Author Topic: Front brake bleeding  (Read 410 times)

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Offline Oldschool

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Front brake bleeding
« on: June 12, 2019, 08:29:14 pm »
I know, I know. I have read more than enough about the difficult time lots of people have successfully bleeding the front brakes of the Concours.

Background....I have a 2 line stainless steel brake hose system on the front end of my 2000 Concours. 105,000 miles.I removed the log that connected the original 3 line system. I have 2 lines, each going directly from the front master cylinder to the individual calipers. 

I have put gallons of DOT 4 through it trying to get a hard front brake lever feel.

I rebuilt the front master cylinder a few months ago, thinking I was not building pressure due to a bad master cylinder piston.

No change..way too soft. I have tried vacuum, gravity method, old fashioned pump brake lever and open/close valve......nothing.

I could rebuild the master cylinder again with OEM parts or aftermarket. I could rebuild calipers (I have zero fluid leakage). I can pump the front brake lever and build some pressure but the lever can still be brought back all the way to the grip.

I do all the work on my bikes...I know what I'm doing. I know " but the Concours is hard to get the right feel on the front brake lever" motto. Gallons of fluid later....crap front brakes. I have new pads, new rotors. I have tapped the lines to move air bubbles, I have built pressure and tied the brake lever to the grip over night many, many times, I have removed the entire brake system from the bike to align it better to allow air bubbles to rise...blah, blah, blah.

Frustrated but looking for ideas. Thank you.

 

Offline connie_rider

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Re: Front brake bleeding
« Reply #1 on: June 12, 2019, 10:04:27 pm »
Put a strap around the brake lever and leave it compressed overnight.
I have no idea what it does, but seems to help some.

Ride safe, Ted


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Offline rgmr250

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Re: Front brake bleeding
« Reply #2 on: June 12, 2019, 11:06:02 pm »
Put a strap around the brake lever and leave it compressed overnight.
I have no idea what it does, but seems to help some.

Ride safe, Ted
Sounds like he's already done that "I have built pressure and tied the brake lever to the grip over night many, many times". I heard that putting the fluid under pressure can help force air bubbles to rise (and hopefully out into the reservoir). It's worked for me before on various bikes, although with some the effect only lasted for a few days, then got a little spongy again.

I'm about to go through the bleeding process as I just replaced the 3 front rubber lines with 2 braided (longer because of the tubular bar adapters) lines. I think I need to buy some more brake fluid before I start this process... then I get to do the same with the clutch as I'm replacing the top rubber portion of the line with (longer) braided line.
1993 ZG1000

Offline TL

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Re: Front brake bleeding
« Reply #3 on: June 13, 2019, 01:56:45 am »
Went through the same issue a few years back on my Valkyrie after changing to braided lines. Did exactly everything you did but to no avail. Was going nuts, it did not make any sense. On the third day of madness I changed tactics and went and bought a large syringe, put a hose on the end and reversed direction of flow by going through the caliper. This helped to dislodge/carry tiny air bubbles up into the reservoir. Had a turkey baster to remove the fluid before it overflowed. Kept this up until no more bubbles appeared. This took about 30 minutes to do both lines this way by myself and victory was mine. Brakes were firm and I was back on the road. Three days of frustration had finally come to an end. Hope this works for you!  :great:

TL
1988 Connie

Offline Kelly E

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Re: Front brake bleeding
« Reply #4 on: June 13, 2019, 02:23:53 am »
A lot of air gets trapped at the banjo fitting. Wrap a rag around it and crack it while holding the lever. That is what cleared up my soft lever when I went to the two line system.
1994 Kawasaki ZG1000A-The Long Rider
1984 Honda VF700S Sabre-The Bike
1986 Honda CB700SC Nighthawk S The Hooligan Bike
1974 Honda CB550 K0

Offline Bud

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Re: Front brake bleeding
« Reply #5 on: June 13, 2019, 10:18:48 am »
Went through the same issue a few years back on my Valkyrie after changing to braided lines. Did exactly everything you did but to no avail. Was going nuts, it did not make any sense. On the third day of madness I changed tactics and went and bought a large syringe, put a hose on the end and reversed direction of flow by going through the caliper. This helped to dislodge/carry tiny air bubbles up into the reservoir. Had a turkey baster to remove the fluid before it overflowed. Kept this up until no more bubbles appeared. This took about 30 minutes to do both lines this way by myself and victory was mine. Brakes were firm and I was back on the road. Three days of frustration had finally come to an end. Hope this works for you!  :great:

TL
2005 Kawasaki Concours
2001 Kawasaki Concours
1982 Suzuki GS1100GK
1983 Honda GL650I SilverWing

Offline connie_rider

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Re: Front brake bleeding
« Reply #6 on: June 13, 2019, 01:19:30 pm »
I missed that he had tried the lever thing.   :-[
I did like Kelly posted on one of my bikes and it solved the problem on that bike.
ie; Wrap a rag around it {top banjo fitting} and crack it while holding the lever

Ride safe, Ted
14 Connie (Traveler II) / 03 Connie (Buddy)
Gone but not forgotten; 87 and 00 Connies..

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Offline m in sc

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Re: Front brake bleeding
« Reply #7 on: June 13, 2019, 01:47:36 pm »
old school way: get an all metal new oil can, fill with brake fluid. clamp a line to the bleeder and one to the oil can outlet, crack bleeder, and pump up though the system.

https://www.mscdirect.com/product/details/38434460


Offline Oldschool

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Re: Front brake bleeding
« Reply #8 on: June 13, 2019, 10:05:34 pm »
Thanks all for the ideas.

Mike

Offline Bud

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Re: Front brake bleeding
« Reply #9 on: June 13, 2019, 11:56:19 pm »
old school way: get an all metal new oil can, fill with brake fluid. clamp a line to the bleeder and one to the oil can outlet, crack bleeder, and pump up though the system.

https://www.mscdirect.com/product/details/38434460
Never thought of using a pump type oil can.  That has to work better than the syringe I bought at Tractor Supply!  Thanks for that one Mark! :beerchug:
2005 Kawasaki Concours
2001 Kawasaki Concours
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Offline rgmr250

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Re: Front brake bleeding
« Reply #10 on: June 14, 2019, 12:35:43 am »
Sounds like he's already done that "I have built pressure and tied the brake lever to the grip over night many, many times". I heard that putting the fluid under pressure can help force air bubbles to rise (and hopefully out into the reservoir). It's worked for me before on various bikes, although with some the effect only lasted for a few days, then got a little spongy again.

I'm about to go through the bleeding process as I just replaced the 3 front rubber lines with 2 braided (longer because of the tubular bar adapters) lines. I think I need to buy some more brake fluid before I start this process... then I get to do the same with the clutch as I'm replacing the top rubber portion of the line with (longer) braided line.

I guess I got lucky - I replaced the front brake lines with a 2-line braided setup and replaced the top clutch hose with a longer braided one. I used a mix of a small hand-pump vacuum setup and traditional squeeze the lever, open the bleeder, close the bleeder method, a quick bleed at the top banjo fittings, followed (for the brake) by the lever clamped to the bars overnight and the brake is nice and firm, and clutch is working well. I only ended up using a small portion of a small bottle of DOT4. I was ready to buy more bottles of DOT4 and have to run tons of it through to get the air out.
1993 ZG1000