hey guys

Been a while since my last post, I have been doing courier work with the mercedes 84 300 sd.

Lotta miles 285,250 and no oil use


anyhow does the lift pump gradually go bad or all at once?

Because my pump does not pulse the return hose like my 300d did and i seem to be down on power despite injector nozzles, filters, tank screen, air filter and valve adjust.

when i did a diesel purge i noticed the return was not flowing much volume as my 300d. like half the volume.

What about the bolt check valve assembly on the return/back of the injection pump?
Do they get sticky or other unforseen problems?

Is there a screen on the lift pump?

Steve

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85 300d in progress

Sometimes stuff that passes through the screen on the plastic (primary filter) can gum up the valves in the lift pump. If the primer pump leaks air (the one that you have to unscrew before you prime with it, it has a seal at the bottom) air can into the system.
The valve springs in the pump can break (they are thin and sometimes rust through) as can the big spring that returns the pumps piston (metal fatigue); sometime the rod inside of the pump that pushes the piston breaks (almost never).
I believe that you have 2 vehicles that have the same lift pump on them you might want to swap them and see if it makes a difference.
You also could call the local fuel injection shop and ask what the price and availability is for the kit to rebuild the lift pump is. On mine there is a number plate between the hand primer, inlet and the outlet (see the pic). Give them that number when you ask about the kit.
The spring inside of pressure valve on the side of the fuel injection pump can sometimes break but almost never.

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84 300D, 82 Volvo 244Gl Diesel

Hmmm ---I might rebuild it!!

Thanks

Steve

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85 300d in progress

OM617.951 and OM617.952 Lift pump Repair kit W126.120 300SD W123.133 300D
OM617.951 and .952 Lift pump Repair kit W126.120 300SD W123.133 300D







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