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johnesmonde
05-28-2005, 04:51 PM
This is the continuing saga of the disc brake conversion for my '62 Hawk. Disc brakes work and are balanced with back drums via the proportioning valve. Have brakes but not good enough. Cannot lock up the discs. Lost the booster when I converted to dual M/C. My brake pedal is for a power brake system and different than a standard brake pedal. If I change to a standard brake pedal with a different ratio I may get enough pressure to make the brakes viable. Will any Stude pedal work or does it have to be off a Hawk? Anyone know where I can get one that will work?
I could use a Stude Hydrovac for disc/drum and dual reservoir M/C from a later year. My booster is for drum/drum and single M/C. Any idea where I could get such an animal? Is my logic correct and am I on the right track?

John

'62 Hawk
'30 Chev Coach

PaulDriver
05-30-2005, 10:39 AM
look at http://www.mpbrakes.com/mpfaqmasters.htm for some tips on the subject.

and have you considered something like this?
http://www.mpbrakes.com/bm1501.htm

studegary
05-30-2005, 01:41 PM
Studebaker did not offer a "...disc/drum and dual reservoir M/C..." on cars.

N8N
05-30-2005, 03:29 PM
Gary is right, all factory disc brake equipped cars were fitted with a single reservoir master cylinder. The only ones that are practical to convert to a dual M/C while keeping the power boost are the ones with the vacuum booster (on the firewall) all C-K bodies had the underfloor MC and Hydrovac so you're SOL.

In your situation I would first try to find a pedal for a manual brake car (or look at your pedal and see if it can be adapted - I know the pedal on my manual-brake '55 coupe has two holes in it, I ASSume the other one is for the power brakes) and see if that gets you the leverage to be where you want to be; if you're not happy with that it's time to start looking for a dual circuit Hydrovac - I believe one of the street rod places sells 'em but they're not cheap.

good luck,

nate

--
55 Commander Starlight
62 Daytona hardtop
http://home.comcast.net/~njnagel

johnesmonde
05-30-2005, 06:39 PM
Thanks for the info guys! My shop manual says that cars equipped with power brakes at the factory have a special pedal which has less travel than the conventional pedal but the linkage is the same. I tried the second hole Nate but the linkage was then too short. I measured the rod travel in both positions and it was approx. 3/4 of an inch. I could weld an extension to the cylinder rod but that wouldn't change the travel distance. The change in position may change the ratio slightly so I get more pressure but I don't think it would be much. It seems I'm looking for a conventional pedal. Paul, thanks for the brake info. Gary, I guess a Stude booster is out of the equation.

'62 Hawk
'30 Chev Coach

N8N
05-30-2005, 07:05 PM
You are right, after more research it appears that the two holes are for different body styles (C/K and non-C/K) and that you do need a different pedal.

good luck,

nate

--
55 Commander Starlight
62 Daytona hardtop
http://home.comcast.net/~njnagel

jcstude
06-02-2005, 10:26 AM
This whole issue cannot be rocket science, at least I hope not. Get Master Power Brakes catalog and study that. It is not 100% correct but who is? The modern (Midland) single diaphragm remote boosters produce about 850 psi which is marginal for disc brakes. The dual remotes that are in the hot rod brake catalogs are just two of the aforementioned single diaphragm units mounted back to back and need a space of 1' by 2' and lots of plumbing to be mounted. I just sent a 63 GT Hawk w/disc brake Hydrovac in for a rebuild. I have a Turner front disc conversion that will be installed in my 57 Silver Hawk. My plan of action is to use an original style single chamber master cylinder with built in residual check valve removed . The rear brakes are drum but not the type that were used in the 63 Hawk. I will try an adjustable Wilwood proportioning valve and 10lb in-line residual pressure valve. If this works, I will put my dual master cylinder kit on the shelf for another project car to be named later.
I will share my success or failure here. By the way, I am told that a 1" diameter master cylinder piston is about the biggest you can go without a booster. If yours is bigger, then a smaller piston unit might work. I am told the trade off is a much lower pedal with the smaller piston. You will also have to closely monitor your fluid level as the pads wear on your discs. All of the above info is second hand so stay tuned for my report on the actual build up. Johnesmonde, do you have a manual that is specific to the Hawk? Reason I ask is the 59-64 Shop Manual that covers all cars is real weak in descibing the disc brakes, in my opinion.

Lew in Escondido, CA

johnesmonde
06-02-2005, 08:25 PM
jcstude, I have the same 59-64 shop manual. My discs are a Turner kit I installed with a dual M/C so the disc brake description does not really apply. My booster is drum/drum type and now out of the loop due to the dual M/C. I am having little luck finding a conventional brake pedal to make standard brakes work. I wonder if welding an extension on the pedal to change it from an 8.5 inch to a 10.5 inch pedal would work?

'62 Hawk
'30 Chev Coach

hank63
06-02-2005, 09:04 PM
You could have a chat with Hot Rod people in your area. Those blokes sometimes adapt modern (small dia) boosters and master cylinders to fit underfloor on their rods. I've seen a 1930 Ford fitted with a Toyota booster & master cylinder. It was well engineered and looked neat and was out of sight under the floor. The owner claimed low pedal pressure and excellent stopping ability - disc front & drum rear.
/ H

jcstude
06-03-2005, 10:02 AM
Hank, thanks for the suggestion. I have talked to the local hot rod shop and they agreed with me that a 7" booster (850 psi, inadequate pressure for discs) is too big to fit under the floorboards and most of the dual diaphragm high pressure units (1000-1200) are even bigger at 8" diameter. It may be possible to mount the unit behind the body brace and have a rather long actuating rod extend from the pedal through the body brace to the booster. This would put the 8" vacuum cannister under the seat where you could cut a hole to allow the unit to mount as high as possible on the frame rail. The upper portion of the booster would extend into the passenger compartment. Another hot rod shop suggestion was to install a Hydroboost unit that is a combo power steering and brake booster affair. Without having one to actually look at it, is hard to determine if/how it will fit. From a picture I've seen one would probably have to rig up a new pump mounting bracket and trim back the inner fender apron. The other issue would be clearance from the Saginaw power steering sector box that I have in my car. If you have the left/right cylinder actuated power steering it may not be an issue. I am determined to get this to work without blaspheming by putting in a Chevy front clip with belly button 350.

Lew in Escondido,CA

jcstude
06-03-2005, 10:18 AM
John, sorry I didn't respond to you in my previous post. Lengthening your pedal may work if you have an auto transmission. I would worry about the mismatch of the clutch and brake pedal positions in a manual trans car. Of course you will have to cut a new hole in the floorboard and if you have big feet, your toes might be up in dash wiring. However, this may be the simplest and most cost-effective solution.