Built in residual valves

[brianj5600]

I am looking for a 15/16" master cylinder for 4 wheel disc. Do all drum brake MC have residual valves built in? If so how do you defeat them.

 

[red65]

National Parts Depot sells a master cylinder for a 4-wheel disc setup, presumably with the lighter residual pressure valves that are appropriate. I'm not sure about the bore size, but I think it's actually 1". I just bought one, but haven't had a chance to install it yet. Might be a place to start looking - it's a Wagner master cylinder and NPD's usually willing to give out the manufacturer's part number if you ask for it...

 

[brianj5600]

Thanks for the reply. What calipers are you running front and rear? And what MC do you have now? I have 99-04 GT fronts and 95 GT rears with a 1.0625" MC and manual pedal. I'm not sure I could lock up the tires if I wanted to.

 

[red65]

I have SSBC brakes all around. In the front, they're the same (approximately) as the original Kelsey Hayes 4-piston brakes that came stock on 65-6 Mustangs with an 11" rotor. The rear has a 10.5" rotor with single piston calipers that SSBC scavenged from an ~'88 Thunderbird Turbo Coupe. The M/C I have now is the stock '67 dual-bowl master cylinder (my car is a '65 that originally had the single-reservoir version), also a 1" bore I believe. Although I'm sure that the '67 has the incorrect residual pressure valves, at least for the rear, it hasn't caused any problems that I can identify.

I open track the car and have found that the brakes are adequate to a point. They slow the car well (yes, a determined poke at the pedal locks the tires), but heat up after extended use and start to get a little scary. They'd be more than adequate for the street, but are marginal for track use. Hope that helps.