Injection Pump Head Seal Replacement Procedure for 1996-2003 TDI engines only
(Do not attempt procedure on any other vehicle.)
1.
17mm open end wrench or flare wrench.
2.
High quality Torx T30 socket (to prevent stripping of screws)
3.
5mm Allen wrench
4.
13mm combination wrench or socket
5.
Duct tape (12 inches)
6.
Clean paper towels or rags
7.
Clean automotive grease or Vaseline
8.
24mm or 15/16 inch open end wrench
9.
8mm or 5/16 inch wrench or socket
10.
Ice pick or mechanics pick set
11.
Small paper clip
12.
Brake cleaner spray (optional for cleaning unions)
13.
One 6mm x 55mm long
Allen or hex cap screw with a 1.0 thread pitch (ask for this at specialty
fastener store). Dieselgeek kits now include a custom made version of this
screw with special features.
1. Always work on a cool car. These engines get hot! You will burn yourself
otherwise.
2. Park car on level ground, set hand brake. Daylight really works best for
seeing what you are doing. Also, try to work in a windless area or clean shop
to prevent contamination of the innards of your injection pump. Pull hood latch
and open hood.
3. Start by placing paper
towels under the injection pump to catch all of the diesel fuel which will
leak out during this procedure. Clean the injector line fittings by generously spraying brake cleaner
on all of the fittings. You may use a toothbrush and compressed air to make sure
these fittings are very clean. We do not recommend cleaning the cast iron
injection pump head since the some of the dirt will wash into the gap
between the pump head and aluminum pump body. It is our opinion that this dirt
will be more likely to find its way into the injection pump during the seal
change if you try to clean it off of the pump head. Of course, if your pump
head is really filthy then you may want to clean it first.
4. Remove the hard metal injector lines with a 17mm flare wrench. Set
aside. Even better: Set the lines inside a clean cardboard box
and close the lid for added cleanliness. If present, place the opaque plastic ring or
red plastic caps over the injector output valves on the end of the pump. Also,
cap the fuel injectors with the red plastic caps if they are included with your
seal kit. (Dieselgeek.com includes them.) This will keep dirt out of the
injector lines.
5. Remove the 8mm
nut from the fuel supply solenoid valve. Next, with a 24mm open end wrench (some
15/16 inch wrenches will fit), remove the fuel supply solenoid valve from
the top of the pump head. If it is not stuck, remove the black plastic plunger
from the orifice and insert it into the solenoid over the little spring. Set
the solenoid (with
plunger) aside in a clean place such as a plastic bag or in the box with the
injector lines. Next, with a clean, lint-free rag, carefully wipe away any
dirt from around the edges of the fuel cutoff solenoid orifice by wiping from
the center of this hole outward
to prevent any dirt from entering the pump. Cover the hole with duct tape to
keep dirt out (assuming the black plunger came out easily).
6. Unplug the injection pumps 8 or 10 pin plug (also
unplug the three pin plug on 1Z or AHU engines). Next, unbolt the electrical harness bracket
from the front side of the pump head. Unclip the pump side of the harness from
any plastic retainers.
Pull the pump-side part of the wiring harness forward and then toward the timing belt side to get
it out of the way of the procedure area. Replace the top front black Torx screw
if you have an AHU or 1Z engine but do not fully tighten it as it is slightly
too long for the hole without the wiring bracket in place. Do not replace the
top front black Torx screw if you have an ALH engine.
7. Remove the lower yellow zinc-plated steel bracket from the lower rear
corner of the pump head with a 5mm Allen wrench, 13mm box end wrench
and a T30 Torx driver.
Set bracket aside.
Replace the lower front black
Torx screw if you have an ALH engine. Do not replace the lower front black
Torx screw if you have an AHU or 1Z engine.
8. Loosen and remove the silver Torx screw at
the bottom rear of the pump head if you have an ALH engine. Loosen and remove
the silver Torx screw at the top rear of the pump
head if you have an AHU or 1Z engine. (ALH engine shown)
9. At this point you should have two opposing Torx screws holding the pump head on at this stage. First, remove the topmost Torx screw from the pump head and replace it with the 55mm long Allen screw (or hex cap screw). Snug the 55mm screw into the bottom of its hole but do not over tighten it as you are tightening into aluminum. Now, loosen the supplied 55mm screw by One Half Turn (1/2) only. Next, remove the opposite lower Torx screw. The internal springs should push the pump head out until the pump head o-ring is exposed. Do not unnecessarily jostle the pump head while it is being held on by one screw.
Disclaimer:
You must leave one of these two remaining screws partially threaded at all
times. Internal parts will fall out of place if the pump head is pulled back
too far or removed from the pump! Removal of the injection pump will likely be
necessary if you pull the pump head back too far or remove the pump head from
the body of the pump. We do not have any procedure for reassembling the pump
head to the pump if you remove it fully. If you suspect that the pump head has
been pulled out too far and parts have fallen out of place you must investigate
by pulling off the quantity adjuster or Middle section of the pump and looking
inside. Remove the pump and have the pump professionally inspected and repaired
if you cannot put the parts back into place yourself. Do not attempt to start
the engine if you hear odd noises or if you suspect something has fallen out of
place during this procedure. Likewise, do not continue to tighten the Torx
screws if you encounter significant resistance (beyond the spring pressure
pushing against the pump head). Please note that this procedure only
applies to TDI injection pumps.
10. With a sharp pick or knife, gently pierce the old
o-ring and pull it out of the groove. Cut the o-ring to remove
it but do not cut the o-ring in the groove since you might damage the
sealing surface. On some cars, the o-ring will be so brittle that it will come
out in hard little crescent-shaped pieces. In this case, make sure you extract
all of the pieces from the o-ring groove.
11. Optional: Tear off a 12 inch section of duct tape and wrap the outer flat edge
of the cast iron pump head with the tape. This will provide a clean surface for
the new o-ring to slide over during install. (In addition, make sure that the
surface of the duct tape-covered pump head is free of dirt just before
installing the new o-ring.) Also, take care to leave the four Torx screw holes
unobstructed as you will need to reinstall the lower Torx screw after the new
o-ring seal is in place.
12. Grease the new pump head o-ring with any automotive grease or Vaseline.
You must stretch the o-ring hard to get it over the pump head! First
stretch the o-ring onto the bottom side of the pump head and hold it there.
Next, stretch the seal over the pump head and slide it into the gap between the
pump head and pump body. It will jump into the o-ring groove but it will rest
on the last remaining 55mm tool screw. During the stretching process the seal
will seem as though it is going to break but they are very tough. It is a good
idea to use a mirror to make sure the o-ring has seated fully in its groove.
You will pinch the new o-ring if it is not fully seated in the groove. (A
pinched o-ring is manifested by a pump that will not prime on Step 21.)
Note: It is our opinion that the non Bosch Viton
seal that dieselgeek.com happens to sell is the only
type of seal that will not stretch to a larger resting dimension during
this process. On the other hand, the green Bosch seals seem to grow in diameter
slightly when stretched over the pump head which means to us that they were not
designed to be installed without removing the pump head. If you use a Bosch
o-ring seal you should pay very close attention to Step 17 since this seal
might hang out of its groove ever so slightly after it has been stretched over
the pump head.
13. If you used it, remove the duct tape by gently pulling it off or
cutting it with a razor blade. Pull the tape away from the pump
(toward drivers side of car) to keep any dirt away from the o-ring gap. Use a
Q-tip to carefully remove any dirt that falls into the o-ring gap.
14. Thread in three of the Torx screws by 5 to 6 turns to hold the
pump head steady. Next, with a small bent paper clip,
carefully hook the
o-ring seal next to the front upper 55mm tool screw. Pull the o-ring gently
away from this 55mm screw as you remove the screw from the pump. Once this
screw is removed, unhook the o-ring from the paper clip so that it retracts
into the groove in the pump head.
15. Thread the
topmost Torx screw back into the pump head.
16. All Torx screws should be threaded at this point. Slowly tighten all
four pump head screws by alternating between them. You want the pump head to be
drawn into the pump slowly and evenly without cocking. If you tighten one of
the sides too much at a time you run a risk of cutting the edge of the new
o-ring. When you are within one sixteenth of an inch from fully tightening the
four Torx screws, remove the front top black screw and replace the electrical harness bracket
around the top front pump head hole and re-thread the top front black Torx
screw. Do the same for the yellow zinc-plated bracket by unthreading only the
front lower pump head black Torx screw. Thread in all three of the M6 Allen screws (5mm
Allen drive) which help secure the two brackets to the pump head. Do not
tighten them fully yet.
17. Finish tightening the four Torx screws. You should alternate between
them while you are doing so.
19. Reconnect the electrical plug or plugs, checking the connection by
gently trying to unplug it without engaging the safety catches. Make sure to
clip the wiring harness back into any plastic keepers it was originally mounted
in.
20. Replace the four injector lines while paying very close attention to
keeping dirt out of the connections. Tighten lines in two steps to ensure that
there in no preload on lines.
21. There is a plastic T-fitting at the fuel filter. On the T-fitting there
is a line that has blue markings on it that goes toward the rear of the car.
Detach this line. Place any vacuum-operated device (ex: Pela or Mityvac) on the exposes nipple
of the T-fitting and apply a vacuum. Diesel fuel will be pulled through the
injection pump by doing this which serves to prime the injection pump. Once you
get a solid column of fuel in the line to your hand-held vacuum pump, detach the
vacuum pump and let the fuel drain into a wad of shop rags. Quickly reattach
the blue-marked fuel hose to the fuel filter T-fitting.
22. Try to start engine. If the engine is slow to start you may crack open
the injector lines at each of the fuel injectors to purge any remaining air in
the injector pump and/or lines. Tighten lines once engine is running. Check for
leaks at the fuel injector line unions and at the pump head unions. You may use
brake cleaner spray (ex: Brakleen) to clean off any residual diesel fuel to
help identify leaks. Check the pump and lines later to confirm that there are
no leaks present. Feel free to report your experience to me at jim@dieselgeek.com.
Any tips or suggestions will be considered carefully for possible procedure
revisions.
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