Mark T

That's a J & J there's a body prop right to the left (driver's side) of your hoist. That should swing up into position and will stop an EMPTY body from crushing you. Trust me on this one kid.... if you have enough brains to figure get'n under an unsupported body is a lousy idea ? you can probably do better finding an air leak than you think

Yes the truck was made with the tanks that look to be aluminum. Then someone added the two. Are you sure one of those two doesn't have a tiny hole rotted through ?

It looks like someone added air tanks parallel to the frame. Those most likely supply all lift axle related air

Empty , a block of wood of some size . Yes the turquoise thing is the dryer

The soapy water trick will get you results. Once you get the hang of it, then maybe a picture of the leaky area or component ???

You have to understand, lots of guys are willing to help, but it's not easy without being there ( lol ) the solinoid ? Depending make ?? They all look a little different. So not easy to describe other than it'll have airlines and a wire or two. But even if the axle has a tiny leak and something else on the same tank leaks more... there's not enough air to keep the axle up

That's probably a picture after it sat and bled down. Really doesn't determine anything about where the leak is

I can almost remember those trucks on The NE Extension and thinking the bags were way over stretched. Like no rolling lobe action at all. Would make sense bags could be shot

That looks like an HLM so it's air up air down...and it looks huck bolted, so probably from the modshop and has a solinoid somewhere

Mack liked that valve, they used it on several things that weren't brakes and used air

That little red cap valve ?? That truck can ( and likely does ) have more than one. Might find one on an air tank you can see from under the truck . And they could be on either system. Make liked that particular brand back in that era

Often brake chambers can blead back from side to side especially those cheap gold ones. Might be what's causing the inversion valve leak ? He said he had a leak upon brake application in the rear and the front is actually rotted to the point of having a hole. The lift axle ? Hard to say what arrangement is on that. Could be electric over air or all air ....or maybe even a make that doesn't even use air to lift ( like Neway) need some pictures of this unit

I'm think'n that no matter what's leak'n on your truck ?? do yourself a favor and replace all four air chambers on the back of it. I'd suggest 4 MGMs . They cost a lot, and if you don't know how to change them you'd be best to let someone who does. You really can't go wrong with new chambers....unless you don't know how to change them. Between putting air lines back on and cutting the push rod to the correct length, let alone it's not impossible to hurt yourself with the parking brake they're nothing to play with unless you know. I think some of your leaks are from the air chambers . those gauges dropping with the application look about normal ???

AOC will be pleased to hear of your repairing that puff limiter .

I think that's the reversing relay for the puff limiter and the line going to the puff limiter taped up

The ones I'm thinking of were kinda nice. A few used ones ended up around where I'm from. They were nice used trucks,and there's still a couple around

They used to run around south east pa and nj. They had trucks similar to yours

That looks like an old Capone truck.

I'd get the red thing from your dealer by the VIN of the truck . I've seen them at parts places, but not sure the port sizes will be direct replacement on your's. Charging the truck from shop air ? not much chance you'll hurt anything. Joey's idea about going in the compressor discharge is a good place, and when it hits @ 120 you'll hear your air dryer go off. ( if you're worried about too much ) Likely charging in the primary tank won't hurt either. If this truck has leaks from valves you may want to consider finding that air dryer and replacing the desiccant at least. Only reason I suggested the governor was it's marked and probably easier to get at....and air will go in the truck much slower through a tire valve in one of those little ports.

I'm going through the same thing. The dealer here just put two on a tractor that came with painted ones. I also see new trucks on lots with them and a variation of the same mirror without the lights. They exist....but getting them ???

The CLs I had, the air dryer was right in the area about where the back of the transmission is. Mounted inside the frame. ( this doesn't mean your's is ) Yes the tire valve you mentioned, you can put shop air in there. The cutoff/ regulator ( thing with red cap ) if it's leaking, it's shot. The brake air leak is likely a diaphragm in a service chamber

That's a cutoff for if the air drops too low. It's purpose is to stop air from going to something less important than brakes. ( like suspension ) they're regulated and colored for how many pounds they allow. With the truck shut off ? The gauge should drop as the lift axle is put down ( air's going to filling the bags ) there's reservoir ports on the govener that'd probably be really easy to charge the truck with shop air

Anywhere there's air, there could be a leak. Your truck has two air systems, primary and secondary. Depending who tapped into where over time it's hard to guess what besides brakes comes from where. Grab the soapy water and put it in an old Fantastic sprayer (or something) After you find an air leak (look for the bubbles and different sound when it gets wet) you'll catch on quick.

That small picture of the dash looks pretty clean, I think maybe some pictures of the whole truck might help 😏 Sounds like maybe something with that lift axle is the biggest problem, but it actually depends on what else is on that system. IDK if that's primary or secondary on your truck. You're gonna need to listen and start squirt'n soapy water . Once you find one ....you'll catch on fast how to find an air leak. Fix'n it ??? well that's another thing

Do you really need to run ducting for the tip fan in this day and age ? Seems like K & N or someone should have some form of filter that would be easily adapted to it and not take up much space . (think like cold air intake on a Dodge) just a thought