W124 E300d Fuel Lines

[spock500]

You won't need to torque them up, just nip them up to a nice hand tightness and you will be fine. Don't overdo it though as they screw into the aluminium head. Get all the bolts back in before tightening up otherwise some holes might not align.

You don't need a new gasket, just rub the rubber coating off the old one if it comes away. There is no pressure or vacuum on yours as it is an atmo diesel, not a turbo.
Even a turbo gasket seals no problem with no problem as it's pressed to form a seal.

Agree on the nipping up bit but a new gasket is a must, not worth doing otherwise.

Its not a traditional gasket ie both faces being squashed by the two components, instead it sits in a recess in both parts (face plate and pump) which meet metal to metal hence tightening has no effect whatsoever.

The seal is created by the rubber gasket being thicker than the recess of both of the parts and therefore gets compressed, see old gasket in mine flat as a pancake

 

[Dieselman]

My mistake, I thought we were talking about the manifold bolts. I agree a new gasket for the IP cover is mandatory.

 

[spock500]

Sorry, cant find the thread on inline pumps which is a bit of a shame - too many common words bring unrelated threads.

Will keep an eye out though

 

[SilverSaloon]

Hi again,

well it was worth a try - i ordered and got a new gasket for the face plate (couple of pounds) from MB and fitted it tonight (from below )....

but sadly, it appears the fuel leak is still happening.....

that leaves me with one last suspect: the delivery valve seals. so thats a job i plan doing at some point soon. Parrots how-to seems pretty good, so i'll start ordering up the parts needed.

Just to confirm, it was fuel that was behind the face plate - not engine oil.

The old gasket was rather flat so i guess it was a job worth doing anyway, but it hasnt fixed the main issue i have.

On the plus side, the car is starting fine since the fix to the fuel filter housing has been done (still got the no-more-nails on it).

Still on 100% veg oil by the way

thanks

Derek.

 

[spock500]

Hi again,

well it was worth a try - i ordered and got a new gasket for the face plate (couple of pounds) from MB and fitted it tonight (from below )....

but sadly, it appears the fuel leak is still happening.....

that leaves me with one last suspect: the delivery valve seals. so thats a job i plan doing at some point soon. Parrots how-to seems pretty good, so i'll start ordering up the parts needed.

Just to confirm, it was fuel that was behind the face plate - not engine oil.

The old gasket was rather flat so i guess it was a job worth doing anyway, but it hasnt fixed the main issue i have.

On the plus side, the car is starting fine since the fix to the fuel filter housing has been done (still got the no-more-nails on it).

Still on 100% veg oil by the way

thanks

Derek.

Thats a shame, but have been there many times

I wouldnt go for the valve gallery just yet, I am sure access is from above with a MB tool but could be wrong - if you still have a leak can you take a picture ?

My money would be on the large O ring between the stop solenoid and IP.

 

[Dieselman]

My money would be on the large O ring between the stop solenoid and IP.

Same here, except there is no stop solenoid and the fuel union is bolted in on a banjo fitting I think.

Get the manifold off, clean and dry everything and tie bits of paper towel round parts of the IP. Any leak will soon be obvious.

 

[spock500]

Same here, except there is no stop solenoid and the fuel union is bolted in on a banjo fitting I think.

Get the manifold off, clean and dry everything and tie bits of paper towel round parts of the IP. Any leak will soon be obvious.

On the 605 the stop solenoid is bolted to the IP above the plate Derek has just replaced - the O ring is the one I ref'd to in a pci a few posts back in blue -

Diagram below, I am reasonably sure this applies to the 606 but not 100%

 

[SilverSaloon]

On the 605 the stop solenoid is bolted to the IP above the plate Derek has just replaced - the O ring is the one I ref'd to in a pci a few posts back in blue -

Circled in blue is where the solenoid plugs into the IP which as a large O ring.

the 606 doesnt seem to have this bit though:

there is a clear plastic pipe that clips in via the usual method just above the plate - however i've already replaced this (and all other) O-rings on the clear fuel lines with viton o-rings. Plus i've added Plumbers tape to create a tight seal. No leaks here.

I did wipe as much fuel off as i could before i re-started the engine after fitting the face plate. it does appear to be leaking from the delivery seals - there is a small amount of fuel at the top here.

Anyone know whether this will be leaking all the time or just when the car is just switched off? Just curious on how much fuel i'm actually loosing and how it is effecting MPG

There is loads of veg/diesel on the undertray - i'll have to de-grease it once i've sorted all this!

 

[Number_Cruncher]

Hi Derek,

Although the delivery valves might be the cause of your leak, I would advise extreme caution.

There have been many threads on the mercedsshop site about people's cars not running well after this job has been done - in fact there's a thread running now about a car which has been made undriveable by doing this job, and will probably need the pump to come off and be set up again by a diesel injector pump specialist.


You might be lucky, or you might be letting yourself in for a serious wallet bashing! I'm a fairly well experienced mechanic, and I wouldn't be at all happy doing the job.

If you are bold and courageous enough to tackle the job, then, you need to spend quite a bit more time in prep than was seen in the howto - the injector pump can easily be ruined by any grit getting in, and you should aim for spotless working conditions, clean pump, clean tools, clean hands [clean rubber gloves replaced frequently during the job would be ideal], and cover the pump with a non-shedding clean cover-sheet whenever you can. Working strictly one element at a time, I would be loathe to disturb anything other than the O ring, and the crush washer, and I would take great care in the cleaning of removed parts and the re-torquing procedure.

 

[Dieselman]

Anyone know whether this will be leaking all the time or just when the car is just switched off? Just curious on how much fuel i'm actually loosing and how it is effecting MPG

There is loads of veg/diesel on the undertray - i'll have to de-grease it once i've sorted all this!

It's leaking when the engine is running and it's under full injection pressure. At least one injector won't be firing properly as a result of this due to reduced delivery pressure and volume.

From experience I'd say you might be losing a couple of mpg as a result of this. The underside and rear of the car will be well coated with oil..

I'm still suspicious of the fuel pump being lubed with fuel and suspect the oil may have been leaking into the pump via the gasket.

You will require a proper splined tool to remove the delivery valves.

 

[SilverSaloon]

Hi Derek,

Although the delivery valves might be the cause of your leak, I would advise extreme caution.

There have been many threads on the mercedsshop site about people's cars not running well after this job has been done - in fact there's a thread running now about a car which has been made undriveable by doing this job, and will probably need the pump to come off and be set up again by a diesel injector pump specialist.


You might be lucky, or you might be letting yourself in for a serious wallet bashing! I'm a fairly well experienced mechanic, and I wouldn't be at all happy doing the job.

If you are bold and courageous enough to tackle the job, then, you need to spend quite a bit more time in prep than was seen in the howto - the injector pump can easily be ruined by any grit getting in, and you should aim for spotless working conditions, clean pump, clean tools, clean hands [clean rubber gloves replaced frequently during the job would be ideal], and cover the pump with a non-shedding clean cover-sheet whenever you can. Working strictly one element at a time, I would be loathe to disturb anything other than the O ring, and the crush washer, and I would take great care in the cleaning of removed parts and the re-torquing procedure.

thanks - i'll have to give it some thought as to whether its worth it. if the car starts ok now and a couple of MPG is all i'm loosing it could be something i could live with.

could you pm me a link to the thread about the guy having problems? cheers

 

[Dieselman]

There have been many threads on the mercedsshop site about people's cars not running well after this job has been done - in fact there's a thread running now about a car which has been made undriveable by doing this job, and will probably need the pump to come off and be set up again by a diesel injector pump specialist.

I'm not disputing you but I can't see how people get into trouble doing this job. The delivery valves are simple spring loaded valves. As long as reasonable care is exercised then there should be no problems.

Obviously I wouldn't advocate doing this int he middle of a sandstorm but otherwise it shouldn't be a problem. The most likely issue will be that the valve hasn't been seated correctly on replacement so needs removing and resetting again.
We had a poster on here did exactly that, he just undid it and placed it back in again. Took 2 mins.

 

[Number_Cruncher]

Here's the thread I was thinking of;

http://www.mercedesshop.com/shopforum/showthread.php?t=225323

This thread is also helpful.

http://www.mercedesshop.com/shopforum/showthread.php?t=216067&highlight=delivery+valve

The O ring seals aren't under full injection pressure - they just have to react lift pump pressure.

It seems to me that when doing this work it is very difficult to avoid disturbing the lapped surface between the top of the pump element barrel and the delivery valve support, and owing to its location in the pump, there's no way to check this lapped joint is correctly located and sealed until you come to start the engine again after the job is finished.

 

[spock500]

How many miles are on the vehicle?

 

[SilverSaloon]

i've looked again at Parrot's How-to and it does appear to be relatively simple job aslong as you take extreeme care and take your time.

i'm going to order up the o-rings, crush washers, special tool and also a new gasket for the IM along with a few of these W connectors that apparently will break when i remove the IM.

once i have these, i will put aside a whole weekend and start the job on the saturday.

I think it looks OK aslong as you just remove whats necessary and dont touch the collars.

 

[SilverSaloon]

My comment earlier regarding lift pump O rings is because the lift pump leads into the IP chamber.
Any oil leaking into the lift pump could cause a problem but more likely is oil dilution from fuel leaking out of the lift pump into the IP as that is fed from the engine oil and returns there as well.

Worth doing, I was meant to be doing mine today, but didn't get round to it...

Dieselman; what model and year of merc do you have? when i removed my lift pump there was no o-rings inside. I fitted a green one to the main screw off part, but thats all.

how many o-rings did you replace in the lift pump and where did they go?

 

[spock500]

Derek are you sure the leak is not coming from the unions where the inj pipes bolt onto the IP?

From what I have read on the valves access is through the top with a tool, I dont think they could leak through the side plate.

 

[SilverSaloon]

Derek are you sure the leak is not coming from the unions where the inj pipes bolt onto the IP?

From what I have read on the valves access is through the top with a tool, I dont think they could leak through the side plate.

you mean the bolts on top of the metal lines?

 

[Dieselman]

how many o-rings did you replace in the lift pump and where did they go?

Couldn't find any other than the small green one on the pushrod, which was in fine fettle so I left it.
I think they go under the screw on unions to seal the threads.

 

[spock500]

Yes, any chance of some pics or are you still accessing the pump from under the car?