Cleaning out a petrol tank

[paintmonkey]

Hi, I'm helping a friend restore a 1975 Triumph Dolomite.
We're at the strip down stage to assess just how much welding is required.
I've removed the fuel tank and there is about an inch of sludge/tar in the bottom. The inside of the tank seems sound where I've managed to scrap some of the sludge off. Since the car was left in a garage for about 12 years I'm guessing the sludge is the remains of the petrol!
Since a new tank is approaching £300 does anyone know the easiest way to strip the sludge from the tank and then maybe recoat the inside of the tank?
The fuel lines are also blocked but we're just going to replace them. Luckily the carbs seem ok!
Cheers
Rich

[Luxobarge]

I've done this by inserting a handful of gravel and some old petrol and shaking it about for as long as I can before my arms drop off. Then empty out, allow to dry and use a vacuum cleaner in the sender unit hole to suck out any remaining dust/gravel. If yours is as bad as you indicate, you may need to do this a few times - hard work on the arms, but it gets the job done.

Also have a look around Frost's site, they have some petrol tank cleaning and sealing products that work OK I believe.

http://www.frost.co.uk/?gclid=CMmTla_Es ... fAod2F51lQ

Cheers!

[JPB]

I've used Frost products with some success before so I second Luxo's recommendation to search there for flushing and sealing products but, as the Dolomite's tank is internal, they're less rustprone than some and it's unlikely that a replacement will be required unless the seal on the underside of the boot lid has been leaking, which is less likely with the original seal than with the alternative replacement that some folk insist on fitting to the lip around the boot aperture instead of to the lid itself.

As for the notion of paying £300 for a tank; that's daylight bleedin' robbery! I suggest that signing up for membership of THIS FORUM (free) will be a good plan for anyone restoring a Dolomite, 1500TC or FWD since non-club members are able to read and respond to the classifieds and/or post wanted ads.
Typically, I sold a new/old stock tank complete with sender last month for a more realistic £80 as it simply hadn't been needed for either of my 1972 Dolomite Autos and there comes a point when stuff has to go.
Other TDC and forum members may have similar bits tucked away.

Regarding your carbs; I have an unused pair of CD150SEVs (the type with the thermal compensator circuits - those elongated oval white plastic things on the throttle bodies - correct for an early Dolomite) available cheaply and even the inlet manifold to attach them to. Yours should be OK as long as the diaphragms are in good condition and there are no major leaks from the float needles which would ideally require removal of the carbs to separate the float chambers and renew the needles and seats, but all of the spares are available in any case.

[Maaarrghk]

I would also be inclined to start with the petrol and "gravel" routine, but would recomend a handful of new nuts rather than gravel that might not all come out and may also break up. You can count the nuts as they go in and as they come out.

If any welding is needed, then flush the tank with plenty of warm, soapy water, before filling completely with more of the same and leaving for a few days, then repeat.

[Willy Eckerslyke]

and use a vacuum cleaner in the sender unit hole to suck out any remaining dust/gravel.

That sounds a bit risky!
There's a story somewhere on the 'net of someone doing that with an old cylinder Hoover, hearing a roaring sound and turning to see a jet of flame setting the contents of his garage ablaze. I've no idea if the story's true, but petrol fumes and electric motors are never going to be a healthy combination.

[suffolkpete]

Given that most vacuum cleaners use the air drawn in to cool the motor, I'd say that was a perfectly possible scenario.

[paintmonkey]

Hi,
Thanks for all the ideas.
The tank it self seems fine. We think a new one was fitted just before it got parked up for a decade and a bit!!
Think I'll try the nuts & old petrol thing and patience rather than a vacuum cleaner.....just in case.
I'll also have a look at the Frosts site.
The carbs are fine just need tuning!
Cheers
Rich

p.s I'll probably be back with another problem soon!

[JPB]

.....The carbs are fine just need tuning!

Maybe that old fuel has preserved the diaphragms, maybe it's just luck, but I've yet to see a pair of CD150s (or those of any other size) that wouldn't need at least diaphragms and probably new O-rings for the access bungs at the bottom of each float chamber. I like the original carbs but would be the first to admit that the SUs from late Dolomites or TR7s have their advantages. Though they do seem to use slightly more fuel.