I understand that the biggest problem with r12->r134 conversion is the r12 compressors just dont kick out the compression needed for r134 to be cool. is this accurate? Is it possible to use a newer compressor?

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

no, not accurate.
the problem is that the system. I.E. the condenser/evaporator/compressor package does not have the capacity to handle the pressures and heat output of 134 in the R12 package.
a LARGER condenser or a paralell flow style would help dissipate the heat and keep the pressures down to allow the compressor to handle the charge.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Ah ok. What years did MB start using r134?

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Anyone? I would liek to see if I can find a parallel condensor that is a bolt in or near it.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

AFAIK The 123 never had 134A in the from the factory. the 124 chassis started using 134A around 1989.
If converting to 134 you should have the compressor flushed and to get the oil out of it it needs to be benched therefore remove compressor, flush it, replace. Flush system including removing the expansion valve, replace dryer, evacuate system and inspect leakdown rate, if OK then introduce proper PAG oil and R134A and it should blow cold but not as cold as R12.
If you find a suitable parallel flow condensor it will blow nearly as cold and should be acceptable in all except some really hot places. The only thing about the parallel flow codns is that they need a small adapter hose between their ports and the existing lines, they are different sizes. Or you can have new lines fitted (it takes a shop that is willing to improvise).

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Flush the compressor with new oil only, never any solvents. You'll never get all of the solvent purged out of it.

I'm not sure that you'll get all of the mineral oil out by flushing, but perhaps a small bit left in there won't hurt anything.

I just updated the AC system on my W114 from R12 to R-134. I used a new Seltec compressor, an aluminum parallel flow condenser, new barrier hoses, and a new expansion valve.

ACkits.com has the compressor and condenser. If you are replacing a York compressor they also sell an adapter.

For new hoses, http://www.rayeveritt.com/ is very reasonable priced.

Here is the thread if you want to read the full story R-134a Conversion Success

Here's what I went with. It's expensive, I think $1,800 for the complete kit. I am still installing it.
http://www.europeancoolerair.com/nonac01.htm
Tom

$1800 would buy a LOT of R-12.

This seltec compressor is it made for r134 and a r4 replacement?

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Exactly!

I'm pretty sure it is to replace the ancient York style compressor. IIRC, it was used in the 70's.

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John Robbins
'05 E320 CDI - 240k
'87 300TD - 318k

To be fair, it is a retrofit kit for a car that didn't come from the factory with A/C...

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John Robbins
'05 E320 CDI - 240k
'87 300TD - 318k

My '92 2.5T has R134. It seems to use the same condenser as my '87 300TD (R12). It cools *very* well... especially for our hot and humid southern summers. One of the improvements over the '87 is the dual fan aux fans...

I lost the link to it, but if you search you can find threads where people have added parallel flow condensers to a W123. Some of them give all the parts/fittings/etc they needed to do the conversion. Of course, they all make it look easy

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John Robbins
'05 E320 CDI - 240k
'87 300TD - 318k

Mine came from the factory with A/C. Yes, it is expensive. If it works out, I'll be happy. Since the car is like 27 years old, the rest of the components needed replacing. So if you figure out the cost of a new or rebuilt compressor, and if rebuilt how long will it last. New condensor, new evaporator etc. Then it is about half that. Some of the hoses are like $250 or $350 each. Now if the performance claims of less HP needed to run the compressor are accurate (3-5 hp vs 12-15 hp), then it might be worth it to some extent. I wouldn't spend that kind of money, if mine was a rust bucket though.
Tom