Even MORE A/C fun...not! - PeachParts Mercedes-Benz Forum

rrgrassi · #1 06-29-2007, 03:03 PM

Driving home yesterday, I noticed the A/C not blowing as cold as usual. When I get home I smell the familiar odor of brakes that are too hot. Turns out A/C clutch is now slipping. I can turn the compressor by hand and notice no abnormal resistance. Since a clutch costs a little less than a remanned compressor, I'm going to bite the bullet and replace the compressor with a brand new one, replace the dryer, and replace the expansion valve.

I did replace the compressor last year along w/the dryer. The flush was less than optimal. My question is this...what is the best way to flush the system a home person can do with out going to the shop?

Thanks!

vstech · #2 06-29-2007, 03:05 PM

http://dieselgiant.com/repairyourac.htm

arew264 · #3 06-29-2007, 03:25 PM

When I did it the second time (the first time I didn't flush and the new compressor died on the first day), I basically took a plastic/vinyl line that fit snugly inside the compressor manifold lines and outside some of the other fittings and connected it to a funnel. Poured the flush in the funnel, let it drain, blew compressed air through for about 5 minutes (until flush stopped spraying out the end) and repeated twice/thrice.

The main target with flushing is the condensor, so flush it very very thoroughly. Flush the rest as well, but pay special attention to the condensor.

rrgrassi · #4 06-29-2007, 03:57 PM

Thanks guys for the quick replies. I found a brand new compressor for $220 at NAPA in Wylie TX. The buy from Hendricks or Hancock in Dallas. I also looked at Diesel Giant's web site and saw the BG Frigi-Quite II for...GULP $39.95. I went to BG's web site and found a local distributor in Fort Worth TX. The charge from a BG rep is $9.95. DG is getting proud of his stuff now. Even the dryer is double what I paid last year...hmmmm. So here is the link for the BG search for distrubutors in your areas....

http://www.bgprod.com/bgdistloc/distloc.php

rrgrassi · #5 06-29-2007, 04:41 PM

I have a line on all my parts. My question is, how effective is methanol or acetone as a flush vs. the aerosol cans? I do have a 150 psi air compressor.

arew264 · #6 06-29-2007, 04:57 PM

I just used a can of interdynamics A/C system flush from the local McParts.

rrgrassi · #7 06-29-2007, 07:29 PM

How did it do, and how much does it cost per can?

arew264 · #8 06-29-2007, 07:32 PM

It worked quite well and it was quite reasonable, as I recall. It started coming out clean pretty quickly, but I flushed it again just to be sure.

I don't have a lot of experience here though, so I can't be sure. I do know it was under $10 for a fairly large canister though.

JimmyL · #9 06-29-2007, 08:05 PM

I've got a flush gun you can borrow if you would like. I'm just on the Dallas side of the lake off of I-30.
You going to the GTG tomorrow?

rrgrassi · #10 07-02-2007, 11:12 AM

Jimmy,

You have a PM

Thanks!

babymog · #11 07-02-2007, 01:57 PM

Did you check voltage to the clutch?

Quote:

Originally Posted by rrgrassi

Driving home yesterday, I noticed the A/C not blowing as cold as usual. When I get home I smell the familiar odor of brakes that are too hot. Turns out A/C clutch is now slipping. I can turn the compressor by hand and notice no abnormal resistance. Since a clutch costs a little less than a remanned compressor, I'm going to bite the bullet and replace the compressor with a brand new one, replace the dryer, and replace the expansion valve.

I did replace the compressor last year along w/the dryer. The flush was less than optimal. My question is this...what is the best way to flush the system a home person can do with out going to the shop?

Thanks!

rrgrassi · #12 07-02-2007, 02:42 PM

I did with the engine off, and the CCU on. 12.5 volts. I have not performed a continuity test on the clutch though. You can watch the engine an compressor run, then see the clutch slip, catch up, slip, slip some more, slip continually when hot. Belt is tight, no slipping or squealing there.

vstech · #13 07-02-2007, 03:03 PM

Hmm, we always used to fill a system with R-11 then let that flush around for a bit, then rinse it out with R-12... hey, what did we know? it was cheap and it removed complete burn out soot! great stuff. really messy, but it worked! to do that today would require several thousand dollars of R-11 (really high on the EPA's no use cfc list!) I suppose Isoheat or methanol /mineral spirits would work well too.

rrgrassi · #14 07-02-2007, 03:07 PM

Yeah, all the stuff we used to do until the pointy heads decided it's bad for us...Leaded gasoline was a wonderful parts cleaner and fire ant tourch fuel... Luckily I have a source for methanol.

rrgrassi · #15 07-23-2007, 11:23 AM

Whew, it sure was warm and humid on Saturday, but thanks to JimmyL, I was able to get my A/C running again! HUGE thanks to Jimmy!!!

I replaced the compressor, drier, pressure switch (got the high/low one), evaporator valve, and every o-ring, except one: The large diameter condensor one. The fitting acts like it was soldered shut. I could not get them to separate with out damagine anything.

I totally flushed the system using methanol. Pulled a vacuum for an hour, let is sit for 45 min to check for leaks. None found, vacuumed for another hour,

I ended up getting a new compressor that had the stepped ports. What a PITA those are. Jimmy advised me to use the red on the suction port and the green on the discharge. YEAH! That was it as far as spacing goes. There was a problem though. The red seal's metal ring fit the discharge just fine, but was really sloppy in the suction side. Compressor's instructions said to use the black seal. Hmmm, package was all factory sealed, no black seal to be found. There was a yellow seal that fit the port fine, but was not tall enough. So out of frustration and curiosity, I managed to disassemble the yellow seal. The rubber is molded around the metal teeth of the ring. Cool. I removed the rubber from the red seal for a look see. Same Outer diameter, and same number of teeth! So I lined up the teeth impressions and put the rubber from the red seal into the yellow's metal holder. That was the fix. The compressor came from Hoydon/Hancock Industries.

I did lose an ounce or more of oil that I added to the compressor. I used the Frigi-Quiet. I bought 8 ounces, so now it's running with 6-7 ounces. I used the bump start method to spin the compressor, since it was too tight for me to do it by hand.

How much oil is supposed to be in the system?

Stupid thing I did. I used the old aux fan switch. Ended up snapping it off in the new drier..

. A litte drilling and ease out fixed that. Now a new switch is on order, and the fan is switch jumpered so I can turn it on for city driving. New switch installed a week later.