I completely agree with checking the belt routing. OP states in the first post that the belt is brand spanking new, so there is a strong possibility of it being routed incorrectly or being the wrong size, if the problem presented immediately after the belt change.

Routed incorrectly, the belt WILL appear to have proper tension on it, but it WILL slip. BTDT, spent hours cleaning my "brand spanking new" belt and cleaning pulleys and scratching my head, until I finally dug out the diagram.

However, if the problem was there before, then looking at the ball joints, power steering fluid viscosity, and any other issues like worn struts is a good start.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

problem was there before the belt change the belt was changed due to the old belt snapping from pump stopping

I was in the driveway trying to see what is happening and it snapped in front of me so I changed the belt thinking it was a bad belt

I checked the routing 100 times I am already past all that.

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2003 GX470
1998 E300 3.0TD
2002 Dodge 2500 4x4 cummins
1998 Dodge 3500 5 speed Cummins

As per post four by Air and Road , relief valve issue

actually, routed incorrectly, the belt will be tight on the ps, and the alt, but slip on the water pump... or the crank pulley...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Ok quick check on the pump.It will mean removal of the belt once more .Put you drill to work .You need to find a way of turning the pully in the right direction with the help of your drill A piece of rubber belt or inner tube over the pully and your drill running on a slow speed . Then if it keeps stoping you will know its the pas pump.

I like where this is going, and that should determine if the pump is bad is it stalls under load

will try that, thanks.

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2003 GX470
1998 E300 3.0TD
2002 Dodge 2500 4x4 cummins
1998 Dodge 3500 5 speed Cummins

Bilk i dont know of any other way to check it out .This is what i would try first.I did not ask, if any other pullys were stopping as well at the same time. It looks like a pump problem . Might have a problem with valve inside.

What's a relief valve do in the ps pump?

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What Would Rudolph Do?
1975 300D, 1975 240D, 1985 300SD, 1997 300D, 2005 E320 , 2006 Toyota Prius

Please let us know how you get on with the pump..

no updates I been very busy with work and the car is just sitting however I found a $129 pump at the autozone anyone had luck buying any of them before ?

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2003 GX470
1998 E300 3.0TD
2002 Dodge 2500 4x4 cummins
1998 Dodge 3500 5 speed Cummins

Ok I gave up trying to determine it myself took the car into a local Benz tech shop and they determined the pump is shot


what to do now ? I can't seem to find any where to buy a pump is there a rebuild kit available ? this is traction control car with the ASD system which makes it impossible to find a pump unless its a similar car

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2003 GX470
1998 E300 3.0TD
2002 Dodge 2500 4x4 cummins
1998 Dodge 3500 5 speed Cummins

been there, done that on my 95 e300d. paid 1200 for a new pump that has all the connections.
http://www.peachparts.com/shopforum/diesel-discussion/364172-w124-e300d-power-steering-pump-failure-dilemma.html

Now I'm fed up with the car, has new p/s pump, starter, alternator, belt tensioners, and a ton of other junk that broke on me usually stranding me somewhere, most parts have less than 5k on them.

Went back to w123s.

Want to buy a car full of spare parts?

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1982 300D (w123, "Grey Car")
1982 300D (w123, "Blue Car")
2001 Ford F150 "Clifford" (The Big Red Truck)
1997 Dodge Ram 2500 12V Cummins
1996 Dodge Ram 2500 12V Cummins
Previous Vehicles:
1995 E300D, 1980 300SD, 1992 Buick Century, 2005 Saturn Ion

Its the safety gate for the pump output, once the pump reaches the maximum load capacity (set by relief valve design) - the valve short circuits the oil/fluid back to the inlet to limit pressure.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

MB does sell a rebuild kit, but I get the impression it is more of a re-seal kit. Not terribly expensive, like $40 or so.

Any tandem pump from a 124 will work, if you can get a pump from a 124 wagon (diesel or gas) that will do the trick. The specs for pressure or flow are slightly different, I think they may be a little higher flow, but that is what I did to replace the pump in my '95 E300 with ASD.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Sounds like I still got hope in saving the old girl after all