No rear brakes? 69 Chevelle
10-24-2013, 12:20 PM
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No rear brakes? 69 Chevelle Alright I don't know why I cant figure this out, but anyway here is the story:
Customer comes in with his own supplied SSBC brake kit for his 69 Chevelle (He was 4 wheel drum) It is not the fancy kit, just the cast steel single piston caliper kit for all 4 wheels, power booster and master.
Anyway I have my installer put it on, says its good, customer takes the car. A year later he comes back as he blew his engine, we put a twin turbo ls1 in it. I take it for a test ride after tuning it and the brakes are pretty scary. They have plenty of assist but just suck. I put it in the air and realize I can turn the rear wheels pretty easily. These cars have that combo valve thing, I bleed them with the special tool, still the same thing.
Taking a stab at it I figure that combo valve is bad and maybe partially stuck so I get a SSBC valve with the proportioning on the rear and re do all the steel lines with nice new nici line. Bleed, Same thing!
Maybe just the master is shot allowing fluid to blow by the seal on the rear when it builds pressure? I take the master off, realize it is a shallow one line the newer style, pushrod length looks correct, I have a used master from a 02 Camaro, I put that on (Yes the front line of this master is rear) and check it again, pedal is softer now but still no rear brakes? I get plenty of fluid out of both sides when bleeding and they are not froozen?
What am I overlooking? Should be a simple task but I must be missing something here.
Customer comes in with his own supplied SSBC brake kit for his 69 Chevelle (He was 4 wheel drum) It is not the fancy kit, just the cast steel single piston caliper kit for all 4 wheels, power booster and master.
Anyway I have my installer put it on, says its good, customer takes the car. A year later he comes back as he blew his engine, we put a twin turbo ls1 in it. I take it for a test ride after tuning it and the brakes are pretty scary. They have plenty of assist but just suck. I put it in the air and realize I can turn the rear wheels pretty easily. These cars have that combo valve thing, I bleed them with the special tool, still the same thing.
Taking a stab at it I figure that combo valve is bad and maybe partially stuck so I get a SSBC valve with the proportioning on the rear and re do all the steel lines with nice new nici line. Bleed, Same thing!
Maybe just the master is shot allowing fluid to blow by the seal on the rear when it builds pressure? I take the master off, realize it is a shallow one line the newer style, pushrod length looks correct, I have a used master from a 02 Camaro, I put that on (Yes the front line of this master is rear) and check it again, pedal is softer now but still no rear brakes? I get plenty of fluid out of both sides when bleeding and they are not froozen?
What am I overlooking? Should be a simple task but I must be missing something here.
10-24-2013, 12:21 PM
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This is the Prop valve I put in, http://www.summitracing.com/parts/ssb-a0730/overview/ Yes I have tried it all the way on increase and decrease.
10-24-2013, 12:24 PM
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Also the customer said when he first picked up car after installing the brakes he said the brakes sucked, worst then the non power/drum setup he had, but just never said anything
