W126 SLS pump / PS pump integration
 

Had a little thought. Thinking it would be possible to run the SLS off the PS pump. This would nothing new. My Mark V ran the brake boost off of the PS pump.

Questions would be operating pressures of each system. And fluid compatibility. Otherwise I would think it would be a matter of installed a t fitting or two and a little bit of work.

The SLS operates at a much higher pressure and much lower volume than the P/S.

I do know that later models in the 124 line and possibly 201 line would run the SLS system off the PS pump.

I don't know which models or if you could simply swap the pump on to an older car...

http://i.imgur.com/dJXJGl.jpg

The 560 SLS system is very simple, just fix it and motor on. The high side hose is only about $80. Leaking pump needs a reseal, big deal.

My pump is warped or something. Resealed twice now, leaks again.

Are you sure its leaking at the pump?

It could be pump-to-block, pump itself, or one of the lines coming off the pump...

Ya, at the two halves. A pressure cleaning and dye run proved that. Well, time to take it apart. Going to a machine shop for a CNC reading.

The 6 cylinder W126s had the W124 style tandem pump.

There are two ways to do hyro boost power brakes. I'll call them the Ford way and the Audi way. The Ford way has the brake booster work like a power steering rack... when there is no assist called for the booster lets all the pressure return to the pump, just like the steering rack, so when there is no assist needed the pump doesn't work that hard. On an Audi the booster only lets fluid back when you release the pedal. There is an accumulator with a pressure relief valve that goes back to the pump. The pump charges the accumulator... the result is you get about 20 pedal presses with assistance after the engine is shut off. On the Ford when the engine stops the assist goes with it.

If you wanted to convert to the W124 style tandem power steering pump I'd think it could work ok. But I'd think it would be easier to get another pump from a 560, considering they all have one.

-J

This. Simply find another replacement pump. I nabbed one from the parts yard for $10... sure it was a leaker but there are reseal kits around for it.

If these cars where around here. I would have. I will have to look at some Chicago yards the next time I am that way.

As for brake boost assist, the Ford version gave at least 3 pumps with engine off for a long time after. That was even mentioned in my manual. Pretty neat system really.

Alternatively you could post up in the parts forum looking to buy one. I'm sure someone on here would be willing to part with one.

Might not be $10 but I think I got one from someone on here for $50, unit worked, no leaks.