I'm setting up my brakes now, and not sure if i'm headed in the right direction...I'm running Buick finned drums on 48 Ford backing plates up front & big brakes on a Ford 9" on the rear. Drum / Drum .I built a pedal assembly with a 6- 1 ratio. This is my question, what is the best un boosted master to use? Another question is, I have a 75 Corvette master new in the box that I picked up some where ....can I use that? Was thinking of early Nova or Camaro...Drum /Drum master???
Far as I know, thats the cylinder of choice... A big reason is, the brake lines exit on the opposite side. I also think it has other values.... Keep in mind, you need a drum to drum MC. I think that one is disk to drum.... double check that I have used that one many times myself with aftermarkey set ups...Disc / drum The company I call for tech advice is Brake Tech Solutions... They do a hell of a job.
I've run the 68 Chev truck manual brake master cylinder on several brake swaps with drum/drum and it tends to work pretty well for me. It does fit several other GM applications and is still easy to find new.
On non boosted systems i generally use 7-1 ratio, I tied the disc/drum GM 1" bore cylinder with 4 wheel drums and it worked very well.
I personally would avoid the Corvette M/Cyl. You will need residual pressure valves (sold by the after market industry) to make it work. I don't trust hotrod parts. It's a long standing tradition that is hard to break. I've always used Mustang M/Cyl for drum drum brakes. 68 I believe. It has the built in residual valves. No need for extra parts that have a shady reputation by some. I believe in the KISS system. Keep It Simple Stupid.
70's mustang, dual well. Drum/drum, no residuals needed. This is what I'm using on my A. You'd have to do a little research to make sure it's right for you.
I agree with the drum/drum master with built in residual valves...I was just talking with a car guy at work about this and he said the same. I was leaning toward GM because of the port location on MC. Maybe someone knows of a early GM master with built in residual valves??? Would you guys happen to know what the bore size of those 68 and 70 mustang masters are? Thanks for all the input and help from all.
You can use the '75 Corvette disc/disc master if the bore is 1" or less. (All Corvette dual masters are disc/disc) Check to be sure the pedal can full stroke the master before it bottoms out, and add a 10 lb residual to each axle. Make sure the push rod bore is over 1" deep if you use an un-restrained push rod. Most power masters have the deeper bore. Drum/drum and disc/drum masters up to the early '70s had internal drum brake residuals. However, some rebuilt/reman masters may not have had them reinstalled, so check the master you use for them. The '68-'73 Mustangs used a 1" master, along with most cars and light trucks.
Do I also have to run proportioning vales front and rear with the Corvette master? I spoke with a guy at ECI today...he said i could use the Covette master with residual valves and proportioning valves front and rear...he also said to use a 1 !/8 bore master with a 5 to 1 ratio.??? I'm learning alot ...I think...lolhaha They will all probable work...but I'd really like the one that works best.
Proportioning valves front and rear That's a new one. Because your rear duo-servo brakes are much more effecient than the non-servo front Lockheeds, (the reverse of what you should have as the bigger better brakes should always be on the front axle) using an adjustable prop valve to the rears isn't a bad idea, to keep the rears from being too aggressive, based on wheel base, tire size, weight, etc. Using an un-boosted 1 1/8" master with a short 5-1 pedal ratio will require abnormal pedal effort. FYI, 1975 Corvette boosted masters are 1 1/8" while manual are 1".
I had never heard of proportioning valve on the front either....iI also agree that the 5 to 1 ratio having too much effort also. My mc is 1 inch gonna run it with residual vales ( if mine doesnt have them) and single proportioning valve...if doesnt work well I;m thinking i can change corvette master to different bore sizes to get the brake I'm looking for. Maybe idk...lolhaha Thanks for all input.
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