Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #46  
Old 07-30-2009, 11:12 AM
Registered User
 
Join Date: Apr 2008
Posts: 125
I never understand why anyone would want to convert to 134. R12 is readily available, works much better, and is not a huge expense. Why bother with 134 when R12 cools so much better?
Reply With Quote
  #47  
Old 07-30-2009, 02:23 PM
Registered User
 
Join Date: Sep 2001
Location: central Texas
Posts: 17,277
Quote:
Originally Posted by lvbizbroker View Post
I never understand why anyone would want to convert to 134. R12 is readily available, works much better, and is not a huge expense. Why bother with 134 when R12 cools so much better?
Well, there are a lot of variables when dealing with cars as old as many of these..
Sometimes the only local AC mechanic has purchased new 134a recovery equipment and does not have R12 equipment anymore... so suggests that when serious service is needed...
Many times a person gets a car which someone else already converted or had converted...

At one point in time ( about 10 years ago ) the cost of R12 was not reasonable and was going higher still.. so many were converted then... only to find what you now describe as the current situation true....

Even when the actual cost to smart buyers was not too bad many shops were charging way more than that thinking they would have to pay more in replacement cost...
Reply With Quote
  #48  
Old 09-02-2010, 01:00 PM
MercedesOtto's Avatar
Registered User
 
Join Date: Dec 2005
Location: Georgia
Posts: 61
AC is still working great with R134 - over a year now

Quote:
Originally Posted by MercedesOtto View Post
Observation:
As a result of the rebuild that is described below my AC works great with R134in the 95F heat of Atlanta Georgia. I believe the bad reputation of R134 in the W123 AC system or its weak functioning comes from underlying problems like not functioning vents, oil and or Freon over fill, cheap aftermarket compressor etc….

The following underlying problems I fixed on my car:
-hidden leak in dryer pressure switch (replaced switch)
-center vent did not open properly due to vacuum leak on vent actuator
-compressor on my car was a cheap aftermarket model
-auxiliary fan was working intermittently (I had to buy a new used one)

Rebuild procedure

1.System completely flushed with compressor and expansion valve removed:
On a 28 year old car it cannot be sure how much oil and what else is actually in the AC system - especially when a leak was present and for safety precaution oil was added here and there.
However since I wanted to try the R134 conversion anyways I cleaned all oil out of the system to replace it with oil that is compliant to R134. I used a syringe to inject cleaner into the lines and than used air pressure to blow it out to the other end. For the lines that end inside the car a big trash bag being wire tied to the other end of the line keeps the mess contained.

2.Assembly of system: I spend a good bit of time cleaning and fine sanding / polishing the O-ring surfaces of the lines. The o-ring seating surface was corroded and had slide pitting. I only discovered this at very close observation. I’m sure most shops would not have taken the time to do this.

3.Vacuum testing the system for leaks: when 29 psi vacuum was reach and stayed stable for a few hours I was confident the system was sealed.

4.Refill the oil: the OEM manual asked for 8oz oil total in the system. Since I cleaned all oil out I was confident that the 8oz was needed. Not flushing and cleaning the system makes the oil amount a guess. I filled the oil by disconnecting the line brake in front of the valve cover. (Careful if the system still has vacuum - the o-ring could be sucked :-( into the line) The oil was filled in the line leading to the compressor intake. I turned the compressor by hand every once in while to suck in and distribute the oil. Once the 8 oz disappeared the line was closed with a new o-ring.

5.Evacuation and filling of the system: A German friend that is specialized in working with W123 here in Atlanta offered me his advice, shop lift, tools and vacuum pump for this AC rebuild. Per his experience only 80% of the recommended R12 filling amount provides best results for R134. Well as always he was right. The AC works awesome!!

6. After half of this summer in the Atlanta traffic without AC it feels wonderful to turn the AC to lower blow because it is getting to cold soemtimes !!!!

7. The whole effort took me a long day (10 hours and ½ a six pack) with my friend’s expert directions.

Remaining issues:
The molecules of R134 are smaller and have the reputation to permeate through the old rubber lines. If my system has lost the Freon before the next season I want to replace the rubber lines as well. Based on what I have seen in this project it cannot be to much work.
My idea is to find the rubber lines and crimp caps. Cut and position lines to perfect fit and have them professionally crimped and pressure tested.

It would be great to hear from others that successfully use R134 in a W123.

MercedesOtto
OK it has been well over a year and my AC is still working great and blowing cold - even with my daily comute through Atlanta traffic (70 miles round trip). At 95F air temp the surroundings of my car actually got up 114F by sitting in traffic still blowing 46 through the vents.
Attached Thumbnails
Successfully converted w123 300TD Wagon to R134-23-07-09_1718.jpg   Successfully converted w123 300TD Wagon to R134-23-07-09_1734.jpg   Successfully converted w123 300TD Wagon to R134-23-07-09_1744.jpg   Successfully converted w123 300TD Wagon to R134-23-07-09_1754.jpg  
__________________
Good Patina Comes With Good Miles Driven.
Drive more polish less

220SEB 1963 (excellent driver with no rust but far from pretty)
300 TD Wagon 1981 (Daily Commuter Tractor)
911 MFI 1973

www.vintagemotion.com
Reply With Quote
  #49  
Old 01-09-2011, 05:26 PM
Registered User
 
Join Date: Apr 2010
Posts: 35
What compressor did you use as a replacement? Thanks Gregg
Quote:
Originally Posted by MercedesOtto View Post
Observation:
As a result of the rebuild that is described below my AC works great with R134in the 95F heat of Atlanta Georgia. I believe the bad reputation of R134 in the W123 AC system or its weak functioning comes from underlying problems like not functioning vents, oil and or Freon over fill, cheap aftermarket compressor etc….

The following underlying problems I fixed on my car:
-hidden leak in dryer pressure switch (replaced switch)
-center vent did not open properly due to vacuum leak on vent actuator
-compressor on my car was a cheap aftermarket model
-auxiliary fan was working intermittently (I had to buy a new used one)

Rebuild procedure

1.System completely flushed with compressor and expansion valve removed:
On a 28 year old car it cannot be sure how much oil and what else is actually in the AC system - especially when a leak was present and for safety precaution oil was added here and there.
However since I wanted to try the R134 conversion anyways I cleaned all oil out of the system to replace it with oil that is compliant to R134. I used a syringe to inject cleaner into the lines and than used air pressure to blow it out to the other end. For the lines that end inside the car a big trash bag being wire tied to the other end of the line keeps the mess contained.

2.Assembly of system: I spend a good bit of time cleaning and fine sanding / polishing the O-ring surfaces of the lines. The o-ring seating surface was corroded and had slide pitting. I only discovered this at very close observation. I’m sure most shops would not have taken the time to do this.

3.Vacuum testing the system for leaks: when 29 psi vacuum was reach and stayed stable for a few hours I was confident the system was sealed.

4.Refill the oil: the OEM manual asked for 8oz oil total in the system. Since I cleaned all oil out I was confident that the 8oz was needed. Not flushing and cleaning the system makes the oil amount a guess. I filled the oil by disconnecting the line brake in front of the valve cover. (Careful if the system still has vacuum - the o-ring could be sucked :-( into the line) The oil was filled in the line leading to the compressor intake. I turned the compressor by hand every once in while to suck in and distribute the oil. Once the 8 oz disappeared the line was closed with a new o-ring.

5.Evacuation and filling of the system: A German friend that is specialized in working with W123 here in Atlanta offered me his advice, shop lift, tools and vacuum pump for this AC rebuild. Per his experience only 80% of the recommended R12 filling amount provides best results for R134. Well as always he was right. The AC works awesome!!

6. After half of this summer in the Atlanta traffic without AC it feels wonderful to turn the AC to lower blow because it is getting to cold soemtimes !!!!

7. The whole effort took me a long day (10 hours and ½ a six pack) with my friend’s expert directions.

Remaining issues:
The molecules of R134 are smaller and have the reputation to permeate through the old rubber lines. If my system has lost the Freon before the next season I want to replace the rubber lines as well. Based on what I have seen in this project it cannot be to much work.
My idea is to find the rubber lines and crimp caps. Cut and position lines to perfect fit and have them professionally crimped and pressure tested.

It would be great to hear from others that successfully use R134 in a W123.

MercedesOtto
Reply With Quote
  #50  
Old 01-09-2011, 06:46 PM
Craig
Guest
 
Posts: n/a
I tried it for a while in my 300D, didn't like the performance and had it converted back to R-12. It's probably OK in a moderate climate, but not really hot weather.
Reply With Quote
  #51  
Old 01-09-2011, 08:31 PM
lietuviai's Avatar
Registered User
 
Join Date: Mar 2003
Location: SW WA
Posts: 5,741
Not to hi-jack a thread, but I've tried to get the A/C system working in my car with just R12. The system never really had anything but R12. After two leaks developing a few weeks after each repair, plus an HVAC control head that seemed to have a mind of it's own, I've pretty much given up. Each time some different component developed a leak. I've tried researching replacement costs of every component, but it seems either some parts are quite expensive or NLA. About the only way I probably wouldn't worry about something leaking anymore precious R12 would be to just replace everything with new parts. That would probably be too expensive if it were even possible.
Is replacing everything just overkill or are there some components that never really need replacing? I just wish I could have a working A/C system in the car. It was really great when it did work.
__________________
DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012
Reply With Quote
  #52  
Old 01-10-2011, 12:34 AM
Craig
Guest
 
Posts: n/a
The only thing that is really difficult to replace is the evaporator under the dash. Everything else is accessible without to much work, but it would be pretty expensive to just replace everything (at one point, I paid about $500 for one hose). You need to get someone to do a good leak test and locate any and all leaks before installing more R-12. Hopefully, the leaks are at connections. If you don't need to replace the compressor or the condenser, you might get it working for a few $100.
Reply With Quote
  #53  
Old 01-10-2011, 01:02 AM
lietuviai's Avatar
Registered User
 
Join Date: Mar 2003
Location: SW WA
Posts: 5,741
I replaced every O-ring in the system plus I replaced the accumulator and the expansion valve under the dash. It was checked for leaks both times and things ended up leaking later. The first leak that occurred was at the pressure switch on the accumulator. The switch itself sprung a leak. After I fixed that the expansion valve stuck. I was lucky I was able to recover the freon that time. After I replaced the expansion valve, the A/C worked great for about a week or two and then something else sprung a leak. I never went back to have the second leak checked. At that point I figured the only way I would have the A/C working would be to replace everything. I started checking prices and parts for availability and that's when I pretty much gave up.
I bought a Crown Vic Police Interceptor for about the price of what the parts for the A/C system would have cost me. The A/C in that car works flawlessly and at times can feel almost too cold.
__________________
DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012
Reply With Quote
  #54  
Old 01-10-2011, 01:27 AM
Registered User
 
Join Date: Sep 2001
Location: central Texas
Posts: 17,277
Well, it has been a while since I saw this thread...

1. It is interesting that DMorrison posted but did not mention his excellent pictorial on cleaning the FINS ON THE EVAPORATOR ( the part hidden in the dash )...

When he described how clogged and dirty those fins were I am not the only one that had an ' Ah Ha' moment. Good flow of air across those fins is almost as important as flow across the Condenser Fins.... the critical bottleneck in any refrigerant system.

Notice that Tyler supported Jimmy's aberrational thinking ... so it is only right that he ended up with Jimmy's vehicles...
Reply With Quote
  #55  
Old 01-10-2011, 12:51 PM
lietuviai's Avatar
Registered User
 
Join Date: Mar 2003
Location: SW WA
Posts: 5,741
I made sure the fins were clean on both the condenser and evaporator on my system before charging it up.
__________________
DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012
Reply With Quote
  #56  
Old 04-28-2013, 11:37 AM
Austin85's Avatar
Smells like Diesel..
 
Join Date: Jun 2005
Location: Boca Raton, Fl
Posts: 2,723
Now that R-12 is harder to get than it was 4 years ago when this OP was started, is keeping the AC this way still the way to go on an 83 300TD ( no T ) vs conversion.

I may need this and 1 local indy is recommending 134A conversion..

....AA
__________________
'87 924S
'81 280SEL

Sold ->

81 300SD -
93 300E w/ 3.2
85 300D-
79 300SD
82 300CD
83 300CD - CA
87 190E 5 spd
87 Porsche 924S

"..I'll take a simple "C" to "G" and feel brand new about it..."

Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 08:30 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page