W123 AC rebuild and upgrade - PeachParts Mercedes-Benz Forum

MercedesOtto · #1 07-07-2009, 01:59 PM

Hope to find some help or suggestions:

1.Has anyone ever tried to purchase individual AC hoses (rubber only) and had those re-crimped to the original fittings?
1.1 Any idea of a source for the hoses.

2. Has anyone experience with fitting modern AC compressor to a 300TD engine?

3. Anybody knows how to rebuild/ clean / check the expansion valve.

4. Any other ideas or suggestion to improve the AC of w123?

Thanks

rrgrassi · #2 07-07-2009, 02:12 PM

I had one high pressure hose (the one that runs along the bottom of the engine) rebuilt/recrimped due to hose failure.

Any good hydraulic shop that rebuilds hoses would be a good start.

Replace the expansion valve.

Use R-12, or if you must go with R134a, get a new compressor and a parallel flow condensor.

Do not know of any modern drop in replacement for R4 hockey puck.

75Sv1 · #3 07-07-2009, 03:52 PM

I did get a kit to update the A/C in my 240D from:
http://www.europeancoolerair.com/nonac01.htm
The kit was about $1800.00 w/S&H as I remember. The kit was for a 134A upgrade. The kit has a Sanden compressor, parrelel flow condensor and a replacement for the control box inside the car. They do sell portions of the kit. I also saw something on E-Bay to change the compressor to a Sanden unit. From what I understand 134A has a higher head pressure, so it does better with a parrallel flow condensor and evaporator.
Tom

leathermang · #4 07-07-2009, 08:42 PM

If changing to R134a you can get an R4 made for withstanding the higher pressures...
Check with Tray Carlisle at Carlisle Auto Air in San Antonio for serial number to look for.

The higher working pressure is not why a parallel flow condensor is recommended in changing to R134a... it is to make up for the approx 20% decrease in efficiency of the molecules compared to R12.

#5 07-07-2009, 10:01 PM

I guess I just don't get it? WHY would anyone even THINK about spending $1,800 on an update kit so that they could save $40 or $50 on refrigerant? This is second grade math folks!

R12 is plentiful and the components that came on your late 123 car in good shape with R12 will make a system capable of making a Polar Bear scream for mercy.

If there are any components that are not in good shape, repair or replace them. Once the system is in shape with a new r/d or whatever else is necessary, evacuate it and put in the correct amount of R12 and you're home free.

75Sv1 · #6 07-08-2009, 07:17 AM

Quote:

Originally Posted by LarryBible

I guess I just don't get it? WHY would anyone even THINK about spending $1,800 on an update kit so that they could save $40 or $50 on refrigerant? This is second grade math folks!

R12 is plentiful and the components that came on your late 123 car in good shape with R12 will make a system capable of making a Polar Bear scream for mercy.

If there are any components that are not in good shape, repair or replace them. Once the system is in shape with a new r/d or whatever else is necessary, evacuate it and put in the correct amount of R12 and you're home free.

Well, do the math. Add up every piece in the AC system, condensor, evaporator, compressor, hoses, dryer. It adds up quick. The main reason I went with the system was for the Sanden compressor. The guy said it took about 3-5 hp to turn the sanden, and about 10-12 hp for the R4. When your engine is only putting out 67hp, that cuts into your power.
Tom

#7 07-08-2009, 11:27 AM

I don't buy it. Even if there IS a difference in compressor efficiency, it will take MORE power with 134 than with R12 due to the increased high side pressure.

A bone stock system in one of these cars, in proper working order on R12 is difficult to beat. An R4, although they are not the rebuilders favorite is NOT an inefficient compressor.

rrgrassi · #8 07-08-2009, 12:33 PM

Do you have the part number for the Sanden compressor? I would change out the compressor, but go with R-12 this time instead of Freeze 12. I have not heard of the Sanden being a short lived compressor like the R-4. If only MB used the A-6 instead...

75Sv1 · #9 07-08-2009, 03:31 PM

Quote:

Originally Posted by rrgrassi

Do you have the part number for the Sanden compressor? I would change out the compressor, but go with R-12 this time instead of Freeze 12. I have not heard of the Sanden being a short lived compressor like the R-4. If only MB used the A-6 instead...

I don't have the part number handy. Part of the problem, is this came in a kit. That kit come with the brackets to adapt the Sanden compresor to the Mercedes engine. He does sell a kit for the Sanden compressor and brackets. I remember it being around $500. I never said this was cheap. As others have suggested, you need to add up the cost and see what direction you want to go with.
I did check on E-Bay. I found a dealer in TX with AC conversions. Mainly, they are for the York compressor. Try Item numbers:
180361426309 and 180361430409.
Tom

RallyRebel · #10 07-30-2009, 01:27 AM

I've done quite a few R134 conversions on our various vehicles including some MB's, mostly with the York, and am about to tackle replacing the R4 on my '82 300D Turbo. I've NEVER spent more than $300 total for any conversion. Sanden compressors can be found for $100, all new hoses can be made up locally for $40 - $70 and the rest is for brackets, expansion valve, drier and an R134 charge (I have someone do it). The biggest hassle with the whole process is getting the adapter bracket lined up properly so you don't eat or throw belts while running the new compressor.

Now for this upcoming conversion from the R4 I haven't found any brackets so will fab up my own, so if it's not too terribly a PITA then if y'all are interested I could make up more if sufficiently coerced.

I'll be sure to post up pics since I've yet to share much of my handiwork on these forums.

R134 conversions are painfully simple and with a little time spent shopping are inexpensive. I've found them to be more than adequate for cooling W123's here in central Florida, and in my Merkur XR4Ti's it was so cold (below 40 degrees at the vent!) I couldn't ever find a happy medium on the thermostat.

Research and reap!

leathermang · #11 07-30-2009, 02:42 AM

I am sure the Sanden takes less hp to run it... and is smoother... and will withstand higher pressures longer... but I am also pretty sure the R4 only takes 6-8 hp to run. I too have a 240 and even that can be felt in the seat of the pants...

kingdoc1 · #12 07-30-2009, 05:35 AM

Quote:

Originally Posted by LarryBible

I guess I just don't get it? WHY would anyone even THINK about spending $1,800 on an update kit so that they could save $40 or $50 on refrigerant? This is second grade math folks!

R12 is plentiful and the components that came on your late 123 car in good shape with R12 will make a system capable of making a Polar Bear scream for mercy.

If there are any components that are not in good shape, repair or replace them. Once the system is in shape with a new r/d or whatever else is necessary, evacuate it and put in the correct amount of R12 and you're home free.

Don't try to re-engineer your car. The Mercedes engineers spent plenty of time and money doing that already. Keep it the way it was designed and you won't have cooling problems. Most of the problems I have heard here on the forum are the result of someone trying to "save money" on "alternate refrigerants " when the real thing is readily available. Don't outsmart yourself.

#13 07-30-2009, 07:56 AM

^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!^!

And who says that common sense is dead in America? KingDoc still has it!

Hit Man X · #14 07-31-2009, 08:27 PM

I do wish the Diesel cars (sans the 603 and later) received the other compressor from the V8 cars, but eh. At least the R4 is inexpensive.

There is a Sanden kit I've seen developed from some dudes on ebay... but you have to buy the compressor, modified bracket, and modify your oil lines.