The no A/C blues

[bittertech]

Short story time: in 97 I got my car refilled with R12 ($250), mechanic then said "well its not cold because the compressor isn't engaging, just hit it with a stick like this" and I was very sad because I live in Georgia.

In 99 my dad and I did an engine swap between our 2 SHO's. His A/C return lines had corroded and leaked, so we installed all new lines during the swap. Unfortunatly we had forgotten about the clutch not engaging, and wept.

Its almost summer again here in GA, and I finally noticed on shotimes the article about the air gap shims. Eureka! I thought. I pulled the clutch off, and it looked pretty worn. I purchased a new one ($54) from ford, and finally got it installed this weekend, but woe is me, for the clutch refused to engage.

I got my friend to help me diagnose it, along with the shop manual -- we shorted the low pressure switch (I think it was the right switch, right next to the radiator, passenger side -- it is getting current), checked fuse #17, checked voltage along the female connector to the clutch (none!) checked pin #23 on the fan controller (did have voltage) and finally tried putting voltage (really thin wire though, cat5 actually) from the battery directly to the field coil with no luck, no "clump" of engagement, nothing. Now, the system is not pressurized, has not been presurized, and since we finished the engine swap ('02) the harness that connects to the compressor has laid snug to the radiator unconnected. Usually tested with the key turned on on, A/C to max, engine off.

So I'm thinking that the field coil is shot. I'm hoping that theres another safety thats preventing the clutch from engaging (the system is not pressurized, has not been pressurized) or maybe something broken in the wiring. It's a 90 SHO, and the shop manuals instructions for removing/installing the compressor says "See section 36-45" for details. Only the manual skips from "36-41" to "36-75".

So, how the heck can I replace this compressor? It doesn't look like I can get to it from the bottom, from the fenderwell, maybe from the front if I remove the bumper, radiator, etc, or from the top if I remove the alternator, battery box, grow double-jointed elbows and wiggle it out sideways. Does anyone have something else I can check? When we did the engine swap, I'll be the first to admit that some wiring harnesses didn't get reconnected (true story -- dangerous too -- I drove for a year without working brake lights, thankfully was never rear-ended). so where does the other end of the field coil coupler terminate? And finally, if all else fails, anyone know a trustworthy AC tech in the Atlanta area if I throw my hands up in the air and take it to someone to get it fixed?

It's already looking to be a hot summer, and I haven't had A/C in 7 years. :cry:

Also, you can tell its getting hot but just the number of A/C-related posts on the first page.

Also, I'm intending to use Freeze-12 instead of doing an R134a conversion in this -- anyone else tried it?

 

[SHO_Diehard]

I got the compressor out the top. I have normal elbows also.

Do an advanced search with rangerj or projectSHO89 in the user name field. You'll get plenty of info, including a procedure for testing the coil.

If you are going to do the work yourself, research everything so you know what you're doing. It's possible to put time, effort, and money into the A/C and get nothing, my first experience on my '89.

BTW, the A/C went out on my '95 MTX three day ago. :cry:

 

[SeanMc]

I'm having the blender door issue. Sounds like a simple task to change, but I'm not one to take on taking off the dash.

 

[rangerj]

Are you getting battery voltage at the clutch coil? Is the gap between the clutch surfaces properly set? Have you tested the pressure in the system?

It takes about 20 psi in the system at a minimum to activate the low pressure switch. There are service manuals at the local library, Chiltons, Mitchells, Motors, etc.

NOTE: Freeze 12 is not authorized for use in automobile A/C systems. If your system needs to be charged it must have a leak. Fix the leaks or anything else you try will be a waiste of time and money.

 

[bittertech]

Are you getting battery voltage at the clutch coil? Is the gap between the clutch surfaces properly set? Have you tested the pressure in the system?

NOTE: Freeze 12 is not authorized for use in automobile A/C systems. If your system needs to be charged it must have a leak. Fix the leaks or anything else you try will be a waiste of time and money.

we shorted the low pressure switch to bypass -- we think (beside the radiator, passenger side). gap is proper now, clutch hub is new.

there is no pressure in the system because we knew the a/c wouldn't work with my old clutch in it. all the hard pipe (condenser and evaporator as well, i believe) was replaced when we did the engine swap. no point in wasting money till we got that fixed. once i have the clutch problem solved then i'll get it solved.

I did a search and found http://www.utahfordclub.com/rac.htm which is no longer at that address. reading other posts, doesn't sound like removing the compressor is terrible, so I guess I should start hunting down a replacement. From what I understand, the clutch assembly replacement and whole compressor unit are generally a 10$ difference, so it'd probably be better to go with a full new compressor. Anyone have a good source?

 

[SHO_Diehard]

From what I understand, the clutch assembly replacement and whole compressor unit are generally a 10$ difference, so it'd probably be better to go with a full new compressor.

I happened to price some parts yesterday at O'Rielly: Reman clutch - $89, Reman compressor (includes clutch) - $281. Check around though, maybe different somewhere else.

I thought you replaced the clutch. That didn't include the coil?

There was a procedure posted about checking the rotating torque of the compressor, if above a certain value, the compressor is bad. I think the number was 7 lb-ft, check with a search.

 

[bittertech]

replaced the clutch hub -- the part that you pull off to get to the air gap shims, that clamps down on the pulley when the field coil is activated.

I'm not sure if I have 2 problems or not though -- we weren't able to get any current to the field coil coupler (I have to see if a wiring harness is unconnected somewhere) and when we applied direct voltage from the battery the field coil didn't clamp.

as for rotating torque -- when I replaced the hub I dropped the key, and was able to pretty easily move the center shaft with a pair of big needle nose pliers.