I found a nice set of 15x8 rims locally, and had new Nexen tires mounted! They look great, just missing a shiny set of lug nuts. First set I bought was 15x7 I was told 4x4 came with the 15X8 rims, the 31x10.5 should sit better on it. Also replaced the old sun faded Lariat badges. Next is repainting the rear bumper and fixing the rust on cab floor and a/c compressor.

 

Looks nice, good find.

Did my rear bumper a qhile back, Rustolume has a nice gray paint. I used grease on the chrome bolts to keep paint off them.

 

Interesting. I never knew the AC compressor could get rusty. If the rust is only on the outside, that would be cosmetic and could be left as is.

 

a/c compressor was an after thought, I should have checked my syntax better.

 

I'm having an issue with my a/c system and I'm a little bit at a loss right now.

I replaced my a/c compressor and clutch field+pulley and added 6oz of pag oil based on what was recovered from the old compressor and the leak. I pulled a vacuum and system kept vacuum overnight.
Then I was filling the system with cans of R134a, I have about 4 cans (12oz a can) in the system which is more than I should have put. I was planning on putting around 36 to 41oz which is about 70 to 80% of the R12 charge for this truck, but since the pressures were low I added some more...A/c is blowing ambient air, switch isn't cutting off and my low side is reading negative pressure, high side is reading 120 psi which is low too for being 80F outside it should be at 175-210 PSI bases on the chart I have. Drier, orifice tube were replaced, and everything was flushed last year. There was no blockage. Need help

 

 

Are you using the adapter ports from R12 to 134a?
Is the compressor spinning and the low PSI switch not jumped out? I would think the switch need to be jumped out.
If the compressor is turned off what do the pressures do?

It sound like it needs more charge. If the high side is low then how can the low side come up?
When you installed the new compressor did the paper say to dump out the old compressor measuring the oil and add it to the new one?
I believe new ones will say dup the shipping oil add so much or no oil needed as it was shipped with the right amount.

Mine was dump and add xxx amount of oil. Add a little and rotate, add, rotate, till all in.
I will tell you if you add too much oil the system does not work too good. Thing is it is hard to find how much oil a dry system takes, this is on top of the compressor.
I have also needed to add 4+ cans and thought that was a lot. But once the pressures started coming up it started to cool.
Are you sure a full can is going in? Sometimes it feels like it does till you disconnect. I find putting the can in hot water to heat it helps empty the cans.
I have a 300 six so U can also lay the can on the exhaust manifold to heat it.

Lets see what others have to say but I think it needs more.
Dave ----

 

I reused the old clutch plate, it was very difficult to remove, I had to pull pretty hard on it, now the air gap between clutch and pulley is wider than before. I've put back the two shims, that were on the old compressor, I tried without but it wouldn't change anything, clutch still engaging...

 

I suspect the clutch is not engaging fully. Sounds like the air gap is too wide and the clutch is slipping.

To test for slippage, put matching paint marks on the pulley and pulley face:


Index marks shown slightly misaligned


You'll need to hot-wire the clutch, as power is removed with the key in the start position. Remove the connector at the pressure switch. Connect a test lead between the battery (+) post and the wire leading to the clutch. You should hear a clunk as the clutch engages. Now the clutch will stay engaged during engine start.

Start the engine and run for a minute or so. Look at the index marks. No official specs that I know, but I've always used a quarter inch as a limit. If the marks are off more than that, the clutch is slipping.

It also sounds like you have too much refrigerant in the system. Don't have my notes handy, but I think my truck originally called for 48 ounces of R12. With the common 80% value for R134a conversion, that is only 38.4, which is about 3.2 cans of 12 ounces each. My truck has been very happy like that.

 

I dont know what the air gap spec is but it was not much something like 60 thou?
It could be slipping so do the test Karl posted.

I have had to add more that the 3.8 cans to get mine to start cooling.
I got a leak somewhere that I cant find and everything is new in the last 2 to 3 years max.
I got dye in the system but that has not helped so far. I picked up a sniffer and going to use it when I refill the system as it is not working ATM
I almost want to send this job out I have messed with it so much.
Dave ----

 

I will try this !! You're going to laugh when you see my air gap . Did you use a special too to pull your clutch plate?

 

I've never done anything with the clutch. When the original compressor wore out, I considered rebuilding it myself. But when I priced the replacement parts, it was nearly the same price to get an entire compressor (with clutch).

 

Ran the test, clutch has not slipped at all, in fact the air gap seems to be normal compare to when I put it back together yesterday..

 

Thanks for humoring me and checking. Sometimes all you can do is chip away at likely faults.

Did you ever inspect and/or clean the evaporator? Long thread, so can’t remember. Not sure a clogged evaporator would cause your exact situation, but it’s one more thing to check.

You can do a quick preliminary inspection by removing the fan motor resistor pack. You can see a little bit of the evaporator face to get an idea if further disassembly is necessary.

 

Yes evap was taken out last year, and flushed with the compressed air tool. I got my hand on a used R134A pressure switch, going to swap and see if it cuts off.