Hi, My 75 Mk1 van has a rusty tank. I am after a clean replacement and there seems to be a few different types. Is there a bigger one or can a new one be purchased.

Dont know about new ones (like for like replacement) you might be able to get one from the UK but freight would be huge. you might be able to find something similar or maybe a drop tank like some of the mkII`s had

Is the drop tank bigger? 

not sure, though this link
http://www.uniquecarsandparts.com.au/ford_escort_mark_2_technical_specifications.htm
says 40 litres, not sure if thats the drop tank or the guard tank though

I have tried a google search and couldn't find what I am after.

The 2 L models had the drop tank.
http://www.uniquecarsandparts.com.au/ford_escort_mark_2_2litre_technical_specifications.htm
This shows it as 40.5  litres (9 gallons)
 
If I remember the side tanks were only 7 gallons.

Don't believe it.. Mk1 and early mk2 tanks are 9 gallons And the drop tank on late mk2 are about 56ltr which is the same tank used in the later mk2 van but with a different fuel entry point.. side not the rear.
To answer if you can install the mk2 van drop tank to mk1 van , yes you can tho you will need the hanger straps to match ..

56ltrs thats about 12 gallons. That is better, I will look for one.

martymexico
Don't believe it.. Mk1 and early mk2 tanks are 9 gallons And the drop tank on late mk2 are about 56ltr which is the same tank used in the later mk2 van but with a different fuel entry point.. side not the rear.
To answer if you can install the mk2 van drop tank to mk1 van , yes you can tho you will need the hanger straps to match ..

What year are you using to splt early from late models marty?
 

Hi Troppo , it's when the pinto came on the scene in mk2 escort. .early to mid 1977.. Also the same time they went to small strut tops. .