1983 M-923 Brake stuck

[Jonathan M]

Hello,

I bought a 1983 AM General M-923 in 2018. Well long story short, it has been sitting. Just put a windshield and power steering lines in it. Thought I was good to go,....NOT. The rear driver's side brake will not release. I tried pulling on pavement and going a few inches forward, a few back, multiple times trying to get it to pop free. Didn't free it up. Beat it with a ball peen, nope. I'm looking at it and is is nothing like commercial brakes I'm familiar with. What's the next step,......bigger hammer?

 

[Mullaney]

Hello,

I bought a 1983 AM General M-923 in 2018. Well long story short, it has been sitting. Just put a windshield and power steering lines in it. Thought I was good to go,....NOT. The rear driver's side brake will not release. I tried pulling on pavement and going a few inches forward, a few back, multiple times trying to get it to pop free. Didn't free it up. Beat it with a ball peen, nope. I'm looking at it and is is nothing like commercial brakes I'm familiar with. What's the next step,......bigger hammer?

.
As stupid as it sounds - yes. The shoe is most likely rusted to the drum. Other trucks like the M1088 with no bed on top of the wheels are awful for doing that. Especially if you park with the left or right side down-hill. Rain water will stick that shoe to the drum.

I suggest that you pull the little blue plug (might have been painted green) on the brake canister with the stuck brake. Insert the Cage Bolt through the slot and turn it ninety degrees (to fit in the slot inside - that you can't see) and run the nut down to snug by hand. USE THE WASHER under the nut so you don't scuff the aluminum brake chamber. Uses a 3/4 inch wrench. Cage Bolt should be in a sleeve on the side of the air brake chamber.

Once the bolt is in place, tighten it up until it stops. the bold should appear longer as you tighten. I would suggest that you do it by hand. Not with a ratchet and a long socket. No need to accidentally break parts... When the nut won't tighten any more, thump the shoe on the bottom (where water stands) with about a 3# hammer. Try not to hit the soft shoe material - just the metal part of the shoe. When I have had to do that, it is obvious when the shoe releases from the drum. Then you remove the Cage Bolt, put it back in its holder and see if everything is back to normal.

Hope it works for you too!

REALLY IMPORTANT: The clamp around Part Number 2 in the picture below is important. Deathly IMPORTANT. If you disconnect that band around #2 without the cage bolt in place, there is a spring inside that could KILL YOU.



The Technical Manual TM9-2320-272-10 on PDF Page 407 gives you step by step instructions for caging.

 

[Jonathan M]

Why thank you Mull. I found the blue plug painted green. Removed. Looks like I should of rotated it 90 degrees. It's a little messed up but it will still work. I didn't know what you meant by cage bold but figured that out. The cage bolt nut is seized. I sprayed it with Kroil and abused my 3/4 box wrench. I won't tell you what I did to it. For now it is soaking. I'm not sure I want to but heat to it if there is a rubber diaphragm in there. I'm trying to figure where to wack it. I can't see the shoes. It is all enclosed. Even if it wasn't enclosed not much room to swing. I could pull the rims off and wack the drum? First time I ever looked at these things.

 

[Jonathan M]

Thank you for the heads up about the spring tension in the chamber (part 2). I will leave the band clamp alone on this project unless I have a cage bolt properly installed.

 

[Jonathan M]

In as I don't believe I will be able to remove the cage bolt from it's storage sleeve will a cage bolt from a commercial truck parts store work in the military brake system? Are they standard sizes?

 

[98G]

In as I don't believe I will be able to remove the cage bolt from it's storage sleeve will a cage bolt from a commercial truck parts store work in the military brake system? Are they standard sizes?

Yeah. Standard cage bolts. About $3...

 

[Jonathan M]

Thank you 98G.

Should I beat on the outside of the brake drum with the wheels removed.? I don't see how I could beat on the shoes.

 

[98G]

Thank you 98G.

Should I beat on the outside of the brake drum with the wheels removed.? I don't see how I could beat on the shoes.

A 3lb sledgehammer to the outside of the drum. You can't hurt it.

 

[Jonathan M]

A 3lb sledgehammer to the outside of the drum. You can't hurt it.

thanks

 

[Floridianson]

Just for reference.

 

[Tow4]

There is a dust cover on the backing plate that covers the shoes. Remove this and you can see the shoes from the back. You may find the wedge actuator is stuck. I had one stick on my M929. That will mean pulling that hub/brake drum to get to the brake parts. It's not hard to do and it's all in the TM.

 

[Floridianson]

Are they standard sizes?

3/4'' key. Yea he spelled bold and he was thinking bolt. Happens to me all the time. Also I keep my cage bolts in the truck as they can rust sometimes and be non useable. Oil the threads before use is a good idea as said above to not over torque. When the nut feels like it is getting tight that is more than enough. Now if your can diaphragm is not blown out just air up the truck and release the parking brake. Another way to cage a can if the diaphragm is holding air is to air up the truck release parking brake and insert the caging bolt tighten nut till snug with you finger. Pull parking brake, shut down truck and all the other cans the parking brake will be set so truck does not roll and you can work on that wheel / hub.

 

[Jonathan M]

Just for reference.

Thank you,......I saved the info.

 

[Jonathan M]

There is a dust cover on the backing plate that covers the shoes. Remove this and you can see the shoes from the back. You may find the wedge actuator is stuck. I had one stick on my M929. That will mean pulling that hub/brake drum to get to the brake parts. It's not hard to do and it's all in the TM.

The corrosion is bad. I'm not sure if I could even get a socket on those bolts. Today I pulled off the wheels and beat the drum. In the end it work but I had not realized what I was in for with the bud wheels. 9 out of ten of the inside and outside nuts seized and I unseated one of the pressed in studs. I used one of the inside nuts and a thick washer to re-seat the stud. I'm just lucky it didn't fall inside. I had to get a special tool to separate the inside and outside nuts. What a work out. No air tools. I'll be sore in the morning. I never seized everything before it went back together just in case I have to work on it again. I think I learned a lot today. After I got it back together I took it for a short ride. All's good.

 

[Jonathan M]

3/4'' key. Yea he spelled bold and he was thinking bolt. Happens to me all the time. Also I keep my cage bolts in the truck as they can rust sometimes and be non useable. Oil the threads before use is a good idea as said above to not over torque. When the nut feels like it is getting tight that is more than enough. Now if your can diaphragm is not blown out just air up the truck and release the parking brake. Another way to cage a can if the diaphragm is holding air is to air up the truck release parking brake and insert the caging bolt tighten nut till snug with you finger. Pull parking brake, shut down truck and all the other cans the parking brake will be set so truck does not roll and you can work on that wheel / hub.

Fortunate for me I was friendly with a mechanic who worked at the same company as me like 20 years ago. I called him up. He gave me a cage bolt and loaned me the special tool to separate the inside and outside nuts and a 3/4 drive wrench and sockets. I never would of gotten it done if it where not for him doing that. I have the 3/4 in drive tools but they are about 350 miles away. I didn't know what a cage bolt was til yesterday. Being it was Sunday I didn't think I would be able to get one until Monday. My mechanic friend didn't think I would be able to do it with hand tools. He uses air power impacts but he didn't have that to loam me. Those tools where all 30 miles away where he works. I wouldn't of asked. Had I failed I would of hired him.

 

[Jonathan M]

Sore muscles keeping me awake. Today I'm going to try and arrange shipping to Maine. Had a quote of $1150 to move it. You might say, "Why not drive it?" What it would cost me for insurance combined with a temp. registration and the risk of break down a long way from home,,,,,,,,, Several years ago my wife and I where taking our RV to Maine and broke down in MA. We got towed to a garage and where stuck there for over a month. They allowed us to stay in our RV and they provided electric and internet. They started referring to us as the residents! Turned out the major issue was a gear that drives the distributor shaft disintegrated. Started for home and the wiring harness caught fire and melted down. Had to get towed back. And the towing company used a jack on the differential and punch a hole in it. We did make it to Maine that time. After a couple of weeks the garage personal drove us back to CT so I could get a car. That way we could go for supplies and out to eat. I have got to say they took a long time to resolve all the issues but they where pretty nice to us. Oh, I forgot to mention they where using ether to try and start the engine and started a mouse nest on fire in the air cleaner. The mechanic ripped it out of the vehicle before it got out of control. That all was enough adventure for one month, plus.

 

[Jonathan M]

3/4'' key. Yea he spelled bold and he was thinking bolt. Happens to me all the time. Also I keep my cage bolts in the truck as they can rust sometimes and be non useable. Oil the threads before use is a good idea as said above to not over torque. When the nut feels like it is getting tight that is more than enough. Now if your can diaphragm is not blown out just air up the truck and release the parking brake. Another way to cage a can if the diaphragm is holding air is to air up the truck release parking brake and insert the caging bolt tighten nut till snug with you finger. Pull parking brake, shut down truck and all the other cans the parking brake will be set so truck does not roll and you can work on that wheel / hub.

Just thinking,..........If I had a set of four I could move the truck if I had air pressure issues. Say have a big 4 wheel drive backhoe towing and a bulldozer on the other end keeping it from running away out of control say to get it to a place to work on it. Just hypothetical.