Hot Brake

[WarrenD]

OK, this is the original issue. The right front brake was running hot. 140F after a 4-5 mile ride with little, light braking. Other drums were around 90. I re-adjusted both fronts and that's when the left front wheel cylinder let go. That was replaced and I bled this morning. Did my usual 4-5 mile road test and no change. Not sure what's going on. Both fronts were adjusted with zero-to-just barely audible drag. It's too hot here right now so I'm not able to check the adjustment; would need to let that rt front cool off anyway.
Only things I can think of are a weak return spring or some sort of fault in the shoe adjusters. Fluid flow was similar during bleeding and the other 3 seem appropriate temp-wise for the light braking I do. Seems like it's dragging.....
Anyone have any thoughts?
I'm starting to think about a disc conversion but not sure I can afford it nor am I up to the work.

[Vaughn2]

Old rubber brake hose will do that over time, they tend to swell and hold pressure. Replace with a new armored brake hose.

[WarrenD]

I thought of that, I have some investigation to do. The adjustment had zero drag. If I have drag now after it's been sitting that would point to one of the adjusters not holding. If there is no drag and I pump the pedal and there is drag, that would point to something holding pressure. I do have a new hose and wheel cylinder in stock. Thinking I might just get the adjustment/hold down hardware and replace everything.

[Vaughn2]

If the adjustment pin is easy to turn, that might be one of the issues and installing a cam kit may not solve it as it might be a worn support. If the rubber brake line has collapse it will hold pressure after the brake pedal is released. The MC/line pressure may be +/- 500 pounds which is more than the shoe return spring can over come. VPW does has used support assemblies if you should need one.

[Cal_Gary]

Perhaps the drum is out of round and heating up on the rotation?
Gary

[WarrenD]

The drum has a little high spot, but so do the other 2 I have. I jacked up the rt front this morning and had all I could do to rotate the tire. Truck had sat for 48 hrs. I tried to back off the shoe adjusters and was able to get enough to get the drum off. I put a clamp on the shoes but they didn't budge. Then, after rotating the adjusters back and forth, something freed up. I was able to get the adjustment with no rub. I tried all three drums and they were almost identical. The 2 spares came off when I got the 2 new ones for the front. They all have a slight high spot but not enough to cause a vibration under braking. With the drum on, I got into the cab and pushed the brake pedal a couple of times. On the second application, I heard what sounded like a spring unloading and after that, the wheel was almost completely locked down again.
At this point, I have a set of good condition take out shoes, a new wheel cylinder and new hose. Next week I'll order the rest of the springs, hold downs and adjusters and just replace everything. If that fails, looks like I'll need to save the $3K for a disc conversion.

[just me]

Sounds like too much clearance. Shoes too thin and drums too worn. You apply the brakes and they over travel and hang up.
There is really only 1 turning of the drums capable because of how thin they are to start.
Measure the drums AND the shoes and compare them to the condemning limits in the manual. A few thousandths out is all it takes.

[Cal_Gary]

Our friend John Bizal at Midwest Military has NEW modern drums if you want to stay with drums.
Gary

[WarrenD]

The front drums were obtained from John maybe 7-8 years ago, new. Truck probably doesn't have 50 miles on it since. I don't think this drum is too thin, the one I got from John at the same time is on the left front and it's fine. Same shoes on both sides bought new also. I just had the left side apart to replace the leaking wheel cylinder and it adjusted fine when I was done. For some reason, even though the shoes on the right side are worn from dragging, I can't get them to back off to leave more than a very small gap between the shoe and drum at most. Could be the wheel cylinder has junk inside that isn't allowing the spring to pull the shoes in or the adjuster cams have an issue. Won't know until I get the new parts and pull everything out.

[WarrenD]

Good news, bad news day. Yesterday I tore apart the right front brakes. Replace the wheel cylinder, spring and lower shoe supports/adjusters. Everything seems to work fine now, shoes adjusted and no drag. Bled the fronts and pedal is good and there still isn't any drag nor change to the adjustment. I looked at the take out wheel cylinder and the front piston was frozen in place. so much so that it took a 2 lb hammer and a couple of hard blows to pop it free. I think that was the issue.
Now the bad. I started it up, pulled it out of the garage. It was running well so I left it to warm up before the road test. After another minute it just quit. Like someone turn the switch off, no sputter or stumble. I tried to restart and it seemed to run but immediately sputtered and quit. Dumped some more gas in the tank (gauge said 1/2) but no go. Took me 2 hrs to get it back into the garage.
I'm done with it. I don't have the money or the ambition to fix it.

[Cal_Gary]

Don't give up on it Warren! We have all been there, fix one thing and another breaks. There's no finish line on these relics, always something else to do. Give it some rest and get back on it when you're ready. Stay strong my friend!
Gary

[WarrenD]

Thanks for the kind words but I've made up my mind. I'm thinking of moving in the near future and can't bear the expense of moving the M37. I'm retired on a fixed income and just had to replace the daily driver. I'm not sure what is wrong now, maybe the fuel pump, maybe the carb or maybe something else. I spent $6k this year on the car and only got $1k back. I've gotten to the point where I can't deal with it.

[JimC]

Depending upon how far you are moving, try to find a volunteer to move it for free.
Same with the ignition/fuel problem. I'd bet there are other M37 owners nearby who would help.

[JimC]

That's a good looking truck and reasonably priced.
However, I would urge you not to sell it.