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AC Clutch Cycle and Pressure

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Nickelplate

Re: AC Clutch Cycle and Pressure

Hey, Gary. I figured I would post a pic of mine in case it was different in any way.

1986 Bronco. 5.0L, Edelbrock Pro-flo 4 EFI, Baumann-controlled 4r70w, 3.55 gears, 31" tires.

Nickelplate

Re: AC Clutch Cycle and Pressure

In reply to this post by mat in tn

Heya, Mat! Thanks for the info and suggestions. I did definitely check those things. I have my dual electric fans set to turn on 100% when the AC is turned on, so airflow shouldn't be an issue. Orifice tube is new, as are all other components. The oldest thing in the system is the condenser, which is a couple of years old, but with not much use on it. And I did end up using a full manifold gauge set with a filler hose from the r-134a can (I purged the hose using the schrader valve before filling).

Adding the high-side pressure switch has definitely alleviated my issue. IF anyone else is going to wire one in, here are the parts I bought.
https://www.ebay.com/itm/144634827521
and the switch was labeled "Ford F5TZ-19D594-AA Pressure Switch for A/C Compressor OEM NOS"

Remove the two unused leads on the pigtail, then just put the switch in line with the low-side switch on the same lead.

1986 Bronco. 5.0L, Edelbrock Pro-flo 4 EFI, Baumann-controlled 4r70w, 3.55 gears, 31" tires.

mat in tn

Re: AC Clutch Cycle and Pressure

good. certainly, wire this switch in series with the low cycle switch. it becomes a redundant switch but so long as either one can cause protection for their own reasons then it works the same.

85lebaront2

Re: AC Clutch Cycle and Pressure

Administrator

In reply to this post by mat in tn

Mat, a number of years ago the company my son was working for hosted a seminar on R134 conversions. Part of the requirement the EPA wanted was a "refrigerant containment" system involving replacing the high pressure relief valve with a high pressure shut-off switch. This would, in theory, kill the compressor power and release the clutch.

Only problem, like most items, mechanical or electronic, it wasn't fool proof. On the older York or Tecumseh twins and Chrysler V-twins, the clutch bearing is on the crankshaft and a seized bearing results in a continuous compressor run. I personally have had an FS10 on my 1994 Taurus, weld the clutch together due to an internal compressor failure on the highway which it spun long enough to weld itself, then snapped the serpentine belt. I have also had a Chrysler C171 explode the high side discharge hose when the expansion valve stuck shut just as it was starting to balance everything, and this was with R12. Pressure spiked so fast I couldn't even unplug the wires in time.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

Gary Lewis

Re: AC Clutch Cycle and Pressure

Administrator

In reply to this post by Nickelplate

Thanks for the pic. But Big Blue's manifold doesn't have a place for that switch. I have a complete 1990 system on BB, including a brand new manifold. So I'm sure there wasn't one from the factory as the old manifold didn't have it either.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Nickelplate

Re: AC Clutch Cycle and Pressure

According to my research (looking at the same part for each year on rockauto and seeing when the style changed), ford trucks with a small-block did not get the refrigerant line with the pressure switch port until 1994.

1986 Bronco. 5.0L, Edelbrock Pro-flo 4 EFI, Baumann-controlled 4r70w, 3.55 gears, 31" tires.

Gary Lewis

Re: AC Clutch Cycle and Pressure

Administrator

Could you check for the 460? Maybe it is the same, which would explain why I don't have it.

Gary, AKA "Gary fellow": Profile

mat in tn

Re: AC Clutch Cycle and Pressure

In reply to this post by 85lebaront2

everything works perfectly when working perfectly. then life happens!

Nickelplate

Re: AC Clutch Cycle and Pressure

In reply to this post by Gary Lewis

Yep! Looks like it changed after 93 for the 460 too.

1994

1993

1986 Bronco. 5.0L, Edelbrock Pro-flo 4 EFI, Baumann-controlled 4r70w, 3.55 gears, 31" tires.

Gary Lewis

Re: AC Clutch Cycle and Pressure

Administrator

Yep! That '93 manifold is exactly what BB's looks like. Thanks!

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: AC Clutch Cycle and Pressure

Administrator

In reply to this post by Nickelplate

1994 was when Ford went to R134. That is why I used 1994 up condenser and evaporator on Darth making his system a dedicated R134 system.

FWIW, Chrysler changed in 1993 at least on the minivans. On my Chrysler I found that the updates were introduced starting in 1992 with different condensers and evaporators with compressors being phased in.

Bill AKA "LOBO" Profile

Gary Lewis

Re: AC Clutch Cycle and Pressure

Administrator

I added over 100 pages of HVAC documentation, as explained in the thread called, oddly enough, Documents Added To HVAC Section. Maybe some of it will help.

Gary, AKA "Gary fellow": Profile