Brakes: Problem bleeding rear wheel cylinders on a Hawk GT 1962

[MontrealHawkGT62]

So here's the situation. Bought a 62 Hawk GT last may and drove 300 miles back home with it with very little braking power. When I had some time off, I inspected said brakes and discovered that FR wheel cylinder was pissing oil. FL one seemed ok. RR one seemed jammed and RR shoe liners got unbonded. RL seemed ok. So I removed everything, cleaned everything, took pictures, tagged n bagged everything. Car sat for maybe a month on jack stands while I waited for 4 new wheel cylinders, a new master cylinder, new rear shoes and 5 tires. Only things that were still in good condition were all the the drums, front shoes L n R , all springs.


Last friday I finally had some time to work on the GT. Was able to put back all the brake hardware on all four corners. I didn't change the master cylinder coz I didn't have so much time and forgot to bring the shop manual. Now came the time to flush the crap out of the system and bleed. I had no problem whatsoever to bleed the front wheel cylinders. My helper was pumping the brake pedal as I was cracking open the bleeder and closing it. We cycled like that until I had nice clean fluid coming out with no bubbles.


Now the rear wheels, that's another story. Nothing came out, not a single drop. We really wondered what was going on. Maybe there is way too much air in the system. No amount of pumping would do it. With the master cylinder's cap off, we could see some sort of back pressure, a mini geyser if you will, at each pumping .


The following day, I tried to bleed the rear wheels by myself, with a hand held vacuum pump. My pump could hold a steady 10 mm of Hg with nothing coming out.


Me thinks that there must be blockage somewhere. I didn't change the rear flexible hose and wonder if it is not blocked. Earlier I checked out the schematics of the brake system, pipes and fittings for my car, a 62 GT, three on the tree, no power steering, no overdrive, not tandem master cylinder and saw the item 1105-1 "valve", which has a lever.... Now I am not familiar with this contraption but I suspect it might have been tripped by removing all the wheel cylinders and maybe nothing is flowing to the rear because of that. Could it be the culprit? If so, is there a way to reset that valve? A procedure to follow ?( I feel like a total idiot .... " lift the lever...")

All you people in the know, please, give me your two cents. I'm a newbie Studebaker owner and I feel I am starting to discover the lil niceties of that brand.

[christophe]

Hello Christian,
I just read your mail. Thanks for sending it.
Sorry about your troubles.
Both the master cylinder and the rear hose could be culprits there.
If you can build up steady pressure in the circuit by pumping the brakes, i'd say that the MC is OK.
Anyway, it's good practise to change all hoses when doing a brake job.
I can't check right now for the valve you mentioned, but this might be the anti creep, used only on automatic cars.
In case you have a hill holder, you should check it too.
Dont hesitate to send a mail if you need further détails.

Nice evening to all.

[thunderations]

Take the steel supply line loose from the rear flex hose and see if fluid will come out. Continue from there checking components one at a time if you have fluid.
Work your way through the system. You might want to start at the MC to see of it is supplying fluid to the rear by way of the junction block. I would replace all rubber flex hoses and even the steel lines. After 56 years those steel lines will have corroded until the inside passages may be clogged or at least nearly clogged. Corroded steel lines will fail too under pressure from new MC and resistance from new wheel cylinders. Hydraulics will seek the weakest part of the system to leak, usually rubber seals and hoses, but also corroded lines.
I would replace the original MC with a dual system while I was at it. That way, if you wanted to add front disc's later all you needed to do would be to remove the check valve in the MC. All of the other work, (splitting the front lines from rear) would be done. Even if you didn't add discs, you would have 2 system brakes instead of single. Just a safety feature and brakes are pretty important.

[StudeRich]

If you look at the Top of the Page for Section 1105 it says: "No-Roll Unit", so if you have the "Valve" on the inside of the Frame Rail, your car is equipped with the Optional Hill Holder.
It HOLDS whatever pressure you applied to the Brake Pedal while the Clutch pedal is down when stopping on an uphill slope, UNTIL the Clutch is released.

The Lever should have a Rod (1105-8 shown on Pg. 345) connecting it to the Clutch Pedal Lever.
If you can Flush it and bleed it, that would be a Great item to have working.

It is extremely SIMPLE! Nothing more than a Cylinder with a Ball inside that rolls back on an upgrade to seal the port. I believe moving the "Lever" forward will release it.

If you can NOT do that, you will have to install a New DUAL Brass "Banjo" Fitting at the Master Cylinder, 2 new Copper washers and possibly a new Brake Line to bi-pass and remove the Unit and it's "Jumper" Line to the M/C.

If you have NONE, it is nothing to worry about.

[JimKB1MCV]

In addition to the above, its good practice to start bleeding the brakes at the wheel farthest away from the master cylinder. Usual sequence is RR, LR, RF and LF.
You really should consider replacing the steel brake lines.

[StudebakerGene]

I just had exactly the same problem on my Coupe Express. Kept thinking it was the master cylinder, power booster, etc. I don't know if your car has front disc brakes or not but, my culprit was the proportioning valve. I about wore the hide off the bottom of my foot stomping on the pedal trying to get it to bleed. New valve and all is well. The reason I replied was I couldn't understand for the life of me why I had pressure up front and nothing out back--- maybe you have the same problem!

[mbstude]

Me thinks that there must be blockage somewhere. I didn't change the rear flexible hose and wonder if it is not blocked.

I think you answered your own question. By all means, replace the front and rear rubber hoses as well.

[jimmijim8]

Replace the rear brake hose. jimmijim

[Xcalibur]

...and, no matter what, use all new rubber hoses, anyway!

[TWChamp]

My 50 Land Cruiser had the identical problem last month when I did my brakes. The front hoses were new 18 months ago, but the rear hose wasn't replaced by the previous owner, and it was plugged solid.

[Jeffry Cassel]

Might want to be sure the mc has a check valve. I recently had the same problem and found the mc had no check valve and with fluid spewing out ,it sounds suspicious.