Brake fluid on Front Wheel

[codyharper15]

So, my brake have been messed up. When I bought my Shop Van, it would take me pushing half way down on the pedal before any braking would happen. So I adjusted the pedal to push the drum in further and I added more fluid (I put in DOT 3 and I was not sure what I had in it). Right after I did that, It seemed like it did nothing. Now, after about a month and it sitting most of the time, I saw brake fluid puddling at my front passenger wheel. So I turned on the Deuce and pressed on the brakes, and they were stiff from the very top of the travel (I could push them down a little, they felt like they were braking). I then went and looked at the brake drum and fluid was squirting out of the brake back plate.

I was wondering if anyone could lead me in the correct direction on how to fix this. I am already planning on bleeding my brakes.

Thanks!

 

[Heavysteven]

99% sure most all Dueces have DOT 5. Sounds like you mixed DOT 3 and DOT 5 if so that's bad. Here is a link to the manuals. You need to fix the leak and ensure your brake system is repaired before you drive the truck.

How about some photo's of were it leaking.

JATONKA's M35 TM download page

 

[73m819]

NEW PILOT, the leak is a bad wheel cylinder
I truely think you need to READ the TMs on the brakes, adjusting the pedal WAS NOT the fix to start with.

You can find the TMs here
-=-=-=-=-=-=-=-=-=-=-=-=-
JATONKAM35s HOME ON THE WEB
OR
Free Military Army Manuals!
OR
Former Military Vehicle Owners - Index
OR
https://www.logsa.army.mil/etms/ind...5fb95459e-A3015A99-D14A-19E1-238F1793FB3D9566
This is the mil. TM web site,
--says bad cert., click to go anyway,

 

[wsucougarx]

Like said previously, you've got to rebuild or replace the wheel cylinder (best to do them all). It's actually alot simpler than you think. I absolutely highly recommend you flush the brake system ASAP. You don't want to mix DOT-3 (hydrophilic) and DOT-5 (hydrophobic) brake fluid together. It's like mixing water and oil together. There's no problem going with DOT-3, but you don't want the mixture in your lines.
While you've got the hub torn apart, might as well replace your inner and outer seals, and, repack your bearings

 

[Keith_J]

One little note on wheel cylinders..the Federal Supply System is flooded with inferior wheel cylinders for these trucks. They work fine for braking but fail in storage.

The root cause is the lack of piston cup expanders on the springs. This means the piston cups will eventually leak if the master cylinder is equipped with check valve breathers. Temperature and atmospheric pressure changes can create a partial vacuum in the master cylinder, this causes the piston cups to lose their seal, letting air into the system. Then the brake fluid can weep out.

The fix is easy, overhaul the wheel cylinders with the aftermarket kits available for about $8. If DOT 5 is in the system, should take all of 30 seconds to hone the cylinder. Compared to the $25 for a new wheel cylinder, it is a bargain.

Now adding DOT 3 to the system probably contaminated the whole. You need a flush and wheel cylinder overhauls on all 6 wheels. Add in at least 4 wheel seal sets to the order, some can be reused. And a few locking tab washers (old ones have 3 tabs, you might be able to reuse) and at least one nut (since jackleg 63Bs sometimes used a cold chisel to remove).

Pedal height is based on the sum of all brake shoe to drum clearances. Proper adjustment of the brakes is easiest with the axles pulled, that way no driveline drag is present. But you must read the TM for the proper method, using feeler gauges.

 

[steelandcanvas]

...and a few locking tab washers (old ones have 3 tabs, you might be able to reuse) and at least one nut (since jackleg 63Bs sometimes used a cold chisel to remove)...

Good explaination, but 63B? You might be showing your age.

 

[Keith_J]

Good explaination, but 63B? You might be showing your age.

Age = experience. I gracefully exited the US Army before DADT was enacted. So yes, I am a bit older. And I can certainly say many of the 63Bs I worked with used the chisel method to loosen the 3" octagon bearing nuts. Not nearly as FUBARed as the federal supply system being flooded with inferior wheel cylinder assemblies, all because the SMR code is PAOZZ, meaning this part was not serviceable and disposed of at the unit level so this design deficiency would never be discovered. Yes, the MAC has removal and replacement at unit level.

Installing correct cup expander springs and removing the silly check valve breather on the master cylinder will positively end the problem. If you are in a damp climate, a desiccant breather might be a better choice. This is a SAFETY issue too, if there is a slight leak, the loss of fluid will create a slight vacuum with the check valve breather. This can cause loss of braking.

 

[AceHigh]

Yeah, they changed the MOS so they quit using chisels.

 

[319]

If fluid was squirting out the back then maybe, just maybe, you have a loose line or bleeder screw. But as stated above, read the TM's, fix the leak, read the TMs again, and flush the system.

 

[codyharper15]

Thanks guys. I appreciate the help. I wanted to be led in the right direction and you did. Thanks!
Here's a picture of where it is leaking just for sakes.

 

[Westech]

Could just be the copper washers.... Really take it to your local auto repair shop if you needed to post on this.
And I am glad your 2000 miles away from me.


Love Westy

 

[319]

And I am glad your 2000 miles away from me.


Love Westy

There ya go! First time I laughed since early today when I was told I need a root canal!

 

[Keith_J]

And it looks like you will also need the copper washer gaskets. Take the old one to NAPA and have them size fit for the application. Check for pitting/corrosion on the fittings and spot facing on the wheel cylinder.