Primer Pump

[cornemuse]

I have an '83 300CD T. I've never run it out of fuel, (yet) mainly 'cause ever since I got it, the primer pump has not worked. (fear of running out = anal issue!) The original was old (?) style which leaked as soon as it was unscrewed. I replaced it with a spring loaded (the black handled one). It still never worked "at all". I have the MB 'CD' shop manual and have everything installed properly, but no cigar.

Any ideas or suggestions??

(I have to print pages from the CD in order to see & understand the pics, for $100 bucks+ its a poor setup, but I could'nt find actual books, but printed images are tolerable)

-corne-

[qwerty]

The hand pump is nothing more than a spring-loaded syringe. It uses the same valves as the main fuel pump. Unless the pump inlet is obstructed, it would be pretty hard for it to not work "at all."

[whunter]

Originally Posted by cornemuse

I have an '83 300CD T. I've never run it out of fuel, (yet) mainly 'cause ever since I got it, the primer pump has not worked. (fear of running out = anal issue!) The original was old (?) style which leaked as soon as it was unscrewed. I replaced it with a spring loaded (the black handled one). It still never worked "at all". I have the MB 'CD' shop manual and have everything installed properly, but no cigar.

Any ideas or suggestions??

(I have to print pages from the CD in order to see & understand the pics, for $100 bucks+ its a poor setup, but I could'nt find actual books, but printed images are tolerable)

-corne-

The lift pump valves are shot = cheap fix.

The kit you need is
MB# 0000900210

The pictures in this thread will help you understand
OM617.912 Lift pump Repair kit W123.190 300TD & W123.130 300D


.

[Diesel911]

Originally Posted by cornemuse

I have an '83 300CD T. I've never run it out of fuel, (yet) mainly 'cause ever since I got it, the primer pump has not worked. (fear of running out = anal issue!) The original was old (?) style which leaked as soon as it was unscrewed. I replaced it with a spring loaded (the black handled one). It still never worked "at all". I have the MB 'CD' shop manual and have everything installed properly, but no cigar.

Any ideas or suggestions??

(I have to print pages from the CD in order to see & understand the pics, for $100 bucks+ its a poor setup, but I could'nt find actual books, but printed images are tolerable)

-corne-

Not sure when you bought your CD Set but I bought mine from Mercedes Manuals at $53 in 2007 and that was already too much because I could have got it from Mercedes for about $27 total cost.
However, if you bought it a long time ago they used to cost more.

Mine ran fine on the 32 Bit windows XP but does not on on the the 62 bit Windows 7.
On the CD intself is some of the stuff you need to run it properly. You need some version of Adobe Acrobat or something like Foxit to view them on the Screen

I have not read of the particular problem you are having.
And, even stranger you have not indicated any other performence problems that might help narrow it down so I am going to ask some questions.

If you were to loosen and disconnect the Fuel Return Hose (a.k.a. Cigar Hose) from where it connects to the Tubing on the Fender Well and Pump does Fuel come out? If it does the Hand Primer is working.

If Fuel does not come out you are left with some large Air leak or obstruction and that is not likely becasue it would have caused some issues when the Car is running.

The Fuel Supply Lift Pump has 2 Valves in it. I have seen the little Valve Springs rust through or Brake and I guess it is possible for someone to assemble a valve wrong or for a Valve to stick or not seat well.
But, if there is some issue with one of more of the Valves is kind of odd you have no performanc issues.

Unfotunately the Lift Pump Valve Kit does not have the 5mm O-ring that also should be changed in the Lift Pump.

Lift Pump Kit Hunter 617.951-952
http://www.peachparts.com/shopforum/showthread.php?t=183451
Lift Pump, Fuel Supply Pump about sanding the Valves has the small O-ring size
http://www.peachparts.com/shopforum/showthread.php?t=266857&highlight=lift+pump+kit
Lift Pump taken apart
http://www.peachparts.com/shopforum/showthread.php?t=249082&highlight=0009934801&page=3
Lift/FUEL SUPPLY PUMP TINY o-ring
Bosch lists now 2 440 210 002 (MB 010 997 86 48) as replacement to the original black(perbunan?). And yes,the replacement is Viton.
The 5mmŲ x 1.50mmŲ 'O' ring is located in a groove in this bore and prevents engine oil in the IP from being sucked into the fuel re-circulation circuit. In most cases this O-ring has either hardened and broken up or completely disappeared.
http://www.peachparts.com/shopforum/showthread.php?t=261822
Fuel Supply/Lift Pump O-ring stuff- has links to 2 sets of pics of old and NEWER LIFT PUMP
http://www.peachparts.com/shopforum/showthread.php?p=2559787#post2559787

Sorry My notes on the lift pump stuff are badly organized. I was trying to find one of the threads with pics.

Under the Hand Primer but on the bottom side of the Lift Pump is a Plug, Crush Washer and in this order the Valve Spring and the T part of the Valve faces upwards.
On the top side of the Lift Pump under where the Plastic Fuel Line going to the Spin-on Fuel filter is; is a fitting that when unscrewed has a Crush Wasner and in order the Valve Spring and the Valve. In this case the T part of the Valve goes downwards.

[whunter]

Originally Posted by cornemuse

I have an '83 300CD T. I've never run it out of fuel, (yet) mainly 'cause ever since I got it, the primer pump has not worked. (fear of running out = anal issue!) The original was old (?) style which leaked as soon as it was unscrewed. I replaced it with a spring loaded (the black handled one). It still never worked "at all". I have the MB 'CD' shop manual and have everything installed properly, but no cigar.

Any ideas or suggestions??

(I have to print pages from the CD in order to see & understand the pics, for $100 bucks+ its a poor setup, but I could'nt find actual books, but printed images are tolerable)

-corne-

I am told this will not run on a MAC.
The W123 service CD set is FREE, but you need Internet Explorer to view it correctly.
Untitled Document


.

[qwerty]

Originally Posted by whunter

The lift pump valves are shot = cheap fix.

That will not prevent the hand pump from working "at all." It will result in the pump working but pumping fuel in the wrong direction.

Originally Posted by cornemuse

It still never worked "at all".

[toomany MBZ]

Originally Posted by whunter

I am told this will not run on a MAC.
The W123 service CD set is FREE, but you need Internet Explorer to view it correctly.
Untitled Document


.

Works on my Mac with safari, albeit slowly, try this site:
Model 123 Maintenance Manual Index

Not sure what "never worked at all" means, be sure to vent the system, see attachment.

[Govert]

If the valves of the lift pump are not working, the engine would not run (unless the valves work partly).

[cornemuse]

I have never had problems with performence with the car/engine.
When pumping (with the old pump) it felt like it never got a 'prime', with the new one, being spring-loaded. cant tell.

I worked with (diesel, mainly) heavy equipment for 40 years, and we ran machines dry LOTS of times. The Cat powered machines almost universally had efficient priming systems for this. (Early on, this is why I got hooked on diesels=no smog! change oil & filters, fix 'only' when broken.) anyways, -corne-

[uberwasser]

I'm not sure what getting a 'prime' feels like on these cars. The primer pump doesn't really change in feel once its primed. Instead you usually listen for a change in sound. A squeaky/squishy noise usually indicates that you're there or close anyway.

[barry12345]

Some of these cars will run with the pressure relief valve on the injection pump wide open or close to it. Close off the return line and see if pumping resistance forms up is one possible test.

If both return check valves in the lift pump where not sealing in a reasonable fashion You would see surging back and forth I suspect in the small primary filter when pumping.

Of course you could have a defective primer pump but if so my guess is it probably would leak. That depends on it's internal design I suppose.

[barry12345]

Originally Posted by uberwasser

I'm not sure what getting a 'prime' feels like on these cars. The primer pump doesn't really change in feel once its primed. Instead you usually listen for a change in sound. A squeaky/squishy noise usually indicates that you're there or close anyway.

If the injection pumps relief valve is in decent condition you should feel the pumping pressure increase until the point it opens. I have not had to do it with the newer style primer pump but logically somewhat the same rule should apply in my opinion.

[pgringo]

Originally Posted by cornemuse

I replaced it with a spring loaded (the black handled one). It still never worked "at all".

-corne-

how many times are you pumping it? i had to pump mine over 100 times in rapid succession before the relief valve would pop (or whatever it is that opens when enough pressure is built up).