5 Ton brake problems

[jokernatas]

I also have 5 ton brake problems, I just got the truck a few weeks ago for the last owner of 9 years. I had a 21 mile drive home when picking it up, did a check of fluids tires lights rolling brake test and so on. The drive went good till less than 1 mile from my place when I felt the brakes draggin a bit.Made it home and parked the truck and about 5 minutes later a loud POP came from the passenger side front duels followed by smoke for a minute or 2. Now it seems that wheel locks up when the air pressure builds up but will free spin when the pressure is low. I am very GREEN in the 5 ton world and I plan a long life with this truck, at is a 1955 M54 ....Any help or info will be great, Thanks

 

[wascomatw74]

Just to get it out of the way , did you download the TM's and read them. Are you losing brake fluid? Anything leaking from inside the wheel/drum? Probably had heat buildup cooked the wheel cylinder and blew it out.Have to tear it apart and rebuild. Hope others will chime in. TM,s are in the resources section at the top of the page. Good luck have fun and post pics

 

[swiss]

The good thing is you got home safely. The second good thing is that you had an indication of where the problem is given the noise and smoke on the passenger side. The brakes are a hydraulic brake with an air assist on them. The air assist provides additional pressure on the break fluid when you are braking to increase the brake line pressure. YOu need to understand your brakes to troubleshoot them but a few things to review and post.

1.) What happens if you press the brake pedal when the air pressure is low? Are you doing this before the air pressure has built up in the tanks?
2.) Does the wheel lock up once the pressure builds in the tank?
3.) Is it only one wheel? Multiple wheels that are locked up with no brake pressure applied?

Trace your brakes starting with the master cylinder below the floor on the drivers side. Follow to the air pack and then to your brake lines. What level is your brake fluid, Are there leaks anywhere in the lines, check on the inside of the wheels on the back side of the hub, do you have brake fluid on the suspected problem child?

 

[m816]

Sounds like a wheel cylinder blew to me. Do you see fluid on the inside of the wheel? Are your fluid levels down after that noise? Looks like you have to remove the wheel and check it.

 

[porkysplace]

Unless the former owner changed it , it should have DOT 5 brake fluid in it , you can't mix it with DOT 3 it will gel up . So make sure you use the correct brake fluid .
Brake fluid -how to tell which kind you have DOT 3 or DOT 5

DOT 3 vs. DOT 5

 

[swiss]

From the description of the symptoms there looks to be more of a problem then just the wheel cylinder. The fact that the wheel locks up when the pressure builds points to a problem up the line and not the wheel cylinder alone. If the wheel brake cylinder failed it would tend not to hold pressure and the brakes would be released. On the other hand the cylinder could have heated up and failed with the pistons in an engaged position and then fused in that position. It that was the case the wheel would be locked up.

The problem as explained is with the brakes engaging when the pressure builds on the line. Unless the brakes are engaged the wheel cylinder should not act any different with low or high pressure.

We need more details.

 

[73m819]

AIRPACK hung up, causing brake drag, guessing the w/c that went, it's shoes were set a bit tight, so more drag on the wheel hence more heat and in turn really heated up the w/c

 

[porkysplace]

Either way it needs to be torn down for a inspection to see if the heat caused damage to the shoes , such as cracking ect. or broken springs.

 

[nk14zp]

Check your front glad hand to make sure it has a vent on the service side.

 

[nk14zp]

Either way it needs to be torn down for a inspection to see if the heat caused damage to the shoes , such as cracking ect. or broken springs.

 

[jokernatas]

Ok so here is the latest... Pulled the wheels on the side that was smoking. I used an 11/16 wrench and adjusted the shoes in (looked in the inspection window on front of drum) Started the truck let the air pressure build up hit the brakes and they pressed against the drum and did not let go when I let off the brake peddle.Also no sign of brake fluid leaking from wheel anywhere?

 

[porkysplace]

Was the truck used regularly before you bought it or was it sitting for a extended period of time ?

 

[EMD567]

Could also be a collapsed hose. They will allow you to apply the brakes, but the springs can't pull the shoes back against the deformed hose.

 

[73m819]

Does it set the brakes when you step on the brakes with the truck OFF, NO AIR, if so master cylinder is not allowing fluid BACK, need to check if all 6 wheels are having the brakes NOT releasing, or just one axle( L/R wheels)

 

[jokernatas]

5 ton, problems looking for local help

I have a couple posts on here about my truck, I am new to the 5 ton so I have more questions than answers. Im looking for any local members close to High Point NC that might want to help out a new owner.

 

[EMD567]

Read the TM's and ask questions here. That's what I did.......

Welcome to the 5 ton club.

 

[jokernatas]

Thanks for the info, I read the TMs and have my own copy, it would however be nice to talk to other people to learn from them.

 

[swiss]

Jokernatas I am sure some members may be near by that one day will reach out to you. Meanwhile we still have a ton of questions on your brake problems that have not been answered in an effort to help you and we need some updates on what you found. Pictures are the best.

 

[jokernatas]

5 ton Brakes

I dont have much to add at this point, I have been trying to pull the brake drum without pulling the hub, starting to think its not gonna happen, I still cant find ANY fluid leaks anywhere and the truck will free wheel untill the air pressure builds, the first time I hit the brakes once the air is right the brakes drag like ****? the Air Pack is a new part put on by the last owner and I have the old 1 in a box.....Im getting tools as I can so I can fix the truck soon.

 

[swiss]

Joker the hubs come off. Start by taking off the wheel. Loosen the brakes pad against the shoes by turning the brake adjustment bolt heads on the back of the wheel plate. Bang the outside of the hub with a big hammer while rotating the hub. Do this in about 6 different places around the outside.

Pull hard and the hub will come off.