NEW BRAKE SYSTEM
C-K Studebakers and Split Master Cylinders do Mix!
By Chris Altenburg
Please read these fully first before proceeding. Though I dearly love the styling of Studebaker's C-K line of automobiles, they are not without some engineering shortcomings. One of the biggest is found in the braking system, adequate enough in terms of stopping distance and resistance to fade (compared to other brake systems of the time), but potentially dangerous in its use of a single chamber master cylinder (m/c) to convert the driver's mechanical energy into hydraulic line pressure. A failure of any single component in this system renders the entire system useless, usually at a time (like a panic stop situation) when full braking is needed. What follows is my approach for redressing this situation. Entropy, our '63 GT Hawk, served as the guinea pig for adapting a modern style dual chamber m/c ("split" type, in Studebaker parlance) for mounting under the driver's floorboard in the stock position. It has a 1" bore, like the stock drum brake unit, and works very well, even with the Hamilton front disc brake conversion kit Entropy uses.
Pedal travel and pressure is fine, as well. This m/c should be adaptable to all nonpower all-drum systems, Studebaker front disc braked cars, or those with an aftermarket front disc conversion like Entropy's. Cars with the No-Rol (hillholder) or anticreep feature will adapt, also. In this last case, the No-Rol or Anti-creep units are plumbed into either the front or rear pair of wheels (but not both); the choice is yours. Entropy doesn't have either option, so I leave it up to you as to how to handle this aspect of the project.
There is one caveat, though, for cars with power assisted brakes. Because the new m/c acts to split the brake system into two, the power booster can only be used to assist the front wheels. The rear drums revert to manual operation, which is actually an advantage, in my opinion. With power up front, and manual in back, it's very unlikely you'll have a problem with locking the rear wheels, even in a hard stop. Entropy's brakes are designed this way, and hard test stops I made brought the car down from speed fast and straight every time, with minimal rear wheel lockup. I have over 20,000 miles on the new system, with no indication of trouble.
Finally, the new unit is positioned in the stock position so the floor access hole may be used to add brake fluid, though the reach is tight for the rear reservoir. A solution I used was to mount a pair of Tilton remote reservoirs (4 oz. size) under the hood, then run 5/16" fuel line to brass hose fittings screwed into the m/c's two reservoirs.
General disclaimer: From an engineering standpoint, this adaptation works very well, and should be more reliable than stock, but I cannot take responsibility for your particular success. The skills you bring to the project, and the quality of equipment and tools used, will determine your end result. My description and directions are written as plainly, clearly and accurately as I know how, but the reader remains accountable for doing it in a responsible manner. Good luck!
Total cost for me was about $130, using a new master cylinder, DOT 5 brake fluid, and remote reservoirs. Time involved worked out to about 8-10 hours, approximately. If, after reading this description, you still have questions, or are confused in any way, feel free to contact me at home, at (813) 530-7734. Call anytime between 6:00 and 10:00 P-m. Eastern time; you stand a better chance of reaching me directly, or leave a message at any time.
Now, on to the details. Parts required:
For Dual Chamber M/C: 1. One dual chamber master cylinder- Raybestos Model # MC36237. New, it cost me $64; rebuilt, it should cost considerably less. It's outlets are marked "front" and "back", and the rear has a built-in residual pressure valve. It looks very much like the unit Studebaker utilized for its split brake systems on the Larks. 2. Two brake line adaptor fittings to match the master cylinder's outlets to standard 3/16" brake line. Any decent auto parts store can help here - just be sure the fittings are designed for brake lines. 3. Two 3/16" steel brake lines, with male end fittings, each about 60" long (you will shorten to suit). 4. One double-female brake line "union" fitting - I needed one to patch the new brake line for the rear brakes into the car's rear brake line. Your car's design may make this unnecessary. Also, if you have a No-Rol or Anti-Creep unit, you'll need to determine how to plumb it into the new system. I think that placing it in the rear wheel brake system only should work, based on what I can figure out from the parts manual pictures. 3. 12" steel/iron strap - 3/16" thick x 1-1/2" or 2" wide x 12" long.
This will be bent like this: |_________ ' with two mounting holes drilled into the short arm for attaching to the m/c. 4. 12" of 7/16" threaded rod, with 3 nuts. 5. Two 3/8" x 3-1/2" fine thread bolts, nuts and washers. No more than 2-1/4" of bolt shank may be unthreaded. (To replace the bolts used to fasten the stock m/c to the frame rail, as the new m/c requires shorter bolts).
If you're handy with taps and dies, simply thread the stock bolts further down their length, and shorten to size. 6. Two 5/16" x 1-1/4" fine thread bolts, with nuts and washers. (For mounting the m/c to the strap iron.) Bolts using allen heads are preferred. In fact, tapping the m/c flange for 5/16" X 24 threads obviates the need for nuts, and makes installation easier. 7. One grade 8 bolt - 3/8" x 1 1/2" x 24 threads per inch. The unthreaded portion of the shank must be at least 3/4" long. This bolt replaces the stock clevis pin, permitting the clevis/actuating rod (brake rod) to mount outboard of the brake lever, rather than straddling it, as it does on a stock car.
An alternative is to weld a steel plate onto the brake pedal lever, at the bottom, to allow moving the clevis rod outboard by the 1/2" to 9/16" needed to line it up with the new m/c's piston. In this event, a longer bolt is needed to act as the new clevis pin. It will pass through, in order, the outside of the brake rod's clevis, the new welded plate, the other side of the clevis, and the original clevis pin mounting hole. Hold the pin in place with a cotter pin.
A second option is to find an old brake lever, knock out the center pivot bushing, cut off the top of the brake lever, leaving only the section that the bushing resides in, and the original 3/8" holes used for the clevis pin and the lever pullback spring. I took this approach, as my stock lever bushing had the needed serrations on it on its very end. I pressed the cut up brake lever section onto the stock lever, lining the clevis pin holes up, and making sure the brake rod will fit between the two brake lever plates. I also installed a new grease zerk in the bushing, placing it more towards the front of the car so a grease gun can reach it. I used two 5/16" bolts, spacers and nuts to fasten the stock and new brake lever plates together, not fully trusting the serrations to do the entire job. 8. Paint - for making it pretty (and to cover all of your mistakes).
For the remotely mounted reservoirs (optional): 1. Two 4 oz. Tilton remote brake fluids reservoirs ($15 each from Speedway Motors, (402) 474-4411), or any hot rod supply shop. You must create a means of mounting them under the hood. 2. Two brass 90 degree hose fittings with 1/8" pipe thread on one end, and a 5/16" ID hose fitting on the other. 3. 5/16" neoprene fuel line - about 7' worth. Black looks pretty good. I know DOT 5 (the fluid I use) will not react with neoprene, but I cannot attest to this being true for DOT 3 or 4 fluid, which are alcohol based. 4. 4 hose clamps. General Tools: 1. 3/8" x 24 die; 3/8" x 24 tap. 2. 1/8" pipe tap. 3. Cable ties. 4. Thread locking compound. 5. 1 qt. of the brake fluid of your choice (DOT 3,4 or 5). 6. Split neoprene hose (used to cover the brake line where it contacts metal, and might abraid). 7. Brake line wrenches (a single double open end wrench, with 3/8" and 7/16" sizes). You'll use the 3/8" size. 8. Drill, with 3/8" and 7/16" drill bits. 9. Equipment for bleeding the brakes. 10. Double flaring tool for the brake lines. 11. Everything I forgot. Installation: 1. On the new m/c, cut the inboard mounting ear off at a vertical line which runs through the inside edge of the 7/16" flange mounting hole (the flange on the opposite side from the m/c outlets). Make sure to leave enough material for two 5/16" holes, and space for the nuts for the attaching bolts. A bracket will mount here that, in turn, fastens to the car's frame rail in a nearly stock position. Of course, I didn't think of it at the time I did Entropy, but it is preferable to use allen head bolts, and to thread the holes in what remains of the m/c's mounting ear also so nuts aren't required. Use a 7/16" drill bit to enlarge the hole in the other mounting ear enough so the 7/16" threaded rod can pass through it and be twisted side ways and down enough to reach beyond the rear of the m/c while missing the unit's outlet ports. (You have screwed on the m/c outlet adapters (with lock-tight) by this time, haven't you?) The threaded rod serves to mount the m/c on its out board side (toward the left side of car), by either passing through a hole drilled through the frame cross member immediately behind the m/c (a very positive mounting method), or by simply butting the rod into the cross member (using a nut mounted on the rod's end to spread the load against the frame). 2. Place a 90 degree bend in the strap iron, cut it to size, and test mount it to the m/c so holes may be drilled in the bracket and what's left of the right mounting ear of the m/c. The bracket will mount to the car's side frame rail using the stock mounting holes in the frame, so measure hole location carefully. Bend the bracket so the m/c mounts as parallel to the frame rail as possible. My m/c ended up slanted a little, with the front more toward the right, but it did not seem to make any difference in performance, or to change the brake rod geometry enough to worry about. It's a tight fit and will take some careful measuring and drilling, so proceed with care. Also, take into account the distance the piston actuating rod needs to go into the new m/c. Test mount the m/c with its bracket, in a fore and aft position against the frame such that the brake rod may be used without adjusting it beyond its range. Again, proceed with care. Some trimming of the bracket will probably be required to make it fit against the frame rail. A final hint: The 3-1/2" bolts need to be run through the holes in the bracket before bolting the bracket onto the m/c. (Seems common sensical enough, which must explain why I missed it the first time.) 3. If remote reservoirs are in the works for you, drill and tap each reservoir for brass 90 degree hose fittings designed for 5/16" hose. Remember to drill these holes on the outside of the m/c. I stuffed each reservoir with brake fluid soaked rags before drilling and tapping. In this way, all metal particles were captured before entering the brake system. 4. Install the remote reservoir adaptor fittings (with lock tight on the threads) in the threaded outlets - pointing them for-ward, and bench bleed the m/c before its final mounting. Then plug the outlet holes with tissue or small pieces of rag so fluid doesn't leak out, connect the external fill holes together with hose and clamps (for the same reason) fill both m/c reservoirs with the brake fluid of choice, close and clamp the top, and bolt the m/c permanently into place. Once completed, you will have a master cylinder that resides in an almost stock position, but a little outboard of the old m/c (by about 1/2" - 9/16"). 5. At this point, mount the 7/16" threaded rod in the outboard m/c flange, using two nuts to fasten it solidly to the flange (a nut on either side of the flange). In my case, I miscalculated drilling the hole in the frame rail behind the m/c. Consequently, I just mounted a nut on the rod's back end and adjusted the rod's length to snug it up firmly against the rear frame rail. Braking effort forces the m/c toward the rear, exactly in the plane the threaded rod serves to resist, and the bracket on the other side also holds it solidly so I'm not concerned. It hasn't loosened at all in 8 weeks, and 2,000 miles of driving. 6. It's time now to connect the brake lines. The front one goes from the m/c's front fitting to the brake line t-fitting near the left front wheel (for a car without power assist). Route the line over the frame rail and bring it forward, avoiding any point where abrasion may occur. Use rubber hose, split down the middle, to protect it where advisable. Fasten it as securely as possible, as vibration could eventually cause it to fail. If the line must be cut to length, remember to use the proper double flaring tool for the ends. I also looped the line a couple of times before screwing it into the m/c (for stress relief and to avoid having to trim the line's length at all). 7. For power assisted brakes, recall that only the front brakes may be boosted in this design. Run the brake line from the m/c's front outlet to the power booster's input. The booster's output must then route only to the front brakes, usually connected at the t-fitting by the left front wheel. Ensure the rear axle is isolated from power boosting. 8. The rear brake line is done up the same way by using the m/c's rear outlet, but is routed to the car's rear axle. The union fitting may or may not be needed, depending on the length of brake line you're using. Carefully determine where the line routes, ensuring it's mounted as firmly as possible to nonmoving frame pieces, using split neoprene hose around it for protection from scraping. For cars with the NoRol or Anti-Creep options, I suggest routing the rear brake line from the m/c, to the No-Rol or AntiCreep units, and from there to the rear wheels of the car. The No-Rol or Anti-Creep will thus only work for the rear brakes, but this should be sufficient, even for the hills of San Francisco or Ithaca, NY. 9. Install the clevis/ actuating rod on the brake lever and into the m/c. There are two ways to do this; my way, and the correct way. First, the correct way: You've probably noticed by now that the m/c doesn't line up with the brake lever. By welding a bracket to the stock lever, positioning it to the left of the stock clevis mounting position by just enough to allow one side of the brake rod's clevis to slip into place between the old and new bracket. Drill a clevis hole in the new bracket in-line with the stock clevis hole. Find or make a new clevis pin (any 3/8" bolt of grade 5 or better will do, but ensure all stresses are taken only on unthreaded portions of the bolt) long enough to reach through the clevis and both brackets, and pin it in place. You're done, and the rod now lines up acceptably well with the m/c piston. And, my way (admittedly temporary, but more than 3,000 miles of use proved it works): No new bracket is added to the brake lever. Install a grade 8 bolt as a new clevis pin, situating the brake rod's clevis outboard of the brake lever. I threaded the bolt to permit screwing down two nuts right to the clevis, leaving unthreaded the segment on which the lever and clevis ride. A second nut is used to keep the first one from loosening. The brake lever is normally held on its pivot via a piece of strap steel that connects also to the stock m/c's mounting bolts. In the "New and Improved Design" this strap is no longer required. Replace the strap with a large washer on the brake lever pivot, holding it in place with the stock nut. After tightening fully, ensure the brake lever still moves freely through its travel. 10. Bleed the entire brake system completely, ensuring neither m/c reservoir ever becomes fully drained in the process. 11. If you don't plan on installing remote reservoirs, you're now finished! Drive around and have fun! Check the entire assembly several times over the next two weeks for leaks and loose bolts, fittings, etc.
Installing remote reservoirs:
1. First, use a pair of reservoirs, not a single unit with a split outlet to both m/c reservoirs. A single reservoir will work, don't get me wrong, but you'll not be able to tell where a leak exists, should brake fluid level drop.
2. Mount the reservoirs under the hood, where convenient. Originality counts in designing a clean, effective method to do this. In my case, I bolted both Tilton units together, then bent a simple bracket that fastened to an already existing hole in Entropy's inner left fender, and to the reservoirs via a pair of 1/4" bolts.
3. Route the 5/16" neoprene hoses from the reservoirs to the m/c, avoiding exhaust manifold and pipes, and any moving parts that might cut the hoses. Connect to the reservoirs and clamp each hose near where they'll connect to the m/c.
4. Fill one reservoir and remove its clamp momentarily to confirm which reservoir connects to which hose. In my case, I positioned the underhood reservoirs front to back; the front one is for the front brakes, the rear for the back. Original, huh? Now, it gets sloppy.
5. Peel back the driver's carpet, remove the floor access hole, and pop the spring clamp for the new m/c's reservoirs. Free the top enough to break its seal with the m/c. Cleanliness is imperative - be careful not to drop crud into the m/c in the process.
6. Remove the connecting tube between the hose fittings on the m/c. Connect one neoprene hose, fill the underhood reservoir completely, and free the clamp crimping off the hose enough until the m/c's reservoir overflows. Reclamp the hose closed again.
7. Repeat step 6 for the other reservoir. 8. Ensure the underhood reservoirs are truly full, place the spring clamp for the m/c's top in place, then remove both hose crimping clamps. Clean the m/c off carefully and check for seepage from around it's top. If it seeps, maybe cleaning the top and the rubber gasket will seal it. (Clamp off both remote reservoir hoses first.) If not, you can always revert to the stock system of maintaining fluid level through the floorboard hole. Comments, criticisms, or testimonials are invited. I can be reached at (813) 530- 7734 (Florida), or you may leave a message. Good Luck!
10/06/93 update: Entropy has now logged over 20,000 miles using the split system with absolute reliability.