A/C Guages and Vac pump

[CruisinGA]

Things are heatin up down here and it's time to fix the A/C on my '93 (again )

I need a set of gauges/hoses and a vac pump. I will be using Freeze 12 in the '93 so I need equipment that can handle R12 as well as R134.

Harbor Freight's gauge set is $30, but it claims only works with R134. http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92649
This venturi-type vac pump with R-12 & R134 connectors is only $15
- Harbor Freight Tools - Quality Tools at the Lowest Prices

There are a number of gauge sets cheap on Ebay that claim will work R12/R22 but do not come with "R134 conversion." I guess this just means I would need some fittings.http://cgi.ebay.com/ebaymotors/AC-M...Z280342371081QQptZMotorsQ5fAutomotiveQ5fTools

This auction has the harbor freight pump and gauges, but claims "complete" for R134 and R12 service. Looks like I would still have to buy a can tap.
R134a AC MANIFOLD GAUGES HOSES AIR VACUUM PUMP R12/22 - eBay (item 380122183914 end time May-07-09 16:46:08 PDT)


Anyone got any suggestions? Don't want to end up with crap, but I sure don't need pro-quality tools for something that will likely get used no more than once or twice a year.

 

[John Smith]

I have the earlier version of that HF vacuum pump that runs off a air compressor and only has the R134a port. I got it on sale for under $10 and it works just fine. I looked at the HF gauge set and I was not ready to trust the China gauges. I used my neighbor's gauge setup but need to buy my own set so I will be following this thread to see what you end up with.

 

[Joe_E]

I think i'm gonna dabble into doing my own a/c as well.
Been looking at sets on ebay, ect. and think i'm gonna go with a Mastercool set. Seem to be high quality. You can get them with two sets of hoses, one for R12 the other for 134 with couplers in a case with a can tap. Been looking around for the best deal. Seem to be in the $125 range. I don't want to waste money on a china set. I got three R12 vehicles and two 134. Figure i'll get my money's worth.

 

[flintknapper]

I think i'm gonna dabble into doing my own a/c as well.
Been looking at sets on ebay, ect. and think i'm gonna go with a Mastercool set. Seem to be high quality. You can get them with two sets of hoses, one for R12 the other for 134 with couplers in a case with a can tap. Been looking around for the best deal. Seem to be in the $125 range. I don't want to waste money on a china set. I got three R12 vehicles and two 134. Figure i'll get my money's worth.

Wise man!

When purchasing A/C service equipment...always buy good/decent products. Otherwise....take your vehicle to a professional and let them do it.

IMO, it is false economy to buy cheap inaccurate tools. A good set of gauges (and the ability to read them) is a MUST HAVE item to properly diagnose A/C problems.

The Mastercool set is an excellent product and will serve you well for a lifetime (with maintenance).

Vacuum pumps can be rented instead of bought (if need be), but the same advice applies, get a decent one.

You are taking the right approach Joe.

 

[Trollhole]

I'm on the other side. Don't buy something your gonna need about a dozen times in your life that's expensive. The set you showed will work fine. Though I'm not a fan of the vacuum pump. I bought one just to see what it pulled. Not the 29 I was expecting but close. Ended up buying a harbor freight oil bath vacuum. Works great and the few times I've needed it it worked fine. But be prepared the packaging stinks like no other.

That being said I have a set of mastercool gycerin filled gauges. Been using it for 15 years now and only rebuilt it once. (I used it heavily for 5 years)

 

[e9999]

do these air fed vacuum gauges have some sort of good one way valves so you don't get in trouble with a weakish compressor?

and so they do indeed pull a good enough vacuum? How long does it take?

 

[Trollhole]

do these air fed vacuum gauges have some sort of good one way valves so you don't get in trouble with a weakish compressor?

and so they do indeed pull a good enough vacuum? How long does it take?

For a car I couldn't imagine it takes long. Maybe a couple minutes for a car but I wouldn't use it for pulling down a home a/c unit.

No oneway on the vacuum but with the gauges you should be able to close it off.

I just went out and tried it again. It's louder than all get out. But then again so is the compressor.

 

[CruisinGA]

I'm on the other side. Don't buy something your gonna need about a dozen times in your life that's expensive. The set you showed will work fine. Though I'm not a fan of the vacuum pump. I bought one just to see what it pulled. Not the 29 I was expecting but close. Ended up buying a harbor freight oil bath vacuum. Works great and the few times I've needed it it worked fine. But be prepared the packaging stinks like no other.

That being said I have a set of mastercool gycerin filled gauges. Been using it for 15 years now and only rebuilt it once. (I used it heavily for 5 years)

Like most people here, I understand buying good equip/tools when warranted (and maybe sometimes when not ) .

But really, what makes up a set of A/C guages? A drilled and tapped hunk of aluminum, with a sight glass and some hoses + fittings. The gauges are the most complicated part, and you can buy gas pressure guages that are accurate to 1% for very little money.
I don't really think the extra psi or two of accuracy or better durability in the hoses/fittings in a set that are 5+ times as expensive is really going to make a difference for me.

I'm saying all this to give someone the opportunity to correct me, it just appears to me that unless you're going to be making a living with a set of gauges or at least using more than once or twice a year, it's not worth quintupling the entry fee.

 

[CruisinGA]

do these air fed vacuum gauges have some sort of good one way valves so you don't get in trouble with a weakish compressor?

and so they do indeed pull a good enough vacuum? How long does it take?

When I worked at a shop, we used a venturi style vacuum pump like this Harbor Freight one to suck down cooling systems and check for leaks, much larger volume, but we didn't draw down as deep of a vacuum. That tool was Snap On, but I don't think it takes Snap On to make a venturi that works.

If these A/C vac venturis are anything like the coolant ones it would have a valve to shut that would maintain vacuum without air supply.

I think I'm going to give this one a go and see if I can't get this job done right with them.

(BTW I have no plans to work on anything other than auto R12 and R134 systems)

 

[cruiser88]

I dont care if it takes 2 days.......watch the guage for around 29.92

Change the oil in the vac. pump for every use.

 

[Trollhole]

I dont care if it takes 2 days.......watch the guage for around 29.92

Change the oil in the vac. pump for every use.

If you can see that gauge show 29.92 you have got a better eye than me. I usually pull it for about 30 min and let it sit for another hr or so. Then when fillinf it up I use a can with dye in it incase something leaks down the road.

In the 5 years we used our vac pump we changed it twice and it worked just fine. I wouldn't change it every use. That's just a waste of good oil and money.

 

[cruiser88]

On the pump......if you ever pull moisture out of the system it will go stright to the oil. Why...I dont remember now?

The guages I have are easy to read. You always want to put nitrogen in the system to check for leaks before you pull a vaccum. Of course you could pull a vac. after you got your vac. Let the guages sit overnight and if they do not show a difference in pressure then you are golden. The dye is a fine idea

If you can see that gauge show 29.92 you have got a better eye than me. I usually pull it for about 30 min and let it sit for another hr or so. Then when fillinf it up I use a can with dye in it incase something leaks down the road.

In the 5 years we used our vac pump we changed it twice and it worked just fine. I wouldn't change it every use. That's just a waste of good oil and money.