I have looked through the many of the A/C threads and post but haven't quite found the answer to this one - my appologies if it has

I have a 1983 300SD with a bad R4 compressor . I check it with UV dye and it seems to be leaking in the back where the back plate piece joins the housing . The system works when there is enough refrigerant in the system
Is this a big o-ring seal which is easily replaceable . A friend has told me that the R4 is not s very good compressor . I don't mind replacing the compressor with another R4 if I can find quality rebuilt for around $ 100 . What GM vehicle applications fit - I saw something about 9 o'clock for my caqr but saw them with other coil clock positions ( 2, 12 ) for other applications) . However, a friend has told me that the R4 compressors are not good and it would be better to go back with something else if posssible. What other will fit most easily ( what mods are required ).

Also, where is the expansion valve for this 1983 300SD system located ? Is it in the same location and R&R the same as DieselGiant's description for the 300D ?

Thanks

don't repeat don't buy a rebuilt r4 go buy a new one.nothing else will fit without a lot of mods.caution. new r4's come with no oil in them.you must oil it up on bench by turning clutch and adding oil [a 3 handed job so get help].the expansion valve in sd[126 body]is under instrument panel above accelerator pedal.you will need large 27mm wrench and crows foot wrench will help.good luck. david poole european performance dallas tx.

I have looked around on the web for one a new R4. An R4 with the 9 o'clock coil position for this car is mentioned . Can you use another clock postion model Delphi - GM - Harrison R4 and extend the coil connection wires to fit or is there something more to this ? - Thanks

Some models use SAE mounting bolts instead of metric. Some have pulleys that are not MB compatible.

Assuming that I found one that is metric and has the same pulley , what if I used one that has a coil terminal in a different clock position and just extended the wire from the body making sure that there was no mechanical interference ?

I installed a rebuilt R-4 from Advance Auto, they had it in stock, one year warantee. It uses the metric hardware, and the clutch connection is at 4 o'clock like the original. Just my 2 cents, YMMV, Chuck.

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2000 C230 Kompressor "Frosty"

2007 PT Cruiser
2001 VW TDI Beetle
1999 Landrover Discovery II
1971 Corvette

Gone: 97 Cabrio, 83 240D, 93 VW Eurovan, 95 Volvo 850, 93 Chevy Astro Van, 77 VW Bus, 99 VW Jetta, 74 VW Bus

N41EF -How muck did you pay for it ? How long have you been using it ? Are you using R12, R134 or Freeze12 - Thanks

There are two "main" style R4 compressors, the regular and the "lightweight", and then several variations (and manufacturers) within those two. There are at least two main clutch systems that we see, and many clock positions on these. There are many pulley designs as well, because the R4 was a workhorse, in its day, for many, many different vehicles. The clock position is relatively easy to reset by removing and reinstalling(rotating) the clutch relative to the body and yoke. What needs to be watched carefully is the yoke position, so that the internal oil channels are pointed DOWN. This is usually marked by an "X" on the yoke, which is UP.

See post #10 inthis thread and the whole discussion is worth perusing:
GM & Aftermarket A/C Compressors vs MB compressors

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

If it is leaking from the back side where the manifold connects to the compressor, try replacing the two seals., they cost about $3. for both. Take the old ones out and take to auto parts store to see if they can match them, or try Carlisle AC in San Antonio, they have them in stock. 800-243-3433, ask for John Coppins.
Try looking in posts under Jimmy L , he has pictures and some good details on this subject., it is a very easy job, but you will need to evacuate and re charge your system. Crushing AC development.....

Good Luck

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Gary
85 300D Ivory, 202,000
Beatus exsisto Jesu, verus et Deus verus Vir

jbj007- How does one identify the the "light" models vs standard ( on what GM models . Also, if the yoke is in the 180 deg off position can it be rotated ( if so what is involved in getting it apart and back together).

GaryF -The problem with the present compressor is a leaking rear casing/shell seal not the manifold seals .

I would really like to go back with something else like the A6, ND, Sanden etc but it looks like a some creative making of brackets and adding an idler pulley . Has anyone here done this ?


Thanks

Advance had the R-4 for my 240d in stock, was $108.00 with a $10 core. www.advanceautoparts.com will tell you in they stock it near you. I'm also using freeze-12

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2000 C230 Kompressor "Frosty"

2007 PT Cruiser
2001 VW TDI Beetle
1999 Landrover Discovery II
1971 Corvette

Gone: 97 Cabrio, 83 240D, 93 VW Eurovan, 95 Volvo 850, 93 Chevy Astro Van, 77 VW Bus, 99 VW Jetta, 74 VW Bus