help with AC tools - PeachParts Mercedes-Benz Forum

lutzTD · #1 06-28-2009, 08:48 AM

so I got the system all back together last night. I pulled a vacm on it with my vac pump through the gages. I have r12 hoses so I removed the r134 fitting to do this. I run the pump for an hour then shut it off and removed the pump leaving the gauges. this morning the vacuum was the same as last night so I am pretty sure the system is ok. I go to pull off the gauges and pfft, the system pulled in outside air. there is no core in the r12 fitting. so I plan to fill the system with freeze-12. what do I need to buy to pull a vacuum, then fill the system? the freeze-12 fill tube doesnt push the shader so there is no way to pull vacuum with the fitting in place. can I buy a set of freeze-12 hoses for my guages? and will these hoses let me pull a vacuum too? I trying to learn to do this but I am finding I am missing a tool at every turn. what should I doo at this point? I cant even go to r12 because the stems are missing in the r12 ports.

jubjub · #2 06-28-2009, 09:24 AM

Say what? You're saying the charging ports on the car have no valve? How are you planning on holding a charge in there?

Ideally, you'd have a 4 port gauge set. 2 to the car, 1 to the charging cylinder, and 1 to the vac pump. If you can't do that, then you can try to get a T that will go on the end of the charging line and allow you to hook up the vac pump there.

tangofox007 · #3 06-28-2009, 09:24 AM

It sound like your hoses are just missing the valve depressors. You can buy a hose repair kit that contasins new seals and depressors. Of course, you will need to install valve cores in the service ports.

http://www.amazon.com/Mountain-Hose-Repair-Kit/dp/B000FMO57M/ref=sr_1_6?ie=UTF8&s=automotive&qid=1246195528&sr=1-6

Also, you have pretty much ruined your receiver drier at this point.

Rafi · #4 06-28-2009, 09:27 AM

That is the shrader (sp) valve in there same as your tire valve

Johnt49 · #5 06-28-2009, 10:05 AM

Discard the Freeze 12 fittings and install new schrader valves in the original ports. Any good auto parts store should have them. Since you're doing your own work, why use adapters at all? Every adapter you screw on is just one more opportunity for a leak. Charge it just like it was an R12 system. As far as compliance goes, nobody but you needs to know what's in the system unless you sell it or take it somewhere for service.

lutzTD · #6 06-28-2009, 10:42 AM

Quote:

Originally Posted by Johnt49

Discard the Freeze 12 fittings and install new schrader valves in the original ports. Any good auto parts store should have them. Since you're doing your own work, why use adapters at all? Every adapter you screw on is just one more opportunity for a leak. Charge it just like it was an R12 system. As far as compliance goes, nobody but you needs to know what's in the system unless you sell it or take it somewhere for service.

I got valve cores for the r12 ports. Now I just need to figure out how to charge through the gauges since the freeze-12 kit doesnt have a guage. I think I can just attach the freeze-12 chrge hose to my center port on the guage set. Is that right? My gauge set has 4 ports. 2 on high, 2 on low and one middle port

Matt L · #7 06-28-2009, 11:14 AM

Connect the refrigerant can to the additional low-side fitting. With the refrigerant valve closed and both manifold valves open, vacuum the system. Then turn off the vacuum pump, close the manifold valves, and immediately open the refrigerant valve.

My manifold gauge set has four valves, which makes things a lot easier.

lutzTD · #8 06-28-2009, 01:26 PM

ok so I charged the system with 2 cans of freeze-12. i got both full cans in which should not have been enough. My low side at idle is about 55 which I thought was too high. when I rev it up above a 1000RPM it drops to 35. Is the pressure at idle allowed to go higher? The temp out of the vents is very cold even on a 95 and humid florida day. but ZI dont want to damage anything. should I bleed it down because the idle pressure is so high or is that normal

79Mercy · #9 06-28-2009, 01:28 PM

I would bleed off a little bit. 55 is pretty high for the low side at idle.

How cold is the air?

Johnt49 · #10 06-28-2009, 01:31 PM

Quote:

Originally Posted by lutzTD

I got valve cores for the r12 ports. Now I just need to figure out how to charge through the gauges since the freeze-12 kit doesnt have a guage. I think I can just attach the freeze-12 chrge hose to my center port on the guage set. Is that right? My gauge set has 4 ports. 2 on high, 2 on low and one middle port

Should only have 3 ports along the bottom of the manifold. Low on left (blue hose), input in center (yellow) and high on right (red). The 2 additional ports you are talking are probably on the sides of the manifold and are dummies that are usually not drilled out. They're just to screw the other end of the hoses to for storage. You may need to get a universal can tap since the Freeze12 hose is probably threaded for their can on one side and their adapter on the other.
Here's what the can tap looks like. I know NAPA up here sells them.

Matt L · #11 06-28-2009, 01:35 PM

The spec for the pressures is generally given at 1500 RPM. Yes, the pressure is allowed to go higher at idle, but I agree that 55 psi seems to be too high.

"Bleeding off" blends should be avoided.

Johnt49 · #12 06-28-2009, 01:38 PM

40 is ideal for low side but should be measured once interior has cooled with blower on hi and air flap in recirculate position The low side pressure will drop as air temp blowing across evaporator decreases that's why you want air flap in recirc. If you're blowing outside air through evap, low side will tend to stay a little high. More critical is hi side. I usually shoot for no more than 200 with R12 or Freeze12

#13 06-28-2009, 04:09 PM

Is your ultimate goal to use R12?

lutzTD · #14 06-28-2009, 04:29 PM

Quote:

Originally Posted by LarryBible

Is your ultimate goal to use R12?

actually if the freeze-12 works there will be no reason to remove it. just wondering why the system took so little to fill. it should have been more than 24 ounces

JHZR2 · #15 06-28-2009, 07:07 PM

seems to me that there are so many variables with filling by pressure - you are better off, if at all possible, to fill by mass. This perhaps makes it easy.