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View Full Version : Brakes: Need opinions on installing dual master cylinder and Turner front discs on '64 Hawk



SuperHawk
06-30-2017, 04:28 AM
Needing advice from those who have done this. Subject car is a factory disc brake car with hydrovac.

It looks to me like if I want to continue using the hydrovac, I'll need to tun the steel brake tubing direct from the rear brake port on the master cylinder directly to the rear brakes, thus the rears would not get the hydrovac assist. Only the fronts would. Would this put an unsafe amount of bias to the front brakes?

Or, maybe not use the hydrovac at all, so I get no assist to either front or rear. Has anyone done this, and if so, do you need so much leg power that its not worth doing?

Its a pretty heavy car, so I'm almost thinking I need the hydrovac.

As an aside, I am happy with the Turner front discs, as I have them on 4 of my '64 Lark types, all with boosters. On one of these cars, I found that it was almost impossible to stop the car at all until I hooked up the booster.

I thank any of you for advice/experiences you can share.

Larry

Ross
06-30-2017, 06:56 AM
The fastest stop that is possible with any car is one where all four tires are are at their limit of adhesion--ie just before the skid begins. You want your rear tires doing their fair share or you will end up with longer stopping distances in a real emergency.

For cars that are not driven in salt, there is no appreciable risk of of new brake tubing failing. In 25 years of working on old cars full time, I have never seen a hose "pop", and actually only 2 plug up though that malady is very often discussed. In an non-salty environment, I consider a single brake system a very minor risk factor provided all brake tubing has been renewed. There should be NO Studebakers operating with original brake tubing at this late date. Ponder that brake tubing pits on the inside just as wheel cylinders do when the fluid is not flushed once in a while.

Now what I have seen on some cars with dual MC installed is that the pedal travel was inadequate to take advantage of the dual system. Whilst bleeding the brakes I discovered that there was no braking effect on the other end of the car and the pedal went to the floor. Because the modification was not engineered to the whole there was no safety improvement whatsoever--a fools paradise.

So proceed with caution or you may end up with a car that is neither safer nor stops more quickly.

wdills
06-30-2017, 11:54 AM
Give Jim Turner a call and ask for his input. I found him to be a wealth of knowledge and very willing to help when I put his disk brake set-up on the front of my car.

FWIW, I still have the single circuit mater cylinder with disk on front and drums on the back. It does take more leg power than a modern power brake set-up, but it is not terribly difficult in my opinion.

JoeHall
06-30-2017, 01:30 PM
While Turners are a good upgrade for drum brakes, they offer little, if any benefit over Stude factory disc brakes. In order to run a dual MC with either system, you must run the rear lines directly to the rear brakes, and use the hydrovac just for the front. So I'd leave the original PDB setup alone, and insure all components are working as new.

If you insist on Turners, and plan to bypass the hydrovac all together, in order to run a dual MC, I'd install a pedal for non-PS brakes, for more leverage. That is, unless you regularly squat 400 pounds or more in the gym. The same would apply for a factory PDB setup, with hydrovac bypassed.

StudeRich
07-01-2017, 05:27 PM
Yes I definitely agree with MOST of the above comments.

#1 Rebuild the complete Bendix/Dunlap Factory Studebaker Power Disc. Brake setup.

OR:

#2 Convert the Front to Turner Disc. Calipers.


DO NOT fool with the Master Cylinder other than to replace it with a New Single with the residual valve removed.

Either way of course the rear Drum setup will need rebuilding, and I much prefer to totally Flush CLEAN all components, most getting replaced, and install DOT 5 Silicone Fluid.

SuperHawk
07-01-2017, 11:51 PM
Note to StudeRich: Installing DOT 5 with a hydrovac will work for awhile, but the silicone does not expand the seals inside the hydrovac. This expansion is what keeps brake fluid from being sucked into the engine via the vacuum hose to intake manifold. Silicone fluid will get past the seals and into the engine. Not good.

Kdancy
07-02-2017, 07:24 AM
While Turners are a good upgrade for drum brakes, they offer little, if any benefit over Stude factory disc brakes. In order to run a dual MC with either system, you must run the rear lines directly to the rear brakes, and use the hydrovac just for the front. So I'd leave the original PDB setup alone, and insure all components are working as new.

If you insist on Turners, and plan to bypass the hydrovac all together, in order to run a dual MC, I'd install a pedal for non-PS brakes, for more leverage. That is, unless you regularly squat 400 pounds or more in the gym. The same would apply for a factory PDB setup, with hydrovac bypassed.

This is exactly what I did on a 58PH, bypassed the Hydrovac and installed a non PB pedal. Duel mc and drum brakes. Very good brakes now.