CCKW brakes sticking

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RANGER
1st Sergeant
1st Sergeant
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Joined: Sat Jul 01, 2006 6:29 pm
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CCKW brakes sticking

Post by RANGER »

The best cure is to pull the wheels and start replacing the wheel cylinders with new ones. The cause is usually corroded 50 year old wheel cylinders with stuck pistons and swollen cups. Many try to get out of it cheap by listening to bad advice by inexperienced owners to just go out and buy new return springs. Why waste your time, do it right in the interest of safety, it is cheaper in the long run.

My CCKW will be in its 24th trouble free year with Wheel and Master Cylinders that were installed NOS along with DOT 5 Silicone Brake Fluid. The Brake system has been flushed every 3-4 years using my power bleeder, yielding brown sludge in the fluid being flushed. The PM Scheduled in 2007 includes replacing or rebuilding all Wheel Cylinders along with the Master Cylinder in order to ensure another quarter century of safe operation.
Years ago, the National Guard OMS shops had a Maintenance Proigram in which the M-35 Series 2 1/2 Ton 6x6 would be brought into the shops and one wheel would be serviced each year, with the wheel cylinder inspected or replaced. That is an easy system to follow.

While you are at servicing the individual wheels, it is not a bad idea to wire brush the Backing Plates clean and paint them.
I choose to repaint thebacking plates with Electric Motor Paint which acts as a primer and dries with a hard shiny surface. It is the color of Red Oxide Primerand is easy to keep clean. In the 40s-50s some Army depots used the same paint on rebuilt backing plates and hub interiors.
Another practice is to use Lubriplate 630AA Grease in the areas of banjo Anchor Plates and the areas where the Brake Shoes contact or slide on the Backing Plates such as Anchor Pins, and pivot points. A little bit is sufficient, it should not be "buttered" on. This is actally done at the factory on new vehicles. If the brake system is carefully maintained using PM, one will not have the problems of others that just drive their truck and complain about and repair it only after it breaks down.
One person has a suggested cure for sticking brake shoes on his Banjo Axles by just taking a pry bar and opening up the slots on the Brake Shoe anchor Brackets to unstick the shoes from the rusty corroded brackets. This practice will result in sloppy fitting brake shoes that will wear out faster. If you stick with the procedures according to the TM, you will experience trouble free operation.
Last edited by RANGER on Wed Jan 07, 2009 1:47 pm, edited 1 time in total.
US ARMY HONOR GRADUATE MECHANIC, Restorer of fine Jeeps, MV's, MVPA 40+yrs, DAV, Army Aircrew member, Donor to Military Museums & CAF, MV Hobby since 1945
Other Hobby- Army Air Force & Busting Big Ass Military Imposters-Good at it
Jason
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Post by Jason »

Doesnt my memory serve me right that with OLD (NOS) rubber parts dont hold up to Silicone (DOT 5) brake fluid?
The 1943 Chevy Bomb truck Shown at Findley Oh 2005
http://omega.ipfw.edu/~davisjr/Truck194 ... ndleyB.jpg
RANGER
1st Sergeant
1st Sergeant
Posts: 6510
Joined: Sat Jul 01, 2006 6:29 pm
Location: Nearest Motor Pool

Post by RANGER »

And the Army found out that some, but not all of the modern rubber parts of the 60s-70s were not compatible. I used NOS WWII Wheel Cylinders on my CCKW, I replaced the cups with NOS from stock that were a mixture of Raybestos and Wagners that we bought in the 50s-70s, and possibly older. There has been no problem with use of Silicone Brake Fluid in my CCKW, MB, M-37 or M-756A2 Pipeline Truck. I started using DOT 5 Silicone at about the same time period the US Army changed over to it

I did find that it discolors rapidly if the Master Cylinder Heat Shield was left off my M-38A1. I had to replace the Wagner Master Cylinder as it started sticking. Apparantly the heat from the exhaust pipe caused problems when Silicone was used. It has not bothered since the Heat Shield was replaced. There never was problems with leaving the heat shield off other M-38A1 Jeeps when using conventional DOT 3. I have over 250,000 trouble free miles in M-38A1 Jeeps.
US ARMY HONOR GRADUATE MECHANIC, Restorer of fine Jeeps, MV's, MVPA 40+yrs, DAV, Army Aircrew member, Donor to Military Museums & CAF, MV Hobby since 1945
Other Hobby- Army Air Force & Busting Big Ass Military Imposters-Good at it
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