Switch to R134 in dash air

[Jim Rodewald]

I am attempting to totally replace the dash a/c with a system using R134.. During the past five years I have spent over $3K on a/c repairs, and still have no system that works.. The latest holdup is finding a dual belt crankshaft pulley for a 360 that uses 3/8" belts.. Has anyone had experience with this?? Any suggestions??

[Cookiecruncher]

Have found such items at local salvage yard. as a mater of fact I converted my 360 from with air to no air as the whole system was done for and I think I still have the 2 grove pully that you talk about
 

[Guinnessecco]

I remember an article in Auto Restorer magazine about replacing an older air conditioning pump with modern axial compressor when converting to R134a.  There are five different sizes and brackets are available to mount these new pumps on the old compressor mount. There is a ten percent loss of cooling with R134a, not enough to matter, but if you are getting a new pump, you may want to go to a larger size.  The new pumps are a lot more efficient and smoother; however, you can use the old pump if you want.  It is very important to replace the old accumulator/dryer because it is not compatible with R134a.  Also, the lubricant used with Freon 12 when mixed with the new R134a causes instant failure of the old pump.  The old pump can be used if the old lubricant is flushed.  R134a uses a synthetic lubricant.  Might be a good idea to replace the seal on the input shaft of the old pump.  The author of the article said that it was his experience that you did not have to replace the hoses, that the R134a did not diffuse through the old hoses as some people reported.  The article did recommend replacing the evaporator orifice.

I though I was going to have to replace my air pump because it was making sounds like it was going to throw a rod, so I checked my service manual about replacement, and there was a note about the clutch becoming loose on the crankshaft causing this kind of problem.  I tightened the bolt and that took care of it.

[Jim Rodewald]

quote:Originally posted by Cookiecruncher:
Have found such items at local salvage yard. as a mater of fact I converted my 360 from with air to no air as the whole system was done for and I think I still have the 2 grove pully that you talk about
 

Thanks, but my problem is in finding a 2 groove pulley for 3/8 inch belts... I have one for 3/4 inch..Jim

[Jim Rodewald]

quote:Originally posted by Guinnessecco:
I remember an article in Auto Restorer magazine about replacing an older air conditioning pump with modern axial compressor when converting to R134a.  There are five different sizes and brackets are available to mount these new pumps on the old compressor mount. There is a ten percent loss of cooling with R134a, not enough to matter, but if you are getting a new pump, you may want to go to a larger size.  The new pumps are a lot more efficient and smoother; however, you can use the old pump if you want.  It is very important to replace the old accumulator/dryer because it is not compatible with R134a.  Also, the lubricant used with Freon 12 when mixed with the new R134a causes instant failure of the old pump.  The old pump can be used if the old lubricant is flushed.  R134a uses a synthetic lubricant.  Might be a good idea to replace the seal on the input shaft of the old pump.  The author of the article said that it was his experience that you did not have to replace the hoses, that the R134a did not diffuse through the old hoses as some people reported.  The article did recommend replacing the evaporator orifice.

I though I was going to have to replace my air pump because it was making sounds like it was going to throw a rod, so I checked my service manual about replacement, and there was a note about the clutch becoming loose on the crankshaft causing this kind of problem.  I tightened the bolt and that took care of it.

Thanks for the info - - but the only way I will change anything is to do a complete change.. I've had a couple of commercial a/c types tell me that is the only way to eliminate a badly contaminated system.. Mine is so bad that the sight glass becomes opaque due to acid etching after 300 miles of use.. I have found all components necessary for the conversion except the dual groove pulley for the smaller belts.. Jim