Bleeding front brakes

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30 Oct 2011 21:42 #486132 by baldy110
Bleeding front brakes was created by baldy110
I did a search and found nothing pertaining to my problem. I am working on an 82 GPZ 750 front brakes using a Suzuki master cylinder. I am not using the splitter I am using two braided lines on the the banjo bolt to the M/C.
I rebuilt my master cyclinder and calipers after repainting them and now I can't seem to get them bled properly. I have tried every trick I know and still nothing, 7 hours and about 1 gallon of fluid. Here is what I have done so far.

1. Bled the master cylinder seperate from the system.
2. Gravity method.
3. Vacumn pump from the calipers.
4. Pushed brake fluid from master cylinder to calipers with air pressure.
5. Old school method of pumping the lever holding it in then open bleeder valve, repeat about a thousand times.

To be sure I do not have a problem with the M/C or calipers I seperated each caliper and bled it by itself then then leaving the other caliper disconnected I hooked it back up to the M/C. I get a good firm brake. Each caliper works fine on it's own with the existing M/C. When I hook the calipers back together no brakes or getting it bled. I have working on bikes for over 40 years and have bled hundreds of brakes on motorcycles but this one is very frustrating.
Any ideas would be appreciated.

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30 Oct 2011 22:02 #486139 by Motor Head
Replied by Motor Head on topic Bleeding front brakes
You could test the master by blocking off the outlet port, with a bolt the correct size/ thread. You still do the pump, hold bleed by cracking the bolt, the fluid should pass the threads, but a bit slower than a bleeder screw. If it pumps up, it'll be like a rock, and doesn't lose pressure or stroke on each pump, then the Master should be good.

1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...

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30 Oct 2011 22:06 #486141 by gengomerpyle
Replied by gengomerpyle on topic Bleeding front brakes
why did you change to a different master cylinder? i know if its the wrong size it wont work right, maybe that is some of your problem. when i bleed mine i bleed the left caliper first and then the right side. i used a vacuum bleeder with no problems.

baldy110 wrote: I did a search and found nothing pertaining to my problem. I am working on an 82 GPZ 750 front brakes using a Suzuki master cylinder. I am not using the splitter I am using two braided lines on the the banjo bolt to the M/C.
I rebuilt my master cyclinder and calipers after repainting them and now I can't seem to get them bled properly. I have tried every trick I know and still nothing, 7 hours and about 1 gallon of fluid. Here is what I have done so far.

1. Bled the master cylinder seperate from the system.
2. Gravity method.
3. Vacumn pump from the calipers.
4. Pushed brake fluid from master cylinder to calipers with air pressure.
5. Old school method of pumping the lever holding it in then open bleeder valve, repeat about a thousand times.

To be sure I do not have a problem with the M/C or calipers I seperated each caliper and bled it by itself then then leaving the other caliper disconnected I hooked it back up to the M/C. I get a good firm brake. Each caliper works fine on it's own with the existing M/C. When I hook the calipers back together no brakes or getting it bled. I have working on bikes for over 40 years and have bled hundreds of brakes on motorcycles but this one is very frustrating.
Any ideas would be appreciated.


1982 GPZ750R1 ELR
1978 Honda CB750F SuperSport
1971 Honda CB750K
1970 Honda CL100 Scrambler

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30 Oct 2011 22:19 #486143 by baldy110
Replied by baldy110 on topic Bleeding front brakes
Already bled the M/C several timesit works fine. This was the M/C that was on the bike when I bought. A P/O had club raced it and the M/C is a litle bigger for a lighter touch on the brakes. An inexpensive upgrade, It worked great before I tore into it all.

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30 Oct 2011 22:26 #486146 by Motor Head
Replied by Motor Head on topic Bleeding front brakes
Could try this, take the brake pads out of each caliper. Get a block of wood to limit the piston travel so it comes out about 3/4 stroke on each. Then Loosen the bleeder and push the piston back in, letting air/ fluid out. Same for both sides. Keeping bleeder straight up as highest point.

1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...

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30 Oct 2011 22:56 #486153 by baldy110
Replied by baldy110 on topic Bleeding front brakes
Thanks Motor Head but already tried that one too.

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30 Oct 2011 23:00 #486157 by Motor Head
Replied by Motor Head on topic Bleeding front brakes
How long do you let it set between bleeding? Is it on its center or side stand? Whats the orientation of the junction Tee is it?
I know I've had some small air bubbles come back up to the masters return port, having the bike on the side stand and the bars turned so the lever is up hill from the hose end. Barely pumping, just enough to cover then uncover the return port.

1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...

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03 Nov 2011 20:42 - 04 Nov 2011 08:59 #486887 by SPARKY47
Replied by SPARKY47 on topic Bleeding front brakes
Im sure I saw a novel way of using a vacumn cleaner and a large glass jar with some tubing.
I'll see if I can find it.

Got it! This is for a car but you get the idea.
forums.acuralegend.org/brake-flushing-bl...e159a84058c23909& ;

and here...but read the comment underneath!
bpostwarclassics.runboard.com/t8332

1980 KZ500 B2
Location: Middle England[/b
Last edit: 04 Nov 2011 08:59 by SPARKY47.

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03 Nov 2011 21:10 #486892 by ramtough_63
Replied by ramtough_63 on topic Bleeding front brakes
if everything works fine seperately I would be lead to believe its in the connection at the banjo bolt. either air comming in between the mated lines (at the M/C) are you using the stock bolt with 2 seperate fittings?? could be the bolt length are you using the brass washers between all mated surfaces? post a pic of the setup

1978 KZ1000 A2
Thrown Together To Ride Til Winter
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1982/83 750R/GPZ
1984 Goldwing 1200 Interstate
1982 Yamahopper QT50
Previous
2 79 HD sporty XLH
02 HD FLSTS Heritage
60's HD Hummer
70's Honda 550 Four
70 Yamaha 100
and various enduros dirtbikes minibikes...

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03 Nov 2011 21:20 #486893 by ramtough_63
Replied by ramtough_63 on topic Bleeding front brakes

Attachment banjo.jpg not found


quick search

1978 KZ1000 A2
Thrown Together To Ride Til Winter
Facebook Page
Free Range Custom Art


1982/83 750R/GPZ
1984 Goldwing 1200 Interstate
1982 Yamahopper QT50
Previous
2 79 HD sporty XLH
02 HD FLSTS Heritage
60's HD Hummer
70's Honda 550 Four
70 Yamaha 100
and various enduros dirtbikes minibikes...
Attachments:

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04 Nov 2011 09:00 #486953 by SPARKY47
Replied by SPARKY47 on topic Bleeding front brakes
here...read the comment...
bpostwarclassics.runboard.com/t8332

1980 KZ500 B2
Location: Middle England[/b

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