Hello

I have read other threads and tried a few things, now I believe my lift pump or fuel pump is faulty and I would like to know how to get the darn thing apart.

I have a 1982 300dt and it lost power and quit running while I was driving at about 35 mph. I changed both filters, checked the oil (which was low) and scratched my head a lot. After I got it towed home, I read a bunch of posts here and tried cranking the engine with the fuel lines cracked at the injectors. I got nothing, so then I tried cranking the engine with rubber line off the spin-on filter and in a soda bottle. I got nothing. Then I took off the first small filter and blasted air back through that line to my fuel tank. Fuel went everywhere. My tank must have looked like old faithful. After I wiped it down and put it back together I still got no fuel in the soda bottle.

I read that usually the o ring in the lift pump will go bad causing the pump not to work. I would be very happy to replace just the o-ring rather than the $130.00 pump. I took the pump off the car then I took the bolt off the bottom of the intake side of the pump and it just looked like a check valve so the pump doesn't send fuel back to the tank. I can not seem to get the delivery side or the big flat bolt out of the back of the pump. Could you please tell me which one I should work on; the back of the pump or the delivery side? Also are there any tricks for getting that big bolt off? As always pictures would be helpful.

Thank you,
Matt

The primer handle is prone to leakage which can let air into the fuel stream.

They are available for $20 on eBay.

Isn't there a newer style primer pump?

Sixto
87 300D

Yes, the new pump replaces all older pumps, is said to be much improved.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Thank you for the idea, but I had already replaced the original primer pump earlier this year with the newer style Bosh. When taking out the lift pump I took the new primer pump off and it seemed snug, so I wouldn't think there would be an air leak. Also I did not see air bubbles in the transparent lines after my numerous cranking attempts.

Could some one please describe how to take the lift pump apart?
Thanks,
Matt

Not allot of folks will know how to take that pump apart because it seldom fails. Too bad you cant just swap it out with a used one too make sure thats the problem.

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1985 Euro 240D 5 spd 140K
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1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

Somebody else just opened their lift pump and cleaned it out. It turned out that the pump was gummed up and did not need any new parts. Do a search on "lift pump" to find it.

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Hi,

Thanks for the ideas. I think I have read that post, but it didn't specifically tell me how to take the lift pump apart. I would really like some pictures. I went back and did a search for lift pump again and went through just 4 pages of results reading 22 threads that sounded good, but I didn't find anything.

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1982 300DT
1989 GMC Vandura 6.2 Diesel
1990 Ford F-250 International Diesel

how much fuel is in your tank? serious question. have you checked your fuel tank screen. i was having the same problems as you are.

__________________
alimony

Don't know how to disassemble the pump, but did you get free flowing fuel out of the line from the tank to the primary filter after you blew air back into the tank?

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'83 300D Turrrbo 295K miles

if your crankcase is filling with diesel then your lift pump is at fault. if its just hard to start then most likely its air leaks.

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As long as they would add one additional commandment for you to keep thy religion to thyself.
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1981 240d (engine donor 1983 240d) recently rebuilt engine hurray! - No more.. fought a tree and the tree won.

pearl black 1983 240d 4speed (Converted!@$$%) atleast the tranny was rebuilt.

Well I never figured out how to take my lift pump apart. For the folks who asked, my fuel tank was about half full when it originally stalled, but after it got towed home I made sure it was all the way full (and it took about 10 gallons to fill it). I haven't noticed anything leaking in to the engine oil and I do get fuel flow out of the supply line from my fuel tank, so I am pretty sure it is the lift pump that is not working. I went to town today and got a lift pump off a car at the junk yard. I didn't think they would have one. Hopefully this week-end I will get to put it in.

Matt

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1982 300DT
1989 GMC Vandura 6.2 Diesel
1990 Ford F-250 International Diesel

need to check fuel tank screen before all the labour intensive stuff of lift pump dismantling.

__________________
alimony