Turkr42

I am converting the front brakes to disc on a 1955 Dodge Custom Royal. The car has a single reservoir master cylinder with power brakes. If I put in a combination valve to control the pressure on the front/rear brakes, couldn't I just put a tee in the line coming out of the master cylinder to hook up to the 2 inlets on the combination valve? I need to figure out this method as my research has shown that there is not a dual reservoir cylinder that will fit on the power booster that is on this car and right now it is not in the budget to change the whole system. Any advice on the matter would be appreciated.

TVLynn

Do the conversion... Try the brakes without first... May be ok ?? Or just put it further back in the system ? On the rear axle ??
A lot of them had ex panders ? in the wheel cyl to keep the residual pressure

Rooty

Theoretically there will not be enough volume of fluid from the master to fill all brake pistons to achieve effective braking hence the dual reservoir. If frugality is a must, the best you can do is to install a residual (not the adjustable type ) to keep the rear shoes close to the drum surface. This can be mounted somewhere as close to the master as possible. Behind the residual valve (going to the rear ) mount an adjustable proportioning valve that will drop the pressure to the rears but understand that this valve is not the same as the residual valve which maintains slight back pressure but does not affect the apply pressure or flow like the adjustable proportioning valve. Ahead of the residual valve you can mount your tee and divide the fluid flow to both the front and rear with no obstructions in the front lines. If you manage to get enough flow and pressure out of the existing master you should be good to go. If the pedal bottoms before attaining good braking ( with a bit of reserve stroke at the pedal) your bitched and a rethink is in order. Best bet would to get a complete brake unit ( master and cylinder ) from the recycler's and install it as a complete unit. You may need a different length "pedal to booster" push rod but these are cheap and readily available. Mounting brackets are also available cheap. Sure a few mods may have to be made to make the unit fit and work, but hey, your a man of talent or you wouldn't be working on it, right? If you have doubts about what you are doing think about this- my '65 has a hydroboost system driven by a Saginaw power steering pump. The system was off a 2001 GMC 2500 and when installed rendered the best braking I've ever experienced. All from a junk yard for $80. If the concorse look is what your after you'll have to research and work your way through existing Mopar parts but hey, safety in braking is not just between the rubber and the road, it's the system as a whole. Stay safe, do it once, do it right. And oh, the manufacturers of both residual valves and proportioning valves recommend they be mounted as close to the master as possible - check them out.

DDodger

There is no way in hell I would go to all that work without going to a dual master. I'm old enough to remember when brakes actually FAILED "pre" 67 or so. My first car was a 57 Chev. First car I drove was Dad's 55 Chev wagon

So far as volume, that is a misconception. Disk brakes do NOT need much volume to operate, because the caliper pistons don't move very far in normal operation.

Master cylinders are not expensive. If you "look around" at "real" parts stores you can find one that would work.

So far as teeing off, yes. Just buy an aftermarket adjustable prop valve such as from Summit.

Turkr42

No, I'm not after the concourse look. I'm after a feasible solution. I just don't want to try something and it not work. Luckily, I work for a steel fabrication shop so making brackets or fabricating parts is not an issue. I just don't have any knowledge with the brake system. Where can you find "pedal to booster" push rods? If these are readily available, I could fabricate any plate for the firewall to fit a different booster/master set up. Right?

Turkr42

I was just looking at booster/master combo units online. I see they're not that expensive. Is it safe to assume that all I have to do is make it fit on the firewall in line with the brake pedal connection and then make that push rod fit? Does the rod that goes from the pedal into the booster come out very easy in case I need to modify it?

78D200

^This.

I'd install the proper master/booster that your brake system needs. You'll need to make an adapter plate for it to fit your firewall (easy enough for a backyard mechanic, should be even easier for you) and then try the pushrod that you have or buy another one. Some master/booster kits come with an adjustable pushrod depending on the throw of the brake pedal. If your rod is too long, you can always install a spacer between the booster and firewall as long as its only a reasonably short distance.