No Brakes
Thread Starter
2nd Gear
Joined: Sep 2018
Posts: 2
Likes: 0
No Brakes
I am redoing a 69 Camaro with 12" disc on all corners . I have replaced the hoses on all 4 corners the master cylinder and booster. I am not getting very much fluid out of the rear bleeders using a vacuum bleeder. Any thoughts of WHY?
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Well, the usual questions:
Bench bleed MC?
Turned the bleeder screws out too far? This will suck air past the threads.
How much time trying to vacuum? It may take awhile if the complete system is dry / empty.
In the event there is a leak somewhere along the lines, the leak may not show up using a vacuum tool. Here is where a Motive Pressure Bleeder on the MC would show a leak, drip-drip-drip, at a fitting, junction block, hose, etc.
Bench bleed MC?
Turned the bleeder screws out too far? This will suck air past the threads.
How much time trying to vacuum? It may take awhile if the complete system is dry / empty.
In the event there is a leak somewhere along the lines, the leak may not show up using a vacuum tool. Here is where a Motive Pressure Bleeder on the MC would show a leak, drip-drip-drip, at a fitting, junction block, hose, etc.
Last edited by HeadsU.P.; Sep 19, 2018 at 05:26 PM.
Thread Starter
2nd Gear
Joined: Sep 2018
Posts: 2
Likes: 0
No Brakes
Well, the usual questions:
Bench bleed MC?
Turned the bleeder screws out too far? This will suck air past the threads.
How much time trying to vacuum? It may take awhile if the complete system is dry / empty.
In the event there is a vacuum leak somewhere along the lines, the leak may not show up using a vacuum tool. Here is where a Motive Pressure Bleeder on the MC would show a leak, drip-drip-drip, at a fitting, junction block, hose, etc.
Bench bleed MC?
Turned the bleeder screws out too far? This will suck air past the threads.
How much time trying to vacuum? It may take awhile if the complete system is dry / empty.
In the event there is a vacuum leak somewhere along the lines, the leak may not show up using a vacuum tool. Here is where a Motive Pressure Bleeder on the MC would show a leak, drip-drip-drip, at a fitting, junction block, hose, etc.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
H-m-m-m-m. If it were me, I would be curious if the MC is even putting out brake fluid. So there's two ways to do that. Buy a MC bleeder kit and attach it to the MC. Pump the pedal and see if fluid is moving through the kits hoses. (You have to remove the lines while testing)
Or, crack open the front brake line fitting just enough that it will leak at the MC. Gently press on the pedal and see if anything comes past the fitting. Use caution here. Wrap a towel around the fitting, keep your fenders covered. Brakefluid eats paint for lunch. If you see seepage, tighten up that fitting and try the rear fitting. If both are showing pressure, you now know your problem is likely down stream from there.
You have a blockage somewhere. You just have to isolate where its at by testing in sections along the route to the bleeder screw. Its possible that a Proportioning Valve is gumming up the works. They seldom go bad, are not repairable and are rather expensive. The valve is also year specific for proper fitment.
Or, crack open the front brake line fitting just enough that it will leak at the MC. Gently press on the pedal and see if anything comes past the fitting. Use caution here. Wrap a towel around the fitting, keep your fenders covered. Brakefluid eats paint for lunch. If you see seepage, tighten up that fitting and try the rear fitting. If both are showing pressure, you now know your problem is likely down stream from there.
You have a blockage somewhere. You just have to isolate where its at by testing in sections along the route to the bleeder screw. Its possible that a Proportioning Valve is gumming up the works. They seldom go bad, are not repairable and are rather expensive. The valve is also year specific for proper fitment.
Safety Car
Joined: Nov 2008
Posts: 3,720
Likes: 555
From: Seattle Washington
No mention of how the master feels when you step on the peddle ? I have no doubt that the Master is not moving fluid. Is there any movement of fluid in the forward and aft chambers when the master is stroked ? Since it and the Booster is new they could be the wrong parts. The ratio of the peddle might not be moving the piston far enough and or the master bore is to small to move enough fluid.
I'd start by disconnecting the lines at the master and installing short brake lines and run them into a paper cup. . Then give it one full stroke and see just how much fluid you get front and rear. I'll bet Your not getting much.
I'd start by disconnecting the lines at the master and installing short brake lines and run them into a paper cup. . Then give it one full stroke and see just how much fluid you get front and rear. I'll bet Your not getting much.
Drifting
Joined: Nov 2013
Posts: 1,572
Likes: 486
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
Redvette2
