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View Full Version : 1955 Sedan Pres brake system problems?



joel
12-02-2006, 02:33 PM
Can anyone address this problem? The power assisted brakes on my sedan keep binding. I can only drive a very short distance as they become progressively worse until they lockup. The pedal is hard and braking is very weak until they just finally lockup, especially if I try to put it in reverse. About 2 years ago I replaced with new the master cylinder, all new wheel cylinders, all new shoes, replaced the flexible rubber lines, replaced hydrovac with a newly rebuilt hydrovac and bled the system, then this problem arose, before that there was no brake at all, the pedal went to the floor. The car has sit since then, no time to fix it, and now I am trying to get it back on the road. Along with the other work 2 years ago, I replaced the master cylinder piston push rod that goes from the pedal lever to the master cylinder. I have herd that some of these were made too long and could be causing the progressive binding of the brakes. Anyone ever herd of that problem? I think I remember reading in the Cooperator about this??? Any idea why my power brake system is in such poor condition, binds up, why the pedal pressure is so hard and the braking so weak? Any help is sure appreciated. Thanks. Joel

Roscomacaw
12-02-2006, 02:40 PM
Joel, the master cylinder push rod may be adjusted too long. That's a possiblity. But if it were mine, I'd initially try bypassing the brake booster to see if that alleviates your troubles.
Either get a brass coupling and connect the two brake lines that attach to the booster OR get TWO couplings and a short piece of brake line and effect the same thing. Bleed the brakes and THEN see if you've still got a problem.
Another possibility is a deteriorated rubber line. If the lines are old, they can break down inside and act as a one-way valve that will retain pressure after you've let off the pedal. After sitting some time, the accumulated pressure manages to bleed by the stoppage and it's good to go - for another few miles. Seen it happen myself in older cars! Frustrating to say the least.:(

Miscreant adrift in
the BerStuda Triangle!!

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe

Guido
12-02-2006, 02:54 PM
I would agree with Biggs, that often times the rubber brakes hoses will get weak and collapse on themselves, thereby retaining pressure at the wheel cylinders and causing a brake to lock up. It would be interesting to know if it was at an individual wheel or at all 4 corners. If the latter, it points to a master cylinder that is not fully releasing or the booster.

http://thumb14.webshots.net/t/53/453/1/21/36/2964121360097493054pVJTFL_th.jpghttp://thumb14.webshots.net/t/57/757/2/88/4/2023288040097493054SEKowB_th.jpghttp://thumb14.webshots.net/t/18/19/8/37/21/2050837210097493054IYBJJL_th.jpghttp://thumb14.webshots.net/t/59/559/1/43/57/2876143570097493054jKVhDw_th.jpghttp://thumb14.webshots.net/t/22/22/0/2/68/2589002680097493054ftBuBw_th.jpghttp://thumb14.webshots.net/t/28/28/8/30/30/2075830300097493054aSSlFv_th.jpghttp://thumb14.webshots.net/t/59/459/2/23/86/2067223860097493054YoeGMx_th.jpghttp://thumb14.webshots.net/t/28/28/5/18/33/2537518330097493054OgEKcN_th.jpg
Guido Salvage - "Where rust is beautiful"

Studebaker horse drawn buggy; 1946 M-16 fire truck; 1948 M-16 grain truck; 1949 2R16A grain truck; 1949 2R17A fire truck; 1950 2R5 pickup; 1952 2R17A grain truck; 1952 Packard 200 4 door; 1955 E-38 grain truck; 1957 3E-40 flatbed; 1961 6E-28 grain truck; 1962 7E-13D 4x4 rack truck; 1962 7E-7 Champ pickup; 1962 GT Hawk 4 speed; 1963 8E-28 flatbed; 1964 Avanti R2 4 speed; 1964 Cruiser and various other "treasures".

Hiding and preserving Studebakers in Richmond, Goochland & Louisa, Va.

John Kirchhoff
12-02-2006, 07:02 PM
I agree with Mr. Biggs as far as isolating the Hydrovac from the rest of the brake system. Before you break the lines and insert the coupler (you can get them at Ace Hardware), you might first check to make sure the brake lines are plumbed into the Hydrovac correctly. The line from the master cylinder enters at the bottom middle close to the vacuum hose port and the line to the brakes comes out the end of the smaller cylindrical tube. If they are backwards, the ball check is going to be working backwards. If the lines are plumbed correctly, try disconnecting and plugging the vacuum hose. If the outside air seat on the control cylinder is leaking or the piston stuck open, that would allow engine vacuum to try to apply the brakes. If the lines are ok and removing the vacuum hose does nothing, then do as Mr Biggs suggested and get the coupler.

I've had brake hoses swell shut internally and that's no fun. However, that would only be either front wheel or both back wheels. If you suspect only one wheel, you might try finding a gravel road or grassy area and stomp on the brakes. You'll be able to tell which wheels are working and which ones aren't. If your wife doesn't want you tearing up your yard, use your neighbor's when they aren't home.