Sanden compressor question - Page 2 - PeachParts Mercedes-Benz Forum

vstech · #16 06-20-2014, 09:48 PM

so, did you add 8oz of oil on top of the as shipped 6oz? or just another 2oz, bringing the total to 8oz?

vstech · #17 06-21-2014, 08:21 AM

Since it's difficult to get a comp with the oil recommended for the car with a mockup assembly conversion, I reccomend getting shipped oil removed, and filling the comp with the exact system amount the car needs...

Keep us posted.

eatont9999 · #18 06-21-2014, 09:36 AM

Firstly, a blockage should have shown up in the gauge readings early on. It would also take a little time after the clutch engages to build enough pressure to lock up the compressor. On my car, it liked to squeal/squeak as soon as it was started up.

I know, without a doubt, that I have exactly 8oz total mineral oil in my system. I had to drain the PAG oil from the compressor before installing it. I got exactly 6oz out, flushed with mineral oil, drained, added 6oz mineral oil and 2oz in the drier.

The belt was tight to get on and I employed a flat head screwdriver to help slide it on. I am assuming The Don received the same size belt as I did. Keep in mind that when tightening the belt, you must loosen some of the bolts that hold the compressor to the bracket so it can move. If you don't do that, the bolt will break off with enough force.

TheDon · #19 06-24-2014, 03:46 PM

Belt snapped on me so I got one an inch longer at napa. Helped get it on and off while
Fooling with the AC

When reving and looking at the compressor the compressor stops and the belt keeps going. I think I have tooooo much oil in the system

eatont9999 · #20 06-24-2014, 04:05 PM

Quote:

Originally Posted by TheDon

Belt snapped on me so I got one an inch longer at napa. Helped get it on and off while
Fooling with the AC

When reving and looking at the compressor the compressor stops and the belt keeps going. I think I have tooooo much oil in the system

How much oil did you add when you installed the kit?

ROLLGUY · #21 06-24-2014, 04:13 PM

Quote:

Originally Posted by TheDon

Belt snapped on me so I got one an inch longer at napa. Helped get it on and off while
Fooling with the AC

When reving and looking at the compressor the compressor stops and the belt keeps going. I think I have tooooo much oil in the system

I have tried a 1" longer belt, and the compressor is near all the way at maximum on the adjustment, and actually came within 1/4" of the frame on one installation that I did. That is one of the reasons I went to the 15375 belt instead of the 15385. A 15380 is as long as I would go, especially as it wears, the adjustment will run out. Also there is the fact that all belts are not the same between different manufacturers. Your NAPA belt may be shorter/longer compared to my belt with the same part number.....Rich

TheDon · #22 06-24-2014, 05:08 PM

Derp

TheDon · #23 06-29-2014, 04:04 PM

I'm trying to figure out what the 134a charge should be for a w123. I did 1.5 lbs and it's not cycling the compressor. I can jump the pressure sensor wires and get the AC clutch to run but any other time it's not running. So I most likely need to add freon, the system passed the vacuum test.

So what is the correct amount of 134a to add. I've read 70-80% of the capacity of r12, until the slight glass shows a few bubbles and clearness going past it, 2.2 lbs, 2.8 lbs. so what's the answer???

Side note. When Colin coon and I were chasing down freon leaks I bought a harbor freight freon detector and I had it on the lowest sensitivity( super duper sensitive) and just poking around the expansion valve would set it off. But on high sensitivity. (1/10) it didn't make a noise. The system holds a vacuum so it should be fine??

ROLLGUY · #24 06-29-2014, 04:34 PM

Quote:

Originally Posted by TheDon

I'm trying to figure out what the 134a charge should be for a w123. I did 1.5 lbs and it's not cycling the compressor. I can jump the pressure sensor wires and get the AC clutch to run but any other time it's not running. So I most likely need to add freon, the system passed the vacuum test.

So what is the correct amount of 134a to add. I've read 70-80% of the capacity of r12, until the slight glass shows a few bubbles and clearness going past it, 2.2 lbs, 2.8 lbs. so what's the answer???

Side note. When Colin coon and I were chasing down freon leaks I bought a harbor freight freon detector and I had it on the lowest sensitivity( super duper sensitive) and just poking around the expansion valve would set it off. But on high sensitivity. (1/10) it didn't make a noise. The system holds a vacuum so it should be fine??

The system takes about 20-24 oz to work best. Don't bother using the sight glass, you will over charge it. The sight glass only works with R12. R134a should be at 80% of the recommended amount of R12. Also, you probably have a bad pressure switch if it is not energizing the clutch.

TheDon · #25 06-29-2014, 05:46 PM

It's a brand new switch. :/.

ROLLGUY · #26 06-30-2014, 01:13 AM

Quote:

Originally Posted by TheDon

It's a brand new switch. :/.

Then it is a bad one. If the tech put even an ounce or more of refrigerant in, the clutch should engage. Undercharging is a matter of volume, not pressure. You could put 10 pounds of refrigerant in and the switch will not energize the clutch if it is bad.

vstech · #27 06-30-2014, 07:23 AM

Quote:

Originally Posted by TheDon

I'm trying to figure out what the 134a charge should be for a w123. I did 1.5 lbs and it's not cycling the compressor. I can jump the pressure sensor wires and get the AC clutch to run but any other time it's not running. So I most likely need to add freon, the system passed the vacuum test.

What is this "vacuum test" you speak of?

Refrigeration leak testing needs to be done under pressure, with a dry inert gas, not compressed air, not refrigerant...

The only vacuum test for leaks requires a digital micron gauge... And rubber lines cannot achieve low micron levels...

I've said it every year, and I'll say it here as we'll... Vacuum is only -14psi... And RUBBER TRYS TO SEAL ITSELF UNDER VACUUM... AND THE REFRIGERATION SYSTEM OPERATE UNDER PRESSURE... 30-250 or so... Vacuum "testing" is a very bad practice...

Even if it was suitable... A failed result would ruin your dryer...

NEVER test with vacuum, ALWAYS test with pressure.

TheDon · #28 06-30-2014, 08:35 AM

Well let me just run on down to the store and buy a pressurized cylinder of nitrogen and figure out how to connect it all together and blow up my evaporator somehow.

Now regarding a bad pressure switch....can I not catch a break with this crap? I've got to discharge the system for a $15 sensor. I should probably just buy a 134a machine at this point. Or maybe the system will have a catastrophic leak....

Is there any other way to test the sensor I refuse to think a brand new BEHR sensor would go bad. Then again my BEHR compressor killed itself too.

How about this... I had a freon detector and under it's most sensitive setting it was detecting freon from the expansion valve
But changing the setting to something less sensitive and it was silent.

vstech · #29 06-30-2014, 09:27 AM

sure.

hook up some gauges.
look at the pressure.
if it's over 25psi, and the switch is still open, it's bad.

TheDon · #30 06-30-2014, 09:43 AM

I'm going to hit up harbor freight today for some gauges... I cannot go on any longer without a set.

Will a 134a set of gauges connect to a cylinder of nitrogen or do I need to add some sort of adapter to the regulator. If I am going to get this thing settled I am going to have to go all out and do it right.