Can a 1960-1963 Chevy pu clutch/brake master cylinder be used with front disc brakes? I want to change from an automatic to a 5 speed on my 1933 tudor and use the Ansen style swing pedals with the Chevy pu master cylinder. If the cylinder can be used do I need to use any other parts such a residual valve? Thanks
If the master is above the calipers and rear cylinders no residual valves are necessary. Don't know about the master off a pu, do a search I seem to recal a post about that master.
The only differences in a Master Cylinder intended for disc brakes vs drum brakes are A) there is no residual pressure valve IN the master cylinder chamber serving the disc brakes, and... B)the bore size might be different to accommodate the possibly greater of volume of the caliper vs a wheel cylinder. In the first instance, the residual pressure valve could be removed if it caused a caliper to "drag".. The greatest case to be made for NOT using the early truck M/C is that it is single circuit and not as safe as a dual circuit system. Not a big deal.......until something goes wrong!
Further, using a single MC designed for drum/drum on disc/drum setup will result in only two of your wheels giving good braking and the other two giving virtually no braking. Bad idea.
I do not understand the prediction given here. You may be correct, but the logic escapes me. The hydraulic pressure will be distributed to all four wheels, the pressure is the same at all locations. It COULD occur that either the rears or the fronts would be more effective with that given amount of pressure, depending on the size of wheel cylinder bores in relation to the caliper piston size/area, but that is not a certainty. And even if it occurs, can be dealt with by changing wheel clyinder size. Tire and wheel diameter also come into play in the effectiveness of brakes on one end of the car vs the other.
not really. clarence has front discs (aspen/volare) and drum rears (8" ford) and runs the original '48 mc. removed the residual pressure valve from the mc; installed proportioning valve; been stopping great that way for 18 years now. don't have any idea of how many miles it's got on it in this configuration. prolly 100K +. can't remember if i put a residual pressure valve in the rear system or not; i'm getting old and senile. discs require more pressure to function than drums (or is it the other way around?), but the proportioning valve solves this dilema.
I agree that discs typically require more pressure than drums, in part because they are not self energizing like modern drum systems. The much larger caliper piston area is one method chosen to 'even the odds' so to speak because the larger piston area exerts more force on the pads for a given psi brake line pressure, the same pressure applied to rear drums does not necessarily lockup the rear brakes. Because they square inch area of the wheel cylinder is selected to allow for that. Proportioning valves are seldom really necessary.........it's just "conventional wisdom" that you have to have them. They can be used to compensate for mismatched caliper/wheel cylinder, brake diameter/ wheel diameter issues. The main reason power boosters are used on brake systems is that a boosted brake can be smaller, therefore lighter and cheaper, whether it is a drum or disc, and still operate with an acceptable level of stopping power and acceptable level of pedal pressure for the average driver. As an example of "size matters", I built a '47 Ford Coupe with stock axle but a disc conversion using 12" F-100 rotors and '71-'76 Full size GM calipers on front and an 8" Ford rear axle with 10" x 2" drums on the rear. Powered by a '67-'72 Mustang M/C. No booster, no pro vale and excellent stopping power with very moderate pedal pressure. The large diameter of the rotor, combined with the large caliper piston area, comared to the weight of the car they were installed on, acted much the same as power brakes would have on a heavier vehicle. And no premature lockup on the rear brakes! Ray
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