Overview. The Delco R4 A/C compressor in the 300SD has a well-earned reputation for noise, leaks and short life. This kit allows you to upgrade to a modern and reliable Sanden SD7H15 compressor. We were the first and only company to offer a Sanden kit for the W126 300SD when we launched it in 2010.
Fitment
- All 1980–85 Mercedes 300SD models (W126) originally equipped with a Delco R4 compressor (R4 photo)
- Uses a Sanden SD7H15 Model 4709 (preferred) or 4272; the two are interchangeable
What’s included
- Mounting brackets and DIN/ISO hardened hardware
- High-pressure hose (compressor to condenser) and low-pressure hose (compressor to secondary firewall) with high and low R-134a charge ports
- Complete HNBR o-ring set for the entire vehicle
- Delco male electrical connector and terminals to connect to stock harness
- New v-belt
- Illustrated PDF instructions
- Optional: Sanden SD7H15 (Model 4709 or 4272)
Installation
No special tools needed. The two original hoses at the compressor are replaced; the liquid line and the TXV-to-firewall suction line are reused, so check them first. Flush the remaining components thoroughly. For best results, also replace the drier, TXV and pressure switch, and add a parallel-flow condenser on R-134a.
Good to know
- Warranty: brackets lifetime; all other parts 1 year
- Lead time: up to 15 days (built to order); please plan ahead
- Instructions: PDF download in your order receipt
- Download: Sanden SD Compressor Service Guide (PDF)
