Unsticking a diesel pump

At my school we have a Cat 3208 fuel pump gummed up with old diesel
and it looks like I'll be the one with the chore of unsticking it.
Anyway, the pump is a series of little pistons with a very tight slip
fit into a cylinder bore and a small collar.
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Like that, with +s as the sleeve, #s as the cylinder, and -s as the
piston. All three are hardened steel and frozen rather tightly. No
other contamination or rust as far as I can see.
Does anyone know how to separate them with minimal damage? I'll have
the rest of this semester to do it if we decide to repair it, so plenty
of time to try lots of hair-brained ideas.
Reply to
B.B.
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Hose it out with spray carb cleaner. This will wick in between the surfaces. Next, soak in ATF for a few days. The ATF will follow the cleaner into the clearances. DO NOT try to move the pistons. After said time, gently try to move the parts. If no, repeat. Any damage caused by forcing the parts will destroy the pumps efficiency. JR Dweller > At my school we have a Cat 3208 fuel pump gummed up with old diesel
Reply to
JR North
In article , "B.B." wrote:
If this is the injector pump, are you quite sure it's "gummed up with old diesel"? The clearances on those are incredibly fussy, and one of several classic ways to catastrophically kill them is hosing off a hot engine (cooling the cylinder(s), shrinking it(them) onto the piston(s), destroying the pump).
Rebuilding these pumps is generally acknowleged (at least among the old-tractor do-practically-everything-yourself folks I've gotten a lot of old tractor advice from) not to be in the realm of normally equipped shops - there are shops that specialize in them, and they have very fussy tooling indeed, as I understand it - I own an old diesel tractor and I've not had to have the pump rebuilt thus far.
You might try an ultrasonic cleaner with the ATF soak step (carb cleaner in an ultrasonic cleaner sounds far too hazardous to me).
Reply to
Ecnerwal
try penetrating oil soak for a few days then make an adaptor that takes a grease gun fitting and fits into the outlet of the pump. A few shots of grease should easy it out ( btw there might be a check valve on the outlet). Make sure that the cylinder is as full of grease as you can get it, air trapped inside hampers this method and can create a missile. Pat
Reply to
Pat Ford
The clearances are very tight on diesel injection pumps. Even the corrosion from touching them with your bare hands is enough to seize the piston and cylinder. The injection pump piston and cylinder should be dismantled in a container of diesel using suitable gloves to prevent contamination
It is normal practice (in the UK at least), for any fuel injection pump work to be sent to a specialist due to the specialist equipment required to set them up.
Fuel Injection pumps are quite a simple design, it's just the tolerances and set-up that require specialist equipment.
Reply to
Moray Cuthill
Remove the top cover on the pump. Drain the diesel. Spray PB Blaster on all the pumping elements inside the pump. Remove the injector lines and spray PB Blaster in all the high pressure outlets . Let it sit overnight. Rotate the pump over and see which ones are still sticking. Buy the tool from cat and remove the offending pump element. Disassemble and free up the element. Reinstall making sure the sleeve engages the rack paw. Torque to 70 ft.lbs. If carefully done settings will remain intact. Do not force anything.
Reply to
Mike
And make sure the timing pin isn't in the pump.
Reply to
Sven
[...]
Thanks for the replies. I'll do the carb cleaner soak and ATF soak method. More info about the pump: it froze up from sitting for two years without operating. It seems the sleeves somehow managed to disengage from the control rack pawls on one side before we attempted to start it, so cranking the engine did some bad things. One, all eight pumps were stuck and got forced up their bores. Two, those four sleeves that slipped off the rack got hammered into the rack and forcefully pushed down their pistons. Three, that rack got turned out of adjustment. Four, after all that one dumbass thought it would help to loosen a few screw on the racks. So it's not a happy pump. It would be best to send it out to get work done, and that's the first option if they can pull it off within the school's piddly budget, but failing that we can borrow all the needed calibration tools and do it on-site. One of the instructors has a fair amount of experience with fuel pumps from long ago, and I'm known for being extremely anal-retentive so the two of us will probably work on it, with me doing the work and him supervising and answering questions.
Reply to
B.B.
In article , "B.B." wrote:
[...]
To those that helped, I reward you with pictures!
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Enjoy. Typos to be correct whenever to have some more free time.
Reply to
B.B.
Interesting stuff, B.B. I admire your persistence. Thanks.
Garrett Fulton
Reply to
gfulton
that sure looks like a simple engine to work on.
Reply to
Erik Litchy
So how does the grease get to the stuck pumping element if there is a check valve??
Reply to
Parker McMillan

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