How can I have AC repaired without being taken to the cleaners? - PeachParts Mercedes-Benz Forum

TedsBenz · #1 03-28-2008, 11:40 PM

My recent aquisition, an 84 300sd, had its AC converted to R134 according to the previous owner. He said he thought it had a small leak as it was not cooling well by the end of last summer. When I set the climate control for full blast AC I do not hear the customary click of the compressor kicking in, or see a change in idle. This what I'm use to hearing in my other vehicles. The air temp coming out the vents is whatever the temp is outside.

Do I walk into a MB repairshop and say, "make it work, again!"????

I need AC. but she is 24 years old...I don't want the repair to exceed the value of the car.

BTW, the heater temp control works great as do the blower speed/auto controls. The pods are stuck so that I get great defrosters....and some air out the side vents.

Any info would be appreciated.

1984 MB 300SD 383,280 miles...and just passed state inspection!

bustedbenz · #2 03-29-2008, 12:10 AM

Quote:

Originally Posted by TedsBenz

Do I walk into a MB repairshop and say, "make it work, again!"????

I need AC. but she is 24 years old...I don't want the repair to exceed the value of the car.

1984 MB 300SD 383,280 miles...and just passed state inspection!

Those two lines are just about incompatible... walking in and saying "Fix it" is about the most expensive option there is. I'd say your choices are either DIY (i'm sure somebody here can figure out what exactly you need to do) or just use 4-60 air conditioning.

vstech · #3 03-29-2008, 08:43 AM

http://dieselgiant.com/repairyourac.htm
not too bad expensive...

leathermang · #4 03-29-2008, 01:55 PM

Quote:

Originally Posted by turbobenz

Try using your finger nail and depressing the little shrader valve onto of of the ac hose near the valve cover, if air comes out you should be ok.

If it is completely gone, then there is air in there, hence moisture, and it should be evaucated and done the right way otherwise it would barely be worth your time

Ok.. first, people should use eye protection when dealing with AC stuff...
and you should also wear gloves... so your fingernail should not be available ... the warning on the can says that skin exposure can result in frostbite.... easy to avoid... use something else handy to depress that valve core if you do that...

While it seems that the AC system is always under pressure... thus unless totally leaked out would not have acquired any moisture due to a leak.... the actual physics are different since it is a dynamic system... and the industry wide agreed upon position is that if you have a leak you should assume that your system is contaminated with moisture.... particularly since that is very damaging ( water and stuff combine to make acid ) to certain places inside your system...

jtwangler · #5 05-01-2009, 04:58 PM

Quote:

Originally Posted by vstech

http://dieselgiant.com/repairyourac.htm
not too bad expensive...

This is great but I have to change out the low side hose (I think that's what its called) on my 85 w123 Euro wagon. I don't have a picture of this but it runs from the low side port back towards the firewall and I believe it must run through and go to the expansion valve but I'm not sure. Does anyone have any experience with this? How do I change this hose?

C Sean Watts · #6 05-01-2009, 05:04 PM

FS: R12 Freon

Graplr · #7 05-01-2009, 05:11 PM

AC work is pretty simple. I had never worked on an AC system before and I totally rebuilt mine for probably around $300 (I didn't need a new compressor and the only real issue was a leaking condenser). Of course I bought some equipment that doesn't go into that price.

You have all the help you need right here.

jtwangler · #8 05-01-2009, 05:16 PM

Quote:

Originally Posted by Graplr

AC work is pretty simple. I had never worked on an AC system before and I totally rebuilt mine for probably around $300 (I didn't need a new compressor and the only real issue was a leaking condenser). Of course I bought some equipment that doesn't go into that price.

You have all the help you need right here.

How many hours did you put into your work? and can you help me identify the hose and where it goes?

ah-kay · #9 05-01-2009, 05:50 PM

Quote:

Originally Posted by jtwangler

How many hours did you put into your work? and can you help me identify the hose and where it goes?

There is what I do to fix my A/C without costing an arm and a leg. Some members here shout at me for using compress air and not nitrogen, but where do I find nitrogen in my garage?

1) You need to make sure there is no leak in the system. I use compress air to pressurize the system and make sure it holds. I then spray soapy water at joints ( reachable one ) to make sure there is no leak. If it leaks under the dash then you are out of luck. It is not worth fixing as it is expensive to do anything under the dash.
2) Assuming there is no leak. If you have a vacuum pump then evac it down real well. If you don't then do step 3a.
3) Then just charge it with R134a.
3a) When you are charging the system from the low side, release the air from the high side valve. Most air would be expelled in this manner.
4) The system would be pressured by now and the switch at the receiver/dryer should close. If it is not close then you need to jumper it to turn the compressor on.
5) 2 to 2 1/2 can of R134a should be enough for most cars.
6) You should have cold air if there is nothing wrong with the compressor or other components.

BTW: I always replace the receiver/dryer if I open the system. Also you may need to charge it with ester oil if you are converting the system from R12 to R134a for the 1st time.

Good luck.

leathermang · #10 05-01-2009, 06:30 PM

Quote:

Originally Posted by ah-kay

There is what I do to fix my A/C without costing an arm and a leg. Some members here shout at me for using compress air and not nitrogen, but where do I find nitrogen in my garage?

Good luck.

I try to help people on the forum do their AC work cheaply and well....
I have the MB Factory AC manual, another book on Automobile AC systems, and the usual huge text covering HVAC used in many schools.
I have studied the posts long and hard on places like Aircondition.com , ackits, etc.. pretty much read everything I can get my hands on for several years.
I have no idea how many posts I have typed just on AC questions... or how many heated debates with people like Redfox and DieselGiant... both of whom are dealers of stuff like Duracool, etc.... BLENDS... who would say how good they were without posting any of the potential drawbacks...

And then someone will say something like this... and I am certainly one of those who have been vocal in saying this is not good procedure...and explaining why... and they use some phrase like ' shout at me for' whatever...

If you would do your research... you would find that because you get it to work today...or the next two months... does not mean it was the correct fix.

So, Again, I will say that moisture is a real threat to the long term service of anyone's air conditioner... why ?

BECAUSE MOISTURE MIXED WITH THE OIL IN THE AC TURNS TO acid... AND THAT COMBO CAN PRODUCE FLAKES OF METAL FROM THE AC PARTS which are then transported by the refrigerant to bottlenecks like the TXVALVE... which has tiny openings.... if they get stopped up A YEAR FROM NOW... you have to stop and fix the system again...

No nitrogen IN your garage... ????
was the R134a indigenous to your garage ????

ah-kay · #11 05-01-2009, 06:44 PM

Quote:

Originally Posted by leathermang

No nitrogen IN your garage... ????
was the R134a indigenous to your garage ????

Did you read the title? "Without being taken to the cleaners". You can do it the right way and spend 1K to get it fix to your heart content, or you can do it cheap and improvise. What have you got to lose for a 20+ years old car?

If you are a purist then be my guest and do it the right way. I am resourceful and improvise and get the job done.

I can buy a can of R134a for $7 which I cannot improvise. I really cannot see how I can improvise N2. The next best thing is compress air. .

Cr from Texas · #12 05-01-2009, 07:18 PM

I after endorse the position taken by leathermang.

A cheap quick fix will eventually become an expensive more detailed repair if anyone want to keep using the AC.

Plan on any DIY repair taking a few hours to accomplish. The first two should be spent doing searches and reading. I've done that and I've started. New R4 compressor, drier, and expansion valve can be purchsed for about $300+. I'm flushing the system. Removing the old hoses and taking them in for rebuilding. It's not hard to find a shop that can replace the barrier hose and reuse the fittings. Much cheaper and probably not too far from the quality of all new hoses. I will reasemble and evacuate to do the first check for leaks. Then refill with 4 oz R22 and nitrogen. No, I don't have either in my garage but it's not too hard to find an AC shop to put in the 4 oz R22 and then go to a tire shop that uses nitrogen to pressurize the system to 70 psi static. Rent an electronic leak detector. Fix all leaks, vacuum, refill with R12. I'm sticking to R12 and mineral oil - that's what the system was designed for and that will provide the best cooling.

After and hour or two of reading (much of it posted by leathermang), you will probably conclude that the right way is the best way.

Wrong way --- you might as well spend nothing and roll down the windows. That's the only cheap fix.

ah-kay · #13 05-01-2009, 07:35 PM

Quote:

Originally Posted by Cr from Texas

I've done that and I've started. New R4 compressor, drier, and expansion valve can be purchsed for about $300+.

No, I don't have either in my garage but it's not too hard to find an AC shop to put in the 4 oz R22 and then go to a tire shop that uses nitrogen to pressurize the system to 70 psi static. Rent an electronic leak detector. Fix all leaks, vacuum, refill with R12. I'm sticking to R12 and mineral oil - that's what the system was designed for and that will provide the best cooling.

I really do not want to post but I just cannot help it. I don't have $300+ to spare. I do not want to go to a tire shop and pay them to use the N2, I do not want to rent an electronic leak detector at a cost. I just want to have cold air on my 20+ year car which costed $700 to buy.

I just offer a cheap solution, it is the readers perogative to take it or otherwise.

Jerry Cohen · #14 05-01-2009, 07:37 PM

So what?. What you spent on the car is no excuse for venting R134.

Because you are so selfish that your air conditioned comfort takes precedence over common sense and the law.

Venting R134a by opening the high side while charging the low side is simply bad/dangerous advice.

Have you ever heard of frostbite?

How about the fact that it's against the law for a good reason, and doing things like that will only help to get R134 banned for public sale someday(soon).

No mention is made by the poster about using guages, or charging to about 75% of R12 charge.

Man, I hope someone doesn't get hurt by some of the b.s. posted here.

leathermang · #15 05-01-2009, 08:28 PM

Quote:

Originally Posted by ah-kay

I really do not want to post but I just cannot help it. I don't have $300+ to spare. I do not want to go to a tire shop and pay them to use the N2, I do not want to rent an electronic leak detector at a cost. I just want to have cold air on my 20+ year car which costed $700 to buy.
I just offer a cheap solution, it is the readers perogative to take it or otherwise.

I do not blame you for being lazy with regards to the AC equipment on your car. It is pain to have to follow so many rules in order to get the physics correct.
I do not blame you for not wanting to spend money on your car. It is YOUR CAR.

But to post a 'cheap' lazy short term solution holding it out to others as a legit fix for their AC systems is behavior totally LACKING in CLASS and empathy for others.