leaking hand primer pump without use.
 

I have never used the hand primer pump and it seems to be leaking now. I have seen threads talking about them leaking but can't find any that say they just start leaking WITHOUT use.

I put an electric lift pump on my 7.3 a long time ago and it makes everything much easier when you do anything with the system and other than noise i don't see a downside. many people here use electric lift pumps?

Not sure, haven't heard of anyone using them. Maybe someone will chime in.

However, just in case you're not fully aware, the primer pump can be replaced on its own. It's not part of the lift pump, so it leaking isn't reason to ditch the lift pump.

Assuming you have the new style pump (black plastic shell), is the fuel running down from inside, down the shaft - in other words, can you see where it is coming from?

I ask because there are two little hose clamps on the short bit of fuel hose that runs from the clear filter into the lift pump assembly, and these can come loose and result fuel in the area.

had a chance to look better, pretty sure it is right at the pump and not the 2 hoses, and no not black, clear/opaque plastic, maybe original for all i know.

Bergsma sells a couple of solutions to this. The first is an "improved" primer and is not too unreasonably priced then the second is a auxiliary fuel pump kit that would assist the lift pump, he says it is especially useful when bleeding lines or putting in new filters and claims if your lift pump is worn that this would help improve performance some as well as make service intervals on fuel filters to be longer. That kit costs around $200+ once you get the pump for it.

The pump can leak at the bottom where it screws in. There is a copper washer there. I have had even a brand new pump leak there a few days after installing. Problem could be dirt or imperfect sealing surfaces. In the end, i used high temp gasket sealant. But had a job to keep diesel away while it was curing. Seems to have been good for a while now.

Those Bosch pumps can be bought on eBay from a truck supply in Florida for about $10 each. I wish i could buy the washers. Even dealer doesnt havd them.

You should just replace the primer pump as suggested. If you want to add an electric pump for priming and such, they are available from most any auto parts store for around $50. Make sure to get one that is rated for Diesel (volume and pressure). If I remember correctly, the last one I got from Autozone was Master brand.

If that vendor clearly identifies them as Bosch products, that is a very good price.

However, last time I checked (~2 months ago) all the eBay vendors selling at that price range did not specify the brand in their listing. Some did show a pump with Bosch markings in the photo, but the listing did not specify that (which means the seller actively declined to enter information into the template when creating the listing).

Conversely, the vendors who did clearly ID the brand of the part were selling at $22-$30.

Given the number of fraudulent Bosch parts now in the system, I would be careful what I buy and from whom, on eBay.

Congratulations on your lovely collector item :D.

Seriously, that is the original style pump. Install a new one. There is a DIY in the tech articles, it isn't difficult apart from the tight quarters.

Make sure to remove the existing copper washer when you take off the old pump, and make sure you install the new one with the washer that comes with it. If you forget and leave the old washer there (easily done), it WILL leak from word go.

I think I remember someone a few years back had removed the whole lift pump and had fitted a blanking plate on the IP - there was some talk about whether he could leave the lift pump in place; would it seize with out diesel in it?

If I find the thread I'll post back

This is the place that I bought from:

Mercedes Diesel Primer Pump Upgraded Style | eBay

The pump says Bosch right on it and it came in typical Bosch packaging. But who knows. Anyone wanting to buy can call Angelo and ask him directly if they are genuine Bosch. With shipping to Canada, pump cost me C$22.00. I think pump was over $50 at dealer and it looked identical.

I previously bought a similar pump locally to replace the original - The seal leaked on that. Dealer gave me a copper washer, but it was wrong size and it leaked again. So I put in the eBay pump. OK for a while, but again seal leaked. I then set it in the hi temp silicone and let it sit to cure for a couple of days (I was doing other work on car). No leaks since then. Pump itself is fine and I would have no hesitation in buying another one. Knock off or not.

According to the link you provided, the pump is $9.95 + $20.95 shipping to Canada.

If the pump is genuine Bosch, this vendor should have no hesitation in saying so in his listing. There is no reasonable explanation why he would not.

In any event, for $1 or so more I can order one from my local import parts vendor and have it the next day. I know this vendor and the chance of them sourcing a knockoff part is low.

If you replace the primer pump with an electric fuel pump, it depletes the end of the world/apocalypse rides we have....because now you need electricity to run the fuel pump :D

I bought the cheap 9.99 with shipping, i checked the sellers review and only one complaint tied to that pump with a lot sold so figure it's worth a shot.

You're right I am already running the end of the world/apocalypse fuel so don't want to screw it up adding an electric fuel pump!