4657 AC Fuel Pump Rebuilding questions

[Mark P.]

I am rebuilding my fuel pump after a very small leak in the diaphram. I can't see light through it but there are some cracks that have very thin fabric causing a little fuel to leak from the weep holes.

Here are my questions:

1. should I leave the arm pivot pin as is since I want to preserve the peened pin (no e-clip) visible in the first fuel pump photo ? There is minimal play. This photo is before cleaning. My kit (FPA-243) from Then and Now Automotive comes with a new pin and clips but I won't use them. This kit is 100% made by them in Weymouth, MA.
2. anyone have a way to clean up the casting better ? I have tried a degreaser and Evaporust and it looks better. Would a light blasting with 100-170 grit glass beads improve but not ruin the finish ? The other photos are after cleaning.

Thanks,

Mark

[Mike M.]

I never replace the pivot pins as the arm rarely wears out. if u glass bead it, keep pump as far from sand blasting nozzle as your cabinet allows. or you could try soaking a small area in metal prep. good luck, mike

[Timothy B.]

One thing I would suggest to do is to broach the pump mating surfaces before you put it back together. If you could tumble it that would make it look great but a fine glass bead would look good also.

[Bob J.]

I'd only blast the center, since it's aluminum.

The lower cover is magnesium and it has pits already visible. Probably many more pits will show up in the soft spots after beading.

The upper is die cast.....up to you.......... but I think uppers never look origie beaded.
It may look pretty, but it will turn grungy faster on a beaded surface. Plus, you're going to have a job getting the media out with the rocker arm still attached.
Good luck whichever way you choose.
Bob Jorjorian

[Bill B.]

Mark,

You might want to try 3M Marine Aluminum Restorer & Polish, P/N 09020. I used it to remove severe corrosion from my '70 coupe rear window frame. Perhaps using a toothbrush or equiv. with repeated application and removals. It might restore some shine to your pump body.

[Ian G.]

I wouldn't bead blast it. I've had good luck using the chelating rust remover (like evaporust) followed by tumbling with rust-cutting resin (plastic) media to clean things like that. Mine is a 5 lb metal vibrator from harbor freight, but not sure if that pump will fit. Probably would all disassembled. They also sell an 18 lb one.

[Mark P.]

Hi Everyone - I lightly blasted it with glass media then tumbled each piece for 2 hours with 12 grit walnut shells. I am satisfied with it but will also try the marine restorer/polish. Black stains would just show up after I thought it looked fine. Thanks for all the great suggestions. Mark

[Mark P.]

I finished the rebuild and everything is working well. Here is what I learned doing this project:

1. after bead blasting the castings I tumbled them in 12 grit walnut shells to improve the finish. I then used the marine aluminum polish and it helped remove some of the black staining
2. I bought my rebuild kit from Then and Now Automotive and they were easy to deal with. Tom, the owner, suggested I check the flatness of the casting by running them across some 100 grit sandpaper very lightly. I put the sandpaper on my table saw table and the scratches were pretty even so I put it together
3. the rebuild was straight forward. The Dave Zuberer article was helpful. I used a ratcheting bar clamp to depress the lever and tightened up the diaphragm
4. it was a bit tricky to get the diaphragm to hook onto the actuating lever. The best way for me was to remove the rocker arm spring then use my finger to depress the actuating lever and feel for the slot in the diaphragm. You can actually feel the diaphragm slot which was really helpful. Once hooked I put it together then installed the rocker arm spring last. I depressed the pump and could hear the diaphragm going up and down and a suction type noise.
5. when installing it I found a 3/8" socket with a 6" extension worked the best. I used a finger ratchet to get the bolts started and snug them up until the casting is about 1/8" from the fuel pump mounting plate. If the gap is farther than that then the fuel pump push rod could have slid down. I learned the hard way to snug up the push rod installation bolt with a wrench because it did slide down during the first installation when the bolt was just finger tight.
6. Thank you for all the help.

[Mark P.]

Here are some photos