Mike C.

Has anyone replaced the original hoses with barrier-type hose? If not, are you getting measurable leakage from the old hose? Some AC web sites insist it is a waste of time to charge with R-134 and still use the old R-12 hoses which are 'allowed to leak' a bit. It would seem that new barrier hose could be installed on the original fittings if the crimp collar is carefully cut off. Anyone done this? I'm also hearing that if you did this, the barbs on the fittings are not correct for barrier hose and will dig into the barrier lining on the hose ID, rendering it little better than keeping R-12 hose.

zoltan944

I have never replaced hoses and more people than not will tell you that isn't necessary. The consensus is to replace all new o-rings, but even some doen't bother with that.
New dryer with o-rings there and a full flush and fill works, do as you want.
Our hoses are aluminum and they can be taken and remade, but needs an aluminum welder to swap out to the other hoses, its gonna get pricey. Think of it this way if your 134 'leaks' a little as described it is like $9 a can which will mean you top it off once a year, who cares

Mike C.

Yea I may just try it and see if/how much it leaks.

zoltan944

Ive never had a problem and as far as I know your AC system is NOT designed to leak. You will see in your owners manual about running the system at least once a week to avoid any possibility of leaks.

Mike C.

Well I meant leak with R-134 in R-12 style hoses (which are not barrier hoses from what I've read).

zoltan944

Oh gotcha. Well the time and cost for the hoses is gonna take a long time to overcome 134 cost IF it does leak.
If you want to just do all the o-rings its not that hard you can PM me if you need any tips..

CurtP

I converted last year when I replaced my compressor with a rebuilt one from eBay. I didn't replace any O-rings, flush the system or even replace the receiver/dryer. The only thing I did was evacuate the system for a couple of hours, verify the system could hold a vacuum for 24 hours, then recharged with R134a. Works very well except on 90°F+/90%+ humidity days. It still cools, but just not as well until after it runs for about 20 minutes.

I need to check my charge with the gauges just to be sure everything looks good, even though it's working well. I haven't touched it since fixing it last year.

John_AZ

I just finished my R12 to R134a conversion on my '87 924S.
Here is a good price on a kit that has most everything needed to begin. It has new valve stems and R134a conversion fittings.
http://www.pelicanparts.com/cgi-bin/...FILTER_TOOL=ON

I did replace all my "O" rings. The "O" rings with the most damage were near the expansion valve and the condensor. Replace as many as you can get to.

Rent or Buy a good vacumm pump. Harbor Freight has a 2.5cfm for $90. The cheap vacuum pumps that work off a compressor will not do a good job. Porsche wants a vacuum fot 1 hour. Your compressor may not handle the job.

I did not replace hoses-R134a is $7 a can at WalMart. Use only 70 % of R134a compared to R12. Usually less than 2 cans. Too much and the system does not work.

If you want your compressor to last you should flush/drain the system to get the old oil out. Then add the correct oil and amount. Too much oil will clog the condensor-at the bottom -and reduce cooling.

GL
John_AZ
1988 924S + 1987 924S

Mike C.

Thanks for the advice guys. On the O-ring kit you mention John, it says for 928 but not specifically for 924/944. They seemed to be the correct o-rings though?

John_AZ

The kit had everything I needed for my 924S.

On my compressor line fittings, I did go with a thicker~--x 2.5mm thick "O" ring not included in the kit. The normal thickness may have worked. The one removed was thicker than the PET indicated. On this issue-the PET has many incorrect "O" ring numbers and size problems. The best way is to remove the old "O" ring--Tape it to a piece of paper and mark the location. Compare it to the new "O" rings.

On the early 944s and 924S- it is a 1 hour job to drop the evaporator/fan without removing the dash. The later cars require hours of labor. I mention this because the PET does not list individual "O" rings for the expansion valve. It is a Porsche only 2 piece kit. ~$4.

The new valves, replacement fittings for R134a and the amount of included "O" rings make this kit a buy.

2 valves are not shown-installed and many "O" rings missing were used-I replaced many "O" rings twice when testing and repairing to hold vacuum.

GL
John_AZ

RT930turbo

When I "converted" mine all I did was evacuate the system, change the fittings, and put the new stuff in. It's lasted 5 years and 50,000 miles, no issues. I did have to top it up once about 2 years ago. Other than that, it's ice cold. The above kit does look very nice, however.

V2Rocket

removed ac from my car in 2006 because the r12 had blown out when i pulled the engine.

ran without it until this year.

put new o-rings on all the hoses, installed a new receiver dryer, cleaned out the condenser, and drained the compressor of oil, then vac'd it and then filled with r134. has been nice and cool for almost 2 months

msailer

How do you should flush/drain the system to get the old oil out?
How much oil is needed in the system?

This is my next project on the car.
TIA

V2Rocket

everything you need to know
http://www.944time.com/porsche/2005images/944_ac.pdf

John_AZ

Step 1. remove the compressor--do not flush--catch and drain the oil in a cup. RINSE compressor while turning the pulley with the oil you will refill with. R12 systems take 3.3oz. On the same car, R 134a takes 5-7 oz usually PAG.

Do not flush the expansion valve. BUT---you should flush the evaporator and the expansion valve is usually connected directly.

Here are the rules:
First from Griffiths http://www.griffiths.com/achelp/achelp2.html

And others
http://www.aircondition.com/tech/questions/25/
http://hecatinc.com/flushing_tech_article.htm
http://www.autoacsystems.com/_faqs/3tiplist.html

GL
John_AZ