Results 1 to 4 of 4

Thread: New tank,fuel gauge problem

  1. #1
    Join Date
    Jul 2006
    Location
    Tumbi Umbi, Central Coast, NSW
    Posts
    5,743
    Total Downloaded
    0

    New tank,fuel gauge problem

    My tank succumbed to the dreaded pinhole leaks caused by moisture between the bottom of the tank and the bash plate.

    Rather than risk one of the various sealing products, I chose the safer option of a new tank.

    Apart from the slight inconvenience of having to remove the towbar to remove the tank, the replacement went fairly smoothly until I turned on the ignition to confirm the fuel gauge reading.

    Having drained the tank to do the job I knew that I had put just under 20 litres back in and expected to see the gauge showing just under 1/4. However, it showed half full.

    Lying awake at about 4AM, I realised what the problem was and what I should have done before refitting the sender unit in the side of the tank.

    The side of the new tank or at least the surface where the sender unit was fitted was obviously not quite as vertical as the old tank.The end of the pickup pipe touched the bottom of the tank before the sender sat flat against the rubber gasket. I solved that by bending the pipe very slightly so that it just touched the bottom when the sender was properly seated.

    With hindsight, I realise I should have bent the float arm slightly too so that it only drooped down as far as the end of the pipe. I removed the sender the next day and made that adjustment.

    Because the float arm is so long a tiny change in the angle of the mating surface (not apparent to the naked eye) makes a huge difference to the position of the float.

    That might be something worth checking if you are fitting a new tank. Maybe most people knew that already.

    1973 Series III LWB 1983 - 2006
    1998 300 Tdi Defender Trayback 2006 - often fitted with a Trayon slide-on camper.

  2. #2
    Join Date
    Jul 2006
    Location
    Tumbi Umbi, Central Coast, NSW
    Posts
    5,743
    Total Downloaded
    0

    Follow-up question

    Would the new tank benefit from a gap between it and the bash plate?

    Some of the older posts here about leaking fuel tanks mentioned spot welds securing the bash plate to the tank. Mine was separate. Even though it had some sort of pads a couple of mm thick the bash plate had obviously touched the tank in a few places and I believe that is where the rust pinholes developed.

    The new tank came with a bash plate that seems to be a very close fit to the tank.

    My thinking is that if the bash plate is touching the bottom of the tank that vibration will cause it to move enough to eventually remove the protective paint. Surely if the gap between the tank and the bash plate is negligible, then there is less chance for the inevitable moisture to dissipate.

    I am wondering if I should put some strategically placed rubber pads to create a gap of about 5mm. That would allow some air to circulate to dry out any moisture that finds its way in the gap.

    Does that sound like a good idea? Is there any reason I shouldn't do that?

    1973 Series III LWB 1983 - 2006
    1998 300 Tdi Defender Trayback 2006 - often fitted with a Trayon slide-on camper.

  3. #3
    Join Date
    Apr 2019
    Location
    Koojan WA (part time Perth)
    Posts
    1,197
    Total Downloaded
    0
    Quote Originally Posted by vnx205 View Post
    Would the new tank benefit from a gap between it and the bash plate?

    Some of the older posts here about leaking fuel tanks mentioned spot welds securing the bash plate to the tank. Mine was separate. Even though it had some sort of pads a couple of mm thick the bash plate had obviously touched the tank in a few places and I believe that is where the rust pinholes developed.

    The new tank came with a bash plate that seems to be a very close fit to the tank.

    My thinking is that if the bash plate is touching the bottom of the tank that vibration will cause it to move enough to eventually remove the protective paint. Surely if the gap between the tank and the bash plate is negligible, then there is less chance for the inevitable moisture to dissipate.

    I am wondering if I should put some strategically placed rubber pads to create a gap of about 5mm. That would allow some air to circulate to dry out any moisture that finds its way in the gap.

    Does that sound like a good idea? Is there any reason I shouldn't do that?
    If I remember correctly, the bash plate and tank are a pretty tight squeeze together
    I was thinking the same thing
    But the 2 I’ve done were on 30+ year old vehicles so surely get the same amount of life out of the new tanks
    Trying to get a 5 mm gap, something would have to distort
    Maybe a good dose of sikaflex or the like to fully seal and glue the 2 together maybe a better idea
    If the 5 mm gap is possible I’d be worried about dust and gravel getting in and not being able to be cleaned out without removing the tank
    1985 110 Dual Cab 4.6 R380 ARB Lockers (currently NIS due to roof kissing road)
    1985 110 Station Wagon 3.5 LT85 (unmolested blank canvas)

  4. #4
    Join Date
    Feb 2007
    Location
    Yass NSW
    Posts
    5,551
    Total Downloaded
    0
    +1 for consideration of the build up of dirt in that space that will result in moisture retention and rust. SWMBO is doing up a Jeep J10 and we pulled the fuel tank and removed a bucket full of dirt from around it and are now dealing with the rusted protection plate. Luckily the tank itself is plastic but the tin worms have been munching on the chassis as well. Maybe a bad example as the design is less than optimal on the Jeep but worth considering.


    242805374_10222971449487137_8682493918574171157_n.jpg


    Regards,
    Tote
    Go home, your igloo is on fire....
    2014 Chile Red L494 RRS Autobiography Supercharged
    MY2016 Aintree Green Defender 130 Cab Chassis
    1957 Series 1 107 ute - In pieces

    Assorted Falcons and Jeeps.....

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Search AULRO.com ONLY!
Search All the Web!