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Old 09-08-2025, 06:36 PM   #1
wlf89
69 c/10 lwb fleetside
 
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Join Date: Jul 2004
Location: saint joseph TN
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need help with bleeding brakes

i replaced both rear wheel cylinder on a 87r10 today along with new pads, the truck has been sitting for along time. i filled the master with fluid and cracked the bleeders and i am getting good fluid flow with gravity. after this i cranked it up and pumped and held pedal while opening the bleeders with a helper, and i got very little fluid and the pedal doesnt go down at all like it should.

is this a proportioning valve issue? ive heard of people resetting them but ive never had to do this and not sure how to go about it. a video i watched said if your not getting fluid to the rear to just pump and hold pedal and bleed the front 2-3 times and that should reset the valve, is that true or is it done some other way? thanks for the help
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Old 09-09-2025, 10:46 AM   #2
kglowacky
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Re: need help with bleeding brakes

check?replace rear rubber hoses. You state been sitting a while. Common problem hoses collapse,
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Old 09-09-2025, 04:36 PM   #3
franken
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Re: need help with bleeding brakes

There's a little L shaped tool/bracket shown in the manual that's used before/during bleeding to keep the valve in the block from shifting. If the valve senses a loss of pressure it shifts and directs fluid to the side that didn't lose pressure. Bleeding is a loss of pressure.
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Old 09-09-2025, 05:04 PM   #4
wlf89
69 c/10 lwb fleetside
 
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Re: need help with bleeding brakes

i have the tool ordered and supposed to be here tomorrow, ive read you can move it back to center with a pick, ill give it a try once i get the tool and some free time
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Old 09-11-2025, 10:10 AM   #5
jayoldschool
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Re: need help with bleeding brakes

Quote:
Originally Posted by wlf89 View Post
i cranked it up and pumped and held pedal while opening the bleeders with a helper, and i got very little fluid and the pedal doesnt go down at all like it should.
This is the exact same thing that happened after I tried to bleed my 65 following a rear wheel cylinder replacement. Rubber line from frame to axle blocked. Confirmed by removing at axle (no flow) then at frame (flow). Replaced line, bled perfectly. Couldn't blow through old line.
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Old 09-11-2025, 11:16 AM   #6
NeoJuice
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Re: need help with bleeding brakes

Bleeder tool & Youtube video.

https://youtu.be/S11p2Isgmu4?si=EZwfqsU75enbN7wZ
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Last edited by NeoJuice; 09-11-2025 at 11:23 AM.
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