Master Cylinder Choice

[Apogee]

I have Wilwood front and rear 12.1" brakes with four piston calipers on a 67 camaro. RIght now the car has power brakes and the pedal is sensative sometimes and very stiff other times. The motor doesnt make much vacuum at idle, and that seems to be the issue. I would go hydroboost, but its not in the budget. I have heard many people say that a manual setup can be just as good with the right master cylinder. Would anyone be able to recommend a master cylinder to convert to manual brakes that would work well with my brake setup? Any info would be great, and I am always willing to purchase from a supporting vendor.

Manual brakes can be made to work quite well, however the pedal feel and travel would rarely ever be mistaken for a power brake setup, which in many ways is a good thing and in others not so much. Since you're starting with a poorly functioning power system, you don't have a very good baseline for comparison. You've ruled out hydroboost due to cost, so your only other power brake option would be to somehow improve what you have. You could add an accumulator and/or an auxiliary vacuum pump, the former is pretty inexpensive while the latter is not. I'm not a huge fan of aux. pumps as they tend to be somewhat costly ($200-$300) and obnoxious in terms of noise and vibration, but in a low vacuum situation, there aren't a lot of options. The accumulator can help with the pedal consistency, although if volume isn't the issue, then it won't change anything.



Then you have the manual option with an appropriately sized master cylinder, probably 7/8" in your application. The pros to manual would be simplicity, modulation/control, driver feedback, consistency regardless of engine/cam, cost and weight...the cons are longer pedal travel, higher pedal effort and less margin for error with respect to pad selection, pad knockback, etc. When we set up C5/C6 systems for manual brakes, we typically run a more aggressive pad to help reduce pedal effort required to achieve lockup. The down side to more aggressive pads is usually more brake dust, noise and rotor wear, but still well worth it IMHO.

Tobin
KORE3

[Smoker03]

Manual brakes can be made to work quite well, however the pedal feel and travel would rarely ever be mistaken for a power brake setup, which in many ways is a good thing and in others not so much. Since you're starting with a poorly functioning power system, you don't have a very good baseline for comparison. You've ruled out hydroboost due to cost, so your only other power brake option would be to somehow improve what you have. You could add an accumulator and/or an auxiliary vacuum pump, the former is pretty inexpensive while the latter is not. I'm not a huge fan of aux. pumps as they tend to be somewhat costly ($200-$300) and obnoxious in terms of noise and vibration, but in a low vacuum situation, there aren't a lot of options. The accumulator can help with the pedal consistency, although if volume isn't the issue, then it won't change anything.

Then you have the manual option with an appropriately sized master cylinder, probably 7/8" in your application. The pros to manual would be simplicity, modulation/control, driver feedback, consistency regardless of engine/cam, cost and weight...the cons are longer pedal travel, higher pedal effort and less margin for error with respect to pad selection, pad knockback, etc. When we set up C5/C6 systems for manual brakes, we typically run a more aggressive pad to help reduce pedal effort required to achieve lockup. The down side to more aggressive pads is usually more brake dust, noise and rotor wear, but still well worth it IMHO.

Tobin
KORE3

Thanks for all the info. Is there a certain master cylinder that would work best? Also, would I be able to purchase it from you? I would need the piston rod as well, and I would guess I could get that from NPD or Classic. I would really much rather upgrade to one of your full C6 brake systems. Hopefully one day.