DIY017 4441 AC Fuel pump rebuild

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DIY017 4441 AC Fuel pump rebuild

Post by 59lincolnrag » Sun 28. Jul 2013, 16:44

4441 AC Fuel pump rebuild: Updated 9/02/2017 Rev D

An NOS pump might appear to be in working order but rest assured it is NOT. It must be rebuilt with fresh components. The fuel pressure needs to be 4.5 to 6.5 psi.

Shown here is a typical rebuild kit for the AC 4441 Pump
Lets look at the pump itself. This view would be the drivers side
This would be the Passenger side view.
Start Dis-Assembly by removing the 2 screws that hold the lid in place.
Don't forget to carefully examine each piece. Look closely at this casting . Do you see where the fitting screws into? (Click on the picture to enlarge)
This NOS pump is not road ready!
Next: Remove the 10 screws that hold the vale body in place. The poppet valves can be knocked out with a medium sized screw driver or punch and a small hammer. Be careful not to damage the casting.
Notice the small gasket rings. (They are supplied in the kit) Be sure to install the new ones when re-assembling.
You can also see where the valve on the right was staked to the casting in 4 locations...
Himmmmmmm. Ok... Now what ?
With a sharp carbide drill bit drill down just deep enough to relieve the "rolled over" materiel.and knock out the clevis pin. Note the washer. Make sure you replace it! (Supplied in the kit)
There's a surprise inside so be careful. Press the diaphragm down so the spring cant pop out when you remove the clevis pin. Take note of the assembly sequence. Also, notice the seal and copper ring pressed into the housing base. When the diaphragm leaks this seal helps to keep fuel from flooding the crank case.
I placed an additional lever in the picture so you can see how it hooks on to the diaphragm and interfaces with the pivot arm.
Look at the two pictures below...look carefully at this professionally rebuilt unit .... I personally purchased this pump from a pro shop. From day one it was nothing but trouble. If you look carefully at the first one you can see that the casting is actually arched between the screws. This is caused by over tightening the screws. The other reason is the fact that someone used a belt sander to make the two casting halves flush with one another. This will weaken the casting. If you see this arched condition with your pump or the half's do not mate flush use another casting. When the casting do not mate flush to one another this can cause hard starts (sucking air). In the second photo fuel is leaking after warm up ....

In the following picture. do you see anything wrong? Where did the metal filings come from? Notice the casting material rolled over and still clinging to the casting. I think I would make use of some 400 grit wet / dry cloth and the kitchen counter top (a clean flat surface) NOT A BELT SANDER!
In this picture there are more shavings. Also the casting ridges are sanded off causing the parts not to seal. The ridges help the rubber diaphragms to seal and allow a little forgiveness if the castings are not exactly flush.
Although the intention was good the fact is, Sanding too much off the casting is not good. This picture shows more shavings stuck in the valves. (stranding me on the highway and costing me an expensive tow). Also notice the valves are not staked. They need to be carefully staked in 3 or 4 equal locations. ( the Pro Shop from the New England area) pushed back after even after seeing these photos. They rebuilt the pump the second time it was worse . I paid the freight. Lesson learned. DO IT YOURSELF!!
When you re-Assemble your pump take your time. Make sure you pre-load the diaphragm before you tighten the 10 screws and don't over-tighten them. Check the castings carefully. If you must re-surface the castings just use some 400 or 320 grit. The rubber diaphragm / gasket will seal. You can paint or clear coat the castings before assembly.


These cars are prone to vapor lock. It's not the carburetor. Cool (as in not boiling) fuel fed into a hot carburetor will not continuously boil off. It's usually at or before the fuel pump on the suction side of the fuel system that vapor lock occurs. The pump is unable to create enough vacuum to pull the fuel from the tank. Check your lines from the pump back. A weak/old fuel pump can make the problem worse. An electric pump near the tank so the line is under pressure usually cures vapor lock problems. Another common problem is the bronze tip wears down on the FP push rod. replace it!........Additionally, I installed an aftermarket carburetor insulator gasket set. And applied some high density black foam insulation on the fuel line as shown below.The reason for this is to keep the fuel at a lower temperature and less fuel evaporates after shut down.This helps in starting after an extended time not running. (leaves more fuel in the carb)
When installing a fuel pump on the 383, 410, 430, 462 CI engines the fuel pump push rod is very very
important.From 1958 through 1962 the fuel pump push rod has a brass tip on the bottom of it that rides against the fuel pump concentric. (The fuel pump push rod from 1963 through 1968 ½ was of solid drill stock and the concentric was a two part unit so it could freely rotate and not prematurely wear out the concentric).
The push rod should be measured to make sure that it is within factory specs. If it does not meet specs it MUST be replaced.
1958-1962 Fuel Pump Push rod with Brass Tip; 4.871”-4.881”
1963-1968½ Fuel Pump Push rod without Brass Tip 4.808”-4.812”
51zQV9+LYjL._SX355_.jpg (5.21 KiB) Viewed 3302 times
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