The Walbro 400 kit I bought came with a rubber sleeve thing that is supposed to go on the outside of the fuel pump. What is the purpose of this sleeve? Do I need to use it? If I use it will the pump run hot since the fuel won't be able to touch the pump case, and the sleeve might insulate the pump holding in heat?

Here is a kit on eBay that is basically the same thing as what I got. The sleeve in question is in the lower right corner of the pictures.

Walbro TCD300HP E85 450LPH Subaru 02 04 Racing Fuel Pump Install Kit 98 12 WRX | eBay

 

The Walbro 255 I put in my Camaro had the sleeve and I put it on... a few years later I had some fueling issues with the car and pulled the tank. The friggen sleeve had caused the pump to corrode severely underneath it. Corrosion was so bad I threw the pump away and bought a new one. Keep in mind this car sets a lot, less than 6000 miles in 10 years, but I wouldnt use the sleeve period.

 

I find that very interesting. You must have had quite a bit of water in the tank for the corrosion to take place, probably from lots of sitting. I ended up using just a small piece of the rubber sleeve to center the top of the pump in the bucket. Most of the case is still exposed to maximize cooling.

 

Anyways, do not install the sleeve. Don't overcomplicate this. Open up the hole in the bottom of the bucket and drop the pump in the basket. Zip tie it to the bucket and be done with it.

Edit: Any reason in specific you bought the WRX kit?

 

That's not the kit I got, it was just a random pic I found that had the sleeve shown. All of the install kits are basically the same anyways. Most of the kit is useless for people like us who do custom installs.

 

Its to limit the noise from the pump by preventing vibration against something hard like the bucket walls. I dont recommend using it either.