for those of you who switch to 134a - PeachParts Mercedes-Benz Forum

ned2683 · #1 06-12-2003, 01:53 PM

i have a question. i attempt to retrofit my car this morning. i know the good and the bads about switching over, but i decided to do so. here's what happened:

1. screwed on the low and high port retrofit kit.

2. hooked up hose and read "0" pressure

3. tapped new 12 oz 134a refrigant

4. about 3/4 the way i took it out. (car running with a/c on)

5. pressure read 70 lbs (left of the red side)

compressor still not kicking in, and still not cold. i believed i did it right and i assume the capacity was 20 oz in these cars 1984 300SD. what did i miss or do wrong? any advices would be appreciated. thanks

ned

jgl1 · #2 06-12-2003, 02:38 PM

R-12 refrigerant capacity for '84 W126 is 2.9 lbs (46.4 oz.)

But before you go any further - did you...

1.) locate and correct all leaks?

2) thoroughly flush all mineral oil out of the system and replace it with a R-134a compatible lubricant? Note oil replacement includes removing the compressor and draining/measuring the oil removed. Which lubricant did you use - PAG or ester? And how much did you add?

3) renew the receiver/drier?

4) pull a vacuum of sufficient duration and depth? A reading of zero is unsuitable.

ned2683 · #3 06-12-2003, 02:56 PM

Quote:

Originally posted by jgl1
R-12 refrigerant capacity for '84 W126 is 2.9 lbs (46.4 oz.)

But before you go any further - did you...

1.) locate and correct all leaks?

2) thoroughly flush all mineral oil out of the system and replace it with a R-134a compatible lubricant? Note oil replacement includes removing the compressor and draining/measuring the oil removed. Which lubricant did you use - PAG or ester? And how much did you add?

3) renew the receiver/drier?

4) pull a vacuum of sufficient duration and depth? A reading of zero is unsuitable.

answer to all questions: no. i am doing it the cheap way to see if my compressor works. PO said i t was empty so i did not flush it or anything. i thought u need to do those steps if u need it done RIGHT, but don't people just buy those $40 kits and recharge them? thanks for your help

#4 06-12-2003, 03:55 PM

Please say it ain't so!!!!!!

Contaminating the R12 that was in there without so much as evacuating is bad news. If this were an old beater on its last legs I could understand, but this is an MB that I assume is a decent car.

If you want a/c you need to look before you leap. There are plenty of posts on here that will describe how to properly troubleshoot the system without contaminating it just to see if the clutch will kick in.

You really now need to completely disassemble everything, flush, replace the filter drier, drain the compressor, put on 134 orings, evacuate and charge.

Had you not done this, it would've been a simple matter of finding the leak or problem, repairing it and recharging with R12.

Good luck,

Rick Miley · #5 06-12-2003, 04:09 PM

Ned, the mix of stuff that is now in your AC system will create an acid that will eat through every part of the system in short order. What may have started as a simple problem can end up with pulling the dashboard out to replace the evaporator, plus changing the hoses, the condenser, and the compressor. That's why people get so upset about the $40 "death kits."

Besides the fact that the system cannot now be evacuated without contaminating something.

engatwork · #6 06-12-2003, 05:59 PM

The problem now is how in the world will you "legally" get the stuff that is in there now out? There are some real stiff penalties for venting it to the atmosphere.

ned2683 · #7 06-12-2003, 07:53 PM

double oops.

the PO said there was a leak and the old R12 all leaked out. by this he means big leak. my idea in doing this was to see if the system was leaking or the compressor was bad (if it will turn when i fill it up). in any case i did not have enough money to do it right or refill it up with R-12. so should i take the old stuff out? should have thought ahead, oh well at least i learned now.

ned2683 · #8 06-12-2003, 08:05 PM

aparently i went down to check the pressure again and it was all gone. so i suppose it was leaking very bad

Rick Miley · #9 06-12-2003, 11:14 PM

Well Jim, he found a way to get it out legally.

Ned, tha bad news it that it isn't really all out. If you want to save the system, especially the evaporator, get it flushed out pronto.