High Pressure Diesel Injector Pump Seal Replacement

rsmarais

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Your Mercedes
2008 W211 E320 CDI Elegance A/T
My 2002 W203 C270 CDI had a leaking high pressure injector/diesel pump . After I had to replace the seals on my high pressure pump a second time I decided to document how I did it to possibly save others from making the same mistakes I made

Pump part numbers:
Bosch part no: 0445 010 019
MB part no: A612 070 00 01

MB seal kit part number :
A000 078 07 80

Required Tools:
T40 torx bit to suite T bar or ratchet.
T30 torx bit to suite t bar or ratchet.
8mm long reach socket or socket with extension.
8mm spanner.
13mm socket.
14mm spanner.
Ratchet with adaptors for torx.
Terminal screwdriver.
Flat screwdriver
Longnose pliers.
Mini circlip pliers.
Bench vice.
Small hammer.
P800 sand paper.
Clean rags.
Washing container with paraffin.

Drive the front wheels onto ramps or raise the front end to gain access to the engine and gearbox covers. Using a 13 and 8mm socket, remove the bash plates/engine protection covers. I recommend doing this as you are bound to drop something into the engine bay while working on the pump.

Open the bonnet and remove the top engine cover to expose the engine and the Injector/ high pressure pump.
HP%20Pump%2001.gif


Remove the vacuum generator by releasing the vacuum pipe and loosening the two bolts that fasten the vacuum generator. Remove the generator carefully. You now have much better access to remove the pump.
HP%20Pump%2002.gif


Using a 14mm spanner, loosen the steel pipe located on the right hand side of the pump that feeds the injector rail.

Take the 8mm spanner or socket and remove the clamp holding the plastic supply pipes on the left of the pump.

The pump is fastened to the engine block with three bolts. Take the 8mm socket with extension and loose all three bolts. Remove the pump by wiggling gently. The o-ring seal will make the pump stick a little. Remove the pump in the direction of the vacuum generator taking care not to drop the pump's drive adaptor that is located on the back of the pump. (This photo shows the vacuum pump in the way however you would already have removed it.
HP%20Pump%2003.gif


Place the pump in a bench vice applying just enough pressure to hold it from moving while you strip it apart.
Use the T40 torx and ratchet to loosen the head bolts. The bolts are extremely tight and I would not attempt loosening it with an L shaped torx. I placed the torx bit on each bolt and gave it one firm tap with the hammer to break the seal before attempting to undo it with the ratchet. The hammer helped for sure :)
HP%20Pump%2004.gif


I took note of the position of each head on the pump and kept all parts of the three heads separate from the other. I am sure this would help with reducing wear and it just felt right doing so.

Remove the circlip from the port and carefully remove the three bits from the pump. (Two cylindrical shaped parts and a spring)
HP%20Pump%2005.gif


Now turn the pump on its face and use the T30 torx to undo the three bolts that holds the pumps main shaft. Use a small flat screwdriver placed in the recess on the casing of the pump. Slowly pry the inner part of the pump away from the casing. Do so little by little
carefully by slowly wedging until there is enough space for another screwdriver on the opposite side then wedge out the inner part of the pump completely.
HP%20Pump%2006.gif


Wash all the parts with paraffin and place them on a clean surface free of any contaminants.

Change the two o-ring type seals and place the unit on a clean surface ready for re-assembly ( if supplied in your kit).
HP%20Pump%2007.gif


Remove the line fittings from the pump using a longnose pliers. Protect the fittings with a rag before using the longnose. Not much force is necessary to remove the fitting. Then remove the o-ring and bush from the casing.
HP%20Pump%2008.gif


With the fittings removed use a terminal screwdriver to wedge out the old seals from the port.
HP%20Pump%2009.gif


Lightly sand down any corrosion from the casing and head where the seals mate between the two surfaces. I suspect this is where many go wrong leaving the surface as is. Sand both the casing and head surface.
Rinse the casing and head blocks in paraffin.

Fit the main shaft assembly back into the casing and tighten the bolts.
HP%20Pump%2010.gif


Fit the cylindrical parts/jet/restrictor and spring back with the circlip. Carefull, if the spring drops and bounces its gone!!! You know it!
HP%20Pump%2005.gif



Install a o-ring into the port followed by the bush and fitting.
Place the bush and o-ring on the other end of the fitting.
HP%20Pump%2008.gif


Start assembly of the head by installing the steel tapered seal into the recess around the hole. Be sure the seal is the right way around i.e. the inwards taper must be pointing towards the hole. This is another part where I went wrong the first time around because of the seal being so small I did not notice the taper.
HP%20Pump%2011.gif


Place the ball valve into the gap and hold it firmly as movement may upset the tapered seal and move it out of position. Build the rest of the components onto the head. Fit the small and main black seals into their respective positions.
HP%20Pump%2012.gif


With the head upside down, insert it upwards into the casing keeping the head bolts handy.( Make sure the eccentric pump contact surface is aligned in the casing hole). Align the head properly with the protruding fitting on the casing and apply pressure to mate the two surfaces together. Use your free hand to fit the head bolts. If at any time pressure was released rather be safe and re-check that all seals are still in position especially the metal ring.

Torque the head bolts down in a cross sequence until they are properly fastened. I applied as much force as my mini ratchet allowed as these need to be really tight.

Repeat the process for all three heads.

Before re-fitting the pump I replaced the plastic clamps for the clear pipe as these are almost guaranteed to be broken. I also replaced the o-rings on the clear pipe fittings.
HP%20Pump%2013.gif


Reverse the removal procedure to fit the pump.
Enjoy a leak free pump and a cabin that smells of leather instead of diesel!
 
Last edited:

Frontstep

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Excellent and nice clear pictures.

I did mine using a Bosch Kit and the points you raise about corrosion of the surfaces I agree with mine has done a few thousand miles and is fine.
The pipe clips and o-ring replacement is also good advice.
My problem was leaking fuel.
The access for a 320cdi isn't so good though.
 

andrew_oz

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Perth, Australia
Your Mercedes
ML270cdi/2004 & 2000
Restrictor

My pump has a damaged restrictor (inside one of the ports (2 cylindrical cups and a spring) behind the circlip) The vehicle is hard to start but runs fine once is goes.

Does anyone know where I can get a replacement restrictor/jet and spring?

Thanks.
Andrew.
 

mersum1es

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W212/-09/350CDI, W219/-07/320CDI, EX:W220/-01/320CDI, EX:W211/-04/320CDI, EX:W210/-01/270CDI
My pump has a damaged restrictor (inside one of the ports (2 cylindrical cups and a spring) behind the circlip) The vehicle is hard to start but runs fine once is goes.

Does anyone know where I can get a replacement restrictor/jet and spring?

Thanks.
Andrew.

I don't know if these are helpful, but some part number are available here (sorry about Finnish language), I don't know if part number vary with different pump models. Quick google gave some results... at least you can contact local Bosch service:
http://s13.beta.photobucket.com/user/joskami/media/rail2-1.jpg.html
http://s13.beta.photobucket.com/user/joskami/media/rail1.jpg.html
 
Last edited:

Silver_Star

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Your Mercedes
W203.006, S211.208 Land Rover 90
It was this post that gave me a kick up the backside to order a seal kit for mine as it has a slight weep.

IMO, this tutorial needs to get moved into the DIY section as it is a regular topic that crops up. Would a mod oblige? :D
 
OP
R

rsmarais

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2008 W211 E320 CDI Elegance A/T
  • Thread Starter
  • Thread starter
  • #9
Im glad I could contribute for a change.

For information it is now months later and the pump is still dry with no trace of a sweat.
 

Frontstep

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Mines dry too !
So many are going the same way your post will be useful, the corrosion point is something I agree with.
Mercedes don't seem to want to get away from corrosion problems.
 

Silver_Star

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Well I rebuilt my pump today. 100% correct on sanding down the corrosion on the mating faces of the heads - I should imagine it contributed in causing the seals to be compromised.

It fired up as quickly as expected once the air was bled and thus far seems leak free after a 20 mile test drive - fingers crossed it stays that way.

DSCF0413.jpg


DSCF0414.jpg
 

Bryndisi

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Think I need to do this on my C220 CDI, got a little leak from the HP pump ;)
ytehe8em.jpg

sa6e4a9y.jpg


Thought I could smell diesel whilst driving :oops:
 

mersum1es

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W212/-09/350CDI, W219/-07/320CDI, EX:W220/-01/320CDI, EX:W211/-04/320CDI, EX:W210/-01/270CDI
Think I need to do this on my C220 CDI, got a little leak from the HP pump ;)

Thought I could smell diesel whilst driving :oops:

Mine was in same condition, fuel consumption doubled :eek:

If you are lucky it's only o-rings of those plastic pipes...

Change the serpentine belt too, diesel bath is not good in the long run.
 

Bryndisi

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Mine was in same condition, fuel consumption doubled :eek:

If you are lucky it's only o-rings of those plastic pipes...

Change the serpentine belt too, diesel bath is not good in the long run.

Unfortunately not, these pictures where take 10 minutes after replacing said o rings and rubber washers.

Have a fuel pump service kit and new belt on order, thanks to this thread should have no problems when they arrive either.

Thank you rsmarais !
 

Silver_Star

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Unfortunately not, these pictures where take 10 minutes after replacing said o rings and rubber washers.

Have a fuel pump service kit and new belt on order, thanks to this thread should have no problems when they arrive either.

Thank you rsmarais !

How did the job go?
 

S.Speed

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Older Citroen Now :-(
Excellent instructions that would put a certain well known DIY manual to shame !!
Well done and thank you for your time and trouble !
 

Bryndisi

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How did the job go?

Finally got time to do this job, unfortunately my cheap eBay find seal kit was the Flag set. But so far so good done a couple hundred miles so far with no leaks.

One odd thing I noticed, when the heads are torqued right down. You can still see a tiny gap if held up to the light?

Has anyone else noticed this?
 

mersum1es

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It's possible, because often heavy corrosion between head and body is reported (mine has some noticeable rust too) and how the rust would build there if no space 'to grow'. When tightning torque is not very high, seals may take the load alone and leave some gap there.
 


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