is there anything i should know before replacing compressor,dryer,& expansion valve?
 

just wondering if there are any "tricks of the trade". any tips? thanks in advance

Nylog and proper type "O" rings for the job.....along with the other tools I am sure you know about.

This is not the psychic hotline....they make a lot more money than we do...
How are we supposed to know if you are missing some key (but simple ) concept ?

1. Tell us what procedures and the order you are going to perform them and we will try to make sure you are ' covered' in terms of knowledge....

2. Have you read lots and lots of the AC threads on this forum ?

3. Have you read lots of the posts on forums like Aircondition.com ?

4. What tools do you have assembled ?

5. Do you own any literature on Auto Air Conditioning ?

I consult THREE books when doing AC work on my MB... the MB factory AC manual , a generic AUTO AC manual , and a generic HVAC manual...

This is particularly important regarding your safety... the warnings don't tend to get posted on the forum with people concentrating on deciphering symptoms and trying to describe fixes....

Listen to leathermang...he is one of the resident experts in the field.

"he is one of the resident experts in the field."

EKK ! TOO MUCH PRESSURE to live up to !

But I will try to consult the normal sources and pass on anything it looks like you have missed....

Hey around here you adn LaryBible are the closest we have to a resident A/C guru............I'm embarking on a project to fix my W123 A/C and convert my W116 back to R-12......so I am reading all I can before I start...

I have an ASE approved textbook (Auto Service & Repair by Stockel, Stockel & Johanson) that I find very helpful for this sort of thing. It's huge, over 1,000 pages, and explains automotive systems and tools in a way that's easy to understand. It assumes that you don't know what you are doing, so it's filled with warnings wherever there is a chance for personal injury.

"filled with warnings wherever there is a chance for personal injury."

About 1972 I hooked up a can of R12 to the high side of a car's AC.... I was really lucky that I felt of it....and realized that it being HOT was not the right symptom... it could have easily exploded in my face.... and I did not have goggles on .... I was just really really lucky that I was not blinded in my moment of ignorance... it was hanging from the hood right at face level...

i'm planning on replacing the compressor first, then expansion valve, then dryer. yes, i have read many of the AC threads, but only the ones in diesel discussion. i have not checked out aircondition,com. i don't have any specialized tools. i'll do some more reading and figure out what i need. i am taking it to my dad's mechanic to have him flush out the system and pull a vacuum on it. i'm charging it with duracool and adding a can of duracool oil.

"i'm planning on replacing the compressor first, then expansion valve, then dryer. yes, i have read many of the AC threads, but only the ones in diesel discussion. i have not checked out aircondition,com. i don't have any specialized tools. i'll do some more reading and figure out what i need. i am taking it to my dad's mechanic to have him flush out the system and pull a vacuum on it. i'm charging it with duracool and adding a can of duracool oil."

1. Order four 12oz cans of R12 on Ebay using your father's mechanic's certification number.. can be shipped directly to his address. It may be illegal to use Duracool in your state.... but even if it isn't illegal it is foolish. Plenty has been written about this... check out ' alternative to R12' and use either mine or Larry Bible's name for search...

The compressor , expansion valve would be taken off to free up the other end of the AC Hoses....so you can flush through them. Do not open up the cap on a new compressor until you are ready to hook the hoses to it... pretty much meaning at your mechanics shop immediately after the flushing.

Your current expansion valve should be modified according to the Mercedes AC manual to be used as a tool for flushing the two hoses as they go forward out of the passenger compartment. The Evaporator is not usually flushed.

If you can find a way to clean the input side of the OUTSIDE of the Evaporator fins... look up Dmorrison's post about cleaning his... you will be way ahead of the game...

The receiver/dryer is the last thing to be hooked up.... the cap should be left on and it installed in the car... then upcap it and hook up the newly flushed hoses to it as quickly as possible and then start evaucation.

http://www.peachparts.com/shopforum/diesel-discussion/63919-r-12-alternatives.html?highlight=redfox

You need a good set of Tubing wrenches for the expansion valve job and I hope you are comfortable working while standing on your head.

Be careful when putting the manifold back on the compressor and make sure you have the correct seals. There are several different seal types on these compressors. Get the bolt threaded through the manifold into the compressor before tightening the clamps on the lines at their mountings. Get everything fit in place with all bolts started, then tighten the manifold bolt first and make sure it is in correct position before tightening the other mountings.

Good luck,

If you are replacing the compressor because it has self destructed and sent trash into the system... then the FSM AC manual says that the metal manifold attached to the compressor must be replaced... it is not a candidate for flushing.
The FS AC manual shows a ' shopmade' holder for holding the expansion valve... and it is a bear to get all those fittings tightened correctly without crossthreading or other bad things...
If searching for ' tubing wrenches' some places call them " line wrenches"... they are basically box end wrenches with just enough cut out to allow you to put it over the line... so as to maximize the number of flats the force is being exerted against... because those fittings are often made from soft stuff like Brass... or copper....

I'm looking into getting these items as well...Compressor...Receiver Dryer, Expansion Valve, New Hoses and Seals......once I have all these things I don't intend to install them, I am going to schedule a visit with whunter down in detroit.... :D

I have found a source on ebay for a brand new (remanufactured) compressor (Raidal R4) for around $89-99 and also a guy selling a brand new expansion valve for $25 (he's selling his stash of a TON of W126 parts) I think I may nab those.....then I will order the hoses/seals and Receiver Dryer from Fastlane.

What seals are needed when replacing the above mentioned items? I don't want to leave anything out....

For a 123 the stock number is #100 at Carlisle Auto Air in San Antonio... this is all already in the archives...

I'm guessing it'd be a better Idea to go with this:

New eBay Compressor #1

vs. this one: Used eBay Compressor


Also....any opinions on this Receiver Dryer? eBay Receiver Dryer

I don't want this project to cost more than it has to but I do want to do it right....are these parts ok?