Today when my wife backed out I could hear a loud belt squeal. I opened the hood and noticed when she turned the steering wheel all the way to the left the pump ,pulley would stop causing the belt to squeal. Is my pump going out. does it need to be replaced,or would a good flush fix it. It's a 85 300sd. Any suggestions what might be causing this. Thanks RAY M

Is your belt tension correct?

A flush fixed mine, but it was making more like a low, moaning noise.

__________________
1985 500SL Euro w/ AMG bits 130k
1984 300SD Turbodiesel 192k
1980 240D Stick China 188k
2001 CLK55 AMG 101k
2007 S600 Biturbo 149k Overheated Project, IT'S ALIVE!!!

when you turn the wheel all the way to one side or the other, it puts maximum strain on the pump. if your belt is old, worn, or loose, it will slip. totally normal.
flushing the pump, while always a good idea will not stop this from occuring, actually it would most likely cause the pump to work even better, making the belt slip even sooner.

__________________
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!

the pulley on the pump stops momentarily and the belt continues. If the belt was loose the pulley wouldn't stop.

Yeah, still sounds like a loose belt, re-read the posts above.

__________________
-Randy Wakefield

1969 220D 4 speed (parts car)
1976 280C
1976 280S
1981 240D 4 speed (parts car)
1982 300D
1983 300TD (Ivory)
1983 300TD (gold)
1985 300TD (gray)
1987 190D 2.5
1970 280SEL (sold)
1977 240D 4 speed (sold)
1974 280 (rusted to death)
---
1927 Chevy 4 door sedan
1938 Chevy 2 door sedan
1950 Willys Jeepster
1955 Studebaker President 4 door
1977 Ford F250
1979 Glastron 17'
1948 John Deere A
1960 John Deere 2010
1979 Satoh S650G
--
2000 Bichon (Doby)

That means the belt is worn or loose as its sliding over the pump pulley because it has a better grip on the (larger) crank pulley. The pump is putting out max resistance in the full lock settings, causing the pump pulley to stop due to insufficient belt grip.

Replace the belt and tension it properly.

Also, its probably a good time to replace the filter and flush out the power steering fluid too.

All cheap and easy tasks.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Great,Thanks I do appreciate ya'lls persistance. I'l do it . Ray