6.3

I have to replace the upper oil cooler line. It disappears below the power steering pump. I think I’ll need to remove the pump from the back of the air compressor to gain access to that end of the oil line. Is there anything special about removing the PS pump from the compressor? I see 2 cap screws holding the pump to the compressor. That looks easy enough, and the rear support bracket will not be an issue. Just not sure about the interface between the PS pump and compressor. TIA, Matt

There is nothing special about it, just tear it apart. Get ready for complete PS pump reseal as removing the the two long screws holding it to compressor are also helping to hold the pump pieces together. My pump started leaking during same operation as the internal o-rings where almost rock solid.

600 #796 (1967 US version)

300SEL 6.3 #1285 (1969 EURO version)

300SEL 6.3 #5346 (1971 US version project)

Flip note that there is a very special "O-ring" between the shafts of the power steering pump and the air pump. This has recessed grooves o both sides of the ring. S standard ring will fail in short order. Good luck finding the proper ring.

Thanks all for the replies. Guess I’ll snake my remote camera down into that area and see what more I can learn. I’ve some “short” wrenches fabricated when I did the air suspension rebuild. Perhaps I can get one on the hose fitting. Regards, Matt

Hello.

Do you mean this one?

Well I used A0005860746 NOS kit + FEBI PS pump seal kit + some standard Viton O-Rings about a year ago and I hope it will stay dry for at least another couple of years. The original ring was dead and leaking so anything was better.

I have to repat the same job on my 600, many parts are NLA so getting seals will be big fun.

600 #796 (1967 US version)

300SEL 6.3 #1285 (1969 EURO version)

300SEL 6.3 #5346 (1971 US version project)

As Jack said -there is a double lip seal that keeps the engine oil from entering the steering pump and visa-versa. That seal is not available and MB does not list the correct seal -their system incorrectly sells you the single lip seal common for non-6.3 applications. Years ago I found a company in France that supplied the correct seal (Jack has one of those in his car). I want to say the supplier was '123' ?

Hello.

I just dismantled untouched original compressor and PS pump from my W100 and there is absolutely nothing special. There was 17x28x7 single lip seal on compressor shaft next to pulley. There was normal single lip 22x35x7 seal on the PS shaft. There was 46x3 O-Ring to seal PS pump body to compressor body. I drove this car for 1000+ km and never had any PS fluid contamination with engine oil even with so old seals. Sure there was leak from the PS pump body and from PS pump to compressor connection as all O-Rings were rock hard.

This should be same for 6.3 as the main difference from W109 is compressor bearing that is roller type on W100 and ball on W109. To reseal it I will use 25x2 and 10x2 O-Ring for the reservoir and Febi 08711 to supply O-Rings for PS body halves.

Here is picture of the seal I removed

Regards

Filip

600 #796 (1967 US version)

300SEL 6.3 #1285 (1969 EURO version)

300SEL 6.3 #5346 (1971 US version project)