metal to plastic coolant pipes?

[dridgy]

Hi, i have a 1981 1.6d kombi, it has the old metal coolant pipes running front to back, these pipes are rusting away, so i have got myself a set of secondhand plastic ones, i have noticed that the plastic ones are bigger as in diameter than the old metal ones.
I have started trying to dismantle the old metal ones.
What i need to know is...
Do i have to drop the fuel tank to get the old pipes off? as they seem solid and i have removed all i can find of the pipe to body clamps?
And will the new plastic pipes fit where the old metal pipes go through the body as the metal pipes look quite tight going through the holes in the chassis.

All help and advice appreciated.
Thanks
John

[Hacksawbob]

AFAIK the hole through the chassis didn't change. there is a metal clip above the fuel tank that his hard to get to, just cut it. I have a vague memory that I fitted mone with out removing the tank but it was a long time ago.

[dridgy]

Thanks Bob, ill have another look at it today. maybe i can release the tank and lower it enough to get to the clamp.?????

[dridgy]

Had to take off the tank, good job i did because the paint on top of the tank was flaking off and the thank was rusting, i will strip and repaint it if its not too bad, and paint the body where the tank resides, before fitting the plastic pipes......