Haven't done that yet.

Have to procure some clear hose.

5/16? Where to buy? Any special material?

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1983 300CD Turbodiesel

1/4" id clear pvc tubing Home depot. Soak in boiling water, stretch over nipples. No clamps needed. Long nose pliers helps to stretch.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

And what am I looking for?

Air in the return line? What would be implicated if there are air bubbles?

Sorry if it's a dumb question.

The om617 fuel circuit confounds me.

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1983 300CD Turbodiesel

Uh, you said yesterday that this problem started when you swapped in a different lift pump. Why don't you put the original lift pump back in?

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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

I can't do that till the weekend
So until then I'm looking for potential fixes/diagnosis...

and learning new stuff.

Also I'm out of crush washers for the supply fitting and primer pump, and gasket.

Order is arriving Thursday.

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1983 300CD Turbodiesel

You are looking for air, best litmus test. When you have the clear line installed, post a video of the clear line with engine running.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

To elaborate on the clear line on the return hose issue:

You are using the clear hose as a "sight glass". If the fuel system is solid and working properly you'll have a full column of fuel returning to the tank. If you have air ingress you'll have a foam or stream of bubbles running through the clear line back to the tank. It's a quick, cheap, and easy way to determine if you have air ingress into your fuel system.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Copper crush washers can be recycled if you have a propane torch (or any method of heating them up so they glow). Copper will work-harden but can be softened up again by heating until it glows and then letting it cool in the air.

The gasket may or may not survive re-use, depending on the quality of the gasket and how long it has been in place.

__________________
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

took the new lift pump off and compared it to the old one.


to my surprise.


the new one is missing the roller. everything else is there, but the roller that riders on the IP is missing.


I don't think this part is available separately so i'll probably have to buy a beat up lift pump just to get that piece.


thanks for all the responses.


I even ordered a bottle of startron, thinking it may have been reduced flow from the tank strainer.


may as well use it as preventative anyway.

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1983 300CD Turbodiesel

Awesome, glad you figured this out.

__________________
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

Where?

Spare/ missing parts are best on the shelf, or installed properly. Please tell me you are not hiding a roller and it's fixings inside the IP. I doubt finding them while driving will improve your driving experience!
A unique situation, if not a little absurd....

Just about complete....


Cheers,

snapped_bolt

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'81 240D For now, a good place to borrow new parts
'80 300TD Probably will be put back into service!
'79 240D BACK IN SERVICE SINCE 09/16; limited use, oil leak. Guide pin r/sealed/replaced. Still a leak. Front crank seal....

My thought is that it was missing when I bought the pump.

It was a mistake not to inspect it before install.

But given that performance struggled immediately after install, I feel comfident that it's not in the ip somewhere.

Or is it????

Seems like a unique situation that I doubt would be documented anywhere. But I'll do some reading

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1983 300CD Turbodiesel

Isn't the lift pump mounted on the block, not the IP?

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

No, it's mounted on the ip.

On the 617 turbo. Can't speak for any other motors.

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1983 300CD Turbodiesel

Shame on a new old stock lift pump. You may want to take off the large nut and inspect the bore and piston now. There was a chance the piston was driven in such a manner it was jamming in the bore. I would want to inspect the bore and piston.


That piston has to remain movable all the time to provide the fuel. Actually it is the pressure regulator as well. It almost had to be hanging up I suspect. .