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5000 series fuel pump R&R
Changed fuel pump in my 86 5K today - turned out the replacement pump was
worse than the old one - the replacement was stuck!
Anyway, here's the procedure for future reference;
Tools required: #3 phillips driver, medium flat screwdriver, small hammer,
BRASS drift, 17mm socket on short extension with ratchet, 7,8,9,10mm
wrenches (for wires on pump), pair of 17mm open end wrenches for fuel line
on pump. Elapsed time - one hour first time, 30 minutes or less subsequent
NO SMOKING!!!!! Drive car until fuel level is 1/4 tank or less.
Open trunk, clean it out, vacuum out dead leaves, etc.
Place tools on left side of trunk floor. Climb into trunk, lying on your
right side. It helps if you're not 6'4" and 300 lbs.!
Pull back carpet at front floor of trunk (raised area). Pull from right
side, fold it back over to the left.
Remove three phillips screws from fuel pump cover, lift off cover, unplug
four terminal connector. Place over toward left side of car, out of your way.
Note orientation of two hose clamps - they should go back in the same
positions. Loosen two hose clamps on two hoses, twist hoses slightly to
break them loose, pull hoses off spigots. They are TIGHT! and do not want
to come off. Help them a little with the blade of the flat screwdriver, but
again, be careful. You are working with plastic spigots here, so be
careful. Once hoses are off, remove hose clamps and set aside. Tuck hoses
under lip of trunk floor, out of your way.
Using 17mm socket, loosen fuel supply union. Keep your eyes closed because
there is residual fuel pressure here, and it will squirt you! Recover banjo
bolt and top and bottom copper washers. Wipe crud away from outlet. Tuck
fuel line under trunk floor lip, again, to keep it out of your way.
Note the slotted retainer ring. Rotating it counterclockwise removes it,
clockwise puts it back. Using the BRASS drift, rotate locking ring so it
unlocks. If you have room to work, this isn't terribly difficult, and you
won't need a big hammer. Remove ring.
Note that there are plastic ears on the fuel sender assembly, and note that
they mate up against three of the studs for the lock ring. Pay attention to
Lift the fuel sender assembly upward about three inches. You'll see a hose
(closest to you) and a hose clamp. Remove the hose clamp completely, then
remove the hose from its spigot. You'll be dropping the end of the hose
into the tank, and if you leave the clamp on it, it is sure to fall off and
then you'll have to root around in the tank, sloshing in gasoline until you
Holding the fuel sender assembly about six or eight inches above the tank
with your left hand, reach down into the tank with your right hand. The
fuel pump is aligned by three thick pins, 120 degrees apart, and there are
three plastic latches which retain the pump in the seated position. They
are not very stiff, so be gentle. You'll be pushing the latches back maybe
3/8", and rocking the pump to one side to keep the latch from re-latching.
It sounds much harder than it is - the only problem is that you are working
blind. The pump will come free, and now lift the sender assembly, float
lever and float, and pump out of the tank. Be gentle since you don't want
to bend the float lever. The pump will have to be wiggled slightly because
the mount is slightly larger than the hole.
Exit trunk, stretch, groan.
Adjourn to workbench. Note alignment of fuel line on pump body. Remove the
silencer (brass knob at top of pump) using 17mm renches top and bottom.
Recover copper washer, noting the three internal teeth. Remove fuel line,
recover plain copper washer(s) as fitted. Remove + and - wires: NOTE
POLARITY!!! These can be reversed. Brown is ground, pump is marked ( - ).
Loosen large hose clamp, press lower half of pump mount downward, slide
upper half of mount off pump. Note that all these plastic bits have
alignment notches, etc., so pay attention to them.
If you are removing the filter screen (per discussion on digest), be aware
that the cut edges are very sharp! The screen can sometimes be pulled out
from under the lip that holds it, but if not, you can trim it back to the
lip. Make very sure that you get ALL the bits of screen shrapnel out of the
pump!!! The screen seems to be made of stainless steel, and if bits of it
get into the pump, you will stop NOW. With the screen removed, you can see
the inlet and the pump rollers. Using a small screwdriver, make sure the
new pump rotates freely before you go through the entire installation
procedure! (How do you think I got so good at this? Someone gave me a
"good" used pump - turned out it was seized!!! Did the job twice this AM.)
Reassembly: Slide upper half of pump mount down onto pump. It only goes one
way - note alignment slot which slips over raised area on side of pump.
Slide lower half of pump mount up onto pump (note alignment slot/tab),
click latches home, tighten large hose clamp. Attach wires (brown is
negative) using 7,8,9 or 10 mm nuts as required. Install plain copper
washer, fuel line, internally toothed copper washer, silencer. Tighten
silencer using 17mm wrenches. The fuel line alignment is such that it
follows the wires. No kinks, please.
Climb back into trunk, again lying on your right side. Feed float and float
lever into tank, followed by fuel pump. Be gentle - lots of tangled wires,
hoses and plastic parts. Reach down into tank with your right hand and
align and seat fuel pump. You can just see this before you put everything
in, so at least you'll know what you're feeling for! Press pump home (not
much effort - if you have to force it, something's wrong). Check float
lever for freedom of movement. Recover hose you dropped into tank, slide it
over the spigot, reinstall hose clamp. Don't drop it into the tank! Check
that the large O ring under the sender unit is in the correct position, and
lower the sender unit fully home, noting the three alignment tabs.
Reinstall the locking ring using the brass drift and small hammer. (The
hard part is now over).
Recover fuel line from under trunk floor, reinstall it with copper washers
top and bottom. Check inside the banjo bolt to be sure its clean - I found
crud in mine. Tighten with 17mm socket. Reinstall other two lines with
their hose clamps. Plug in four connector plug (only goes one way - more
alignment tabs), reinstall cover, put the carpet back, climb out of trunk,
wash up, and drive away. You're done!