Earlier this year, my pressure relief cap on my auxiliary fuel tank failed and ended up cracking my tank. I had it welded, and it was fine.
A couple weeks ago, I drove over a fairly rough set of railroad tracks, and my tank cracked again. I haven’t decided if I’m going to have it repaired again or just buy new one, but I need to figure out something to protect it on my bed.
I have seen other auxiliary fuel tanks with some form of a bushing set up that acts as a shock absorber and keeps the tank up off the floor of the bed. A friend of mine recommended using rubber horse stall mat underneath the tank.
Any thoughts?
I was going to recommend a bushing setup before I even got to your third paragraph. I'm thinking some soft squishy transmission mounts would work nicely. And maybe a second, redundant pressure relief cap.
In reply to SyntheticBlinkerFluid :
Can you tell if it cracked by torsion, or by impact/vibration?
Pressure relief valve? Like, vent?
How is the tank retained?
Where is it cracking?
A squishy mat would probably better distribute the load vs a few bushed mounts.
jfryjfry said:
A squishy mat would probably better distribute the load vs a few bushed mounts.
True, but I'm assuming the tank has to be bolted down somewhere and that stress applied across these mounting points caused it to break the 2nd time...if load distribution is a problem then a combination of both might be best.
After I fixed it the first time, I bought a new pressure relieve cap, but have a secondary pressure relief valve that I installed. The tank is bolted directly to the bed.
The first crack was on a spot weld did the baffle on the inside and being in the middle of the tank, I’m pretty sure it was caused by expansion. The second time it definitely was from an impact, seeing it happened right after I hit the railroad tracks. I don’t know where it is yet, I need to get home so I can remove it. The leak is 3 times worse than the previous one.
Has anyone used the Permatex Fuel Tank repair kit? I found it at TSC for $8 and I figured that if I can find the leak on the tank, maybe this can keep me from spending $400 on a new tank.
I've heard that kit works well, although I haven't used it myself.
In reply to SyntheticBlinkerFluid :
It’s been many years, but I’ve had success with that type of kit. If I recall correctly,I used wax to fill the hole and stop the leak temporarily and surface prep is critical to a good bond.
I don’t think it was from permatex, but it was the single pouch style with the divider to keep resin and hardener separate.
I would install bushings between the tank and the bed. Use ones that have separate bolts for the tank and bed, preferably a fail safe style from these::
https://www.mcmaster.com/rubber-mounts
Or this:
Suspend it on strategically placed valve springs?
I like those failsafe compression mounts.
SkinnyG
UltraDork
10/6/18 11:01 a.m.
Those look like old Jaguar motor mounts.
More info would help.
Is it like what you'd buy at TSC?
Is it cracking at the angle mounts?
Forces from going over the tracks could cause torsional forces on the tank to crack it. No impact needed. Even the sloshing of the fuel can crack a tank. How old is your tank?
wheelsmithy said:
More info would help.
Is it like what you'd buy at TSC?
Is it cracking at the angle mounts?
Mines bigger than that and steel. It’s a big rectangle. And no, it cracked at the spot welds for the baffle. The new one I have no clue.
Cracking at the baffle welds suggests fuel slosh over stressing a poor design. I would suggest it may be one leak after another, design is at fault. Any possibility of whining at the tank manufacturer? It is remotely possible they could make it right for you...
Streetwiseguy said:
Cracking at the baffle welds suggests fuel slosh over stressing a poor design. I would suggest it may be one leak after another, design is at fault. Any possibility of whining at the tank manufacturer? It is remotely possible they could make it right for you...
Honestly, I don’t even know who the Tank manufacturer is; it was a “in house” branded tank from the Atwood’s chain out in Oklahoma. The first crack conveniently happened right after the one year warranty ended. I could try, I don’t know if it would go anywhere.
And honestly, these tanks are not built to last, they are made from thin gauge metal and just can’t handle the fluid capacity. My good friend who also does what I do, has gone through three different tanks that have cracked. 2 aluminum and one steel: I know a couple other people whose tanks have cracked.
