www.harbourfreight.com (probably a store near you)
has 134a gauges with three hoses starting at $39.95. Get a long digital thermometer and keep it stuck in the middle vent. Look for 41-48 degree vent temps at 80-85 degree Min weather.

The gauges-red goes to high side (going from compressor to condenser), blue goes to low side. (dryer can to firewall).

__________________
1993 Mercedes Benz 300D 2.5 205K (ex wife's)
1984 Mercedes Benz 300SD 320K (SOLD)
2004 Mercedes Benz C240 75K
1995 GMC Sierra 2WD 5.7L 188K
1983 Mercedes Benz 300SD 239K (SOLD)
1987 BMW 325i 220K (SOLD FOR SALVAGE)

609 Certification

Today I took my car to a shop and had them do an AC-check up. They told me that the car had 1.1lbs of refridgerant in the system and that capacity was 2.2lbs. Therefore they would have to evacuate the system and recharge it. They quoted me 69.90 for the service and then about 70 or 80 more for the refrigerant (and oil) at 35.00/lb. I obviously said no to this and was hoping you guys could help me do this on my own. The car is a 94 E320 and should take r134a refrig.

Can I DIY this one (for under $150) and what do I need? (refidgerant, etc.)

.. well , seeing you know there is still over a lb pf refrigerant and you are not wanting to spend to do it up the best way.. you can just add 1 can of 134 and that should top it enough to get you going..
Not the best, but usually when there is still a decent amount left in a system, the leak is to the outside , ] usually high side] so moisture is not usually a problem and you can get away with a top off..
taking a chance , mind you...but it has worked in many many cases..

You know the proper way, but sometimes finance dictates..

Do not add more than 1 can til you see where you are at..and of that is suuficient , leave well enough alone

For the a/c guys .. yeah , I know ..but ....

Where on the car do I put the new refridg? I am a complete newb to AC systems (as you can probably tell). Is 150 a reasonable price to pay? Does anyone know of a reputable AC shop in south eastern minnesota (i live in rochester)

See attached thumb -> is this the port?

Attached Thumbnails

 

...It is , but if you are not hip to this stuff, give it to someone who is willing to top it off for you.

As in...take it to a shop Thats probably what I'll end up doing. I just wanted a fair price and a reputable shop.

$35 a lb for R134 seems way high.... I've heard it's been going up, but $35 a lb?
You might want to look for a dedicated AC service place, preferably one that advertises 19.99 refills
There is one locally (ok, Allentown PA) that had a 300D parked there a lot, assuming it was either an owner or an employee....
I had my indy shop fix the 300SD's AC a while back and it cost about $400... and I think the R12 was around $48 a lb...

__________________
Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic

You can get R12 gauges at the local supply hose that caters to the commercial/residential heating and air conditioning trade.

Good luck,

Sorry, but I don't see how R12 gauges would help me, since the car is R134a.

Your right smarty pants your 1994 car is factory R134a, as mentioned above go to harbour freight, northern tool, ect...and get some R134a manifold gauges! Starting at $39. Or your tightness can go to Autozone and rent them for free, while there get the $8.99 DVD or go ahead and pay the shop. For what they charge you can get gauges ect....12oz 134a is $10 at Autozone vs there $30?

__________________
1993 Mercedes Benz 300D 2.5 205K (ex wife's)
1984 Mercedes Benz 300SD 320K (SOLD)
2004 Mercedes Benz C240 75K
1995 GMC Sierra 2WD 5.7L 188K
1983 Mercedes Benz 300SD 239K (SOLD)
1987 BMW 325i 220K (SOLD FOR SALVAGE)

609 Certification

You can buy the gages at almost any auto parts supply house. You said that this is a 134 system? If so the high and pressure taps are designed so that you can't reverse them the low pressure tap is at the suction of the compressor (between the compressor and the evaporator. the high pressure tap is at the discharge of the condenser. The pressures are available from the dealer. I'm more familiar with R12.


Another possible cause for low rpm capacity reduction is worn compressor reed valves. I have a similar problem to yours. Mine was dignosed as worn reeds. Mine will cool down to a liveable level in abouit 10 minutes. I have no problems at >20mph after initial coldown.

To correctly evacuate the system I would need to rent a vacuum pump, but what is the procedure for this? I didn't mean to sound smart, I obviously need help if i'm going to do this myself. I called a few other shops today and the price was about the same everywhere. I found r134 as low as $20/lb but then their evac. and recharge fee was higher (so the total came out the same). I'll check out the local auto shops tonight and see if theres a set of gauges and a DVD that I can rent/buy to preform the recharge myself. I'm interesting in learning to do this the right way, I just need help. Thanks!!

renting a vacuum pump is going to be a waste of money. It will cost you more to rent one and refill the system yourself since if you evacuate the system you are going to need approximately 3 cans or 134. The way I see it if you want to do it the cheap way add a can of refrigerant and see what happens. If not it would be economically more viable to have the shop do it. On the other hand if you want to do it yourself, you see yourself doing this again and you don't mind investing in tools then purchase a pump and gauges and your good to go.

So if i bought this:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92475
(vacuum pump)

and these:
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=2435
(R134 gauges)

I could do this myself. I am not confident with the general procedure, what are the steps to evacuate and then recharge. Reading the manual for the vacuum pump it tells you to attach the vacuum line to the vacuum port on the A/C system. Where is this located?

Not to upset the party, but this is what you should be buying before anything... I can see by your postings/questions that you are in dire need of some basics before continuing and have a feeling you are going to get youtself into trouble.

Autozone/ $8.99 AC repair DVD by Bruce Bone......
Do it...