Brakes: Turner Brakes and Master Cylinders

[studebro2]

A couple of years ago I purchased a 54 Commander w/ Avanti R1 and power shift, custom seats, Hawk dash yada yada.
It had manual drum brakes but has power steering which I suspect were from a GT Hawk parts car. I have purchased and mostly installed a Turner disk brakes kit and suspect I may have a MS issue. I am having problems getting the brakes to 'pump up'. BTW there was no residual check valve in the MS. All 4 brakes have been bled per instructions. The MS is a split system, see attached. I am hoping someone can identify the MS for me. Looking at Master Cylinders on SI's catalog page 264, I am trying to figure out which MS would be appropriate. Because the brakes are not power assisted, I may need a different MS due to the disk brakes? The only split system MS without power appear to be for Larks but they look to be for drum brakes?
Thanks,

[karterfred88]

Since it has a Turner conversion, I would ask him. I would think that an under floor M/C would need check valve since the pistons are below the wheel cylinders, but Jim can fill you in on the correct setup. I does sound like you need one somewhere if you have to pump up the brakes and there are no leaks.

[Warren Webb]

I'm sure Jim will chime in on this but it is my understanding that an inline residual check valve should be installed on the rear brakes, assuming they are drum brakes. He provided a #10 for the rears on my purchase of a master & bracket for my 62 Champ.

[1oldtimer]

Looks like a Jeep or AMC master, I would ask him because I think they come in different bore sizes. If it's under the floor and lower then the calipers you'll need a 2lb for the front and 10lb for the rear drum. Also check to make sure they're not in the master before you add an inline one. I use the ones from SSBC as others leak (I think he uses the "right stuff" brand and mine leaked), but I've also seen Wilwood leak also.

[StudeRich]

Most AMC and AMC Jeep Dual Master Cylinders have the Line ports to the Engine, the same as Studebaker, as this one, the similar looking Ford's are on the Fender Side.

Of course mounted on the Firewall, where they were designed to mount.

A residual check Valve is needed in the Rear circuit port and a Equalizer Valve for the Rear, since you chose a Dual Master Cylinder and now have front Discs.

This Master Cyl. may work with the correct parts added, it is still best to contact "The Master": Jim Turner.

[52 Ragtop]

Yep, looks like the 2# and 10# residual check valves are missing, as well as the prop valve. Gary called me and Parts are boxed up and will go out tomorrow.

Jim

[Tsanborn]

I have a recurring problem with my Turner Disc Brakes. I have a '57 Hawk that has not been getting much exersise recently but thought I'd pull it out for IDYSD. After a few miles, I was turning into a mechanic friend's parking lot and the brakes froze up. We jacked up the front end and found that both calipers were clamped tight against the discs. Taking a close look at the left brake line, I could see that it had been pinched by the suspension. As soon as I cracked the line, pressure was relieved and both fronts rotated. I replaced the compromised line and drove home. But as I started to drive into my garage, they froze up again. This has happed before and I had to install a new master. The master is I believe a Mitsubishi duel m/c with two ports for a double remote reservior. The current m/c probably doesn't have more than 1000 miles on it but it has been inactive for 6 months or more. I could replace the master again (third one since I installed the discs) but I'm concerned it will continue to occur. It was fortunate that this time, the problem occured at my mechanic friend's parking lot and later in my driveway. Could anyone weigh in on what may be happening? See photo of the m/c below.

[enjenjo]

Make sure the master cylinder pushrod is not too long, holding the piston slightly depressed masking the compensation port that allows the pressure to release when the pedal comes up. There should be 0.060" clearance between the pushrod and the master cylinder piston. The other possibility is a lazy pedal return spring that allows the brake pedal to be slightly depressed when released.

[jetboat]

I had simular problems, as stated the the rod was a half turn to long.

[Tsanborn]

The M/C looks good, o-rings are lubed and back in place. I'll remount it and check on the rod play. Many thanks to all! BTW, I regret that my initial message started with "I have a recurring problem with my Turner Disc Brakes". Jim Turner is a prince of guy and his products are outstanding. Sorry Jim, I'll try to phrase things more carefully in the future. I should have said, "I have a recurring problem with my own shoddy work!"

[StudeRich]

It is not My car but, the FIRST thing I would do is get Rid of the "Foreign Car" or "New Car" remote reservoir Master Cylinder !
Does it EVEN have a correct USA 1 Inch size bore, or proper stroke?

The recommended M/C's for Disc Brake conversions are AMC/Jeep or Ford Cast Iron with integral reservoir, older Car US design with correct Fitting size and Proven to work correctly.

A M/C for a Disc/Drum car will always have a Large Reservoir for the Front, and a smaller one for the Rear Brakes.

[Steve Winzar]

Yep, looks like the 2# and 10# residual check valves are missing, as well as the prop valve. Gary called me and Parts are boxed up and will go out tomorrow.

Jim

Hi Jim- I have a particular interest in the subject of Combination/Proportioning Valves and have only recently replaced the ancient, obscure Kelsey-Hayes Valve on my '81 Avanti II with a GM style P2 valve (to blazes with my penchant for originality ). This valve fits the same location exactly. Pray tell, what Valve did you end up with?

[Tsanborn]

Thanks StudeRich, you're probably right that my current M/C isn't doing me any favors. Ever since I installed the disc front brakes along with the current M/C, I've had a long throw on the brake pedal. Maybe 1 1/2" off the floorboard. I'd like to check with Jim Turner before I scrap it since I believe the Mitsubishi was his recommendation at that time. The only way I can see to keep the current M/C and decrease pedal throw would be to increase the lever arm between the brake pedal pivot point and the point of attachment of the push rod. And even if I had the talent to machine that up, I'd probably find that the rod would no longer align with the M/C. Are the master cylinders you are recommending (cast iron Ford or AMC/Jeep) dual M/Cs? Are the integral reservoirs accessed through the through the floor?

[StudeRich]

Jim modifies the AMC/Jeep Dual Master with a hole between the two reservoirs, and a hole in the side of one half, connecting one chamber to a Remote Fill Cylinder Repro. of the Studebaker optional and GT Hawk Disc Brake standard bottle. It is all in his Remote Fill Kit.

Otherwise, you have to cut a larger hole in the floor and make a cover for the floor.
That's the type on the right firewall with the Red fluid warning label on it.

[Tsanborn]

Many thanks StudeRich! I'll check it out.