Re: Disc Brake Conversion
 

Any thoughts on juggling the proportioning valve settings on the disc systems to aid holding on the starting line?

Re: Disc Brake Conversion
 

My own experience is not the starting line that will be the problem. Quick story I bought a set of willwood front brakes for my chevelle from a speed shop. The counter person did not listen to what my car was and I ended up with a set of brakes for a 2400 pound chevelle (a tube chassis car, mine is a 3500 pound stocker). The brakes worked pretty good until I tried to haul it down from 115 MPH.....left the backside puckered a little bit. Called up willwood and they speced out the proper front set, got that set installed no problems. I have a disc front and drum rear setup currently and have two stepped up to 3200 rpms with around 800 pounds brake pressure with this configuration. FWIW

Re: Disc Brake Conversion
 

This one will have the 2-piston up front along with the 4-piston rear. It won't take long to find if it's going to be a problem. Putting a brake pressure gauge alongside the proportioning valve so I will know what's what. With the PG the car was pushing just below 3000rpm with drums, but come spring it will have a 3-speed metric and another convertor.

Re: Disc Brake Conversion
 

Greg, which master cylinder are you using?

Re: Disc Brake Conversion
 

Strange with the bore diameter a little bigger than 1 inch.

Re: Disc Brake Conversion
 

Same here.

Re: Disc Brake Conversion
 

Hope I am not stepping on this post, but I would like to know if a "typical race", rear disc brake conversion kit, changes the rear wheel spacing?
I want to use one of these kits on my GM "A" body with a 12 bolt with "C" clip eliminators, but I have no room to move the wheels out..... TIA

Re: Disc Brake Conversion
 

I believe the proportion valve goes on the rear brake line to limit the pressure to rrears as to not get rear lock up, and equal brake bias for correct stopping.
If you switch from rear drums to rotors I think it is based on the thickness of the rotor where it goes over the axle hub, which should be very close to the thickness of the drom, just slightly thicker, in the thouanths range. That is my take on it. I do not think it would be a problem. Hope someone who performed it already will chime in.
Chris

Re: Disc Brake Conversion
 

I just went thru this conversion. I had 4 wheel drum brakes on my Fairlane and the car stopped fine at 130mph but it would push thru the burn out every once an a while if you didn't jump on the gas to get it going. I had always heard that drum brakes hold better and disc brakes stop better. That was not true the disc brakes do every thing better. No more 1 wheel lock ups trying to wheel race no more pushing thru the burn out no matter how slow I bring the RPMs up and you can stage on a flee if you want to. Plus I loss 67 lbs. I have strange 4 wheel disc and started with the stock 1" bore MC but switched to a 1 3/32" MC for a Mopar from NAPA.

Re: Disc Brake Conversion
 

Just got the the rear system installed last night Bob and we found the spacing to be nearly identical to original. Going to work on the master cylinder today.

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Front -

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