2001 Symbol - Dropping the waste tank

Hi after a long time without posting! Well, the van is now 16 years old and having sorted out all the problems at purchase in 2012, since then, and 16,000 miles later, it has just carried on doing what we bought it for! Anyway, last week, somewhere between our home in Aberdeenshire and the Beamish museum near Durham, the waste outlet tank fitting broke off, losing the drain valve behind the sill and the length of hose back to the tank. I can only assume that the drain valve came adrift from the ageing spring clip behind the sill, dragged on the ground, got caught on something and wrenched the hose off the tank. Now back home, yesterday I decided to bite the bullet and drop the tank (the fittings on the tank all have back nuts inside the tank, so I needed access to the inside of the tank). Turns out this was not as difficult as I had thought. Firstly, I dosed each of the four screwed hook rods and nuts with Plus Gas (much better than WD40 in my experience) and wired brushed same vigorously. I was able to loosen all four with a rachet spanner reasonably easily. However, the front two nuts didn't allow a decent swing on the ratchet. So, I took the back ones completely off first. With the front ones just loosened, it is then possible to shift the tank slightly and completely remove the front two hooks complete with nuts and tank brackets. This leaves the tank, which is plastic and very light, hanging on the four inlet and outlet hoses. It's now much easier to undo the hose clamps and pull off the hoses. I then had to jack the van up a couple of inches to clear other stuff under the van, drop the tank and slide it out sideways. Less than two hours and that's the tank dropped and out!!

Now the best bit - this is was I found on the waste tank that I wouldn't have if I'd left it on the van:-

• Inside of tank lined with a thick greasy build up
  
• Several large flat lumps of "slime mold" loose in the tank and large enough to block the tank outlet (I had suspected this from previous non-draining incidents)
  
• Several small bits of thick paper - suspect from bars of soap, the kind that have a piece of paper stuck to the middle of each face)
  
• All four of the in-tank nuts holding the hose fittings were not even hand tight (explains the sealing gunge that had been liberally applied to the outside of each fitting, presumably to stop previous leaks)
  
• Corrosion of the topside of the aluminium straps holding the tank up.
  

So I've now thoroughly cleaned the tank inside and out, de-rusted and re-threaded the hooks and nuts, and cleaned and painted the tank straps. On order are a new hose, one tank fitting to replace the broken one, a new drain valve, a new spring clip and a tube of sealant. I will be remaking all the tank fitting joints, this time bedding them down with sealant as each joint is put together, and tightening up the inner nut with an adjustable spanner. If you do them in the right order, you can get a spanner on to all of them. I also intend to leak test the tank with its new fittings, before it goes back in the van.

I thought I would relate my experiences on this job, as clearly the final result should be a nice clean tank with no leaks and little expense.

Regards

Mikebro 

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Hi I have just "done" my tanks on a Montana, ie taken them down, cleaned them up and replaced the 2 white beer barrel type drain taps. I tightened mine by hand by rotating the tap and holding the nut inside the tanks. Also cleaned up the sender unit which was covered in lime scale and now the little level gauge works! My waste tank was spotless inside which is not surprising as I only have a cold fold down tap in a sink. so I've cleaned it up and connected it to the fresh water tank with a valve in between so it can be used as a 30 ltr reserve and the sink drains into a collapsible bucket under the van. I use a small washing up bowl in the sink anyway so not much goes down the plug hole. I use a smear of Sikaflex on the threads of the drain taps and tank connections to seal them and stop them coming undone which they are prone to do. I have replaced the ply support boards, tank straps and hook bolts

Nice modification Biffo, if you don't need the waste tank. Your new tank interconnection valve looks the same as the one I have on order as a replacement waste drain.