A compressor cycling frequently, in my experience on my vehicles, has meant that system is on the lower end of its R-134a capacity.

So you may have a leak. Check pressure on the low port.

 

Take it to a pro. If you attempt to mess with it, and you screw it up, it'll cost a LOT more.

 

When mine did this it was low on Freon. It was low because the compressor seals were shot.

 

Just pop a gauge on it and look before you 'take it to a pro' and waste a bunch of money. You can't screw it up through simple observation. If you're made of money take Steve's advice.

 

yo,
yo,
Gauges to check pressures and level are needed.
see this in 1996 Bronco/F-Series
Workshop Manual (PARTIAL by Ford via http://www.diesel-dave.com/vehic/manual/stj/stjleft.htm


Section 12-00: Climate Control System, Service
SERVICE PROCEDURES
Refrigerant System Tests
Refrigerant System Pressure and Cycle Timing Evaluation Chart for A/C Evaporator Core Orifice Cycling Systems
NOTE: Normal system conditional requirements must be maintained to properly evaluate refrigerant system pressures. Refer to charts applicable to system under test

Refrigerant System Pressure and Cycle Timing Evaluation Chart for A/C Evaporator Core Orifice Cycling Systems
http://www.diesel-dave.com/vehic/manual/stj/stjc0025.htm#extract_1261
NOTE: Normal system conditional requirements must be maintained to properly evaluate refrigerant system pressures. Refer to charts applicable to system under test.

TSB 98-12-08
http://www.tccoa.com/articles/mn12-techinfo/tsb/TW1208.pdf

 

I would take it to a professional if I knew a good qualified one and I wasn't familiar with and had done a bit of a/c work over the years. Plus I like to at least try to fix things myself as it helps me learn.

Anyway, I had a chance to take a quick look over the system this morning. The high pressure port looks as if it's not sealing completely. I can look in the port and see bubbles around the sealing valve and there is also oil residue on the outside of that section of the a/c line. The little plastic cap was also wet and oily.

I have manifold gauges and I can always rent a vacuum pump from the local parts store, but with an obvious leak, there's not much reason to put them to use until obvious leaks are fixed first. I'm not sure as I didn't look at it too long, but this appears to not be a serviceable part where I could just change out a valve, and it looks like I will need to replace the line this is in to fix it. Is this correct?

 

It is a schrader valve like any tire valve - try and unscrew it a little bit and tighten it back down.

A/C isn't complicated - there is a pump, a low pressure switch, a high pressure switch, oil, refrigerant and an electric clutch. Too high it shuts off, too low it won't turn on. If you have a slow leak and the system is still functioning - repair the leak and add refrigerant. I would get the kit form the parts store that comes with the re-usable gauges, multiple use out of those.

 

It doesn't look like a schrader valve unless the schrader valve is under the 134 fitting and that needs to come off first to get to it?? It's a large port and looks to have a round black plastic piece (maybe it's a cover for the valve) in the middle that presses in and out. It's leaking/bubbling around that piece.

 

The low pressure port is a shrader valve. The high pressure port where mine is leaking is not. Is the high pressure port a serviceable item or will I need to replace the line?

 

The black plastic cap is just, that, a plastic cap. Take your fingers and unscrew it. Under that is the valve.

 

Maybe a picture will help. It's not a shrader valve.

 

It either has a schrader-style core, or a rubber ball. They work effectively the same, but the rubber balls leak if they get scratched.

 

It's the ball type. Is a replacement available or can it be switched to schraeder-type and if so where can I get the parts?