Super88chris

I bought remanufactured fuel pump for my 55 olds super 88. It’s been great for a few months until now I noticed it’s wet around the fuel pump diaphragm section. Before installing the pump to the engine I tightened down all screws. Is there anything I can do to make it stop leaking? It is still working

Olds64

Where did you buy the fuel pump and what type of fuel do you run in your Oldsmobile? If the body of the fuel pump is leaking I'd say it has failed.

Super88chris

I got it on eBay and I run the cheap 86 octane ethanol fuel. So the body has failed? The diaphragm hasn’t because it still pumps

Olds64

If you're able to get 100% gasoline that's all I would use. Generally there's a gasket between the fuel pump and the block. Make sure that's present and in good condition. If it continues to leak from the body of the pump you'll have to decide whether or not to replace it.

Super88chris

there is a gasket I just replaced it. There’s not supposed to be a gasket between the diaphragm? Seems like that’s where it’s coming from. You mean non ethanol?

justacog

The diaphragm is the gasket. I would recommend pulling it off and tightening the screws around the diaphragm. Sometimes these things "settle in" and the screws securing the diaphragm just need to be retightened.

Super88chris

That’s exactly what I did, seems ok for now. I also added lock washers because there wasn’t any

Tedd Thompson

My car has run on alcohol 87 gas for somewhere around 75 thousand miles with no gasket problems. I would think that with the new gasket material in your fuel pump, you would be safe. Have you smelled and looked at your oil to see if it is thin, your diaphragm may have leaked some gas into the crankcase, probably not, but it is a cheap check and a little piece of mind if you catch it now...Tedd

BobsFiftyEight

Was the diaphragm that was replaced with the "modern rubber" that will withstand modern alcohol fuels?

Terrill Machine in Texas sells the "modern fuel pump rebuilding " kits.


Bob

Wally

I usually go overboard with things but I would use my torque screwdriver to tighten all the screws to the same value in order to assure even force on the diaphragm. If the screws aren't uniformly tightened you could cause a leak.
But I tend to go overboard with my torque wrenches, no bolt or nut gets hand tight, it's taken to the proper torque.
Wally

Olds64

What torque spec would you use for the screws on the fuel pump?

Wally

I'm not at home right now and I tried to upload my torque chart without any luck.
If you can tell me what thread size is for the screws, I can tell you the recommended torque.
Wally
It did post after all.

Super88chris

yes mine has a modern rubber. I noticed it stretched out tho because after I loosened it all up the holes in the rubber didn’t want to line up with the screw holes but I got it pretty evenly tight all around

Tedd Thompson

The screws are 8 32 and I just tighten them up just enough Tedd

Wally

"Just enough" is never good enough for me, that's why I have four torque wrenches and a torque screwdriver.
Wally

Supernice88

When you tightened the screws you probably caused the diaphragm to slip inwards and it started leaking. During the assembly the fuel side has to have a preload done which flattens out the diaphragm while the screws are fastened down evenly.
At the position 20:18 in this video it's shown You might want to watch the whole video and learn about the pump. 'Then and Now' sells the rebuild kits for many pumps.

maineolds

hows it going with that leak? I replaced my 1949 fuel pump with a replacement from Fusick last year. It was a drop in, no rebuild required. Ive found that the pump diaphragm "gasket" has swolen as if its reacted with ethanol fuel. It's suppose to be safe for all modern fuel, but its leaking just the same around half of the screws. That diaphragm "gasket" is soaked. I can see it. Seems like the screws are tight. I going to call Fusic on Monday and see what they say about a replacement. Did yours stop leaking by giving it some additional torque?

Super88chris

I just gave mine a good muscle torque haha. It hasn’t really leaked but I do notice a shine just around that gasket. It’s not the screws cause mines doing the same thing. It seems like just rubber but my old ones were a cloth rubber material