I'm getting ready to install my Walbro pump in the next couple days, I got the rubber o-ring seal but I'm wondering if I also need to use RTV or some other sealant along with the o-ring.

 

I've never replaced the pump on my car, but since no one else has answered this I figured I would. Only use sealant between two mating surfaces. On a mechanical fuel pump you don't use sealant on the o-ring, but where the pump connects to the block. If it wasn't there when you took it out, I wouldn't put anything there when you put it back in. Hope that helps.

 

Sorry, I should have specified that this is an intank pump, not mechanical.

 

I did mine about a year ago and didnt use any kind of sealent and have had no problems at all.

 

Right, I know it is in tank. I was just guessing based on how to do a mechanical one. Looks like I may have guessed correctly

 

Silicone is soluble in gasoline. Don't bother with it. Just use the O-ring.

 

RB is right (as if I needed to mention that). The only thing I can add is that you need to make sure the two surfaces are clean. You are very likely to find rust and debris on the float/pump cover, so try to brush all the loose particles off the parts before reassembling them.

I've never used a sealant, but to facilitate easier installation and engagement of the bayonet ring that holds the cover in place, I have used clean engine oil on the 'O' ring and bayonet clamping ring and the little ramps that it engages on the top of the tank flange. Just keep it clean.

And as a reminder, as long as the tank is out, it might be a good idea to flush/clean it out as best you can. Any debris in the bottom of the tank is going to get sucked right through your new pump as soon as you fire it up. The inlet filter only keeps out the big particles, so don't rely on that alone.