Hello everyone,

Since I just did this on a hit & miss basis (trying to find the perfect spot to cut out an access hatch to the fuel pump), I figured I'd share my experience. Although the standard recommended way to remove/replace a pump is dropping the tank, my reasons for doing it this way instead are many... starting with not having the means to drop the tank on the driveway on this low-rider SLE Jimmy and a local garage charging $300 to put in my new pump (and that's under perfect conditions, assuming the tank straps or other parts won't break in the process and need a replacement as well).

This information is posted elsewhere on various Blazer/S-10 forums, but I haven't found anything for a 4 door model, like mine is... so here it is, I'm bringing this new info to the world of internet!

Ok, enough intro... let's get started:


Picture 1 : The first thing to do was to remove the carpet under the reclined driver-side rear seat (one of the seat brackets, the seat cover and the middle seat belt assembly had to be unbolted to do so -- very easy to do) and determine where to cut the opening. Because of the low suspension and crappy visibility thanks to skid plates, it was hit & miss. Two large holes were drilled to determine the center of the fuel pump (later sealed with large rubber caps). With these photos, however, there will be no guess work for you. It's the reason I'm posting this, to save other potential DIY'ers from having the same "hit & miss" issue.


Picture 2 : Once the place for the opening was established, it was time to prep my tool of choice: the Dremel 4000 and its' flexible accessory. With its' metal cutting wheel, you get minimum sparks (as opposed to a full size grinder) and very good maneuverability. I knew my pump/tank were well sealed (no fumes could be smelled), so I didn't mind chancing it with a grinder-type tool in the absence of fumes. Otherwise, you may use a metal hacksaw (which will probably be a lot less precise though).


Pictures 3 / 4 : The cutout opening / hatch completed. I had to use up about 5 or 6 Dremel cutting wheels to get that done, as the sheet metal is quite thick. Note: the old pump's lock ring was so badly corroded and fused to the tank that even Thor's hammer wouldn't make it budge. It was removed by drilling sections of it off (very carefully) and prying on it with a large screwdriver / pliers, combined with generous amounts of PB Blaster and WD40. It finally gave in to the abuse and the pump was removed safely.


Picture 5 : New pump installed and in process of wiring the supplied "upgraded" plug for the new fuel pump (Airtex brand). Although some people claim that aftermarket pumps are junk and die prematurely, the price difference (and ease of replacement with this access hatch in place) justify taking a chance. Also, one thing I have noticed is that the supplied squeeze connectors that came with the pump (for wiring the plug) will be prone to deterioration in the long run. I decided to abandon the idea of using the squeeze connectors and to it properly by soldering the wires, then protect the soldered connections with shrink tubing and electrical tape (picture 6). Perhaps deteriorated connections are a part of the reason why aftermarket pumps tend to die prematurely.


Picture 6 / 7 : Wiring completed (soldered, shrink tubed and wrapped with electrical tape.


Picture 8 : A cover for the access hatch made using some a thin steel flatbar and rivets. Since the hatch is made with the piece that was cut out, it fits perfectly.


Picture 9 : Hatch resealed with the "custom" cover siliconed and riveted to the rest of the floor, plus the seat belt assembly reinstalled (just a few rivets will do the job, no need for an overkill).


There ya have it... done and working like new again!

 

Hey man great job - I noticed you didn't leave the hatch removable if you were stuck on the side of the road in the future, but that could be a while

Any chance at some measurements of the panel you cut or the placement of the hole edges? I can kinda guesstimate from the photos

Cheers and thanks for the write up.

 

Forgot to mention that the procedure was performed on a

2001 GMC Jimmy SLE
4 Door, 4WD (4.3L Vortec V6)



Thanks! The hole is not perfect, mind you... in fact, the top part is cut out slightly too big (too high by an inch or so unnecessarily, as it provided more room than was actually required to unplug/replug the fuel lines). I had to do a lot of guesstimating myself in order to get it where it is. The important thing, though, it to start your measurements right where the center seat belt bolt bracket ends under the sheet metal. You can see weld spots in the sheet metal in the center of that bracket, so it ends approx. 1/2 inch further out (towards the pump). It's a bit hard to explain in words, but you'll figure it out once you see it. In essence, the seat belt bolt has a bracket that runs under the floor - try not to cut it! In my pictures, I got it perfect (luck was on my side that day).

Unfortunately, I was busy with the work and the weather was really crappy, so I didn't take any measurements... just the photos you see using my cell phone. I did try to zoom in on the important areas and take pictures from all angles, so estimating the cut should be fairly easy. If it's any help, the center of my fuel pump seemed to be approx. an inch towards the passenger side from the corner of that black stick-on rubber on the truck's floor (the rubber is factory glued on). You can see that stick-on rubber prior it to being cut in the first picture.

As for the hatch cover and removing it on the trail, this GMC Jimmy is an SLE model and has a very low suspension for some reason, so it ain't gonna see much trail (lol). The hatch can still be opened in an emergency by hacking at the three or so rivets that seal the cover to the floor and by unbolting the center seat belt assembly, which pins the hatch cover down when bolted down. No big deal, I could get the rivets off with my Leatherman if I needed to and I almost always carry a socket set. In any case, getting the hatch open is no big deal, it's usually the lock ring on the pump itself that's the real b*tch requiring multiple tools, especially if it's rusted (hence why I was sure to seal the new lock ring with very generous amounts of anti-seize!). Trust me, the rust on the lock ring is the real enemy in this entire procedure, whether you drop the tank or cut an access hatch... I ended up drilling out bits of the old lock ring and prying it out in sections and only after I soaked it in WD40/PB Blaster for over a day. A new lock ring was obviously a must, since the old one was in bent/rusted out pieces (new one was $22 CDN at a local parts store).

Also, there will probably be people who will talk about how I "destroyed" the floor of the truck. To them, all I can say is:

1. The truck is probably worth $3000 or less on a good day;

2. The floor is just as solid as it's been before - on the 4 door model, you don't need to cut through a reinforcement bar like you do on the 2 door models, which I must say was a great relief! It's all sheet metal, nothing else is in the way;

3. If you make a good hatch cover, seal the hole properly and put the floor mat back the way it was, no one will ever know... except you! ;

4. Any future fuel pump changes will take 15 minutes and save you a few hundred bucks in labor. A lot of import cars/trucks already have factory hatches installed for that very reason (fuel pump servicing made easy).


Last but not least, while I was changing the pump, I inspected the inside of the tank. They say you should remove the tank and drain the fuel (when performing a pump change) so that you can "pressure wash" the tank inside and get any dirt out of it. In my experience, the tank was extremely clean on the inside. I could clearly see the bottom and no particles (other than a few tiny bits of rust that fell off the lock ring into the hole) were visible in the fuel. The truck is 13 years old (2001 model) and has over 100k miles on it, so the cleanliness of the tank's inside was a nice surprise.

All in all, I'm very glad I decided to do it this way. No working on the floor, no dropping the tank, plus I was shielded from the elements while working (inside the truck), which was very useful with the weather we had. What's not to like?

 

Nice work! Nice wright up.
When I changed mine I chose to drop the tank. Inside of tank was extremely clean and no need to flush it out. My tank had 3/4 tank of gas in it. I did consider cutting a hole like you did but...it all turned out well. I also put in the airtex pump. That was years ago and I never had a problem with it

 

Good to hear, thanks for the feedback. I've read conflicting stories (reviews) about the Airtex fuel pumps. Some said they were made in the USA and were up to the same standards as the original equipment, others claimed they received Airtex fuel pumps that were made in Mexico or... China!

To tell you the truth, I didn't even check where mine was manufactured. I'll have to take a peek at the box, provided it's still in the recycling bin somewhere (I examined the new pump assembly before putting it in, but couldn't find any "made in..." sticker or print on it. Just an Airtex sticker and the model number).

The one thing I can say though is that the Airtex unit is almost an exact copy of the original GM pump assembly, minus one of the connections on top that's different (they call it the "upgraded" plug - why is it considered upgraded, I have no clue. I do know you have to solder the bugger to the old wires though!). I got the pump assembly off Rockauto for about $160 all in shipped to Canada. I should've bought the damn lock ring too while I was at it... it was $10 instead of the $22 locally (and I get the shop discount locally, without it it'd be probably closer to $30). If you live in a climate where you get snow and road salt in winter, a new lock ring will be a must. Water just tends to accumulate in that recess on top of the fuel tank, it seems. The lock ring was beyond gone... even though I rustproof the truck every year and it has no visible rust anywhere on the outside.

Anyway, cutting the hole was a fun project and I'll be doing the same if the fuel pump ever dies on my other truck, a 1999 Ford Explorer (which has been a lot more reliable overall than the Jimmy, despite being older). Now the Jimmy has been "upgraded" with a feature that is only available on the more expensive import trucks. Yeehaw!

 

*Moved to 'Article Submissions/Discussions'*

 

great post. gotta do this to my 1998 blazer. a lot better then dropping tank. thanks

 

My pleasure. Getting the lock ring off is the biggest challenge; if yours is shot like mine was due to rust, you might have to soak it in a penetrating oil (WD40, etc) and drill sections of it out. To do so, you make a "line" of drill holes with a medium sized drill bit and then cut the connecting metal between those holes with wire cutters. The small sections come out very easy after that, you can pry them off with a screwdriver and pull on them with pliers. Simple as that.

I wish I had taken a picture of the old ring that was removed in pieces (there were approx. 6-7 pieces of mangled rusty metal). It was a real PITA at first to figure out how to get the lock ring off (because it seemed to be fused to the tank and wouldn't budge), but the drilling out / cutting it in sections method worked great. I don't think anything else would've done the job.

Just be careful not to drill through the tank!

 

Great advice. Just replaced mine in 2001 Jimmy. Went like clockwork, just followed the step by step pictures.
THANK YOU SO MUCH