To Rebuild Or Not To Rebuild Fuel Pump

1967 CJ5 F head 4 cylinder

In trying to get running I have found the fuel pump to have failed after initially pumping fuel.
This is a double pump with the chamber for the vacuum.
I see both Kaiser and Walck have rebuild kits however at drastically different prices. $40 vs $87.

My hesitation to just order a rebuild kit is that the internals in the rebuild kits show 6 small press in diaphragms. My pump has 4 small and 2 large press in diaphragms.
I have looked all over the pump for info and cant find any other than Made in USA on the outside and FP 1141 cast inside.
Then to add to fun, the price of a new pump is approx $10 more than the most expensive rebuild kit.

I would to keep the double pump setup because of the vacuum wipers I have.

Anybody have any thoughts on this situation?

 

Rebuilt mine this summer, sucessfully.

AS I recall... Only four small poppet valves to press in, which I did using a "precision' hammer, and set them with a punch.

Two large diaphragms are clamped by the casing/screws.

Then there are two seals on the pushrods. (Pullrods?)

Fairly easy - but you really need to pay a lot of attention to the orientations and locations of all the bit-n-bobs. I ended up re-opening the pump about three times as I learned.

Best price I could find for a kit was about $110 with shipping. Be sure you are looking at the correct item.

 

That makes sense.
So far all the kits I can find have only 6 diaphragms of the same size. I cant find any with 2 large and 4 small.
Do you remember where you found yours?

 

If I cant find a rebuild kit does anybody have preference for where to purchase a new complete unit?

 

Maybe I'm mis-remembering the number of valves. But you please need to be clear if you are talking about diaphragms or valves.

My pump was tagged #AC 4032. The kit had the number #9797. They were also used in Ford trucks and other vehicles of the same era, early 50's.

I specifically looked for a statement that the parts were ethanol-proof.

 

Pause for a second. AC Delco and Carter both licensed other companies to manufacture their designs. Along the way, these subs changed a few things in the design. Then, over the years (I say that a lot) pump rebuilders swapped in what they had on hand if a part was bad. I have come across more than a few dual-action pumps with mismatched tops and bottoms that actually worked. If you have already disassembled the pump, (and I hope you marked clearly the orientation of the top and bottom to the center as PeteL mentioned) count and measure all of the valves. Search diligently for ANY numbers inside. "FP1141" is probably a KEM Pumps number. Next, examine the shafts of the diaphragms. One tip style is the square keyhole, the other is a flat with two slots on either side. Now that you have all of this data, call Then & Now. Tell them what you have. They will put together the exact kit you need. They're not cheap, but they're the best I've found.
Proper assembly to ensure that it works correctly involves a procedure where the top and bottom are only snugged, not tightened, to the center. Chuck the pump arm in a vise so that you can manipulate the pump to a full stroke. I use a narrow ratchet strap to hold the unit in that full stroke, careful not to over-extend the stroke and cause damage to the external spring keeper. Then tighten the screws. This procedure puts a preload on the diaphragms and ensures proper vacuum pressure on intake and outflow for both ends.

 

So I apologize for the wrong description, I am specifically talking about the qty and size of the valves.
I did take pictures of the orientation of everything as it came apart.
Thank you for the guidance, I would have never thought of mismatched parts.
It seems that Now and Then is the missing info I needed.
I will give them a call as soon as I can measure the diameter of the valves.

 

Thanks to scoutpilot jogging what I laughingly refer to as 'my memory,' I can confirm it was "Then and Now." Seems to be working fine.

 

So after a bit more digging I found more info cast in to the center section. I found 2 cast in markings. FP 767 and FP 762. The upper section had FP 1141. So far I cant find anything on the lower section other than made in usa, in, out, and wiper with an arrow.
I measured the valves. The large valve is 1” diameter and the small valve is 3/4” diameter.
Will call Now and Then tomorrow and see what they might be able to do.

 

Don't forget the diaphragm shafts!

 

Well crap!!! Would have never thought to look there.
They do have the square holes in the end of the shaft and hook onto the pump levers.

 

Thank you all for the advice. I reached out to Now and Then for a rebuild kit. They were great to deal with and the parts worked great. I am now pumping fuel and with the rebuild of the carb now have the jeep running. Fighting an idling issue and still need to check the timing.

 

Time it first, after setting the points. Get everything possible to FSM spec before tinkering the rest.