Cutting hole in floor to replace fuel sender

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

nbkk43f

Full Access Member
Joined
Aug 16, 2023
Posts
55
Reaction score
101
Location
charlotte, nc
First Name
Nick
Truck Year
1977
Truck Model
c10
Engine Size
5.7
I’m with @xm20k on this one…. I’ll add rusted out or clapped out shitbox to the racecar or rock crawler statement
Agreed - I cut a hole in my rust 96 1500 to replace the fuel sender. Tackling the rusty bed bolts didn't seem like a fun job.

This truck doesn't see a ton of miles these days so I bought the cheapest sender/pump I could find, expecting it not to last long - figured the easy access would be handy. Tacked on a hinge and a lip to keep it flush, all of which is covered up with the drop in bed liner!

As others have mentioned, I was a bit nervous making the cut, but took my time laying everything out. Thinking back, I reckon I could have used the nibbler to avoid sparks.
 

YakkoWarner

Full Access Member
Joined
May 29, 2024
Posts
643
Reaction score
1,049
Location
Central Texas
First Name
Wolf
Truck Year
1989
Truck Model
R2500 Suburban
Engine Size
454
If you can get the pump to run one last time, jumper the relay and pump it out. If not you need a HD pump for a motorhome to create enough suction to get the checkball to move. Puny external pump won't do it, it has to be a big-un. Pop told me this trick, but didn't specify the size of the pump. I bought an in-line pump and it wouldn't suck enough to move the check ball. Fortunately the pump still ran and I was able to pump out the fuel.

It might run intermittantly, or it might not. I'm actually thinking its not the actual electric motor but either a broken or partially plugged pickup tube, a partially blocked sock or something like that. I'm pretty convinced its an in-tank problem since there is no secondary high pressure pump on the frame for this truck, the filter is new and blows thru easily, and the whole TBI assembly (with the intergral regulator) is new. I appreciate the tip; there is a dead RV up at the rental shop, so getting a heavy duty RV pump might be possible.
 

Catbox

Full Access Member
Joined
Jul 12, 2018
Posts
4,874
Reaction score
19,038
Location
Just Outside of Portland Oregon
First Name
Peter
Truck Year
1979
Truck Model
C20 Silverado Camper Special
Engine Size
461
I dropped the tank on our 1995 Sub.
Not a difficult project and the 40 gallon tank was damn near full when it crapped out.
So we pumped out as much as we had gas cans for.
You must be registered for see images attach

ATV jack for the win!
Just look at all that nice rust free metal.
You must be registered for see images attach


You must be registered for see images attach

Cleaned the filth off the top of the tank before opening.
You must be registered for see images attach

I could not imagine trying to weasel this thing out of a hole in the floor I had just cut.
Hoping I made the hole big enough.
You must be registered for see images attach

When it happens again, I'ma just drop the tank again as it is simple enough.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
9,940
Reaction score
19,065
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
It might run intermittantly, or it might not. I'm actually thinking its not the actual electric motor but either a broken or partially plugged pickup tube, a partially blocked sock or something like that. I'm pretty convinced its an in-tank problem since there is no secondary high pressure pump on the frame for this truck, the filter is new and blows thru easily, and the whole TBI assembly (with the intergral regulator) is new. I appreciate the tip; there is a dead RV up at the rental shop, so getting a heavy duty RV pump might be possible.
Jumper the relay and pound on the bottom of the tank hard. It will probably fire backup,drive it home,don't turn it off for anything!!!!. To empty put your supply line in a bucket can ,whatever, plug the vent use a red rag and a compressor hose to blow some pressure in the tank( not 100 psi) your rag should bleed off pressure.I dropped my 88 burb tank in a gravel driveway,with a reciever hitch and factory exhaust in a gravel driveway NBD . As mentioned I don't think I could have made and patched an access hoke in the amount of time it took to drop and reinstall the tank. Also I think you can pull the fill hose right at the tank to siphon it,Been too long since I did mine
 
Last edited:

CountKrunk

Full Access Member
Joined
Aug 3, 2023
Posts
980
Reaction score
2,274
Location
SW VA
First Name
Count
Truck Year
1984
Truck Model
C20 Custom Deluxe 3+3
Engine Size
v8 350
Fuel pumps are probably the #1 thing i hear about new parts sucking. Even the "name brand" ones.

I need to drop mine so i can get the fuel gauge working, and access overall condition. It pumps fine though so I'm not in a hurry.
 

bucket

Super Moderator
Staff member
Moderator
Joined
Aug 3, 2010
Posts
35,095
Reaction score
43,609
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
I dropped the tank on our 1995 Sub.
Not a difficult project and the 40 gallon tank was damn near full when it crapped out.
So we pumped out as much as we had gas cans for.
You must be registered for see images attach

ATV jack for the win!
Just look at all that nice rust free metal.
You must be registered for see images attach


You must be registered for see images attach

Cleaned the filth off the top of the tank before opening.
You must be registered for see images attach

I could not imagine trying to weasel this thing out of a hole in the floor I had just cut.
Hoping I made the hole big enough.
You must be registered for see images attach

When it happens again, I'ma just drop the tank again as it is simple enough.

Iirc, the '92 and later are significantly easier to deal with.
 

Catbox

Full Access Member
Joined
Jul 12, 2018
Posts
4,874
Reaction score
19,038
Location
Just Outside of Portland Oregon
First Name
Peter
Truck Year
1979
Truck Model
C20 Silverado Camper Special
Engine Size
461
Iirc, the '92 and later are significantly easier to deal with.
Well be that way.
Max just did his '84 tank a couple of times in the driveway as well.
Now you are going to tell me it was easier because it is lifted!
Bwahahhhahhahahahhaa....

You must be registered for see images attach
 

bucket

Super Moderator
Staff member
Moderator
Joined
Aug 3, 2010
Posts
35,095
Reaction score
43,609
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Well be that way.
Max just did his '84 tank a couple of times in the driveway as well.
Now you are going to tell me it was easier because it is lifted!
Bwahahhhahhahahahhaa....

You must be registered for see images attach

Lol. I only remember ever dropping the tank on my '88, no other squarebody Burbs. The big 40 gal capacity makes it difficult enough. The trailer hitch makes it a pita. The stock single pipe was in the way. Then the dual pipes later on... no thanks.

And that was back when I could do things on a lift, with the help of a trans jack.

I've dropped the tank on several later Burbs and I don't remember them being as difficult.
 

YakkoWarner

Full Access Member
Joined
May 29, 2024
Posts
643
Reaction score
1,049
Location
Central Texas
First Name
Wolf
Truck Year
1989
Truck Model
R2500 Suburban
Engine Size
454
Jumper the relay and pound on the bottom of the tank hard. It will probably fire backup,drive it home,don't turn it off for anything!!!!. To empty put your supply line in a bucket can ,whatever plug the vent use a red rag and a compressor hose to blow some pressure in the tank( not 100 psi) your rag should bleed off pressure.I dropped my 88 burb tank in a gravel driveway,with a reciever hitch and factory exhaust in a gravel driveway NBD . As mentioned I don't think I could have made and patched an access hoke in the amount of time it took to drop and reinstall the tank. Also I think you can pull the fill hose right at the tank to siphon it,Been too long since I did mine

Thats sort of how I got it from the gas station where it failed the first time to the parking area where it wouldn't be immediately towed/impounded last weekend. It will start up and run for a bit but get progressively worse like its running out of fuel - it cut out the second time a few hundred feet shy of where I needed to put it - fortunately a good # of people around to help push.

I don't trust it enough to try a 70 mile trip, and if it fails on the highway then you have hours to get it moved instead of days or weeks. Its safe where it is now at the moment (property owners know the situation and are not pushing for immediate removal - worst case is we use their skid steer to pull it over to a more out-of-the-way location if I can't clear it in a couple weeks). I'm trying to pull together some contacts to get a heavy duty diesel pickup with a flatbed out there to move it for something less painful than commercial towing rates.

I like the idea of pulling the fill hose and siphoning - our air system isn't that robust out there but its a good tip to try. I'm pretty sure its a 30 gallon (RPO codes say 40 but I suspect its not original and even when only showing 1/4 or less on the gauge it takes less than 25 to top off). Wish these things were like my old British car which has a drain plug on the bottom of the tank.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
9,940
Reaction score
19,065
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Thats sort of how I got it from the gas station where it failed the first time to the parking area where it wouldn't be immediately towed/impounded last weekend. It will start up and run for a bit but get progressively worse like its running out of fuel - it cut out the second time a few hundred feet shy of where I needed to put it - fortunately a good # of people around to help push.

I don't trust it enough to try a 70 mile trip, and if it fails on the highway then you have hours to get it moved instead of days or weeks. Its safe where it is now at the moment (property owners know the situation and are not pushing for immediate removal - worst case is we use their skid steer to pull it over to a more out-of-the-way location if I can't clear it in a couple weeks). I'm trying to pull together some contacts to get a heavy duty diesel pickup with a flatbed out there to move it for something less painful than commercial towing rates.

I like the idea of pulling the fill hose and siphoning - our air system isn't that robust out there but its a good tip to try. I'm pretty sure its a 30 gallon (RPO codes say 40 but I suspect its not original and even when only showing 1/4 or less on the gauge it takes less than 25 to top off). Wish these things were like my old British car which has a drain plug on the bottom of the tank.
If you really want a drain plug,NBD. Use a punch and punch a hole below the sender location. Be fore you put the tank back in drill the punch hole out use a bolt nut and sealing washer, the sealing washer will be on the bottom of the tank to seal between the bolt head and the tank bottom,hold the nut from the top through the sender hole. Also a Burb tank is less than 11 inches tall, so other than how ever much room you need to slide under the truck,at stock height I don't even think you need to jack up the truck. Also a stock height truck I'd be half tempted to just let the tank fall,full onto a couch cushion,then dump it in to buckets to make going in easy.
 
Last edited:

YakkoWarner

Full Access Member
Joined
May 29, 2024
Posts
643
Reaction score
1,049
Location
Central Texas
First Name
Wolf
Truck Year
1989
Truck Model
R2500 Suburban
Engine Size
454
If you really want a drain plug,NBD. Use a punch and punch a hole below the sender location. Be fore you put the tank back in drill the punch hole out use a bolt nut and sealing washer, the sealing washer will be on the bottom of the tank to seal between the bolt head and the tank bottom,hold the nut from the top through the sender hole. Also a Burb tank is less than 11 inches tall, so other than how ever much room you need to slide under the truck,at stock height I don't even think you need to jack up the truck. Also a stock height truck I'd be half tempted to just let the tank fall,full onto a couch cushion,then dump it in to buckets to make going in easy.

If its that shallow than maybe it won't be as bad as I expected (the last one I did was on a Jeep and was very not amused when done). Any tips for disconnecting the threaded lines on top? The truck is stock height but has slightly taller tires because those were the only ones available as a complete set when I needed them (maybe it was an omen - the first time I drove it the tires started to disintegrate and I had to borrow $$$ to buy 4 right then and there because I only had enough for 2).
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
9,940
Reaction score
19,065
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Been pondering about doing the same in my crew cab.
Saddle tanks are a CAKE WALK to drop. Seriously It only takes about 15 minutes. Drop the tank,filler tube,everything in one wack,provided it's 86 or earlier or a diesel take some cutters underneath with you to cut the supply and return hose.
 
Last edited:

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
9,429
Reaction score
17,282
Location
The Right side of Washington
First Name
Todd
Truck Year
1986, 1977
Truck Model
K20, C10
Engine Size
454, 350
Apologies refuting the “cut a hole in the floor” recommendations.
Sure, it’s easier. Especially when dealing with rusty parts.
My opinion didn’t come from the daily driver/beater/gotta fix it now thought process. It came from the I can’t imagine cutting a big hole or 2 in my nice bed floor and ruining its appearance while at the same time having to fab up some sort of decent cover for the hole without being able to make sparks right over an old gas tank.

Sometimes you gotta do what you gotta do to get back on the road, understood. We all do it. IMO not to be confused with taking the easy way out at the expense of hacking up an expensive hard to replace piece of semi structural sheet metal if appearance matters.
 

gmbellew

Full Access Member
Joined
May 27, 2018
Posts
1,567
Reaction score
1,807
Location
Kansas city
First Name
glen
Truck Year
1990
Truck Model
suburban 1500
Engine Size
350
There is a difference between cutting an access hole(s) in the bed of a pickup that is always visible and an access hole in a burb or blazer where it is on the interior and covered with carpet or vinyl flooring.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
9,940
Reaction score
19,065
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
I just had waffles,what happens if you tie a buttered waffle to a cats back and drop it. Some of you will understand this. :)
 
Top