Fuel pump delivery valve seals.

[Parrot of Doom]

I shall be attempting this job today (with help). Wish me luck. I have been warned that 7k must under no circumstances be disturbed.

http://homepage.ntlworld.com/tom.jeffs4/car stuff/merc tech/diesel delivery reseal-1-1.pdf

I'm changing the o-rings and crush washers.

Wish me luck! I will of course document everything.

 

[Richard Moakes]

Good Luck, I always like to see someone willing to have a go

Weather looks better this weekend, my hands are itching to get to the spanners, I can feel some SL fettling coming on

 

[mebobster]

Good Luck, may the mercedes force be with you! You can do it, I have faith in you...

 

[kth286]

"Great Stuff"

You know, when I first started looking at this forum (quite sometime ago now) I thought it was a rather shallow place for the likes of myself that are keen DIYers.

I felt that the majority of members were IT profs, office based, and with newer cars and maybe even a lot of comapany cars and so not really interested in the technical stuff but more interested in "chrome".

However, over the years I have been very encouraged to see more discusssion based around older cars and people wanting to get their hands dirty and wanting to learn the DIY aspects of their cars.

For many people, this may be a modern classic second car.

You could do no better than have a Mercedes as an older car because Mercedes take their heritage seriously and consequently still make available parts for very old cars, and the parts are at reasonable cost bearing in mind the quality of the car.

So, when I saw Parrots post I thought "Great Stuff" - and may it continue and prosper.

 

[Parrot of Doom]

Done and dusted. A bit of a pig of a job, but mainly because you have to remove the intake manifold - why Mercedes didn't make the bolts easier to access I don't know, but anyway, here's how the job went.

 

[Parrot of Doom]

Most fuel leaks on the OM606 engine happen around the fuel pump, specifically the plastic fuel lines between the pump and the two fuel filters. These, while a bit inaccessible, are generally a quick and easy job to replace.

Tools:

Mercedes splined tool part no - 617 589 01 09 00
6 x copper seal (7f)
6 x o-ring (7h)
Sockets, torque wrench, torx bits, extensions, etc

The fuel leak we fixed today was on the other side of the pump - the injector side. This is where fuel is pumped out at high pressure, down hard metal lines, into the injectors, and thus into the engine. The leak was at the 6 valves on top of the pump (1 valve for each cylinder). There are 6 o-rings (the source of the leaks) and 6 crush washers to replace. To access these valves, the intake manifold must be removed, as well as the washer bottle and all 6 injector lines. Its probably not a job for an amateur DIYer like myself, which is why I was very glad to have my mate with me, who is much more experienced in these matters than I am. Its a good idea to have 2 people on this job anyway, since a spare pair of hands is invaluable for catching hold of loose springs, holding clamps, etc.

1) Remove washer bottle

1 bolt holds my bottle in place. Remove that, and pull the bottle to the front of the car - it will unclip itself from a small bracket. Remove any connectors on the top, and put it out of harm's way (I left it resting on the +ve battery terminal).

2) Remove intake manifold.

Full instructions can be found in the EGR cleaning thread. Essentially theres 1 bolt accessed from above, this unclamps the small pipe that enters the EGR valve to the back of the engine. Another bolt below (allen IIRC) holds 2 aircon pipes to a clamp, said clamp also is bolted onto the chassis. There are 12 torx bolts on the top of the manifold screwed into the head.

Once these are all removed, the intake manifold should come completely clear.

3) Remove injector lines

The 6 injector lines must be removed from the pump, and the injectors. This is easy enough, just a normal spanner can be used. Unscrew each line, its easier to start with line 6 (rearmost cylinder) and work down to line 1. As you unscrew each line, take care not to mix them up.

A simple way to avoid mixing them up is just to leave each line hanging in the relevant injector well. Another tip is to take a photograph of the arrangement, or you could tie a small label on each one.

Once you've removed all 6 lines, you should be looking at this:

You can see we've grouped 4 injector lines together on the right of the pump, the other 2 are at the left of the pump out of shot. If you look closely, you can see diesel welling up at the top of each delivery valve (its blue).

4) Remove splined collars

Each delivery valve is held in place by a splined collar. This collar is designed to stop the delivery valve from moving once it has been torqued to the fuel pump - if this collar wasn't there, then once you put the injector line on the valve and began tightening it, the delivery valve would start rotating in sympathy.

There are 6 collars, held in position by 3 bolts. Remove all 3 bolts. The collars will be stuck to the head with age and grime (and diesel). Get a flat bladed screwdriver and bend it 90' in a vice - this gives you a nice lever to get them up. Work them back and forth, they'll start moving. Then just lift them off.

From the picture above you can see the installation order - collars 1, 3, 5 are first on, followed by 2, 4, 6. They overlap.

 

[Parrot of Doom]

Once all 6 collars are off, you should be looking at this:

The collars will be filthy - chuck them in a bucket of degreaser for now.

5) Removing the delivery valves

With the special Mercedes tool, unscrew delivery valve 6 - carefully.

As the valve is removed, there will be a tall slim spring resting inside the pump - take care this doesn't fall out into the engine bay.

The o-ring should be above the thread on the valve you just removed - if it isn't there, it will be stuck in the fuel pump here:

(you can just make it out, above the thread)

 

[Parrot of Doom]

In the image above you can see the crush washer (part 7f). This needs to be removed. Insert the end of a flat screwdriver under the lip of the washer, and gently slide it out.

Now the crush washer rests on a metal collar, the collar holds a very small cylinder of metal. This cylinder, from what we could gather, when the engine is running pushes against the spring and allows a small amount of fuel up the lines, through the injectors, and into the engine. I have been repeatedly warned not to disturb this but to my surprise the collar and little cylinder were quite happy to slide around inside the pump - they can't really not move, because the pump isn't horizontal anyway, its tilted to one side.

I think what may have happened is that someone has torqued the delivery valve back down, not taking care to ensure the collar is correctly centred in that little well, and the little cylinder hasn't been able to fully move - which would probably lead to damaged seals inside the pump, and a damaged delivery valve.

Anyway, we removed it just to have a look:

There appear to be no keyways or anything, the pdf file (I will link it at the end) just says "observe the installed position". There is a groove along one edge, we just compared it to the collar on valve 5 and aligned it in the same direction. The little cylinder is flat to the top edge (with a small serial number stamped in), the bottom edge looks like a phillips screwdriver blade - probably so the diesel can counteract the rotational forces applied on the top edge when it pushes against the spring.

Obviously you don't have to remove this collar or the little cylinder, so don't unless you're curious. If you do remove it, make sure it goes back in the correct orientation, and clean.

Put the new crush washer in place, and slide your new o-ring over the thread of the delivery valve. Your fingers will be covered in diesel and oil anyway, but if they're not just make sure the o-ring is wet with oil/diesel, to ensure a better seal while torquing down.

Carefully put the spring back in the pump, and ensure the collar (7g) is centered in the chamber.

Screw the delivery valve back down with your fingers, waggle it back and forth as you do so the collar, crush washer, and spring are all forced to align themselves correctly inside the delivery valve (the inside of the valve is slightly fluted to aid this).

 

[Parrot of Doom]

Repeat the above steps for the 5 remaining valves.

6) Putting things back together

Once the valves have all been screwed in by hand, get the torque wrench out and torque each valve up to 26 ft/lb (35 nm). Slide the collars back over the spines (taking care to observe the order they were removed), and screw the collars back down with the 3 screws. You should be looking at this:

Screw each injector line back onto the valves, starting with line 1 working through to line 6. No torque figure for these, just tighten them up, then an eighth/quarter turn more, and that should be that. Then screw each line back onto it's injector, observing the same degree of tightness:

Take care that the fuel lines are correctly aligned - there are plastic clips to guide them. Watch that no plastic fuel lines get in the way.

Reinstall the intake manifold - this is a pig of a job and you'll need 4 hands to do it. Theres no way to describe it, just put it back together (refer to the EGR thread if you like). Use gasket paste to ensure a better seal between the manifold and the head (we reused the existing gasket, its metal and still a good seal)

You can of course clean the oily crud from the intake manifold if you like, and the EGR as well. You'll need a bottle brush and some degreaser for that.

7) Crank like crazy

This is where your battery gets tested. There will be loads of air in the system now, and you're going to have to crank for a good 2-3 minutes (crank no more than 10 seconds a time, with 20 seconds inbetween).

My battery gave up the ghost here, so I nipped down the local autofactors and bought a new one. Well its had a good 5 years anyway, and was getting a bit tired. Plus I got it at trade price, so it only cost me £50

Eventually the engine should fire back to life, it will stumble a bit but once the air has been pushed out the system it will be fine. Leave it running for 5 minutes to restore some charge to the battery.


I did have a heart in mouth moment on the way home, a massive THUNK from under the bonnet - fortunately it was the pipe from the turbo popping out of the EGR valve under the manifold. Either not inserted fully, or a clamp has broken, either way at least it wasn't the fuel pump exploding

Hope this all helps!

 

[Parrot of Doom]

Schematic of delivery valve here:

http://homepage.ntlworld.com/tom.jeffs4/car stuff/merc tech/diesel delivery reseal-1-1.pdf

Bigger pictures here:

http://www.flickr.com/photos/soundman/sets/72157603792018546/

I forgot - heres a picture of the reason why they were all leaking:

And here's a very square (should be round) cross sectioned o-ring:

 

[motormen2]

Great Job Again

Fantastic piece Parrott of Doom...please advise all to also change the rubber '0' seals on the plastic fuel lines to the filter and pump...I counted 11 seals in total with the MB parts man...haven't done them yet though!

 

[redmilly7]

Parrott......yet again you have saved my life...without this site and the knowledge of members id have bought a pushbike by now..

Did the job over 2 days whilst dodging the snow, hail, rain and wind....got so fed up with the weather and the fact that like parrott said its a "pig of a job".....two things went wrong I lost a clamp off the inlet manifold recirculation gas pipes and a glow plug has given up the ghost now as well..

Results are remarkable, I hadnt realised how much fuel I was losing and how the performance had dropped, dont understand why it shud have dropped, maybe due to air in the system, Im not sure..but anyhows the results are great..

So thank you to the member who loaned me the tool to remove the injector valves (name supplied if you want but i think he would be too embarased) and to parrott for a very good write up...cheers people.

 

[Bolide]

Excellent write-up

Can I add two caveats? The gungey "holes" at the top of the 4th photo are the tracts to the inlet valves. The removeable part of the inlet manifold mates to these tracts. Directly below are the valves. If any parts fall into these tracts it will spoil your entire weekend so I'd suggest blocking them with foam or cloth

Secondly I would think it'd be a good idea to clean the top of the IP before stripping it down

Nick Froome
www.w124.co.uk

 

[Parrot of Doom]

I did think about cleaning the top of the pump but the dirt there was stuck down with a year of diesel and gunge, the photos make it look a lot worse than it actually was, and I didn't want to risk loosening dirt that would fall inside the pump as the valves were removed.

 

[Cosworth]

Excellent right up. I have done it myself some time back and the only thing i did differently was that I steam washed the area around the pump in order so that there is less chance of dirt getting into the pump.

 

[sharky1]

I had the same problem and still do, I have persistant leaks from 2 delivery valve holders, I purchased complete new kit including o rings washers and springs, used special spline tool and removed all valve holders replacing o ring-copper washer & spring in each, re fitting valve holders by delicately rocking and screwing them from side to side so everything would fit snugly, I then Torqued all valve holders to 35Nm as recommended. I re fitted everything back together and after considerable false starts merc started with plenty of power and idled perfectly but unfortunetly fuel leaks appeared from base of return valve holders just as before. I removed everything again cover, accelerator assembly, intake manifold etc etc etc, I removed all collars -valve holders again checking that everything was fitting perfectly and alligned properly paying particular attention to proper seating of springs, I re- screwed everything back in place and re torqued to specified pressure & fitting retaining collars but still no joy and have done this 4 times already, which has been time consuming and soul destroying when the outcome is sadly still the same?
Don't know what I am doing wrong if anything, I am wondering what I can do to resolve this major problem?
Kind Regards
sharky1

 

[redmilly7]

Hi Sharky,

sorry you are having so much trouble, all I can say is that I followed parrots write up and it worked fine.

Ive just thought, I had a fuel leak some years ago and it was from one of the plastice supply pipes and the fuel was ending up on the injection pump so it was a case of tracing it back. I took it to a local indy who traced the problem.

 

[steve kane]

Excellent artical and really very straightforward to do, if anyone needs to Borrow the Special Tool for removeing the Delivery Valves I have bought one and lent it out for a very small contribution to several other forum Members, PM me if you want to borrow it, the cost to buy is about £35 if you can locate the little darling!!,,,

 

[howiiix]

Fuel pump delivery valve seals

Thank you for your superb description for this job. I found on my 606 non turbo engine (W124 1994 E300D) that the rear three valves could be accessed without taking the main manifold off eg there is sufficient room to access them when the crossover inlet pipe is removed. In the end, I had to replace all the seals and thanks to Steve Kane for the hire of the special tool required.

 

[Alex Crow]

hi all, we made a tool up from a spare locking tab and an old socket £0.00! have probably done 8 to 10 now and it works a treat. as others have said cleanliness is vital here and steam cleaning is a good idea (with locking tabs removed).

sparky1, you may have a corrosion problem there. the aluminium immediately above the o-ring corrodes and can in time sneak past the o-ring and go further down. this is why the o-rings are very reluctant to remove (when unscrewing the elements). remove them again and inspect the aperture for corrosion. you could clean up with wet and dry but better would be something like one of those green pan scrubs or similar. OBVIOUSLY CONTAMINATION OF THE PUMP IS A CONCERN!! so remove the loose internal parts and block hole with something suitable like an appropriately sized rubber bung first. blowing out with an airline and rinsing with diesel after cleaning corrosion is required then put back together and bob`s your mother`s brother. have only had to do this to a couple of cars but i`d bet that is your problem.