w140 Power Steering Replacement
 

I took my '92 300SD in to get a new alternator put in because I did not want to crawl around in the cold and I suspect that the mechanic broke the power steering mount while he was at it. I can't prove it, so I'm on the hook to replace the pump. I've looked around for a used one and the ones for w140s w/o load leveling are scarce. I've looked at the blowups of the two different pumps (with and w/o load leveling) and it looks like the ones for the load leveler models have the same P/S pump body with an additional pump or something slapped on front and attach to the motor the same way.

I wonder if I can use a pump which has the load leveling attachment and just plug the holes for the load leveling connectors. The high pressure side is a banjo connector and the low pressure is just a clamp.

Any ideas as to whether that will work or not?

http://cgi.ebay.com/ebaymotors/POWER-STEERING-PUMP-Mercedes-S320-1992-92-99_W0QQcmdZViewItemQQcategoryZ33588QQihZ027QQitemZ400040156589QQrdZ1QQsspagenameZWDVW

http://cgi.ebay.com/ebaymotors/Power-Steering-Pump-94-95-96-97-98-99-Mercedes-SClass_W0QQcmdZViewItemQQcategoryZ33588QQihZ001QQitemZ110371311508QQrdZ1QQsspagenameZWDVW

http://cgi.ebay.com/ebaymotors/POWER-STEERING-PUMP-Mercedes-S320-1992-92-99_W0QQcmdZViewItemQQcategoryZ33588QQihZ027QQitemZ400043018658QQrdZ1QQsspagenameZWDVW

Doubt if the mechanic caused the problem by working on the alternator.

Perhaps not, but the arm on the front of the pump connecting it to the head is broken and now makes a thumping noise I have not heard before and I noticed it for the first time ere I drove off from the garage. I have to agree that the alternator is nowhere near the pump. Is there some experience with these things just breaking—seems like that mount point is pretty sturdy. In addition, the thing is now kind of loose as the lower screw is not enough to hold it fast and, having filled a couple of times before I found a leak in the hoses, I think I would have noticed it flopping about. However, not much to be done for it except to replace it. Sigh…

Compatibility of P/S Pumps
 

So I looked at the three of these and the first one looks best. It looks just like the one I have, but the seller says its not compatible. I looked in epc for the relevant pumps for the models listed on the seller page and the part numbers are different. I suspect that they are constantly making engineering changes to these things and that they might be backward compatible, but I don't know. I can probably find out from the agency if they are compatible, but, then again, they may not know. What can be the difference? Pressure?

SD... My bad. 603 engine?? a pump from a 350 sdl or 300 sdl might work. Check the part numbers. Could be a rare one, and you might have to try to fix the one you have....
The pump for the gasser might fit....

Yep, it's a 603 engine. I wonder what the differences can be. If the hoses fit and it fits physically on the bracket, it seems a 140 is a 140 is a 140. They should all require about the same power to turn the wheels. Seems its just a box that produces pressure for the steering box. If it fits the mounting and hoses, it seems it ought to work if there is not a significant pressure difference between them. Am I missing something?:confused:

For what it is worth, I wound up with a P/S pump for an S350 with load leveling. I did not ask for one, but that's what I got from the salvage yard. I plugged up the supply line for the load leveling with an appropriate bolt and plugged the return with a 2" piece of high pressure hose plugged with an appropriate (3/8") piece of rod. The pump fits fine and seems to run just fine. From what I can see in the parts blowups, there is only one impeller and the pressure specs on the ID label are both 125 bar, so I suspect that it's fixed up so one chamber does not affect the other adversely, but there appears to be no reason not to use the Load leveling pump on a non load leveling 140. :)

There are several cases in the archives of 603.97 power steering pump cases cracking. Maybe you all have the same mechanic :)

A 91 350SD/L pump is like $200 at ********.com

Sixto
87 300D

After I got it off, I think you may be right, i.e., it just cracked. Funny, though, both front attachment points were broken.