replacing om617 fuel primer pump

[janhermann]

Hi All,

I have a leaking fuel primer pump to replace on the OM617. I purchased the prescribed crowsfoot wrench and bosch hand pump but still can not gain access around the brass nuts that hold the lines from the big and little filters onto the fuel pump body.

My question is can I simply unscrew these two brass nuts from the pump body to gain better access and if so are there any gaskets or o rings that I need to have handy to put back together? They seem to be on pretty tight and I don't want to damage anything if they're not meant to come off. I was hoping it was a simple job I could do myself.

Regards
Jan

[mathuisella]

Hi there, I've replaced the primer on mine, the primer itself and another time the whole lift pump.

First thing is, you will have to remove the lined from the lift pump.

Also, if any of the lines are " hardlines" or stiff plastic from the primer pump, loosen them up from both ends so you don't snap it.

if i remember right, it's a 20 or 22 mm you need to undo the fuel hose barbs. this will give you access to the plunger behind them.

It's dark now, but happy to make a short video tomorrow when the sun is up :)

[Henry Schuman]

Those can be a pain all right.IF you Remove those Brass Nuts you will find check valves beneath and they need to be noted as in there position and put back the same direction .Also there are THIN Copper seals which can be reused so be Careful and keep everything Squeaky Clean and you should be good to go . I would recommend using a Can of Brake Kleen or similar product and spray generously around those fittings and blow out with compressed air before removing them .
I have had to actually Remove the whole pump assy (not the injection Pump )and get the damn thing out too. Be advised there are probably 3 10 MM nuts holding this on depending on your model and a paper gasket that generally tears in half when you remove it so you will need to Source one of those or Make one.

[tsharkey]

I have had to actually Remove the whole pump assy (not the injection Pump )and get the damn thing out too.

Hi Henry - Did you have to pull the oil filter housing off to get the IP off ?

[janhermann]

Thanks to all for their assistance. I tackled this job this afternoon and having followed all advice it went very well.

I was able to get access to the primer with the crows foot wrench after I removed just the nut from the hose going to the big filter after taking both hoses off. The nut with the hose coming from the pre filter didn’t need to be removed. There was no crush washer on that one but an o ring inside the nut that was due for replacement from my metric set. The check valve etc was left inside. All hoses were very cracked and needed replacement. Hopefully the supercheap fuel hose is up to the job!

[mathuisella]

So, looks like my lift pump is dead :'(

did you get a replacement whole pump or a rebuild kit ?

P.S where did you get it ( either pump or rebuild kit please )

[Tony From West Oz]

Don't replace the lift pump, just replace the non return valves (2). Get them from a Bosch accredited Diesel injection workshop. Get the numbers off the side of the IP as these will be needed to get the right NRV.
While at it, replace the primer bulb. It is most likely OK, but they are cheap enough.

[mathuisella]

Don't replace the lift pump, just replace the non return valves (2). Get them from a Bosch accredited Diesel injection workshop. Get the numbers off the side of the IP as these will be needed to get the right NRV.
While at it, replace the primer bulb. It is most likely OK, but they are cheap enough.

:)

Will do,

I'll call tomorrow after uni.

Just for clarification, the primer bulb, is that what you mean by the hand plunger/primer that you push up and down to prime it ( bleed all the air out ) ?>

If so, i have a brand new spare Monark all metal one here i got on a special a while ago ( they were $7 USD ) for future use.

[janhermann]

So, looks like my lift pump is dead :'(

did you get a replacement whole pump or a rebuild kit ?

P.S where did you get it ( either pump or rebuild kit please )

It was just the priming bulb I had to replace thankfully.

[mathuisella]

Don't replace the lift pump, just replace the non return valves (2). Get them from a Bosch accredited Diesel injection workshop. Get the numbers off the side of the IP as these will be needed to get the right NRV.
While at it, replace the primer bulb. It is most likely OK, but they are cheap enough.

So, contacted mercedes....

it was quoted $180 for the parts to rebuild :(

[tsharkey]

As these are Bosch IPs (Not Mercedes), you may find they are cheaper from Bosch or a Diesel Injection specialist.

I miss MB Spares ......

[Tony From West Oz]

Don't replace the lift pump, just replace the non return valves (2). Get them from a Bosch accredited Diesel injection workshop. Get the numbers off the side of the IP as these will be needed to get the right NRV.
While at it, replace the primer bulb. It is most likely OK, but they are cheap enough.

So, contacted mercedes....

it was quoted $180 for the parts to rebuild :(

Well you did contact the $tealer$hip didn't you?
Bosch are where MB gets their fuels system parts from, so go to someone who deals in Bosch parts.