Question
I've got an 87 528e (about 300,000 mi (odometer broke at 167m), runs fine, uses no oil. I have the Bosch/Behr compressor. It did fine on r12 until last year or so when a shop said it was low on r12 and would be cheaper to convert. We did, my wife drove car while I was gone with military. Conversion lasted maybe a few weeks at best, then blew basically outside air. When I got home a few months later I saw that rec/dryer was not replaced so I questioned the quality of the conversion and have not returned to that shop. Since then, I've read that the particular compressor on my year 528e HAD TO BE replaced before converting AND that system had to be flushed (I've also seen differing ideas/opinions on that). Before the freon went low, we were told 4 or 5 years back that the expansion valve needed to be replaced. I've decided not to take it back didn't take it back to that shop after I noticed the rec/dryer not replaced since I thought that was a "must." The car runs great, cranks fine, uses no oil, has no leaks, no rust--all works except the AC--I just want that to work as best as I can get it to and I don't want to go back to a shop that didn't change out the rec/dryer.
I've quit working and now hopefully have the time to try fixing this myself. I'm retired as of May and I want to fix it properly myself. IA friend loaned me his vacuum pump and guages and I've been working with them on my daughter's old cavalier. It had a bad hose which I repaired and, after a couple of tries, I was able to evacuate it and get it down to 43 degrees at the vents and it stayed there in stand-still traffic for over 2 hrs on a 90+ degree-day.
I figured I try to do the BMW. However, when I tried to evacuate the 528 I couldn't get the guage to come down to 29-30 on the low side. So, I guess I have a leak. I don't know how to find the leak if I cannot get any freon in to see if it blows out. Having read that I need to start clean with a new R/D and in my case, a new expansion valve, I've got those. I've ordered and received a new receiver drier (from azautohaus) and an expansion valve(from Rock Auto). I thought they'd come with o-rings but neither did. I understand I can get these from Autozone for $4 or $5. Now, I'm wondering where to go from here.I think I'm capable, but after buying a 134a rec/dryer, a new expansion valve, I'm told the old compressor won't work w/r134.
First, Why cannot I not keep old compressor?
Second, is it possible if I completely drain the compressor, use whatever oil YOU recommend, changeout rec/dryer and expansion valve, that I could get it to work with 134? All the BMW info I've seen says you have to replace compressor--I'd really rather be meticulous and use what I have and stay as original as possible. It worked fine, just got less cool, until the changeover.
Third, I read that the expansion valve was brazed in--what is entailed in unbrazing and rebrazing? I would think just a little solder over the connections.
Fourth, Do I have to flush it? If so, what's the safe procedure?
Fifth, Do I install the new pieces without finding the leak, if that's what it is?
Sixth, If I must replace, is there an alternative setup using a more easy-to-come-by, less expensive, reliable compressor such as GM, and what would I need to have to do so?
Sorry for the wordiness but I really love this car and do want to keep it forever--I just want to fix it right myself the second time around.
Thanks in advance for your assistance,
Paul
AnswerI think since you are having problems holding a vacuum you first have to address the the leak.There is a tool to check for freon leaks,you will have to add some to find your leak.I have converted many systems and have not had to change a thing.I have heard about the r/d being changed as this is where all the contaminants(moisture) is kept.The orings are made of a stronger type of rubber that is compatible with R134.If the r/d is contaminated you should flush your system before you add a new one.If your compressor turns I would use it.Good luck!
