Locking Gas Cap?

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keocera

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Oct 28, 2012
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I went to one of the local auto parts stores intending to buy a locking gas cap.  I was told that auto/truck manufacturers a few years back started building the fuel filler tube with a blocking device to prevent someone from siphoning fuel from the tank.  Is this true or does anyone have information regarding this?  They could not find a locking cap specifically for the Ford F53 chassis, so I'm curious as to whether they were just trying to ease my mind with their info regarding filler tube construction to prevent siphoning.
 
I know this to be true in an old Cad I had.  I found this out when I tried to drain the gas tank before lower it.  i wasn't able to siphon gas out of the tank.  I'm curious also about the tank.  I was looking for a locking gas cap for my Fleetwood MH awhile ago and gave up.
 
Geez. Fuel thieves don't bother with that anymore that pack several buckets and a cordless drill. Drill a hole in the bottom of the fuel tank drain it out in buckets and move on. Locking caps.  ::)
 
It's true for regular production cars and light trucks, but probably not true for a gas chassis motorhome.  The actually filler is installed by the coach body builder, though Ford may supply the filler spout extension as a loose part. 

On the other hand, the fuel filler hose on an F53 is usually very long, so the thief would need an unusually long siphon.

If your filler has a door, you may be able to put a lock on that instead.
 
I was unaware the primary purpose of that 'plug/flapper' was to prevent gasoline theft. I always believed it was put there so that only the smaller nozzle used by unleaded fuel pumps used could be inserted to fill up. Older leaded fuel pumps used a bigger nozzle at the time of changeover.... Of course, it could also serve as an anti-theft device too but I have, out of necessity, successfully siphoned fuel through it in the past , not easily, not fast, but doable......
 
The flapper is actually a fume (evaporative emission) prevention device, though it also makes siphoning more difficult (hard to get the hose out when done). The older, larger filler didn't have the flapper because there were no EPA rules on gasoline fume emissions at the time.

The small neck simply means the siphon hose has to be a bit smaller than the traditional garden hose, but that would hardly daunt a fuel thief.
 
Ahhh, true Gary. I seem to remember now that it was at that point they vented the tank (filler) via the charcoal canister and sucked the accumulated fumes from that into the engine intake to burn.....
 
As is pointed out a thief will find a way, And via the filler is the least damage method of emptying your tank.

The locking gas cap is fairly good at stopping vandals who sugar your tank however. 

As to stopping theft.. Only one way I know to do that.

Sit outside with shotgun across lap.. You don't need shells, just the shotgun, and a solid wall behind you so they can't sneak up.

This usually encourages them to steal.. Elsewhere.
 
Thanks for all the great thoughts.  As Mr T would say "I Pity the Fool", especially the one with the drill trying to bore through the gas tank with little to no concern about an errant spark igniting vapors and sending himself to a come to Jesus meeting reeking of low octane cologne.
 
My current MH has a locking door on the gas fill and non locking cap.  On my previous 2004 E-450 Super Duty chassis I used a locking cap by Stant.  Don?t know what year your F53 chassis is, maybe you could take your gas cap off and go compare it to these numbers at a auto parts store. 

Regular Locking Fuel Caps for 2004 E-450 Super Duty V-10 chassis.
Stant Regular Locking #10502 ,  also is listed for other models of the E-450, 550 650 & 750 ford trucks
NAPA Locking #703-1714
AutoZone CST Locking #5502
O?Reilly Motorad Locking #5902

Stant #10501 is also is listed for many newer models of the E-450, 550 650 & 750 ford trucks
Regards, Dick
 
Lou Schneider said:
My 1994 F53 chassis uses the same filler and locking gas cap as the F250/350/450 trucks.
Yep, the same for my '95 F53. The only reason I bother with a locking gas cap is because I had standard caps "borrowed" twice.  :mad:
 
Hi everyone, I'm new today to the forum and appreciate the sense of humor that abounds.
I never understood why the manufactors don't put locks on the door to the gas; there is a lock on all the basement doors, so why not?!
I have a locking gas cap that fit on my last RV but doesn't really lock on my new one. It looks like it is locked though - fooled my poor husband when he tried to fill up.
And I can't imagine drillling into a gas tank either.
 
Some do both car and truck makers.. On cars there is often a lever next to the driver's seat that releases the gas cap door.. Some RV's have key locks on the door.. Some RV's have doors (Implies properly that some, mine for example, do not)
 
There is no item intended to stop syphoning your gas. There is how ever the small door that only allows the unleaded nozzle to fit in it, though we do not have the leaded fuel any more but when we did the leaded nozzle was bigger. There is also a floating ball type devise in the fill neck that shuts off the fuel flow in the event of a roll over, and this is the device that stops one from putting a hose in to steal your fuel. Still it works as an anti theft devise but is the roll over fuel shut off.
 
There is also a floating ball type devise in the fill neck that shuts off the fuel flow in the event of a roll over, and this is the device that stops one from putting a hose in to steal your fuel. Still it works as an anti theft devise but is the roll over fuel shut off.

I might be out of date on this, but I don't think you will find that device in most Class A motorhomes - just in passengers cars and light trucks. No full pump shut-off safety device either. Neither is required in a medium or heavy duty chassis.
 
Bought a couple locking gas caps at auto parts store that fit perfectly and when locked the cap just turns and doesn't come off.  Cost about $13 each.  Be sure the threads are the same.  Take gas cap into store with you and they can often match it.  If it doesnt work, they will refund your money.  I think the store in this case was O"Reillys but Auto Zone or NAPA should have them as well.
 
Gary RV Roamer said:
I might be out of date on this, but I don't think you will find that device in most Class A motorhomes - just in passengers cars and light trucks. No full pump shut-off safety device either. Neither is required in a medium or heavy duty chassis.
Our '95 Coachmen Class A on a Ford F53 chassis has a fuel pump impact cutoff switch mounted near the bottom of the steering column. That's where I connected the relay control wiring for the external pump I added.
 
Found one that works on late model Ford F53 chassis. If your gas cap has just a couple threads, this one will work. Syphoning may be a thing of the past but vandalism is alive and well.

Stant    10512

NAPA    703-4115

Gates    31846

CARQUEST    35075
 
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