Brakes: 64 Hawk Master Cylinder for Disk Brakes

[studebaker-R2-4-me]

I woke this morning with a pool of brake fluid on my shop floor.... not happy after just dealing with a Hydrovac in South Bend a few weeks ago.

Here's my question I was checking out Nate interchange page and he lists Wagner 2797 Raybestos MC2797 and Napa UBP2797 for all CK up to 1964 but he also has a section for Disk Brake cars. Mine is a stock disk brake car.

Is the Wagner the right master cylinder for my Hawk? Is there residual valve to remove?

SI has them listed for $116..... Ebay under $50

Here is a link:

http://cgi.ebay.com/ebaymotors/WAGNER-MC2796-Brake-Master-Cylinder-_W0QQcmdZViewItemQQhashZitem5ae0884eacQQitemZ390314086060QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Is this the MC that I am looking for?

Allen

[skyway]

If the MC with disks is the same as for drum cars,
then it's real common, and used to be spec'd for lots
of commercial applications such as TowMotors and such.

If that's the one then try a fleet/commercial parts joint.

[Jim B PEI]

The 63 Lark disc/drum M/C is a single and quite different from the drum/drum which a dual circuit. I thought all C/K up to 64 were still single circuits, and require yet another M/C. ISTR that there were originally something on the order of 5 or 7 M/C in 63 depending if you had all drums, or disc/drum, or manual or power, and if it was a Lark, Avanti or Hawk.

There is some difference in the Studebaker disc/drum having to do with residual valve or lack of it, isn't there?

[studebaker-R2-4-me]

The 63 Lark disc/drum M/C is a single and quite different from the drum/drum which a dual circuit. I thought all C/K up to 64 were still single circuits, and require yet another M/C. ISTR that there were originally something on the order of 5 or 7 M/C in 63 depending if you had all drums, or disc/drum, or manual or power, and if it was a Lark, Avanti or Hawk.

There is some difference in the Studebaker disc/drum having to do with residual valve or lack of it, isn't there?

Sorry Jim, I suppose the Lark picture threw you. I have a 1964 GT Hawk also. This is a very specific question regarding 1964 Hawk Master cylinders with little information in the technical archives. My Hawk has Stock bendix front disk brakes with a Hydrovac. It is single circuit similar to the Ebay link I provided. I am not sure the difference between disk brake and drum brake Masters. My question again is whether I can purchase the Wagner 2796 master and remove the residual valve and install it or is the disk brake MC different totally from this unit?


Allen

[Warren Webb]

Its the same master cylinder, just remove the residual pressure valve. This master was used on Studes until 1960 for cars, Hawks until the end in 64 & Champs to 62. With disc brakes the residual pressure valve was left out. The parts book has a breakdown of all the parts of the master so you can compare them.

[Jim B PEI]

Ah, that is the answer to the disc/drum for C/K--not that it takes a special valve, just that you remove it. Allen, yes, I lost track of the conversation. I think it was talking about the Hydrovac and then mentioning you had a stock disc brake car which I misread as 'manual' (but manual disc brakes--would be a beast to stop!) and then there was the picture of your 63 so....not enough coffee

[jimmijim8]

My experience

I bought mine from NAPA, Stude Vendor, Fork truck parts supplier. All three were priced differently and most likely made by different manufacturers. cheers jimmijim PS I've got a line on a firm that remanufactures the brake boosters used in conjunction with the frame mounted master cylinders. Disc or drum. 3 yr warranty. CASO- Great price. PM me if you want Info. I don't have a dog in this race but had mine remanufactured by them. Works great and cosmetically right up there. I ain't Lion. cheers jimmijim

[studebaker-R2-4-me]

Its the same master cylinder, just remove the residual pressure valve. This master was used on Studes until 1960 for cars, Hawks until the end in 64 & Champs to 62. With disc brakes the residual pressure valve was left out. The parts book has a breakdown of all the parts of the master so you can compare them.

Thanks Warren for the information especially about the parts book, I forgot what a good resource that book is. I pulled the Master this afternoon and it is indeed the MC 2796 with no residual valve. I ordered the master cylinder here locally and will have it in the morning. I will have to take it apart and remove the residual valve and I should be good to go once again.

Allen

[royvaldez]

Okay, what is the part number for 1964 master with disk brakes. I need to buy one . I was told they were dif. from those that use drums.

[studebaker-R2-4-me]

Okay, what is the part number for 1964 master with disk brakes. I need to buy one . I was told they were dif. from those that use drums.

I bought a MC 2796 Raybestos you have to take it apart and remove the residual valve at the back of the cylinder. See the parts book for exploded view.

Allen

[royvaldez]

I just bought one for my 64 gt disc brake car. Please post pictures of what you did.

[jimmijim8]

Not the same animal

Booster on a K mobile is different for drum vs. disc application. I ain't Lion jimmijim

[studebaker-R2-4-me]

Booster on a K mobile is different for drum vs. disc application. I ain't Lion jimmijim

Hydrovac boosters are different but we are not talking about hydrovac here, so lets not confuse the post. Master Cylinders are the same with the exception of the residual valve for drum cars. Simply removing the residual valve in the MC 2796 you will have the right master for a disk brake car. Believe me I just pulled it out of my Hawk and took it apart.

[jimmijim8]

OK? DISC not DISK {like a discus}

At least now I know there are 2 of us here on the forum knowing of the two different types of boosters used on 63-64 Hawks because of drum brake and factory disc brake set ups. Just thought it was a good time to share the info with others. Although the boosters look very much like the same animal to the untrained eye, I thought it appropriate to enter said information so as to educate ones not knowing of this. Some people inadvertantly have confused and used one in place of the other due to the subtle physical differences upon not real close examination. This has caused some to have a misconstreud conception of what a properly functioning brake system of these 2 different type equipped cars feels and performs like. All clear now? I thought my post was somewhat remotely related and didn't intend to confuse any body. If you like I will delete my insignificant, confusing remark. However, I do consider your reprimand a bit chicken sh#$. thanks for your input. cheers jimmijim QUOTE=studebaker-R2-4-me;553721]Hydrovac boosters are different but we are not talking about hydrovac here, so lets not confuse the post. Master Cylinders are the same with the exception of the residual valve for drum cars. Simply removing the residual valve in the MC 2796 you will have the right master for a disk brake car. Believe me I just pulled it out of my Hawk and took it apart.[/QUOTE]

[studegary]

Jim - I, too, use disc rather than disk, but I believe that they are two acceptable spellings of the same word.