Could be the rust is at the interior release lever or at that end of the
cable. Remove the trim or cover so you can get at the metal pivoting
bracket underneath and where the cable attaches. Use PB Blaster on that
metal lever to see if the mechanism frees up.
Is the cable rusted so it doesn't move freely? There are tools that let
you lube a cable by clamping onto the end of the cable and using the
pressure in the spray can to push lube into the cable.
https://www.youtube.com/watch?v=NG6JO9f0Q6U
However, that pressure isn't high so it is not going to push the lube
all the way along the gas door cable unless you do it from both ends.
You can only hope that the lube reaches the rusty area. Also, you need
to get at both ends of the cable which can be a bear: probably not bad
at the interior release lever end but you'll have to get through the
trim to get at the mechanism at the gas door. If lubing the cable
doesn't work, well, you're going to have to remove all those panels,
anyway, to replace the entire cable.
Even if you lube the cable, rust expands. You'll loosen the rust but
the expansion of the metal due to rusting might prevent smooth
operation. I would NEVER use WD-40. That gets sticky and attracts dust
and dirt. Use chain or teflon lube but I'd probably start with PB
Blaster for breaking the rust and then use chain lube.
If you don't really need an interior release but just want to prevent
someone from siphoning out your gas (although a big flat blade
screwdriver will defeat a little plastic pin to hold the door shut), you
could use a locking cap. Disable the gas door release (e.g., snip off
the plastic pin that locks the door in place) and use white Gorilla glue
with ceramic magnets (might need to layer the magnets in some spots) to
hold down the gas door.
https://www.youtube.com/watch?v=y_4NjeyZ-6c
(Presumably your door is still on its hinge so you only need to add the
magnets and disable the release.)
Or is the problem the gas door doesn't pop open when you lift the
release lever on the inside of the car? If so, maybe the spring plate
is too bent and not applying enough pressure to push the gas door open.
Never heard of PB Blaster. Judging from the video, it seems to be being
used for throttle cables, seems a little overkill just for a fuel-door
cable, afterall I'm not expecting millisecond responsiveness out of the
fuel-door cable.
Just used the WD-40, just a little while ago. It seems to have worked
beautifully. It's moving nearly freely now again, did nearly a dozen up
and down movements on it, and it started getting looser and looser after
each movement. So it seems to be fixed for now, at least until next
winter when more salt gets introduced.
Yousuf Khan
https://www.google.com/search?tbm=isch&q=pb+blaster+penetrating+lubricant
The rounded top cans usually do not come with a straw to direct the
spray. The squared top cans come with a straw, so you can get the lube
into small or recessed spots (and the straw might be usable with the
cable oiler tool that I mentioned to get the lube along the cable).
It is a high-temperature lube, so it's good for lubing up cables or
parts near the exhaust or other high-temp locales, plus it's a penetrant
and works pretty well to unsieze rusty metal parts.
I thought you claimed you knew the *cable* going to the gas door was
rusted. PB Blaster is pretty good at breaking up the rust. It is a
penetrating oil. I've used it on cables, like bicycle brake cables
which also don't need millisecond response, either, along with the hood
release cable and latch, door hinges, or anywhere there might be rust
(now or later) where there is metal-to-metal contact, like inside the
wire cables used in cars and bicycles. I wouldn't use it, say, on a
bicycle chain since that needs something like chain, teflon, or moby
oil. Although a high-temperature lube, it is too thin for constant
high-friction use, like a chainsaw. The right lube for the job, and
WD-40 is really only good for cleaning (it doesn't affect rust), not for
long-term protecting.
Likely the gas door cable is inside a sheath which is coiled metal wire
surrounded by vinyl or other plastic. That is metal-to-metal wear:
stranded wire cable against coiled wire sheath. Don't know where you
are, so maybe PB Blaster isn't available there, but you should be able
to find another penetrant lubricant, like what gets used on rusty bolts
and nuts. I like the high-temp penetrating oils so, for example, I
could use a torch on a nut to expand it and help break the rust along
with the penetrating oil. In the USA, PB Blaster is at Menards, Lowes,
Walmart, Fleetfarm, car parts stores, and lots of other places.
Although you think it's the cable, and mentioned before, I'd first check
the release lever in the interior of the car. If it is on the floor
then it can get wet from rain or snow on your shoes along with any salt
used on the roads to speed up the corrosion. The release lever has a
pivot that you can use the penetrant lube plus gets you at that end of
the cable without a ton of trim removal. Quite often not-so-fastidious
car owners let dirt, salt-laden snow, and water pile up in their carpet
and the carpet is around the release lever (unless it is a dash-mounted
lever). In fact, I've seen there a combo lever (pull up for trunk
release, push down for gas door) was rusty at that end of the cable
causing the plastic end of the cable to break that holds the cable into
the bracket for the lever. Pulling works to open the trunk but pushing
results in pushing both the cable and sheath backward so the gas door's
latch pin sees no effective movement of the cable relative to the
sheath.
A shot of penetrating lube around the pin that holds the gas door is
probably a good spot, too, as well as the gas door's hinges (since the
objective is for the door to pop out when the pin retracts).
WD-40 will displace water but won't keep it out. It gets sticky over
time and why it's a bad choice for door hinges or any moving metal
parts. When it gets sticky, it attracts dust and dirt. Use it on
hinges and they will get dirt streaks and start squeaking again. It's
great when you want to *clean* something but poor when relied upon as a
lasting lubricant. The dirt that sticks to the WD-40 attacts water (and
any salt in the water) again resulting in a recurring problem when using
that lube.
Where'd you use the WD-40 that fixed the problem (for now)?
https://www.wired.com/2009/04/st-whatsinside-6/
WD-40
WD = Water Displacement
40 = Number of formulae testing before settling on this formula.
WD-40 is good at water displacement, not at water resistance since it is
not a true lubricant. It is also good for breaking rust but you'll need
to clean the parts to apply real lube (so you'd have to pull out the
stranded cable from the sheath, clean both (e.g., brake spray), and
apply real lube; else, you'll have the same or worse problem later
because the mineral oil gets sticky.
Since you don't want to pull apart a cable to use WD-40 to remove rust
and then reassemble the cable -- which assume that you can disassemble
the cable which is unlikely -- you want a penetrating oil that actually
lubricates when left behind, like after injecting into a cable.
WD-40 works better than PB Blaster (and Gumout Freeze Out) to unsieze
rusted nuts and bolts. That's not what you are trying to do. After
breaking the rust, you need to clean off the WD-40 to use a real lube
and that's not going to happen with a cable (well, some you can pull
apart, like a bicycle brake cable since one end doesn't have a crimped
lug on the end). Similarly, Gumout doesn't leave anything behind so you
will add lube. Some swear by a 50-50 mix of ATF (automatic transmission
fluid) and acetone to break rusted nuts from rusted bolts; however, I
suspect the ATF is the main player. Obviously for nuts and bolts you
wouldn't be lubing them after, so cleaning off the WD-40 or not having
any Gumout Freeze Out left behind is the next step before putting them
back together (perhaps with some anti-sieze compound). If you cannot
follow up with a cleanup after using WD-40, you want to try adding a
real lube. You don't want mineral oil as the lube.
Of course, no penetrating oil is going to work if it cannot penetrate.
A severe rusted spot in the cable would dam up any penetrating oil from
getting further. Sometimes chemicals just won't salvage a part and you
need a nut breaker, cable replacement, or a new part. Where is rust
means the metal has swelled, so there's permanent damage to the metal.
Swelling is what causes the siezing since rust is by itself pretty
fragile.
I have had a 18 year old Impreza and a 19 year old VIVIO which did not
have that problem. So it's not an 'age' thing but clearly the cable
contracts moisture somewhere; irrepairable. I would replace it.
Gerard
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