VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 fuel pump?

Why would my fuel pump on my 28 chevy be sucking gas into the vaccum tube and in to the manifold and flooding the engine? What should I check for? It was rebuilt not to long ago but has not been used much since the rebuilt. Been restoring the car for the last year and ready to get it on the road and now have encountered this issue.

There are a few of reasons
1. most common is a cracked or leaking float.
I'd start checking these first, the float is easy, look for cracks in the walls, and see if the solder holding the hook shaft is not cracked. This can be fixed easily, if the float is cracked that is not so easy.
2. the valves in the top cover aren't seating.
The top cover has two brass shafts with a hook on the end, hanging from the top inlet. The best way to see if they're seating ok is to hold both closed by pushing up with your fingers, then suck on the top where the vacuum line connects. If it is OK it'll stick to your tongue, if it doesn't they'll not be seating, and this is very hard to fix.
3. the flapper valve at the bottom of the inside chamber isn't seating properly.
Turn the chamber upside down and try to blow through, if you can then the flapper valve isn't seating properly, again hard to fix.
Chris

Can anybody tell me were to repair these?

Why dont you have a go at it yourself, they are a lot easier to work on than you think.

Go on, have a good try at fixing it yourself.... You'll be surprised how easy those things work

Not scared of the challange and will give it a try but is there a manual on these at least to help a little bit?

go to www.geaaonline.org/vacuumfuelfeed.htm and you can download the manual. I found it somewhere else and down loaded it as a pdf file.

Dougs27

Good Luck,

There is nothing like the feeling that you fixed it yourself, and they are so simple to work on, even a country boy from up Gippsland way was able to fix one with a bit of fencing wire and a 4 pound hammer. Sorry, that was a 3 pound hammer.

Cheers

Ray

The link shows the '27 and earlier vacuum tank. The '28 was different as the two valves were activated from a central shaft on the float. It was much simpler that the one illustrated. The basic operation is the same so the procedures shown can be used as a guide in checking the '28 version.

Will give it a try over the weekend. Thanks for the help and will let you know how it goes.

To check the float for holes/cracks simply hold the hook on the top and put the float into hot water.If there is a hole or a crack there wil be a bubble stream.

Well got to look at the pump this weekend. All the vales are good and work as they should and found the problem to be that the float some how got stuck in the up position so a simple fix. But for the bad news the float had a small amount of gas in it. Upon further examination it had a bunch thin rasied lines on it and they were all hair line cracks. It looked like a bunch of ripples on water it was sorta weird never seen anything like it. So needless to say will be looking for a new float.

Sounds like you are talking about a bell shaped float. That unit is available in reproduction at several places. Contact me if you can't find one.

Your old float may be fixable. Put it in hot water like said above and find the holes. then put the float in the freezer to get cold. When you take it out, put the holes at the low side and as the gas expands, it will push the gas out of the float. Then clean the hole area realy well and solder them shut. Then file down the solder to remove the excess solder (weight). The bad news is this may just work for a while as the vacuum and pressure changes may "work" on the float to make new cracks or open up the old ones. You also might get lucky and be able to use it forever. Give it a go and see if it works.I have fixed many brass carb floats this way and all of them held.

Thanks I will give it a try.

Once the floats begin to have the long cracks they are really just junk. Unless there is no other option just throw it away and buy a replacement. Replacements are available from Stanley's Parts Stanley's parts website

If you really want to try to save it you will need to drill a small hole at the end of each crack (to stop further cracking) and then solder it. If you don't drill the crack (to relieve the stress) will eventually continue past where you have soldered.