300SDL 603 lift pump, can it be repaired?
 

I have experienced fuel problems, engine is starving at higher speeds uphill.
I’ll replace filters and clean strainer but on top I wonder if I can look into rebuilding the prime lift fuel pump. Who has done it? What are the specs, flow rates? How difficult to get parts and do? Any pictures? Martin

First do the filters -- I had that problem when I bought my 240D, and filters fixed it 100%.

EPC shows that the pump internals are available as separate parts, that tells me they intend for you to be able to disassemble the pump and rebuild it.

Looks to be a handful of springs, seals, and diaphragms.

Go to epc.starkekinfo.com and register for EPC. It is free for US people looking up US VINs. It will give you an exploded view of everything on your car, VIN specific, and is the same thing the counter at the dealer uses. You have to provide a credit card, it will authorize a $1 but no charge will post, just to verify you are a US resident.

Also, in case you didn't know, the factory maintenance manuals for this car are available online from startekinfo.com for free.

Thanks Bob, can't register at EPC, I do get an error message.
Anyway I have seen on a German website that there are about 7 parts (4 different seal rings, a spring, 2 valves and the gasket) needed to rebuild the pump. Has anyone done it? Any pictures? Probably not that complicated.
I also don't know what can go wrong with this pump. Which parts get worn out? Martin

What makes you think the lift pump is faulty? I had similar problem with the SDL. Car will not rev up and then die. I removed the lift pump and connected a hose to the intake and dipped the other end into diesel. I pressed on the pumping rod. The travel distance is short and is hard to push but I can see diesel being sucked up, albeit very slowly. So I concluded that the lift pump is good and re-installed it. The problem was eventually found to be air in system and there is nothing wrong with the lift pump. May be you can hook up a small fuel tank under the hood and see whether it has the same problem.

As no one is answering...is the lift pump not prone to failure?
Who has experienced a lift pump failure?

went and got the rebuild kit from the stealership ~$15.00 for o rings and springs and valves
turned out that my issue was a leaking shut off valve, so an easy fix if that is really your issue.

I think the below links will have the info you need. When Fastlane was around they sold the complete rebuild kits for the. The only difficulty is that the outlet Valve is crimped in place. However, if I picked the right threads the OP will show you that the Crimp can be ground or filed off and the Valve replaced.

Newer Lift Pump Repair with Disc Valves
95 E300D (606.910) Fuel Lift Pump Rebuild Question - PeachParts Mercedes ShopForum
606 Fuel/Lift Pump Rebuild
OM606 Fuel Pump Rebuild - PeachParts Mercedes ShopForum

If I did not pic the right threads you need to look (I believe there is threads on rebuilding all of the lift pumps):

Repair Links
DIY Links by Parts Category - PeachParts Mercedes ShopForum
PeachPartsWiki: Do It Yourself Articles - Mercedes Vehicles

Some Members have said the Fuel Pressure Relief/Overflow Valve on the newer models have a tiny plastic piece inside that distorts or falls apart.

Great info. Seems to be an easy job to replace the few parts. I ordered the 4 seal rings and valves, not the spring (I guess o-rings..prices are insane. I paid $28 for 4 rubber seals!! that costs a few cents..and I ordered the 2 valves for $30).
Outlet valve is the one that shoots right up into the transparent hose with the screwed connection?
Martin

Martin, I recall you describing an intermittent problem. Is it consistently unable to face a load now?

Sixto
87 300D

The Outlet Valve is the last one before the Fuel exits the Fuel Supply Pump. I have never seen them installed so I don't know if it is a Plastic Tube or not.

Not sure why you did that. The complete rebuild kit was about $37.

You are also going to need a tiny O-ring for the Push Rod and I don't see that on the list.

If I was you I would locate a source of the complete Kit and speak with whoever you bought the individual parts from and maybe pay a 10% restocking fee to turn the individual parts back in.

In the Pic #1 is the tiny O-ring and #4 is the outlet Valve.

I would ask the guy in the link I posted in post #8 why he thought the Lift Pump was not working.

I am going to make a guess that the Disc Valves are where the problem is on the Newer ones.
On My 84 300D the Valves in the Lift Pump are T shaped somewhat hard Plastic ones and they last like 20+ years.

What I think is od is the Models with M type Pumps I believe have a lift Pump with Disc Valves although the Pump Body looks similar to My Year and model.

Due to the self Air Bleeding I believe the Newer Model Lift Pumps move a larger Volume of Fuel than the older ones do.
Do they have a higher pressure also: I don't know.

Hi Sixto,
yes, that problem is intermittent. It mostly happened to me on the highway and uphill driving 70/75mph. engine will starve and die if I am not slowing down. Driving slower won't cause the starving.
So the flow is restricted ...by a) clogged filters/strainer or/and b) pump
I ordered the o-rings and valves to rebuild the pump but I think that higher chances are that it is the filters.
I just want to do the pump as well as I don't want to deal with this problem any time soon again.

No one was offering the kit any more. I ended up ordering at Tom Hansen


1 x 430, 000-091-17-80 $2.50

1 x 557, 023-997-86-48 $7.50

1 x 560, 023-997-87-48 $12.00

2 x 554 000-091-13-10 $15.00

1 x 563 005-997-47-45 $3.20

1 x 566 006-997-56-45 $2.40

So there are 4 seal rings (o-rings) included. I guess this is correct if Tom is doing the job? I guess the small one you are referring to is 557?
Actually when I am doing the rebuilding I'll note and report the size of the o-rings for the ones who do this after myself.

Martin