How can I tell and I’ll look and see?

 

Check your rear wheel cylinders. Your front discs will stop an empty truck just fine. Wheel cylinders can lock up and just feel a bit odd but seem to be working. Rebuild kits and even new cylinders don't cost that much. A 1/2 ton should handle your trailer so a 1 ton shouldn't sweat. It's also possible your rear flex hose is bad, but I would look at the wheel cylinders first. What you describe sounds a lot like brakes I've dealt with before.

 

Should be wheel speed sensors on the axles, or front wheel bearings. If there are wires going to the front wheels, those are likely sensors. On the rear, dodge was putting it in the top of the pig. If no sensors, then no ABS. (and being a 90, not sure trucks were that 'advanced' back then.)

Aside from that, what the grouch has to say is definitely something to look into.

 

These trucks typically had RWABS but never any front wheel sensors.

the old iron prop valve is also bad for sticking/seizing if one half has lost full pressure. Mine had to come apart to be cleaned out.

 

No sensors and yeah I probably need to replace the wheel cylinders I’m sure they are bad enough not to stop it or cause what I was talking about because the truck sit for years so then again I might replace them and all lines as well. Thanks guys.

 

Are you saying my truck has rear wheel abs ?

 

Ouch, if it sat for years, the rear cylinders almost certainly need rebuilding. Especially if you try to bleed and the bleeder breaks off. You can probably get new or rebuild cylinders fairly easy and cheap. A full brake flush would be in order too. Brake fluid is hygroscopic and sucks moisture out of the air. Just plenty of DOT 3/4 fluid and you should be good to go. Just do ONE side at a time. That way, if you forget how it goes, the other side is a mirror image of it.