jeff spahn

I have been searching around and was wondering if anyone had a thread on a step by step AC remove/install. I bought the Griffith compressor, hoses and dryer and need to do this myself as my local shop doesn't want to touch it.

The oil cooler on top of the condenser has me a little confused, can I just remove and plug those lines? Is that trans oil cooler or an additional engine oil cooler. I haven't been able to trace the lines yet as the car is being driven.

Also, just take out the condenser is the easiest way to work on things?

Looks like I need a 34mm wrench to do the hose fittings. Where the heck do you get one of those. Fastenal, nope. Sears, nope. Lowes, nope. No harbor freight around here. Amazon my only choice?

The remove/install of the compressor looks very easy, it's the condenser, dryer area is what has me all flummoxed. I don't know what I am getting into here.

Any comments welcome

dprantl

The cooler right above the condenser is the transmission cooler on later auto cars. You do not need to remove the condenser, you just need to flush it. I always flush condensers in place, just disconnect both ends of the condenser, connect your flush kit to one end and connect some hose to the other end that goes to a bucket. If you are replacing the hoses anyway, you may as well keep the condenser <-> compressor hose connected at the condenser side, just disconnect from the compressor. You need to do the same for the evaporator (both evaporators if you have rear A/C). Once flushed, blow out with compressed air and let dry for a couple of hours to ensure no remnants of the flush liquid are present in the system. Some people also flush the hard lines, but IMO that is not really necessary since there will be so little oil in the lines themselves. Remember to replace EVERY o-ring in the system, the one you don't replace is the one that will leak all your refrigerant out. Install a new drier, and do not break its seal until you are ready to button everything up and recharge with refrigerant. Also I would replace the expansion valve(s) with new ones.

For the hose fittings, which ones are you needing a 34mm wrench for? I think the biggest nuts in the system are the ones for the fuel cooler. I just used an adjustable wrench for those. The rest should be 32mm or smaller.

Btw, what are you going to do with your old 10PA20C compressor?

Dan
'91 928GT S/C 475hp/460lb.ft

Rob Edwards

I bought one of those A/C flush-in-a-bucket kits:

http://www.toolfetch.com/a-c-convers...-fjc1996.shtml


and didn't have much luck with it- the rubber fittings that come with it to connect the flush gun and drain hose to the fittings are cheap Chinese crap and mostly I managed to spew flush solvent all over everything. Proper #6, #*, and #10 flush adapter fittings are frickin' expensive:

http://www.autobodytoolmart.com/robi...7-p-15791.aspx

All the DIY videos I have come across have the evaporator or condensor out of the car- dunno whether that means they HAVE to be out or it was just easier to illustrate on the bench.

Removing the condensor is a PITA, the spoiler, oil cooler, and its air guide have to move:

https://rennlist.com/forums/928-foru...-marathon.html

If if were me, I might remove the compressor from the car (should be 32, not 34 mm connections on the suction line- pretty sure that's the biggest fitting in the AC system on a '90), remove the passenger seat to get at the lines from the rear A/C (IIRC your car has rear air, yes?) plug all the connections, and beg the local shop to flush the condensor and the two evaporators for you in situ. If they still won't touch it, I'd be happy to ship you the flush kit and fluid, if you want to play with it. But get yourself a hazmat suit and good safety goggles, it'll be messy.

Ed Scherer

I've done the flush 'n' charge (replacing various components along the way) a couple of times on my '90 S4. I installed a Griffiths compressor, too.

A few things that come to mind right away (I might add more tonight):

• Make sure you've got a nice metric crowfoot wrench set. They're very handy for uncoupling/coupling some of the plumbing (especially one of the connections that runs parallel to the receiver/drier that's quite hard to get tools on, but a couple of crowfoot wrenches on a couple of long extensions does the job relatively easily).
• Make sure you get a good feel for where all the A/C plumbing goes and work out a good flush plan. I've both flushed components individually, and I've also flushed whole circuits at once. If you opt for the latter, you can use drilled-out expansion valves temporarily (you can't flush through unaltered expansion valves).
• IIRC, I remember reading that the hard lines under the car that go to the rear A/C collect oil since they're a low spot. Since last time I did A/C work, I was changing oil type, I wanted to make damn sure that I got all the oil out of the system, and thus elected to flush those (as part of a a whole "rear circuit" flush).
• Note that there's a solenoid-controlled valve under the passenger seat that controls refrigerant flow to the rear evaporator (if you have one). If you're elect to flush the whole rear circuit, you'll need to energize that solenoid (there's an electrical connector you can disconnect and then power the solenoid by itself; I use a portable power supply). It's easier to get to this with the seat removed, but I've done it with the seat moved forward and up. If you're replacing all the O-rings anyway, I'd just remove the seat; I'm not sure if you can get to all the O-rings with the seat in (I removed the seat when I did my complete O-ring replacement).
• I found it easiest to get to the screw for the receiver/drier clamp by going in through the openings on the bumper cover. IIRC, it took a long 1/4" socket extension and a U-joint adapter.
• Rob is right about the condenser — it's a bitch to remove. There are two screws from the bottom, and IIRC, a lot of stuff has to come off to get to those. I had mine out once. I hope I don't have to do it again.
• When you're putting everything back together again, you might run into a little trouble with the high-side Griffiths hose where it connects to the condenser; I had trouble with a little interference between that hose (at the elbow and crimped fitting with the hose) and the elbow of the fitting for the output side of the receiver/drier. I was able to solve this problem by loosening the fittings and clamp for the receiver/drier and repositioning it a little. My advice would be to leave all the fittings in that neighborhood and the receiver/drier clamp somewhat loose until everything is connected and then tighten them down.
• If you've never removed a front expansion valve before, you're in for a treat. There are a few tricks and tools that make it easier (probably covered in other threads). Ask if you need help with that.

Assuming you had a Denso 10PA20C compressor before, you'll have a fair amount of original mounting hardware left over when you're done installing the Griffiths, which has simpler mounting. Here's all the old mounting hardware (and tension adjuster):

SeanR

Hey Jeff, got your message this morning, just getting caught up. Sounds like these guys have it covered for ya and can't think of anything else right off hand. No need to come down for it, you can do it all, besides, I will not touch one of those compressors.

Jadz928

Subscribed. Will be doing this shortly.

jeff spahn

The expansion valve in the dash looks like a major PITA to do.

This looks like I should budget a good long time to do. Think I might wait a few more weeks for it to get warm.

I don't know about rear one, never even had the cover off the rear air before.

I don't know what I am going to do with the old compressor. Probably sell it cheap for someone to rebuild.

jeff spahn

I'll ask since you offered. The front expansion valve needs to be replaced for sure? I'll take any advice you can give on doing this. WSM makes it look like a **** do.

Same goes for the hoses and the drier. It looks like taking the front of the passenger fender liner out will make things easier.

This does not look like a Sunday afternoon kind of job.

Looks like 5 or 6 hours minimum to do.

Ordered a metric service wrench set, flare and regular metric crows foot wrenches. I have found just little tool tweaks can make a bad job pretty easy. Best example I have is the cam covers. With a micro drive ratchet set from sears and a 5mm 1/4" drive hex key bit, The bolts that are a pain in the *** and can take a long, long time to do by hand take seconds. $24 well spent in my book.

Keep the tips coming. I am going to attempt to do a Dwayne style write up when I do this so there is something better than the WSM's "remove compressor, installation is reverse of removal."

SeanR

Expansion valves are really quite easy. A set of long, round headed allen sockets will make pretty simple work of the bolts. You will want to take the fuel cooler loose (have to change that seal anyway) and it will make removal of the loose expansion valve that much easier.

The rear cover is two screws facing the rear of the car, pull the plastic part off and there will be two screws in the middle. Pull those out and the entire a/c cover comes up from the rear. You won't bust anything. Plan on a couple of days to get it done. Have a vac pump at the end of it and see if it holds over night, if so, fill and go.

edit: You WILL need to replace the expansion valves seal (4ea) and since you are in there, you might as well put new ones in.

As far as attaching the hoses to the compressor, I attach the condensor hose up first so it is run properly, then using a floor jack angle the compressor at about 45 degrees with the back side on the jack. Attach hoses and line them up so they are not near the pulley, tighten them up and then have loads of fun getting it all positioned up on the bracket.

dprantl

Sean is right. Since you need to replace the o-rings for the connections to the expansion valves, you will need to do all the work to remove them, so may as well replace them anyway since they do go bad sometimes and are not expensive. Whatever you do, DO NOT strip an allen head bolts that hold the hose assemblies to the expansion valve, or you will be in for a really fun time grinding them out. Other than that, it really is not that difficult to remove. It lives right under the plastic cover below the windshield wipers. I don't have access to the WSM right now, but it may be referring to the older expansion valve that had male beadlock fittings screw into the expansion valve, instead of a block that is held in place by an allen screw. The expansion valve changed to the new version I believe in '86.5.

I would be interested in the old compressor, would love to try my hand at rebuilding one of those.

Dan
'91 928GT S/C 475hp/460lb.ft

Ed Scherer

Yeah, all that.


BTW, Jeff, it'd be helpful to know what all you're doing (how much stuff are you replacing and why?). If you're replacing the compressor due to a compressor failure, you might have crap (shavings, gunk, etc.) in the lines. What refrigerant were you running? R-12? If so, are you staying with R-12? Have the O-rings ever been replaced before? Do you have rear A/C?

Also, what additional tools do you have on hand? Vacuum pump? Micron vacuum gauge? Gauge set (gauges/manifold/service hoses)?

Rob Edwards

Here's one way to get to the front expansion valve 3mm allens - through the grommet that the high side pipe runs through. 4 or 6" Long ball-end allen socket, HF FTW. Make darn sure the bolt head is cleaned out and that you're completely seated in it, the bolts can be tight.

SeanR

Yup, as said above.

I usually use a normal allen key and break them loos by hand first, then do as Rob show.

Don't forget the seals at the bottom of the car too.

Ed Scherer

O-ring part numbers and locations

If you're doing these, I'd suggest having an ample supply. More than you need, just in case.

SeanR

Also recommend getting a bottle of Nylog

clicky here

Depending on if you are using 134a or r-12.