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Discussion Starter #1
Hi guys

Once again i need your help. The rear brakes are almost new.

If i go testing center on the brake dyno there is 0 brake power on the rear. (showing on the meter)
Handbrake works perfect. if i pump two times on the pedal 100% working perfect. Im not getting it what it could be?!

It is not air as we checked several times. I saw on the master cylinder in the engine bay there is 1 hose going to the engine (liek a valve) and goes on a T piece wich goes to an black plastic box (round) anything with Dole Valve Inc it says. From this bo 1 hose goes back in the inside of the car. Is it possible that this piece is kind of a brake interupter? I have no idea.

Thank you!!!
 

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What is your brake set up?

Drum/Drum

Disc/Drum

Disc/Disc

Is this a newly installed or upgraded system?
 

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If rear drum brakes, has the rear brakes been adjusted using a brake spoon? Adjust for a drag.
The hose from master booster should have vacuum with engine running at all times.
The valve is an anti-backfire valve for master vacuum booster diaphragm protection from engine backfire.
Hose going inside may be for heater/AC actuator for inside/outside air when MAX A/C selected.

When installing brake master cylinder onto booster, make sure the booster rod sticking out is max 1/16 inch shorter than the depth of the hole in master cylinder piston.
 

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I had a similar issue a while back nothing at the rear brakes mine were drums
ended up being the hose above the rear where it feeds a distribution block
some say they collapse on the inside could try checking that.
 

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Discussion Starter #5
Thank you all for the answers.

Rear Brakes are Drum/Drum and were installed pretty new few years ago. Not many miles driven. the hosing of brake is almost new but the distributor seems looking not so fresh. But it makes no sense that there is no brake power, but if you push two times brake pedals it is suddenly perfect 100%.

Brake fluid checked
No air inside checked
New brake parts /drums) etc checked
hose lines look almost new checked.

Possibility:

rear Distributor?
Brake master cylinder?
any setting or thing that is interrupting that for drift purpose??
 

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Moreno,
Take a look at the brake system tech articles on the Camaro Research Group website (Camaro Brake Valves). You don't mention what type of MC you have, but is there any chance that someone installed a MC for disc/disc that does not have the residual pressure valve built into the rear port of the MC that is necessary for rear drums? If you go to the site you can read the purpose of this valve in the MC for rear drum cars. While in that site, take a look at the information for the other valves in the Camaro brake system to verify the rest of your system is in good shape and intact. I'd pull the rear junction block above the differential and make sure there is no restriction or junk lodged in it that might be restricting the fluid flow to the drums.
 

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I was thinking the same thing. Residual valve for the rear drums.
 

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Let us all know how you finally resolve this.
 

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If it works right after a couple of pedal applications, it sounds like the rear brakes are set too loose. To adjust them you have to knock out the plug in the brake drum, then use a tool (brake spoon) to turn the adjuster wheel. Common adjustment is to first tighten the adjuster until the drum cannot be moved, this seats the shoes on the drum, aligning them, - then loosen until it turns freely. I'd have to check my manual to get the exact instructions. If you do not first seat the shoes, then you might see the drum drag but it's only due to a mis-aligned shoe. There is an automatic adjuster that only adjusts when you back up and hit the brakes. Often they get rusty and stop adjusting.
Performance Tool W80630 - Brake Spoon | O'Reilly Auto Parts
 

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Discussion Starter #12
We found this one here (pic) seems that the took away the distributor and directly attached straight. We will check now and let u guys know .

thanks
 

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Discussion Starter #13
OK guys finally we found the problem. There was air in the system, but not in the back or elsewhere but the first piece at the brake cylinder in the engine bay which goes in to the distributor there was one piece we descrewed it and starting getting the air out it was stocked. Suddenly air came out then oil fitted back perfectly. Strange but u could have trying getting air out as much as you want from the brake side never ever would be getting good. Thanks all for the help and have a wonderful end of week :)
 
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