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Old 05-19-2002, 05:09 AM   #1
don t. - 72gmc
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Post brake lines and bleeding ?'s

Woo-Who...wifes gone for the weekend and im actually making progress on my truck!!! Yesterday I finished r&r on the entire brake system, and suprisingly the new lines don't look bad (that bender really helped). I've bench bled the master, and its all set to make the final connection.
Q #1=>should I have used thread sealer? I've never had problems b/4 but??????
Q #2=>how do i test for leaks?

Im the only one at home, and I can't get a hold of my bro. How do you gravity bleed the brakes? He told me a long time ago how but I think you jack the front dr. higher than rest, bleed rear dr. first, rear pass, front pass then front dr. I've never done grav-bleed b/4. Its all level on jack stands right now.

Thanks for any help...don t. .....


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Old 05-19-2002, 07:18 AM   #2
Zkast
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When bleeding the brakes, you start with the wheel furthest from the master cylinder and work your way in.

As for gravity bleeding, start with the Right Rear, open the bleeder, take the master cylinder resivour cover off and allow it to do its thing. Since everything is new and dry, the fliud has a natural tendancey to crawl through the line pretty quick (acks like a wik). After you feel like you have moved all the air from the lines, pump the brakes to get a good high pedal, then just stand on the brake pedal (if you have power brakes start the engine)and put maximum pressure through the system. Go around and check all fittings. You should really have someone else there though.... its best to check them WHILE there is pressure on the system. Plus, I always like to bleed the brakes again after this is done.

Oh, there is no need for thread sealer... The threads are only there to press and hold the line against its sealing seat. If you have a leak, check both surfaces of the connection, dont use thread sealer.

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Old 05-19-2002, 08:14 AM   #3
don t. - 72gmc
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Thanks Zkast. I talked to the neighbor whos a shade-tree as well. He said same about sealer. He also said he'd come over later today for final bleeding (i'll pump bleed as well).
I started on the rear dr. side. Found one leak by master, fixed. Started flowing well. Now its stopped, haven't added fluid in over 20 minutes. I don't see any leaks. And it aint comming out the bleeder valve on wh. cyl. Since its a dual master, figured I'd bleed fronts. Fluid flowed from both calipers real well. Checked rear fluid level, no change.
What happened w/the rears?
Thanks....don t. ....


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Old 05-19-2002, 08:22 AM   #4
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Might have to elevate the front.. The rear lines are longer and smaller diameter. Or just wait for your neighbor to come over.

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Old 05-19-2002, 09:17 AM   #5
don t. - 72gmc
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I put on the rear tires and lowered. Front dr. side is about 18" high, fr. pass. about 12 (+/-). Aint helping/no flow. Guess I gotta wait for neighbor.
Even tho i've dbl checked, would a leak down stream cause it to stop flowing? Just wondering why/trying to understand. I understand that downstream pressure exceeds flow but???
Thanks for your help....don t. ....

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It aint gonna be a trailer queen, its gotta work, just like me.
3/4 ton,350 w/HEI, 79 q-jet, th400, Dana 60.
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Old 05-19-2002, 12:39 PM   #6
Gordo
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You may need to reset (center) the proportioning valve to get the fluid out the rear cylinders. Pumping the brakes with a lot of air in the lines may have tripped the prop valve.

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