im running 63-67 econoline spindles with drum brakes up front and the drum brakes off of a stock mustang 8.8 in the rear, with a speedway adjustable proportioning valve and a mr roadster dual master cylinder. Having a problem when i put it in gear, the car pulls back even when the brakes are applied and the front brakes lock up completely, where do i start?
i'm not understanding what you mean by "pulling back". FYI , you shouldn't need a proportioning valve with drum/drum brakes.
Not really true, depends on where your M/C is located. If your M/C is under you car and lower than your wheel cylinder then yes, you need one, My .02 worth.
What im saying is that when i put it in reverse the front brakes lock up and drag. the rears seem to be fine. and my m/c is lower than my wheel cylinder thats why i put the prop valve
Drums warped? Wrong shoes? Have you driven the car at speed? Kinked brake line letting fluid in but not out at the same rate.
Remember short shoe/lining to the front of the car with self-engerizing brakes ie Bendix style. Loose the prop valve no need on drum/drum system.
make sure your master cylinder doesn't already have built in residuals, otherwise you'll be doubled up and brakes wont work right. These are what is needed when the master cyl is lower than the brake. The prop valve may still be needed due to the wheel cylinder sizing, and front/rear weight distribution and/or tire size. and double check that the big shoes are towards the rear of the car. how high is your idle? stock converter?
adding residual valves inline in a system with a master cylinder that already has them will cause absolutely no harm...they are not cumulative
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