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. 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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