Thanks.

I was just out there now looking over the tank by looking through the wheel well. Looks like there is only one rubber hose connected to the tank from the steel filler neck. My old Jimmy had two, the larger filler hose and a smaller vent(?) hose. When I replaced the pump on that truck, I ended up just cutting these hoses off and getting new ones cut at Napa after struggling for hours trying to get the old ones off. I'd rather not waste time this time around, so I'd like to have a new hose on hand in case it's tough to get the old one off. Any idea on the size of the rubber filler hose? Definitely smaller in diameter than the four door version.

 

Should be two rubber lines, one for the filler and a smaller vent hose. Not sure on the size though. When you have it apart, make sure the anti-siphon ball works freely in the steel filler neck. If it sticks, it takes forever to fill the tank. I usually remove them on my own vehicles. I don't cherish the thought of standing outside for 20 minutes when it's raining or 10 below zero

 

Still haven't done the pump swap yet, been waiting until I had more time off from work so I wouldn't be rushed. Going to do it in a couple of weeks though. I'm still trying to figure out what size filler hose I might need. I want to have a spare on hand in case I need to cut out the old one. I went to Napa and Auto Zone today to try to get one, came up empty at both. Neither one even had the filler neck either so I could try to get the size from that. Looks like it's a dealer only item, and of course the local Chevy dealer parts department is closed Saturdays. I don't mind spending the money for a new hose if it will save me the time and hassle of trying to get the old one out intact. Anyone done a pump replacement on a two door and know the filler hose size? It's a 2003 if that makes any difference.

Also, I hate to disagree with the Captain since he knows a hell of a lot more than I, but I'm almost positive that there is only the one rubber filler hose going from the filler neck to the tank, no vent hose. I attempted to take some pictures, they kind of suck though since I have a crappy camera. Also, there's a diagram that seems to agree with this:

 

Part #11 in the diagram is the vent tube. (you can see it in both of your pictures) It attaches to the top of the tank, above the fuel level. It allows the air/vapors to escape to the atmosphere that the fuel displaces during refueling. It is sealed when the filler cap is reinstalled. If it leaks fuel vapor when the EVAP monitor runs, a DTC will be set and the service engine soon light will come on.

 

Ah, I see. I was looking for a larger diameter rubber hose that attached next to the filler hose like on my old four door Jimmy. That's where my confusion came from. Thanks for clearing that up. I assume the part I circled in the pic corresponds to part #11 in the diagram?

 

Yup, exactly, part #11. Might be plastic on 2003 2 door.

 

Thanks. The more info I have before starting the job, the better.

 

Sorry for the double post, but I'm a little confused here. According to this illustration under "Two Door Utility Fuel Tank Replacement" in my FSM, it shows a large diameter vent hose (#1 in the illustration) attached directly adjacent to the filler hose. I guess in this case the FSM is wrong?

 

Interesting, my 98 2 door looks just like that, and the filler neck is available aftermarket by Dorman. They don't list a filler neck for a 2003 S/T series Blazer 2 door. The filler neck for a "Trail Blazer", is different, (GMT series). The tank in your first diagram does not look like an S/T series tank, looks more like a Trail Blazer tank. Which filler neck/vent line does yours look like? BTW, the vent tube on the S/T series is about 3/4" in diameter.

 

The first diagram I posted I got from GMpartsgiant, and my setup does look like that one, since it doesn't have the vent hose next to the filler hose. Not sure why the FSM is different, I figured it would be the most reliable source of info.

Before I get too deep into dropping the tank, I'll try disconnecting the hose, maybe it won't be stuck on there as bad as I think. I'm still going to check with the dealer though and see what they say.