Fuel pump rebuild kit

[Pinder]

Hi everyone. Its been a long time since my last post as life diverts your attention. I have attempted to rebuild my original short pumps for my 69 and 70 . With limited success. It worked but fuel leaks persisted. Can you please recommend a good rebuild kit? Thank you for your help.

[garwoo]

You might try Vintage Euro Parts Inc. About $100, or with a new impeller $170. They have a technician to give you any help You need, although He refused to come over to my garage in Person!

[Pinder]

thanks you. I will check it out. Appreciate the guidance. Best regards. Pinder

[mdsalemi]

We have our own pump guru here, in the forums. Bob “Baron” Youngman. His expertise on the short pumps is without compare.

If I had any question or issue or a problem with a short pump Bob would be my first and my last call.

[BaronYoungman]

So just a short run down the original Mercedes gaskets and the new mercedes ones are neoprene which do not hold up as well against ethanol gasoline. Viton gaskets are what you want. The neoprene ones will initially work fine matter fact they might work fine for a number of years, but if you're in it for the long haul I do suggest viton. You might try dosing the pump with baby powder and seeing where the leak is actually coming from. Because of the way the pump is shaped sometimes it can be deceiving what is actually leaking.
Bob

[mdsalemi]

...are neoprene which do not hold up as well against ethanol gasoline. Viton gaskets are what you want.

Actually, neoprene doesn't hold up well in the presence of any organic solvents--gasoline, oil, alcohol, mineral spirits, etc. Viton is the superior "rubber" gasket and O-Ring material for nearly every application.

I learned this the hard way owning a car wash...neoprene was about useless. I had all kinds of o-rings on all kinds of check valves, etc. and teflon and Viton were the only suitable materials.

[Pinder]

Thats great. Where can I get that rebuilld kit. its the rubber o rings that just didnt seem to work when I did the rebuild. its the smaller o ring of the 3.  the kit mentioned in the earlier post is the one I used last time and it did not work well. started leaking a bit. Maybe I did it wrong but I used the same kit on two pumps both leaked.

[BaronYoungman]

So where exactly is it leaking from around the electrical connectors? Or the seal from the can to the electrical piece? Or from the bottom plate? Again make sure that you're making sure it isn't leaking from a different part. If you can let me know where it's leaking from I can give you some ideas. or you can ring me at 630-903-9877 Bob

[Pinder]

it leaks from the commutator housing to the pump housing the thing that looks like a fan / propeller. at the join.

[BaronYoungman]

Then my guess is that the lower part the one that has the inlet on it is bent. If you take it apart and lay it on a table that is flat preferably glass just see if it lays flat or if it wobbles. That part is most likely to get bent when pulling the pump apart. Bob.
If it is bent it doesn't matter what type of gasket you use the gasket itself won't be strong enough to hold back the gasoline.

[Pinder]

I will look at it this weekend. Thanks for the guidance. Bob.

[Pinder]

I got the rebuild kit from Authentic classics. And did a rebuild. I made sure all mating surfaces and the impeler were flat by wet sanding  with fine wet and dry paper using the kitchen quarts counter top as its dead flat. (Wife was not home at the time). I also replaced the o rings on the electrical connections. I tested for leaks by blowing air into the inlet side at 15 psi and  checked for air leaks. It held up fine. I put it in and pump did not leak. I have yet to do a pressure and flow test.  The only thing I did not do which i may try on another pump is to replace the commutator bar and re do the windings. I looked at a few videos on how to do this and it does not look too difficult.  I have rebuilt two pumps and ill test both for flow and pressure.  I plan to retest after  i do the commutator rewind and see if it made any difference. Will report back when i  get some time to do this. What i have also done is to install a new carter pump until i am confident the flow and psi re to spec  on the rebuilt pumps. The carter pump seems to work surprisingly well and also a lot quieter than I expected.

[Dave]

I’m new to this site having trouble with the fuel pump. As per this post, the leak that I’m seeing is from the electrical connecting plates. Is it a case of replacement of those O seals? Are these standard seals available on the market or should I look for a full rebuilt kit?

Thanks,

[Pinder]

they are o rings.  I ordered Viton 0-rings 180 piece set. one of those sizes fit.

https://wilmarllc.com/w5239/w5239-180-pc-viton-o-ring-assortment

[BaronYoungman]

Keep in mind not all o rings are correct. I just took a pump apart to rebuild ( the gasket was not dried out so definitely a replacement) and the electrical o ring shown on right the outside diameter is significantly smaller so when compressed I doubt it would seat against the outside metal cylinder to cause pressure both downward and expansion outward see pictures Bob

[BaronYoungman]

To illustrate a proper gasket should need to be pushed in to fit (see picture1)while this one picture #2  where thegasket drops in with gaps around the edges