anybody replaced AC compressorfront seals?

[jwhughes3]

In an 86 300E? Mine was cooling fine through the warm Winter and Spring - then as temps hit 90's a while ago - seemed like best I could do was mid 70's-80 at the vent even on highway. In the cool mornings when it is 70 I can hit vent temps of 65.

Checked for low 134a - not low - took in for AC check - they tell me $1100 for new compressor, drier and exp valve stuck open - I said I'll pick up as is.

Picked it up and have vent temps of 58-62 idling in afternoon and as low as 48 with low fan in shade with outside temp 80. That is normal vent temps to me - so what gives? How did they magically "fix" it without fixing it?

I had UV dye in it and will be checking for front seal leak as described when I have a chance to find my light.

I figure if I have to (for $1100) I can do the exp valve, flush, drier, vac and recharge myself - compressor is fine - can I buy just the front seal and replace it? Special tools or knowledge required?

John in San Antonio

[mbdoc]

Several special tool required to install that seal...I would think a factory "Denso" reman would be a better idea.

[mramay]

Are you sure it's the front seal? The nippondenso on one of my W126s turned out to have the 2 high pressure o-rings in the Top Hat (my term - see picture) blown and my other W126 has a bad o-ring for the refrigerant hoses attachment to the top hat. Once the system is empty of refrigerant (either by leaks or recovery), then this is a DIY repair. I put six (6) o-rings ($3) into my 560SEL five years ago and it cools nicely in Vegas today. Worth a try.

[Randy]

Somewhere on the 'Net, on a Porsche forum site, a gentleman posted an illustrated seal replacement for his NipponDenso compressor, very similar to our compressor. As I recall, it was not bad to do. If I run across the site I will post.
One link: http://www.pelicanparts.com/techarticles/911_Nippondenso_rebuild/911_Nippondenso_rebuild.htm

[samiam44]

I would'nt consider a rebuilt now that NEW denso compressors are avaliable again. If you need a rebuild kit- I have one. I pulled my low-mileage one off the car and one cylinder had a score in the cylinder wall, so I replaced it.
80F isn't a good test of the system. No real heat load. You have to put gauges on the car and watch closely. Temp probe is helpful. Eek- those early cars are 15cc compressors instead of 17 ccs. I consider my white 86' marginal with a perfect R12 system.

M

[jwhughes3]

I guess a new compressor is the way to go if I'm gonna do all that work, but I'm still not convinced this front seal "leak" isn't just the normal leakage that is accounted for and they just want to replace the compressor.

Seems like every AC shop wants to replace the compressor for everytime the cars go in with a problem.

If I do get a new compressor - I am likely going back to R-12 though!

John in San Antonio

[samiam44]

Good deal- R-12 is the way to go... Just flush the system to get rid of the old oil. New o-rings, dryer and expansion valve. Have any leaky hose rebuilt.

Generally, the ceramic seals don't loose much freon. If you have leakage at the front seal- the seal is cracked.
I read the new Denso press-release last week. I think it is a year old.
M

[CWW]

Originally Posted by samiam44

Good deal- R-12 is the way to go... Just flush the system to get rid of the old oil. New o-rings, dryer and expansion valve. Have any leaky hose rebuilt.

Generally, the ceramic seals don't loose much freon. If you have leakage at the front seal- the seal is cracked.
I read the new Denso press-release last week. I think it is a year old.
M

+1

R12 is soooooo much better than 134a. No comparison at all. Both of my W126's had R134a retrofits, and both were mediocre in our Florida heat, until I switched to Freeze12 in the first one and R12 in the second one. R12 = 20f (or more) colder vent temps than 134a. My 85 380se with properly working R12 system could make the cabin about 60 degrees inside on a 90+ degree day. It would hurt your hand if you put it front of the vents. With 134, I was lucky if it was 75 inside on a hot day.

After those experiences, I wouldn't even consider having 134 in an older car again. R12 is plentiful, it's still manufactured in China and parts of Europe and imported legally. This "we're running out of it" thing is a TOTAL myth. All you need in my state is a sales-tax license and then you can buy it wholesale by the 5-gallon cylinder "for resale purposes" (read between the lines on that one).

[Matt L]

How is it imported legally? The EPA's website says otherwise.

But we're still not running out. The stuff is being imported (legally or otherwise) and plenty exists. Sure, it's more expensive than 134a right now, but once 134a is banned, that won't last long.

People in northern climates can get by with 134a in the old systems. Floridians really shouldn't try it.

One more thing. It's easier to get the 609 license than a sales-tax letter. And then you aren't evading taxes.