Where to start on A/C? '83 240D

[QS23]

Hey All,

Sorry for adding another A/C thread to the mix, but I really couldn't find the answer searching the forums - and my current 265 A/C just isn't cutting it right now.

First and foremost, I've got the manual climate controls and I haven't touched anything A/C since I've had the car. Second, I've got no belt on the system. Third, I've got no r-12 in the pipes. Fourth, I'm hoping to keep it an R-12 system. Why? If this is the same R-4 compressor that was in my 83 Caddy (which I converted to r-134a) the conversion really doesn't work.

So my questions is where should I start? Is there any way to test the system without putting the belt on and filling it up with r-12?

[vstech]

least expensive way to test for leaks is to fill the lines with helium. small balloon party can for $20 fill it up and check the obvious joints with bubbles for leaks.
next, grab the clutch face of the compressor *(three flat metal bars) turn it with your hand, if it turns, it's not locked up.
get a belt, and install it, then evacuate the system, and charge it up!

[Mark DiSilvestro]

Also inspect for black, oily dirt buildup around the front of the compressor. It's not unusual for these compressor seals to leak after 20 - 30 years. I agree about the R12 for a decent vehicle that has a known history of minimal freon loss.

I tried a 'quick & dirty' conversion to R134 on my first rustbucket 240D and the (very old, rebuilt) compressor was noisy, cooling barely adequate, though it was better than nothing, and it so happens there WAS a leak since it lost it's charge after a few months.
I have seen a few W123s, mostly 300Ds, with more comprehensive R1134 conversions that seemed to perform OK.

OTOH, last year I did major AC repairs to my latest, solid-body 240D. System still held some pressure after several years but compressor-wire had been disconnected due to some mechanical defect that allowed the compressor to spin smoothly for several revolutions but then mysteriusly lock-up. As the system had never been converted, and there was no trace of 'black-death' or metal shavings in the lines or compressor ports, I gambled on a rebuilt compressor, filter-drier and R12. System runs nice & cold, compressor runs quiet and doesn't drag on the little diesel as bad as the R134-AC on my previous 240D.

Also note that, if you do plan a conversion, or have a newer vehicle that uses R134, read the product-labels very carefully. Many retail outlets are now carrying alot of R134 with 'stop-leak, which opens another can of worms!

Happy Motoring, Mark

[QS23]

Originally Posted by vstech

least expensive way to test for leaks is to fill the lines with helium. small balloon party can for $20 fill it up and check the obvious joints with bubbles for leaks.
next, grab the clutch face of the compressor *(three flat metal bars) turn it with your hand, if it turns, it's not locked up.
get a belt, and install it, then evacuate the system, and charge it up!

Ok, Just curious... how am I going to hook up the helium tank to the recharge hose?

[vstech]

you won't be able to do it easily, but you can put a hose onto the nozzell on the tank, and adapt a connection to your manifold.
the easiest thing to do is get the CO2 kit from lowes and hook it up. really cool kit with belt mounted kit to charge with!
it's around 100.00 though.
if you can get a nitrogen kit with regulator from craigslist, it will have a 1/4" fitting to connect your manifold to.