Mercedes-Benz Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
732 Posts
Discussion Starter #1 (Edited)
First a little background...

At some point a bolt managed to shear off into my a/c compressor. The top passenger side bolt to be exact. The compressor has been held into the bracket by two bolts and w/o a belt attached for some time now, but heat rapidly approaching I decided it was time to do something. Unfortunately in the process of trying to get the bugger out I managed to break the EZ out bit (ahhhhhh!). A friend of my stepfather's has a machine shop, but obviously this entails taking out the compressor. Thus I have a few questions.

How long is it safe to leave the system open to air? What damage will it do leaving the system open to air for too long?

Someone mentioned having to replace the receiver/dryer is the system was left open to air for more than a day. Is this the case?

When I put the compressor back on could I just have the system vacuumed and recharge it myself, or is the latter something I should leave to the pros?

Also, and I'm sure my understanding of what this word is is waaaaay off, but orifice tube? Do I need to replace this after leaving the system open?

Thanks,
Bill
 

·
Banned
Joined
·
4,583 Posts
Has this car been converted to R134a or is this an R12 (factory) car?

Either way, the drier MUST be replaced whenever the system is exposed to the atmosphere for even just a couple minutes. This is not an optional step.

Once you have the compressor back on the car, if the car is R12 you have two options. Get the system together 100% (install compressor and new drier), evacuate the system, leak test it, add R12 oil and R12 (48oz or so). Monitor the charge so you don't overcharge otherwise it could explode. R12 cannot be purchased at any autoparts store. You have two options. Buy from an EPA licensed mechanic or buy it with intent to sell from a wholesaler OR on on ebay. You can legally sell it to your licensed mechanic for 1 cent and then he can put it into the car for you.

If the car has been converted to R134a or you want to convert it,
Install the drier and compressor. Evacuate system, leak test, change fittings and seals to R134a, add R134a oil, then R134a (about 48oz). Again, don't overcharge. The system will not be as cold, nearly off by 6-10 degrees. These cars were not designed to run on R-134a, but they can. Their condensers aren't large enough to offset the in-efficacy of R-134a (like modern cars are). I'd stick with R12, but it won't be cheap.
 

·
Registered
Joined
·
732 Posts
Discussion Starter #3
Well, thankfully it's been converted (or possibly unfortunately from what you're saying).

How will I go about installing the drier? Is there anything special I need to do so that the new one is not exposed to regular air? Also, is there a way for me to vacuum the system myself when I'm putting the condenser/drier on after getting the bolt out?

Sorry for the game of 21 questions BTW, but I'm totally clueless in this area.
 

·
Banned
Joined
·
4,583 Posts
Unless you have the proper vacuuming machine, take it to a pro to have this step done. You are also better off having a pro install the new drier if you have never done it before. You can EASILY destroy one after another learning.

This is your chance to convert back to R12 if you would like do. If you are going to do it, this is the time. You will have to change the R134a fittings/seals back to R12.

You might want to have almost all of the labor done by a pro, just supply them with all the parts and the R12/R134a and you will save a load of cash and not mess anything up.
 

·
Registered
Joined
·
1,648 Posts
First a little background...
How long is it safe to leave the system open to air? What damage will it do leaving the system open to air for too long?

I don't understand why you would leave it open. Don;t you have some tape to put over the manifold openings? If you don't recover to a vacuum the R12 vapor will still be in the system so if you do it right away the system will basically be filled with R12 - just at ambient pressure.
 

·
Registered
Joined
·
208 Posts
Where can we buy R12 cans, are they available. My system was filled with "freeze 12", not as efficient as R12. Thanks
 

·
Registered
Joined
·
324 Posts
Well, thankfully it's been converted (or possibly unfortunately from what you're saying).

How will I go about installing the drier? Is there anything special I need to do so that the new one is not exposed to regular air? Also, is there a way for me to vacuum the system myself when I'm putting the condenser/drier on after getting the bolt out?

Sorry for the game of 21 questions BTW, but I'm totally clueless in this area.
Drier is easy to replace but you will also need to replace the A/C pressure switch and A/C temp switch. These 2 switches bolt onto the drier itself. Don't forget to get new o-rings too.
 

·
Banned
Joined
·
4,583 Posts
Where can we buy R12 cans, are they available. My system was filled with "freeze 12", not as efficient as R12. Thanks
My first post above tells you exactly where to get R12. Freeze 12 is more efficient then R134a, but slightly less efficient then real R12. The temp difference between Freeze 12 and R12 is VERY minimal. 1-2 degrees F. If my system was filled with 100% Freeze 12, I would leave it. The stuff is good.
 
1 - 9 of 9 Posts
Top