71 SB Fuel Pump leak

[lostintime53]

It was the first beautiful day this month and I decide to drive the 71 SB coupe to work. I backed it out of the garage and let it warm up for a bit. I noticed "nickel coin" size wet spots in a neat little row from the garage to the front of the car. One touch and it smelled like gasoline. I opened the hood while the car was running to check for the source of the leak. It appears that the gas was coming from the top of the fuel pump housing near where the hoses attach. The “S hoses” (Doc Rebuild) were replaced last year, are like new, and the clamps are secure. Gas seemed to be coming form a little hole in the housing itself. After sitting five months, my car is deadlined for a fuel pump leak.

Questions:

What is the probable source of the fuel leak?

What is the trick to replace the pump without the pump rod sliding out of the block?

Does a seal go between the pump and the block (I have had an oil leak around the pump housing for the last year)? We used black RTV for a seal (bad idea) last time we removed the pump.

Can engine oil blow around the fuel pump housing if the seal is poor?


Thanks in advance,

Rick in Tennessee

 

[mike weyman]

not sure i can help with the pump, but you can buy a product called "seal all",red and yellow tube, it's the only thing i know that gasoline won't eat.

 

[JohnZ]

Fuel coming out of the vent hole on the pump says the diaphragm has ruptured and it's time to replace the pump before you have an engine compartment fire. There's a gasket between the pump mounting plate and the block, and another one between the pump and the mounting plate; you don't need to remove the mounting plate when you replace the pump, but you need a new pump-to-plate gasket. Adhere that gasket to the fuel pump with Permatex "High-Tack" or equivalent gasket sealer/cement before you install it. The gaskets seal oil from the fuel pump mounting cavity, not gasoline.

 

[corvettegreg]

a couple tricks I have used on keeping the pump shaft from sliding down when replacing the pump.......

some blocks have a threaded hole inline with the shaft, and have a short bolt installed. You can remove that bolt and install a longer one. VERY CAREFULLY tighten until it just touches the pump pushrod....push the rod up and as it slides down slowly tighten the bolt. You want to just touch the shaft to hold it from sliding...overtightening can cause problems. After installing the pump, remove the long bolt, put some sealant on the short bolt and reinstall.

On blocks without the threaded hole, I have put some grease such as axle bearing grease on the shaft and pushed it up. The sticky grease will hold the shaft long enough to insert the pump and will eventually be washed out by the engine oil.

Good luck

 

[brusso]

I've used the longer bolt trick and it worked very well. Someone else, on a previous thread some time ago, mentioned using a magnet that will fit in the bolt hole instead. that way you don't have to worry about over torquing the longer bolt. The bolt in question is located on the front of the block very close to the fuel pump. You'll know which one it is because it doesn't appear to have any other purpose. In other words, it's not bolting anything to the block.

 

[wishuwerehere82]

Like JohnZ says, ruptured diaphram in the pump.Make sure you change your oil and filter after you are finished. There's a good chance that gas is in your oil now.