Grease on Brakes

[M371954]

PROBLEM: I have grease all over the inside of the brake budd, brake shoes, etc etc....

QUESTION: Is this a hint at another large problem?

BACKGROUND: My newly purchased M37 has sufficient brakes for the few miles that I drove it. Then, the brakes became very soft and then non-existent. I've notice that in the garage I have fluid coming from the inside brake shield on the inside of the wheel. I'm in the process of replacing the wheel cylinders and Master cylinder on the truck. Should I be concerned about where the grease / grime came from?

The old guy that owned this truck before me did do a good job at "Lubing" all the components. There has only been one place on the truck where the bolts haven't had grease on them to keep them from rusting and that was the muffler. Any ideas?

 

[glcaines]

When you say grease, I'm assuming that you are referring to chassis grease, and not wheel bearing grease or differential fluid? It sounds like you have two issues. Grease on the brake shoes / drum will normally cause that wheel to lock up when the brakes are applied so this shouldn't cause your brake problems. You mentioned that your brakes became soft and then non-existent. Here, I'm assuming that the pedal goes to the floor due to loss of fluid? Try to find out where the grease came from and repair any problems. I'm assuming that it probably came from the guy's exuberant use of a grease gun. Clean all of the grease off of the brake components. Since you are replacing the wheel cylinders and MC, I would also replace the brake hoses at the same time. You will then have a brand new brake system, assuming that the brake lines are in good condition, and your brake problems will be gone. If the brake lines don't look to be in very good condition, replace them as well.

 

[Tuko]

Ya sounds like a wheel cylinder went south

 

[T. Highway]

I would look at replacing the inner axle seals, inner hub oil seals and flanged outer oil seals. The front axle CVs are packed with allot of grease to function properly.

A word of caution, do not use NOS seals, they will start to leak in a very short time. When you replace the flanged seals do not use the rawhide replacements, they will fail in a short time (Use the synthetic rubber stlye). Only use new production seals.

Inner hub oil seal # CR 28116
Inner axle seal # CR 14864
Flanged outer axle seal # CR 20766 remember to ask for the synthetic seal material, there are two options on this seal type.

Don't forget to check out the G741.org site. It's for M37s only and has allot of great info and people to help you with your project.

 

[M371954]

Great feedback, Thank you!! I pulled the brake shoes and WC, then got to cleaning as much as i could. It was pretty nasty but remarkably little decay I've got new hoses for it as well so I'll put those in too. I want to make sure this thing will stop when I need it too.

 

[scottgs]

Fix the leaks first, then the brakes. You need to stop the oil/grease leak before you do anything with the brake system. As already mentioned, replace inner axle seals (front only), axle flange seals (rear only) and hub seals before bothering with the brake system. Otherwise your brakes will be fine for a while, but then you'll be just back where you started after oil and grease ruins everything again. I also concur on using only new production seals. Old NOS leather seals will only dissapoint, and are absolutely not worth the effort of fooling with, especially when you're talking about ruining expensive brake shoes at $25 a whack. Also, I seriously doubt the previous owner's excessive use of the grease gun would have caused this problem, as there's no real way to put extra grease into the hubs with with just a grease-gun. Grease or oil leakage onto the brake shoes is a common problem on any vehicle of this age and axle design.

When replacing the seals, you also need to be sure the surfaces they run on are in decent shape, and not grooved or pitted. Sometimes they need to be sleeved to work well again. Also, if there is a significant amount of oil or grease on the shoes and drums (such as you see it leaking from outside), the brakes won't work very well, if at all. It will not cause them to work better or lock up.

 

[Superdave]

As a quick note on the rear, don't forget to put that little bit of cork in the key way area between the lock nuts as over time oil can seep past it.

 

[M371954]

Thanks Superdave, Scottgs and others. I pulled the brakes, cleaned a ton of funk (Grease, mud, clay, brake fluid, etc etc) off of the brakes, hubs, wheels and associated hardware. It looks like the brake fluid and lots of lube over time has helped to create a real nice mess. The good thing is that, after a lot of scrubbing I got it cleaned up. The metal was very well preserved under all that stuff. A fresh coat of brake paint (caliper paint) and such, I will be ready to road test and tune the brakes this week. From what I understand, I am pretty lucky since I seem to have four budds that are in very good shape. We'll see how to tuning goes.

Thanks again!

 

[vtdeucedriver]

What everyone has failed to mention is before you go do any testing and are still under the truck. Remove and clean the axle vents!!!

It's not going to matter if you use NOS seals or the new MFG, if those vents are not clear, your going to blow a seal again.
As for bashing the NOS leather seals. If you read the book and see to soak the seals in neetsfoot oil first, they will work fine.

 

[Superdave]

neetsfoot oil ?? What is that as I have not heard of it before.

 

[Cycletek]

Neatsfoot oil is a yellow oil rendered and purified from the shin bones and feet (but not the hooves) of cattle. "Neat" in the oil's name comes from an old name for cattle. Neatsfoot oil is used as a conditioning, softening and preservative agent for leather. In the 18th century, it was also used medicinally as a topical application for dry scaly skin conditions.

Amazon has it......http://www.amazon.com/Fiebing-PURE00P032Z-Neatsfoot-Oil/dp/B001DDORQQ

 

[vtdeucedriver]

Any leather or tack shop will have it. I got mine at my local tractor supply store.