56 f600 brake problems
Super Moderator
Joined: Apr 2004
Posts: 34,491
Likes: 2,806
You posted about this truck earlier here and in Large Truck.
https://www.ford-trucks.com/forums/1...s-lock-up.html
Have you ever pulled the wheels and brake drums off and looked at your linings?
Beware it appears you had widow maker wheels so be carefull handling them.
https://www.ford-trucks.com/forums/1...s-lock-up.html
Have you ever pulled the wheels and brake drums off and looked at your linings?
Beware it appears you had widow maker wheels so be carefull handling them.
Laughing Gas
Joined: Dec 2014
Posts: 774
Likes: 10
From: Simsbury, Connecticut
They could be too tight. You may also have a slow leak in any one of the two brake cylinders. Brake fluid is very sticky. It'll become gooey with heat after driving a bit but lock-ups are likely. Are they new cylinder or just re-honed?
Logistics Pro
Joined: Feb 2005
Posts: 3,952
Likes: 117
From: Upper Left Coast
I had a similar problem with my 55 F-600.
I rebuilt mine also and exchanged the booster for a rebuilt one. Once in a while the brakes would still lock after coming to a stop. After pumping the pedal a few times they would release. The Shop Manual says to test the system to determine if it's the MC or the booster causing the problem.
Also, according to the shop manual, there could be a restricted by-pass port in the master cylinder (which was my problem)....... you can verify this by opening a bleeder valve and releasing some pressure. It won't take much, a few drops maybe to relieve the pressure.
The manual also mentions improperly adjusted pedal linkage, swollen piston cups and dirt in the system. It also says if linkage adjustment doesn't fix it, to replace the master cylinder piston and cup assembly.
I then went in a different direction with my F600, I installed a master cyl (1.5" pistons) and hydraulic booster identical to the one in my 2005 F-350 Super Duty so I would have the split system.
The hydraulic booster required me to add a power steering pump. and will very likely require a proportioning valve since the fluid requirements are a little different between the front and the back, and the fact that I have single-piston wheel cyls in the front and dual piston/dual wheel cyls in the back.
I did not want to have the possibility of a single leak anywhere in the system resulting in complete loss of braking in a 7000+ lb vehicle.
Cheers,
I rebuilt mine also and exchanged the booster for a rebuilt one. Once in a while the brakes would still lock after coming to a stop. After pumping the pedal a few times they would release. The Shop Manual says to test the system to determine if it's the MC or the booster causing the problem.
Also, according to the shop manual, there could be a restricted by-pass port in the master cylinder (which was my problem)....... you can verify this by opening a bleeder valve and releasing some pressure. It won't take much, a few drops maybe to relieve the pressure.
The manual also mentions improperly adjusted pedal linkage, swollen piston cups and dirt in the system. It also says if linkage adjustment doesn't fix it, to replace the master cylinder piston and cup assembly.
I then went in a different direction with my F600, I installed a master cyl (1.5" pistons) and hydraulic booster identical to the one in my 2005 F-350 Super Duty so I would have the split system.
The hydraulic booster required me to add a power steering pump. and will very likely require a proportioning valve since the fluid requirements are a little different between the front and the back, and the fact that I have single-piston wheel cyls in the front and dual piston/dual wheel cyls in the back.
I did not want to have the possibility of a single leak anywhere in the system resulting in complete loss of braking in a 7000+ lb vehicle.
Cheers,
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jrmwilson
1948 - 1956 F1, F100 & Larger F-Series Trucks
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Sep 4, 2014 11:45 AM
