Compressor not holding vacuum

[fhorta]

Hi all. Recently I changed the condenser on 91 jeep Cherokee because it had a huge hole and leaking. After putting everything back together I pulled vacuum but did not hold it. I isolated compressor by turning service valves all the way clock wise and still leaking which lead to assume maybe shaft seal is leaking. I have another post about that process hope I didn't incorrectly open another post.

My question is this. If After installing new shaft seal and still not holding vacuum:is it possible that the service valve/s are bad? When valves were seated all the way clockwise, that isolated the compressor. But did it expose the schrader valves also? Or were schrader valves taken our of the equation by seating them like that, hence completely isolating compressor from other factors? This compressor was R12 before and was converted to 134 on 91 jeep Cherokee.

Also, is it possible that there is a leak through the actual stems that you turn to back and front seat the service valves? Just thinking ahead. I will post results hopefully seal fixes issue. Thanks

[B52bombardier1]

Add a little UV dye to your refrigerant and then buy the UV light and goggles kit. That will reveal all leaks though its probably best to check things at night or a darkened garage.

Rick

[Cusser]

On my 1984 Jeep Cherokee there were NO schraeder valves, if I remember correctly. The manual shut off valves simply either closed off either the compressor or the threaded fittings. Once I replaced its compressor with a used unit, and did not lose the remainder of its R-12 because I had the compressor isolated with the manual valves.

I liked the manual service valves.

[fhorta]

Thanks for replies. So put new seal in and still not holding vacuum. The compressor is off the car . Don't want to reinstall until I'm sure compresssor is good to go.

So I went ahead and pumped compressed air (don't know why i don't do this before) and heard air hissing out of both manual valves; the stems I was referring to. I guess they have some kind of seal and probably from back and front seating them after years they wear out.

I want to order the whole both assemblys , low and high service ports, if that's what they are called. I have had my share of issues ordering wrong parts and want to avoid delays. Problem is I'm not sure what model or specific type of compressor i have. It's on a 91 jeep cherokee 4x4 inline 6. Based on my research, it has to be Sanden, York, Denso, or GM. Then it goes on to different series of each.

On the back plate, there are letters SD and MD. The serial number reads 0370105170 7701.Compressor was R12 and converted to R134. Any ideas how i can derermine what compressor i have and the name of part i need to order. Thanks!

[fhorta]

Forgot to mention on top of compressor it reads 709T.

Also, do i have to get the service valves with the manual valves? The system was retrofitted with R134a fittings which have the schrader valves. The manual valves would no longer be needed, right?

[Cusser]

Also, do i have to get the service valves with the manual valves? The system was retrofitted with R134a fittings which have the schrader valves. The manual valves would no longer be needed, right?

I'm not a pro, but I think if you had schraeder valves that you would not need manual valves.

[tbirdtbird]

" Problem is I'm not sure what model or specific type of compressor i have"

Based on the front and back seating valves I strongly suspect this is a York.

PICTURES will give it away....

[fhorta]

Thanks

[tbirdtbird]

I am just assuming.....better to post a pic!

[Tim]

On a 91 Cherokee, with either motor. All I list OEM is a Sanden compressor, 7701 or 4828. With the fitting description. I think it's a 7701. Numbers are on the Sanden tag.