else might be in the middle? That might help you narrow down where the problem area is.
 
William Wolfen said:
Have you tried just putting a simple piece of brake line between the master and the caliper, bypassing whatever else might be in the middle?
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I don't have any brake lines that long. The only thing between master and calipers is a simple 3 inch long tube that has banjo connections at each end. Plan to burp the banjos, starting at the master and working my way down.
 
Manfred said:
I don't have any brake lines that long. The only thing between master and calipers is a simple 3 inch long tube that has banjo connections at each end. Plan to burp the banjos, starting at the master and working my way down.
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Well, technically you could take the master off the bars to get it closer to the calipers. Just a thought if you're still unsuccessful.
 
Manfred said:
The only thing between master and calipers is a simple 3 inch long tube that has banjo connections at each end. Plan to burp the banjos, starting at the master and working my way down.
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Hmm...
If that tube is the junction/splitter to dual front calipers, I could theorize there is an elusive bubble in there that is moving from one side to the other as you bleed from each caliper. That would be diabolical.
Burping all the banjos is a good plan.

The only other thing I know of is to pressure bleed rather than vacuum bleed. It should not make a difference with hydraulics but you've already done everything else.
 
Prior to replacing the seals on the calipers, I pushed fluid up from the left caliper, blew fluid with no air through the master and the right caliper. Did nothing to resolve the problem. I have never had this much trouble bleeding brakes on a bike.
 
Let me ask a few questions. You said it's a new master cylinder. Did you bench bleed master sans brake lines to the bike? Asking because I've had new and orignal master cylinders extremely hard to bleed darn near next to impossible.
 
Pedro 2.0 said:
Let me ask a few questions. You said it's a new master cylinder. Did you bench bleed master sans brake lines to the bike? Asking because I've had new and orignal master cylinders extremely hard to bleed darn near next to impossible.
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I did bench test it with no lines. It was putting pressure against my thumb. When half pull it when it's connected, it pushes fluid out the banjo on the master and the ones below.
 
Update: Filled the master, jiggled air out of the master then burped it at the banjo and each of the 4 banjo bolts below. Then sucked air out of each caliper from the bleeder valve - keeping fluid level in the master.

No change.

Have brake handle tied back half way, letting it sit overnight.
 
I jiggled a lot of air bubbles out through the master today. When that ended, still no brakes; so I put my vacuum on the right caliper and opened the bleeder a quarter turn. I had put red brake grease on the threads before installing the bleeder valves. When I pull vacuum, lots of air with a little fluid. On the left caliper, nothing but fluid. New seals on both calipers. No fluid leaks anywhere. Air getting into the right caliper. Seals and/or bleeder valve - banjos are new and no weeping of fluid. Anything else I should consider?
 
Are the calipers squeezing the pads? Just for grins, try the old banjo bolts. Can't hurt.
 
Liteitup said:
Are the calipers squeezing the pads? Just for grins, try the old banjo bolts. Can't hurt.
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No - there is no pressure being applied to the pads in either caliper. I drained the system. When doing this, I had tube on the bleeder valve of the left caliper and opened it to drain. Fluid with no air came out. I removed the banjo bolt and let it drain. Then I took the left caliper apart, found a thread of what looked like part of the old dust seal. Cleaned out the barrels, coated the pistons with brake fluid, and reinstalled them. Pulled the brake handle half way and fluid with no air came through. Removed the bleeder valve, put some more red brake grease on the threads, blew air through it and sucked air through to make sure it was not clogged. Reinstalled the caliper and filled up the master. No air bubbles came up in the master when I jiggled handle as before. So I hooked up my vacuum on the left caliper and opened the bleeder a quarter turn. Air bubbles and fluid. Had to refill the master 3 or 4 times - did not let it get too low. Still lots of air and fluid being pulled through the bleeder. Before this "repair" of that caliper, it would pull air and wee bit of fluid and never draw down the master. Now it does. There just doesn't seem to be an end to the air.
 
This morning, checked the bike. No air bubbles were forth coming from the master when I worked the handle. For the first time, no air bubbles in the right caliper - all fluid. Left caliper still all fluid. Found a fluid leak at the master banjo. Fixed that by sucking most of the fluid out of the master rather than draining the system again. No air bubbles anywhere - still no brakes. Have strapped down the handle again (with a screwdriver in place to insure it only compresses half way). Am about ready to haul it to a shop.
 
That's what I had to do. You'll be glad you did when you can ride it again instead of dealing with the smell of brake fluid...AGAIN!
 
If I am impressed with the braided steel brake lines - like everyone says I will be - plan is to replumb the clutch with braided steel line as well.
 
If I put a braided steel line on the clutch, I will try that myself.
 
Bike is back from the shop - unrepaired.
The mechanic did disassemble the OEM master cylinder but said he would not rebuild it.
Here's a picture of it. I think it can be cleaned up and rebuilt.
What say you?

OEM MC.jpg
 
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The critical part is the cylinder bore. Too much corrosion in there that cannot be cleaned up will continue to be a problem with new seals.
 
dukey33 said:
The critical part is the cylinder bore. Too much corrosion in there that cannot be cleaned up will continue to be a problem with new seals.
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It looked OK - will take a more careful look. Thanks!
 
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