1964 GT Hawk R2 Brake Issue

[JoeHall]

Hi Art,
Here are the parts you'll need, as listed in the Studebaker International (ph 317-462-3124) 2014 catalog: 802101 Hydrovac, 63-64 Hawk w/front discs; 536652 Hydrovac flex hose (need 2); 1543003 Rear flexible hose (connects to 'T' on rear end housing); 1558124, Master cylinder, 63-64 Hawk w/front discs (cap not included); 679927 Master cylinder cap and gasket; 189696 Master cylinder screw (special bolt that holds 'Y' fitting in place); 195470 Master cylinder 'Y' fitting.

Hopefully I did not forget anything. The correct cap for your MC is not listed in SI's catalog, but they may have one one hand. If not try other vendors, i. e. Stephen Allen in Florida. I listed the regular cap, in case you have to use that for awhile till you can find the correct one. Need the correct one to plumb the reservoir to the MC. You may also need other plumbing parts, will need to inventory yours and compare with the Parts Manual. I listed the HV rubber hoses because unless yours are nearly new, I'd replace them, as they tend to swell on the inside and restrict flow after a few years; ditto for the rear rubber hose. Retain your vacuum check valve, as you will probably not find another, "correct" one (yours appears correct in the pix). Test it to be sure it seals well, but it does not have to be perfect, a little bit of leak down is OK. Install new vacuum line, and insure the check valve flows the correct way. It appears to have been reversed, comparing the two sets of pix. The correct HV looks similar to the one you have now. Best way to insure they sent you the correct one is that it will only have one bleeder valve, whereas the wrong HV has two (like the HV on the car now).

When you check the 11" rears, if you need anything, I have a full set of everything: new drums, wheel cylinders, shoes, etc., with maybe 2000 miles, and 1-2 years old. But our vendors same, brand new. Long story, but for, "the wife's" factory PDB equipped 63GT I replaced the 11" with 10", retained the tandem MC, and plumbed the rears to bypass the HV. It works great, but yours will too, with the 11" rears. Wife had another 63GT with factory PDBs for about 10 years, and the OEM brakes were excellent. The wife drove it 50,000 miles before totaling the car.

I suggest keeping your 11" as it will: retain factory front/rear balance; be closer to stock; simpler to do, and require less parts. But if you decide on 10" rears it is doable, but pretty sure you'll like the 11". The main difference between 10" and 11" rears is the 10" are self energizing, whereas the 11" are not; they work just like discs, so need lots of line pressure to squeeze the shoes hard enough against the drum to stop. Without the HV boost, the 11" brakes are all but nil. But the 10" don't need near as much line pressure, and balance well with the HV boosted front discs.

Hope this helps.

[CO64]

I was curious, what does "OP" stand for anyway? I think I even saw "PO" somewhere in the thread, lol, and I wasn't PO'd at all : ))

Back to the topic:

OK, to recap: I get a proper HV for Power Disc Brakes (I think there was a place to purchase one noted back in thread, but want to confirm. I think the forum member noted that without a core, they are all but impossible to get. So, a part number (also I think there was one listed) and supplier would be great.

Second was the MC: So, go back to a non-split OEM MC? Not an issue, did it on my 64 Marauder and it works fine. I just have them on 6 year replacement or rebuild plans. Again, source and part number would be great.

I will remove the proportioning valve when I re-plumb the brake lines. If I understand, a brake line will go directly from OEM MC to one side of the HV then leave the HV and split into serving front and rears. That will also allow the pressure switch to perform its task. Please confirm.

Last. Should I or should I not replace the brake pedal. It appears to be original, and per one of the posts, the car with the performance package would have had Power brakes. So, the pedal design should be of the appropriate mechanical leverage to work with the system, once corrected.

As to brake fluid, I will have the entire system flushed. What is the recommended replacement fluid? Please confirm.

Oh, and as you noted Joe, I will do complete servicing of the rear brakes and drums. The front brakes and rotors are pristine. I was really surprised. I am thinking that the car got a lot less driving once the brake mods were made and it was difficult to stop. Therefore there is little wear on at least the fronts.

If possible, please confirm the couple of items above and I will get into purchasing the items and then will be ready to get her on the road with confidence.

Thank you to all who have contributed to the post. It is great to be a part of a great car community. A 64 R2 Hawk has been on my wish list for a long time, so I am very pleased to now have one of my own. I look forward to exploring the car. I am sure I will find other "interesting" things that I will post up on the forum, seeking the wisdom of the experts. As Jay Leno always says: ' When you decide you want to buy a car, you need to find "the guy"'. The Studie Forum appears to have a number of "the guys" who know the cars inside and out.

Thx

Art

[StudeRich]

It may remain a Mystery why the Serial Number Plate "appears to have had" it's Welds cut and was mounted with Rivets.
It IS "possible" that Engineering for some unknown reason actually did switch the Serial Plate from a Standard Production Car to this Prototype R2 Jet Thrust Show Car.

I could understand a car being Re-Serialized after having an Engineering Number "EX" Originally, but they were screwed on and would not need to be Cut, and of course this plate is the standard Production Plate.

[JoeHall]

Hi Art,
Will stop referring to you as, "the OP" LOL. Yep, the 13" backside, wheel cylinder backside, and backing plate all confirm OEM 11" rear brakes. Technically, the only, "incorrect" components in your brake system are: Turner front discs (a good upgrade), the drum brake HV (definitely need the one for discs), and the tandem MC. The tandem MC is a good safety upgrade, but with the 11" rears bypassing the HV, you lose about 900 PSI in the rear lines, going to factory, "detuned" 11" brakes. So you'll get about 90 percent stopping power from the front discs, and maybe 10 percent from the rear drums. But with the OEM type MC, and front & rears plumbed through the HV, you will have nearly restore the factory front/rear balance. I say nearly, because the Turner front discs are generally thought to be more efficient than OEM.

To recap, there are other options, but most feasible to me: install the correct HV for discs; replace the tandem MC with an OEM type, and open the rear proportioning valve all the way, or simply remove it. Of course the rears should be disassembled and inspected, repaired/replaced as necessary. Everything is available, albeit some may be repro.

[JoeHall]

I am in the process of converting my 64 Hawk R1 from drum brakes to Turner disc front brakes and 11" rear drums. This is under the assumption that Studebaker and Bendix knew what they were doing, and the non-self-energizing drum braking characteristics are better matched to discs than self-energizing drums on the rear. If I am wrong it would be good news in a way as I can more easily put the 10" brakes back on the car than finish the conversion to 11" rear drums.
-Dwight

You are correct, as long as you use an OEM type MC, and plumb both front and rears throughout the HV. Also, you will be sorely disappointed if you do not use a HV, preferably the one for PDB, since it puts out much more PSI to the brakes. Also, if your car originally had powered drum brakes, you will greatly benefit from the 63-64 PDB/59-64 standard pedal described above, and shown in the pic I just now posted.

[CO64]

Back again.

Crawled under car and took a few pics while I was there.

First things first, Joe, the OD of the rim of the brake drum measured 13", yes 13. You can see that it fills the wheel pretty well. I did not pull the wheel, because I was able to get at it from under the car.

Also took a couple of pics of the backing plate. As noted above, that may provide clues.

In addition, there is the infamous drain plug, verification of the 3.54 twin traction rear end (very cool) and a close up of the door jamb tag.
I saw the notes above discussing the originality of the car, all good. Good to challenge. I have captured the data from the D/S website, so I have it.

I called Timeless Horsepower and talked to Brett Watson, the person who sent the car to Mecum.
Here is the backstory:

Car was purchased by a gentleman named Dwayne. Extensive collection of 80+ cars, in a "museum-like" environment in Colorado. He is the one to purchase the car from Daniels/Schmidt in 2016/2017. He had 80 cars, so that is why he only raked up a couple of hundred miles not the Hawk.

Brett knew the documentation was important, but Dwayne is sadly suffering from health issues, causing him to liquidate his collection : (. Dwayne and his curator could not find the documentation. Brett also Called D/S and they remembered the car, but did not have the paperwork and were confident it went with the car.

So, Brett is still working with Dwayne and his curator, as they are almost done selling-off the collection. Brett has my contact info and will pass along to Dwayne and let him know I will have the car for a very long time, if the paperwork is found. FYI, I don't sell my cars. I search for the ones I want, and if lucky-enough to buy it, it becomes my kids or surviving spouse's issue to sell : ). I get way to attached to my lady friends.

I plan to call D/S as well, just to see if they can point me to the previous owner, so I can continue to build the history.

I really appreciate anyone on the forum that thinks they have some knowledge of the car, previous owners, or any other aspect. I love this aspect of classic cars. The stories are as much fun as the car : )

Please take a look at the pics and I am interested in hearing the options for upgrading the brakes.
Joe, quick question, would pulling the pressure switch (or buying an alternative) and have a tee in brake line and put it in (temporary) be possible short term solution to getting brake lights? (I need to check that I have juice to the hot side of the switch, but it I do, then I can use that circuit). Other recommendations are welcome for quick-fix on brake lights.

Thanks as always,

Art

[JoeHall]

Here's a pic of the two different pedals. The OP's car has the one with 1.75" distance between holes, easy to discern, on or off a car.

[Dwight FitzSimons]

Since your priority is on brakes that work well, and the Turner kits are already in place, consider yourself lucky if your GT came with front drums (power or standard). The reason is, it will have 10" rear drums with self energizing shoes. If it came with front PDBs, it will have 11" non-energizing rears. The 11" are the worst balance match with front discs and tandem MC, with rear brakes plumbed to bypass the HV. Easiest way to know whether your car has 10" or 11" rears is to remove a rear wheel and measure. I will attach pix of 10" and 11" drums for comparison, so you can figure out which you have. With either 10" or 11" rear drums you can still have good brakes, but let's hope yours are 10"!

I am in the process of converting my 64 Hawk R1 from drum brakes to Turner disc front brakes and 11" rear drums. This is under the assumption that Studebaker and Bendix knew what they were doing, and the non-self-energizing drum braking characteristics are better matched to discs than self-energizing drums on the rear. If I am wrong it would be good news in a way as I can more easily put the 10" brakes back on the car than finish the conversion to 11" rear drums.
-Dwight

[JoeHall]

If it is an R2, then it would most likely also have been equipped with factory disc brakes (Dunlop/Bendix). It also would have the type "F" Bendix Hydro-Vac brake booster. There would have been a remote filler reservoir mounted on the passenger side of the firewall. Also the brake pedal leverage would be set up for the power brakes, and is far less mechanical advantage over non power brakes. That is probably the biggest issue with needing so much pedal pressure to stop it after the booster being disconnected. Yes, the original system was a single circuit, and there is only one line in, and one line out of the booster. The easiest way to get where it stops safely and well, would be to purchase a new disc brake type booster from Studebaker vendors like SI. and hook up the front circuit to it. It is ok to have the rear non power assist, since the rears only contribute 30% of the stopping power.
The 2nd route to go would be to find a non power brake pedal with more leverage and see if that makes it good enough for your satisfaction. Also a higher coefficient of friction brake pad will also contribute to it stopping better than the stock friction materials.

Just read your post carefully, checked the 59-64 Parts Manual, inspected both of my GTs (62 & 63), and looked up a pic online. I mostly agree, except: 59-64 Hawks used the same pedal for non-powered drums as 63-64 GTs with PDBs. A different pedal was used on 59-64 with PB drums, and it is easy to tell the differences. Put another way, the OP's car has the correct pedal for his car, whether it came with PDBs, or non-powered drums; as such, his pedal already has the most mechanical advantage available.

Considering the car now has Turner front discs, and likely needs a HV anyway (current one inop), it is a no-brainer to get the correct HV for PDBs. Since his current HV will not serve as a core, and cores for the PDB type are near unobtainium, I suggest SI's repro (part #80201). I am on my 2nd one, and got 4-5 years out of the first. At over $400 each, I wish they'd last longer, and maybe this one will. But having ran the wrong HV (as this one is) with PDBs before finally installing the correct one, I can say there's a world of difference in required pedal pressure. So SI's #80201 is what I recommend, no matter which rear brakes are now on his GT.

As for plumbing his rear brakes, if he has 11" drums, I advise an OEM type MC and plumbing the rears through the HV, as original. The factory PDBs were engineered for a near perfect front/rear balance. When the rears are re-plumbed to bypass the HV, that balance is all but destroyed. Without power assist, the 11" rears are little more than what you can get from the hand brake. Been there, done that. OTOH, if he has 10" rear drums, I advise to keep the tandem MC and by-pass the rears around the HV. That produces a very good balance also, since self energizing 10" rears provide about 50-75 percent more stopping power than the non-self energizing 11", with 3/4" wheel cylinders. So plumbing and MC choices are why I am waiting on the OP to tell us which rear drums he has.

[JoeHall]

Item #37...R2 high performance package....That would automatically include Disc brakes, red line tachometer,160 speedometer, radius rod (traction bars) return fuel line and 3/8 fuel line, power shift OR 4 speed. n a Lark, it would also include bucket seats. It looks like the booster has never been upgraded to the type "F" higher pressure booster. (if it is the Daniel Schmidt car).

Thanks, I thought I'd read that elsewhere, but wasn't sure. Now you've said it, I believe it, and that settles it. I see the 160 speedo, and red line tach. But despite what the original brakes were, they are clearly a hodge-podge now. So the simplest way to determine what is actually on rear of the car now seems to remove a wheel and measure a drum (no need to remove the drum). In retrospect, I coulda took pix of the two type backing plates though. But all things considered, I'd still prefer a measuring tape.

The OP mainly wants good brakes, and that won't be difficult, but a key issue is to determine what is on the rear now. Based on the answer, there will be some choices to make for good, better and betterer outcome. LOL

[JoeHall]

OK, I need to edit my last comment as I found a picture of the production order for the car I had. My car was built on August 13 '63, shipped on 8/23/'63 and the only difference between the 2 cars was that mine had the am/fm radio and this one was built with the am radio only. I also looked at the production order for this car and it was indeed built the day before mine was, that being 8/12/'63. the body #'s were off a bit as this car has body #108 and mine has body #105. By the way my car was serial # 64V1205, so apologies are sent for my question about this car being the first '64 GT built. I know James Bell also has one of the "show cars", but I don't know any of the specifics. Quite interesting, Bill.

Also interesting, this car didn't come with an AM/FM radio, yet has one now. I also noticed the drum brake HV has had the vacuum line, 1-way check valve reversed, at some point between the pix on the link and those the PO took yesterday. To me, that indicates the HV may have failed, and someone was smart enough to bypass it, and reverse the check valve, but did not bother to re-locate the brake light switch so the brake lights would work. Lotta mysteries. OTOH, the presence of the gas tank drain strongly indicates it was one of the show cars.

[Ron Strasser]

An easier way to tall what breaks are on the back of the car. Is to look at the backside of the brakes backing plate. No need to remove a wheel or brake drum to measure it. If it has a rubber plug (about 1 inch by 3/8) the brakes are 10 inch self energizing.
If the backing plate does not have the plug but has 2 bolt-nut adjustments about midway on each side of the backing plate; it has the non self energizing 11 inch brakes. As used on disk brake cars.
My GT (long gone) had non disk manual brakes and for the time (1970.s) stopped fine.
Ron

[bezhawk]

Item #37...R2 high performance package....That would automatically include Disc brakes, red line tachometer,160 speedometer, radius rod (traction bars) return fuel line and 3/8 fuel line, power shift OR 4 speed. n a Lark, it would also include bucket seats. It looks like the booster has never been upgraded to the type "F" higher pressure booster. (if it is the Daniel Schmidt car).

[Colgate Studebaker]

OK, I need to edit my last comment as I found a picture of the production order for the car I had. My car was built on August 13 '63, shipped on 8/23/'63 and the only difference between the 2 cars was that mine had the am/fm radio and this one was built with the am radio only. I also looked at the production order for this car and it was indeed built the day before mine was, that being 8/12/'63. the body #'s were off a bit as this car has body #108 and mine has body #105. By the way my car was serial # 64V1205, so apologies are sent for my question about this car being the first '64 GT built. I know James Bell also has one of the "show cars", but I don't know any of the specifics. Quite interesting, Bill.

[Colgate Studebaker]

Something I noticed in the pic's provided that adds some suspicion to me is that the serial # plate is pop riveted onto the door post instead of spot welded as it was done in the factory. Another thing that I noticed is that the car was claimed to be the first '64 GT produced and has a delivery date of 9/4 63. The "show car" that I sold to Brian was built very early in August of '63 and shipped around the 20th to San Francisco. Not trying to put a damper on this car, but things aren't adding up to me. Bill