1977 F150 Low Side Service Port?
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Junior User
Joined: Mar 2008
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From: Thomasville, Georgia
1977 F150 Low Side Service Port?
Hey guys I was wondering if anyone could tell me where my low side service port is in my 1977 Ford F150. It has a 400 in it and I bought the retro fit valves to convert to r-134a with. I believe it to be located on my compressor but I want to make sure. Thanks a lot.
Posting Guru
Joined: Sep 2003
Posts: 2,313
Likes: 12
From: Northeast LA
It's on the fitting that attaches to the compressor, and there is a valve on the end of the fitting that has to be opened too after you hook up the gauge set. But there is a lot more to converting to R-134a than just putting those fittings on and sticking a few of cans of cheap r134 in it. It may work for a while but I doubt for very long.
I converted mine to R-134 last year and I bought new fittings, new hoses, new drier (a must), new expansion valve, and new o-rings(also a must), used condenser. The only things original in my A/C system are the York compressor and the factory evaporator core.
Here is pic to answer your question though.
I converted mine to R-134 last year and I bought new fittings, new hoses, new drier (a must), new expansion valve, and new o-rings(also a must), used condenser. The only things original in my A/C system are the York compressor and the factory evaporator core.
Here is pic to answer your question though.
Fleet Mechanic
Joined: Feb 2006
Posts: 1,776
Likes: 5
From: Lorain County, Ohio
Also make sure you understand how those valves work.
-Back seated (full out counter clockwise)- Normal operation. Service ports are sealed off from the system.
-Mid seated (half way between full in and full out) Service position. The service valves are open to the system.
-Front seated. (Fully in, clockwise) Isolates the compressor from the rest of the system. NEVER front seat the valves with the system running. There are exceptions, but not in a normal DIY situation.
There is a square drive ratchet wrench made to operate those valves and it's cheap. Please resist the temptation to use an open end wrench or adjustable wrench on them.
Unlike a modern system, your compressor has an oil sump like a small engine. The oil needs to be drained, flushed and new oil poured in. The aerosol can of oil in the kit won't work.
Like jsutton said, there's a lot more to an R134a conversion than installing a Death Kit. Do some research first:
Automotive AC Information Forum - ACKITS.COM
-Back seated (full out counter clockwise)- Normal operation. Service ports are sealed off from the system.
-Mid seated (half way between full in and full out) Service position. The service valves are open to the system.
-Front seated. (Fully in, clockwise) Isolates the compressor from the rest of the system. NEVER front seat the valves with the system running. There are exceptions, but not in a normal DIY situation.
There is a square drive ratchet wrench made to operate those valves and it's cheap. Please resist the temptation to use an open end wrench or adjustable wrench on them.
Unlike a modern system, your compressor has an oil sump like a small engine. The oil needs to be drained, flushed and new oil poured in. The aerosol can of oil in the kit won't work.
Like jsutton said, there's a lot more to an R134a conversion than installing a Death Kit. Do some research first:
Automotive AC Information Forum - ACKITS.COM
Cross-Country
Joined: Apr 2011
Posts: 93
Likes: 3
From: Chandler, AZ
low side service port
Two questions:
1) So when I open up these valves midway, I leave them open while I'm adding a can of freon?
2) What's happening during the freon going in is there is a high pitched squeal almost like some pressure releasing, then the blower in the dash stops and the compressor stops.
If I turn off the truck and wait 2 minutes, I can fire it back up, the a/c switch on the dash makes the blower spin up, air blows, then again 5 minutes later t here is this squeal and hiss and the compressor stops and the blower stops. Any ideas?
1) So when I open up these valves midway, I leave them open while I'm adding a can of freon?
2) What's happening during the freon going in is there is a high pitched squeal almost like some pressure releasing, then the blower in the dash stops and the compressor stops.
If I turn off the truck and wait 2 minutes, I can fire it back up, the a/c switch on the dash makes the blower spin up, air blows, then again 5 minutes later t here is this squeal and hiss and the compressor stops and the blower stops. Any ideas?
Lead Driver
Joined: Apr 2007
Posts: 5,958
Likes: 105
From: Houston
Also make sure you understand how those valves work.
-Back seated (full out counter clockwise)- Normal operation. Service ports are sealed off from the system.
-Mid seated (half way between full in and full out) Service position. The service valves are open to the system.
-Front seated. (Fully in, clockwise) Isolates the compressor from the rest of the system. NEVER front seat the valves with the system running. There are exceptions, but not in a normal DIY situation.
There is a square drive ratchet wrench made to operate those valves and it's cheap. Please resist the temptation to use an open end wrench or adjustable wrench on them.
Unlike a modern system, your compressor has an oil sump like a small engine. The oil needs to be drained, flushed and new oil poured in. The aerosol can of oil in the kit won't work.
Like jsutton said, there's a lot more to an R134a conversion than installing a Death Kit. Do some research first:
Automotive AC Information Forum - ACKITS.COM
-Back seated (full out counter clockwise)- Normal operation. Service ports are sealed off from the system.
-Mid seated (half way between full in and full out) Service position. The service valves are open to the system.
-Front seated. (Fully in, clockwise) Isolates the compressor from the rest of the system. NEVER front seat the valves with the system running. There are exceptions, but not in a normal DIY situation.
There is a square drive ratchet wrench made to operate those valves and it's cheap. Please resist the temptation to use an open end wrench or adjustable wrench on them.
Unlike a modern system, your compressor has an oil sump like a small engine. The oil needs to be drained, flushed and new oil poured in. The aerosol can of oil in the kit won't work.
Like jsutton said, there's a lot more to an R134a conversion than installing a Death Kit. Do some research first:
Automotive AC Information Forum - ACKITS.COM
Why wont the aerosol can of oil not work? Even though the york compressors like mine has a sump they are all interconnected with the refrigerant system. Even if you were to use the oil check opening to fill your compressor with the correct amount of oil on the initial start up the compressor will pump the oil out of the crank case into the system and within a few minutes the sump will get most of the oil back and there it will stay.
personally since I was installing a new compressor I poured the right abount of oil into the suction port then capped it off till I was able to get it bolted in and hook the lines up.
But I am curious why though you said the aerosol cans of oil will not work.
Fleet Mechanic
Joined: Feb 2006
Posts: 1,776
Likes: 5
From: Lorain County, Ohio
Why wont the aerosol can of oil not work? Even though the york compressors like mine has a sump they are all interconnected with the refrigerant system. Even if you were to use the oil check opening to fill your compressor with the correct amount of oil on the initial start up the compressor will pump the oil out of the crank case into the system and within a few minutes the sump will get most of the oil back and there it will stay.
personally since I was installing a new compressor I poured the right abount of oil into the suction port then capped it off till I was able to get it bolted in and hook the lines up. Also, if you drain the compressor and add aerosol oil, the compressor will run dry.
But I am curious why though you said the aerosol cans of oil will not work.
personally since I was installing a new compressor I poured the right abount of oil into the suction port then capped it off till I was able to get it bolted in and hook the lines up. Also, if you drain the compressor and add aerosol oil, the compressor will run dry.
But I am curious why though you said the aerosol cans of oil will not work.
With modern (post 1978 or so) systems, there IS no crank case, so the oil HAS to circulate or the compressor starves.
With the aerosol cans and a sump type compressor, the 2 incompatible oil types mix over time and form something like tar that really do a number on the whole system.
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Lead Driver
Joined: Apr 2007
Posts: 5,958
Likes: 105
From: Houston
With a sump type compressor, like your York, very little of the oil flows through the system. Most of it remains in the crank case to lube the compressor. Oil out in the system is much like "blowby" in an engine.
With modern (post 1978 or so) systems, there IS no crank case, so the oil HAS to circulate or the compressor starves.
With the aerosol cans and a sump type compressor, the 2 incompatible oil types mix over time and form something like tar that really do a number on the whole system.
With modern (post 1978 or so) systems, there IS no crank case, so the oil HAS to circulate or the compressor starves.
With the aerosol cans and a sump type compressor, the 2 incompatible oil types mix over time and form something like tar that really do a number on the whole system.
I know mixing oil types can cause all kinds of trouble, but I never seen any problems with using aerosol oil cans on the york compressors. The oil will find its way back to the sump in the york even if its in the line. It just would be nice if you could still find the dipsticks to check the oil level. But Ford says if the system is working fine theres no reason to check the oil level.
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Fleet Mechanic
Joined: Feb 2006
Posts: 1,776
Likes: 5
From: Lorain County, Ohio
I dont mean mixing oil types. I took it as you saying the aerosol cans of oil is no good at all. I dont exactly agree with that considering the design of the York compressor.
I know mixing oil types can cause all kinds of trouble, but I never seen any problems with using aerosol oil cans on the york compressors. The oil will find its way back to the sump in the york even if its in the line. It just would be nice if you could still find the dipsticks to check the oil level. But Ford says if the system is working fine theres no reason to check the oil level.
I know mixing oil types can cause all kinds of trouble, but I never seen any problems with using aerosol oil cans on the york compressors. The oil will find its way back to the sump in the york even if its in the line. It just would be nice if you could still find the dipsticks to check the oil level. But Ford says if the system is working fine theres no reason to check the oil level.
A dry, sump type compressor would starve and be damaged before the aerosol oil accumulated in the crankcase to lube it.
Aerosol oil is made for post 1978 systems with no oil sump. Most systems in recent (retail) memory are sumpless.
A dipstick is easy to make. I don't remember how offhand, but the info is widely available online.
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