Power Steering Pump - Longitudinal Slop in Shaft

[JimVillers]

We are restoring a 1969 280SL engine and after installing the power steering pump, I noticed a 1/16 inch in-out movement of the pump shaft.  I found a discussion of this topic in 2011 where 1/2 inch movement was "too much". 

The pump was working and not leaking when we pulled the engine but I have not seen lateral play like this before. 

Should I take the pump off and disassemble it and rebuild it with new seals?  Would that fix the lateral "slop".  I just do not know what is inside that would allow the movement and still allow the pump to work and not leak.

Any insight or recommendations would be appreciated.

[Benz Dr.]

A little bit of end play is something I have seen before so it may be kind of normal. Ideally, you would want it tighter but some have end play. May not be an issue.

[mbzse]

.../...rebuild it with new seals?  Would that fix the lateral "slop".  I just do not know what is inside that would allow the movement.../...

Jim, The pump shaft (spindle) is governed by a ring that is divided and fits around the groove (slot) in the pump shaft when one assembles the pump. Parts (10) in instruction sheet below "shell halves".
See photo attached for axle kit part No. Press or tap your pump shaft out, in order to remove it. If you then see that the groove in the shaft is quite worn and too wide, you probably need such a shaft kit. Max axial play allowed is 1mm (per M-B spec).

[JimVillers]

Thanks for the responses.  I am looking for another pump with less end run out.  My understanding is that this is not "terminal" but good to be repaired or replaced.

[hkollan]

Jim, The pump shaft (spindle) is governed by a ring that is divided and fits around the groove (slot) in the pump shaft when one assembles the pump. Parts (10) in instruction sheet below "shell halves".
See photo attached for axle kit part No. If, when you press your pump shaft out, you find that the groove in the shaft is ruined, you probably need such a shaft kit. Max axial play is 1mm (per M-B spec).

I used one of those repair kits to rebuild a spare pump last year.
As I recall it the shaft came out pretty easily knocking it out from the rear, which is the only way to get it out. Shaft came out undamaged although it showed some slight wear. Not sure why the groove in the shaft would be ruined by carefully punching out the shaft in this way.

Hans K

[ja17]

Plenty of good used pumps around.  They were used on all the Mercedes sedans of the era. Later pumps had the tapered shaft, in front. Your 280SL engine has the tapered shaft.  The early versions are not quite correct, they have a straight shaft in front.

[mbzse]

.../...why the groove in the shaft would be ruined by carefully punching out the shaft.../...

He he, I was a bit unclear in my writing there...  altered my text. Tapping spindle (shaft) out does not damage things

[JimVillers]

A friend has a couple of spare pumps; of course they have different numbers.  One is a Vickers 4 (number in the upper right of the tag).  The two others are #8 and #9.  All have the same tapered shafts as my current pump.

Does anyone know what the differences of the different models.