VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Vacuum fuel pump oil leak

My son rebuilt the vacuum fuel pump on our 1950 Chevy 235 engine several years ago using a kit from Antique Parts Cellar. The top end of the pump that moves the fuel works great, the bottom end that is supposed to supplement the vacuum to the wiper pump leaked oil from the start and never seemed to help the wiper operation. We ordered just the parts for the lower end and ended up with the same result, the pump is probably the worst leak on the engine. Is there a trick to rebuilding the vacuum end of these pumps?

Gary,

Seeing that no one has responded up to now, let me comment.

I don t 'know the answer to your question. I have no experience with that type of fuel pump. Double-action I think they're called.

You may have a bad gasket or a crack in the pump's casing. Accordingly, you may want to inspect the pump's casing for a crack. Using a little oil-resistant sealant with the gasket may help also.

Anyway, my suggestion would be to install a regular fuel pump and take the vacuum for the wipers from the intake manifold. This of course will result in a decrease in wiper action than that provided by the double-action pump.

Just an annoyance when you are climbing hills in the rain. Remedy: Let up on the accelerator pedal now and then to help clear the windshield momentarily. If hard rain is forecast, then leave the car home and find some other mode of travel if you must go somewhere. Don't even use it for an emergency trip to the hospital. Call an ambulance. Getting blood out of the upholstery is hard to do.

If you love your old car then nothing should interfere with you taking care of it. Driving your old car in the rain is a no-no. I'd rather die than abuse mine by getting it get wet (except a hand wash job now and then) or have to travel without clearly seeing where I'm going. Would too!. Of course if yours has been modified or personalized, then have at it without reservation; blood and all.

Best,

Charlie

There was a vacuum fuel on my 52. When I rebuilt the engine, I noticed that it took a lot more pressure to operate the vacuum pump. So I did not use it. I will send it to somebody free for cost of shipping.

Having had 3 of these combination vacuum/fuel pumps on my 1950s, I don't recommend them. Every pump eventually blew oil out of the vacuum section vent.
Even here in the rocky mountains, engine vacuum is sufficient to run the wipers. If you get in a situation where you have to keep the pedal on the floor, do as Charlie says: "Let up on the accelerator pedal now and then to help clear the windshield momentarily."

I agree with the above. They are nothing but trouble.

You could add a vacuum tank under the dash if you struggle - there are hundreds listed on Ebay.