So, I am at a compete loss as to where to go from here. Situation: 47 dodge coupe. Brake system has been replaced Stock pedal hooked up to what looks to be an eBay style 7"dual diaphragm booster and master cylinder with remote reservoir. All round calipers from OT Aust cars (Front: 1990 VN Commodore, rear from an 1995 EF Falcon). Problem: No matter what I do I can't get a firm pedal, let alone lock up the brakes. All new rubber hoses. System bled with a vacuum bleeder. It feels like air, but there isn't any present. No visible leaks. I continue to suspect air as, every so often, fluid will spurt out of the breather on my small Moon alloy remote fluid reservoir and F#ck up my paint… Apart from that, I'm all outta ideas. I did not install the system, but the work appears to be of a pretty decent standard. No random high points for air to get stuck. Thoughts? Leary
Verify the calipers are on the correct sides and that the mounting angle allows all air to be bled out. If that's not the problem, then most likely a bad master cylinder.
Sounds like the components aren't properly matched. If the master cylinder doesn't have a large enough bore the symptoms are just what you describe. Often you can find the "same" cylinder with a different bore for a simple bolt in fix.
Brake bleeding is as much art as it is science....... and sometimes a little bit of witchcraft when dealing with homebrewed brake systems. Somewhere in my travels, I've heard tell about the "Hillbilly Brake Bleed". As the story goes, it was born out of frustration of multiple, failed bleed attempts. It entails pumping the brake pedal 10 or more times as fast as the return spring lets you. I believe the point is to move any bubbles in the fluid column forward into the reservoir faster than they can roll back into any high spots. You all know how honest I am, so........ though I've got my fingers crossed, I swear I've never tried this.
sure sounds as if the master needs to be bled properly.only takes a little time and does not cost any money what have you got to lose
Being Aussie components have you tried posting on Ozrodders? What brake fluid are you using to damage your paint??
I assume the master is under the floor? Residual valves in line? Calipers on correct sides with bleeders at the top?
Throw that Ebay master with the 7" booster in the trash! I've built 20 cars, the one I had a problem with the brakes on had one of those ebay master cylinder & booster kits with the pedal and bracket assembly. A master cylinder that matched the front disc brakes solved the problem. Install a booster and master that match your front disc brakes. Gene
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