Mark IV dealer installed A/C
 

Anyone have any experience with this unit? It's on my newly acquired '63 Suburban "Coral'. Seller says it doesn't work; has no belt connected. I assume the compressor will need rebuilding; who does that?

Brad

Re: Mark IV dealer installed A/C
 

62burg,

I have a Mark IV AC set-up on a 1964 GMC 3/4 ton with a 305E engine. The in-cab unit has a rectangular set of air deflectors, which is different than some of the round units I have seen, but my compressor looks the same. Mine is a York brand that is still available for purchase. The one on the truck still turns, and the belt is on it, but the refrigerant seems to be gone and I have been told that the compressor leaks. Of course it uses Freon based R-12 that is expensive. My thought is to replace the compressor and look into converting to the newer refrigerant (R-34?), but I have not gone far enough with this to talk about details.

JRMunn

Re: Mark IV dealer installed A/C
 

The York, you have, is used by many Jeepers and off road guys as an air compressor to run tools and tires. It is, of course, also an A/C compressor. lots of info, parts online. Read the tag to see which model and then search companies who can rebuild or trade in. Many rebuild their own compressors.

The R-12/R-134a was proven to be a scam. Bad ozone science. The conversion is not a big deal. There are many types of conversion kits available.

Re: Mark IV dealer installed A/C
 

62burb, this is lewis matkin. That is a york compressor, as has been previously stated. The compressor can be replaced as they are still being manufactured for the h/d market. I personally don't like the york because of it being all aluminum. I believe the tecumseh hg1000 is a better compressor, being made from cast steel. The compressor you have is the flange type of cylinder head which may be hard to pick up. If you aren't able to find the flange type, i would go with a rotolock or tube-o style of compressor. By going with this style of compressor, the service valves on the cylinder head will have to be replaced with new service valves matching the type of compressor you purchase(roto-lock or tube-o). Also, when you start to reassemble the system, lay the compressor down on it's side and check the oil in the crankcase of the compressor. It takes a 9/16" socket or end wrench to remove it. Then take a unfluxed welding rod or a piece of metal coat hanger (approx. 8") and use this for a dipstick. The oil should be approx. 1 3/4" up on the rod ater having inserted it completely through the compressor. If it isn't (most rebuilt compressors come dry-no oil) fill the crankcase with ester 100 oil until you have the proper amount in the crankcase. Please do not think that you can just add oil through the line, it won't get into the crankcase as that the head and crankcase are sealed from each other. You can reuse your clutch asm. By removing the 3/8" bolt holding the pressure plate on to the crankshaft, and inserting a 5/8"uss (course) x 1 1/2" bolt into the clutch hub and tightening down until it "pops" off. The magnet underneath is held by 4- 1/4" screws to the face of the compressor. Remove those screws and the magnet from your old compressor, and install them on the new compressor in reverse order, using the 3/8" bolt to install the clutch hub. After reinstalling the compressor on the engine, replace the drier and vacuum down the system for at least 12 hrs before recharging the system. I understand that the vacuum time is long, but a system of that age needs that time to pull all the air and moisture that has built up inside the lines, condensor, and evaporator asm. Vacuum the system at the beginning and put one can of r134 in through the high side (discharge) to sweep the system of trapped air, then reattach the vacuum pump to the system and pump down the system. After the vacuum operation is finished, lock down the valves on the set of charging gauges to test for leaks. The system, if not leaking, should hold 28-29" of vacuum for a minimum of 20 minutes. If it holds a vacuum, then start to charge the system with r-134. Look to see if there is a label or tag telling the refrigerant capacity of the system. It will give you the amount in ounces of r-12. Charge the system with no more than 80% of r-134. I will be happy to give you more advice in a pm if you want it.

Re: Mark IV dealer installed A/C
 

Lewis you blow my mind! That is priceless detail that will make this (over the winter!) project doable. Thanks!

Brad

Re: Mark IV dealer installed A/C
 

Jrmunn, this is lewis matkin. The seal can be replaced on that compressor. I have done it when my dad's shop in cullman was open. It is very easy, but you must determine which seal your compressor has. I think there are 3 different types of seals, and the only way to determine which one you have is to remove the clutch plate as i described to 62burb.