1975 Blazer ....fuel filler question

[leverhead]

Hello. Long time browser...first post. I have a 75 blazer i've been working on for a while. Chassis and drivetrain all done and getting ready for initial startup.
Attempted to introduce some fuel via gas cans and as I was filling, the fuel would trickle into the tank but after a short period would spill out the filler.
Checked the venting ...all is good there. Then I noticed that the rubber hose that connects the filler tube to the tank spout angles up a bit as it connects to the tank.
So it looks like it inclines (iow, the tank spout is higher than the filler tube) which makes the fuel more diffucult to get to the tank. Compared to the original, the repo tank
looks identical. So it seems fuel could be pushed thru with pressure via a gas pump but a tank pour is an issue.

Tried lowering the tank via the straps which improved a bit (the remaining fuel in the hose trickled in)....so question:

Is there supposed to be a downward angle from the fill tube to the tank? Any pics i can find just look horizontal so hard to tell...

Has anyone shimmed the tank dowrn to get this angle?

Is this just a factory quirk?

Thanks.

 

[Wes Harden]

mine is level (77) If 2 tanks are the same I would check the fill neck, might have been changed, with a different year or model

 

[leverhead]

mine is level (77) If 2 tanks are the same I would check the fill neck, might have been changed, with a different year or model

Thanks. I may use some blocks to shim the tank down and modify the fill tube/mount to bring it higher.

 

[mrk5]

I have trouble with the fill on my 73. If I try to run the pump full speed, it will splash back out the fill once the tank is full. If I run it on the slowest, it usually shuts off okay.

 

[leverhead]

I have trouble with the fill on my 73. If I try to run the pump full speed, it will splash back out the fill once the tank is full. If I run it on the slowest, it usually shuts off okay.

Thats interesting. Seems if the horizontal between the tank and the fill tube isnt just right the gas can splash back.....fuel stays inside the fill tube and hose and starts to back up....

Going to attempt some mods to attempt to correct the problem......will post pics if i can....

 

[Bigb55]

My 74 has a similar issue. I have to use the slow setting on the pump. Even then if I angle the nozzle wrong it will fill to fast and dribble out. Vents are fine. I played with it and no matter what I did, same issue.

My rubber fill hose to fill neck is angled down and all replaced with new.

I came to the conclusion the newer nozzles pump to fast. Since it seems to works fine on slow speed and auto shuts off near full.

 

[leverhead]

I assume angled down to tank......thats strange. I'm thinking there are too many bends in the entire fill system that create resistance therefore slow the fill rate.

I've pushed the area around the tank spout down lowering it about 1/4" +. Cant go much more than that without effecting the tank sender.

I'll reinstall tomorrow ......I cut some hard rubber shims to lower the tank . May be some trial and error to get the tank shimmed correctly. I'll post back.

I have a pic of the tank with the spout 'adjusted' but cant upload from my computer. Am I allowed to post pics here?

 

[Wes Harden]

Mine works fine, with a non vapor recovery nozzle. I must hold the nozzle if it has vapor recovery lift up at handle, gap at boot to car seal, and run on slow. Is a work out for 40 gal fill.

 

[mrk5]

I assume angled down to tank......thats strange. I'm thinking there are too many bends in the entire fill system that create resistance therefore slow the fill rate.

I've pushed the area around the tank spout down lowering it about 1/4" +. Cant go much more than that without effecting the tank sender.

I'll reinstall tomorrow ......I cut some hard rubber shims to lower the tank . May be some trial and error to get the tank shimmed correctly. I'll post back.

I have a pic of the tank with the spout 'adjusted' but cant upload from my computer. Am I allowed to post pics here?

I think as a "registered" member, you have to post 10 times before you can include pictures. Helps to keep spammers at bay. But I also might be remembering old information.

 

[leverhead]

I think as a "registered" member, you have to post 10 times before you can include pictures. Helps to keep spammers at bay. But I also might be remembering old information.

I figured it was something like that. Thanks

 

[leverhead]

figured it was something like that. Thanks

 

[leverhead]

So I reinstalled the tank and used blocks, (about 3 1/2 x 1 1/2) made from 3/4 Pvc board, attached to the tank where it bumps up to the crossmembers,
to shim the tank down. Now I have a downward angle from the filler to the tank. Poured some gas in via cans and no backups/spillage.
Tanks still looks ok from outside the truck and was able to reconnect everything without frame interference. I suspect the previous tank was a replacement also as I believe the spout attached to the tank is higher than stock but cant verify. Hope this helps.

 

[RaisedK5]

Have you replaced your body mounts? If not then they could be compressed to the point of causing this problem.

 

[leverhead]

Have you replaced your body mounts? If not then they could be compressed to the point of causing this problem.

Good point...no I havent...plan to eventually when I get to the body working phase....wishing to get it running and driving first....then see where I go from there.

 

[Wes Harden]

Not a horrible job to do. You'll need to pull the interior as far as floor covering.
But after I did mine the doors closed much easier, much less slamming.