M135 troubles continued.

[Brad]

We been trying to get this 52 M135 tuned up and tightenup for the upcoming parade season. We use it to ride veterans in all the parades in our area. It was my Dad'esdream for his truck, and it has served uo well for some years now.
We finally got six new tires and tubes on the truck and will now be able to safely travel farther to more events. All vetrans are encouraged to get on board.
We have had a problem with the brakes hanging up since the very beginning. Have rplaced all the rubber lines and several wheel cylinders, rebuilt the booster. Really not much improvement.
But the lastes problem has me perplexed. Running along just fine and all of a sudden it starts romping and jerking like it is shutting off and restarting. We have drained the gas tank, replaced the filter and cleaned the air cleaner. Which was pretty cruddy. It ran ok with the filter off but when we replaced it, it started acting up again.
My next step is to remove and clean the carb, or am I overlooking something??
Any suggestions on this or the brake problem is greatly appreciated?

 

[Barrman]

Fuel filter and taking the carburetor apart enough to make sure the float needle and seat are clean probably should be done.

What about the ignition points? If it has been a good number of years since you even looked at the points they could be carboned up and causing the issue. However, normally when points misbehave and you have fuel a nice loud back fire type sound from the exhaust happens. Since you didn’t mention that I think you have a fuel issue.

 

[G744]

Make sure your gas tank is properly vented to the atmosphere.

Otherwise, as gas is used and air is not let back in a vacuum will develop and stall it out.

For the brake problem, make sure the MC pushrod has a tiny bit of slack, as the lack of same can keep it from totally releasing.

 

[m1010plowboy]

We found out G749 points can be fine for a long time. Then one day, on the way home from a parade, they break at the mounting screw. It still ran and made it home but kinda had the intermittent power you described.

Fuel cap set on fording, screwed down too hard, could cause problems. Most caps have two settings. There is a process in the manual to test fuel flow and that's an easy trouble-shoot to eliminate fuel as a problem.

Dragging brakes symptom is often the air-pak/air hydraulic cylinder. When you lift your foot off the brake, it has one job. One of the tech tips was to lubricate the air cylinder yearly so the big piston slides easy. Another thing we found on an airpak was a small dent on the canister that would sometimes hang up the piston.

At one time the fellas would find the air-pak repair kits on shelf but haven't seen them lately. Let's hope it just needs some lube.