This is a guide for repairing a rusted top lid of a fuel sender unit. This part is screwed into the top of the fuel tank, and as such, the fuel tank will need to be dropped, or completely removed to get to it.
The last Cally's are getting on for 12-13 years old now, and this seems to be an increasing problem for owners, first signs of which will be a fuel leak around the tank area. This part has not been available from Vauxhall for some years, and any part you get off a scrapper is likely be in a similar or worse condition. You'll be unlikely to find one on ebay either, so a repair job is recommended as the best way to fix this problem.
Note the actual part shown in this guide is from a late 1997 Calibra. Earlier Calibra's had an out of tank pump, and as such, the fuel sender setup will look slightly different, but the repair process will be the same.
Here are the steps needed for repair:
1) Use a dremmel tool or similar, (I bought a silverline one off ebay for £25 posted and with various attachments included) with a wire brush attachment to remove all the rust, including as much as possible from the pitted areas. Sandpaper is no good for this, as you won't be able to remove the rust from the pitted or hard to reach areas, plus the dremmel (or similar) tool will make light work of this, and do a much more thorough job.
2) Soak overnight in a suitable liquid to lift off any remaining rust in hard to reach and pitted areas. You can buy certain products for this, but i just used vinegar which i read is good for this. Reading on the net, you can also use coke (as in Coca Cola, not the more expensive variety
)as it contains phosphoric acid which is an ingredient for rust removal products.
3) Use Chemical/Liquid metal compound (you can buy this in Halfords for a few quid) to fill any holes and layer up on thin or weak areas. If you have to patch up any holes in the pipes themselves, poke a straw through it to ensure the pipe doesn't become blocked. Allow to dry.
4) Sand down repaired areas to leave a smooth finish.
5) Paint over with 2 coats (allow to dry between coats) of Hammerite No 1 Rust Beater (comes in Brown and Beige). You apply this directly to the affected metal, and it also acts as a primer and undercoat.
6) Paint over with 2 coats (allow to dry between coats) of Silver Hammerite Paint to give a nice finish and added protection.
7) Refit part to tank and admire your handiwork.
Here's some pics of the stages of repair.
The rusted lid of the fuel sender still in tank.
Tip: Use a block of wood and a hammer to start to unscrew the plastic cap, as it will likely be too tight to unscrew by hand.
Sender lid removed. Not looking in too great condition.
Hmm, a small hole. I think this could be the source of the leak. The fuel system is pressurized, and i reckon i was losing a 1/3rd of each full tank through this small hole.
The road to recovery. Here's the Sender lid, after wire brushing and an overnight soak in vinegar. Starting to look a bit better now
Use some of this to repair the holes, and sand down to finish.
Then apply 2 coats of this to the entire exposed area.
After painting with 2 coats of Hammerite No 1 Rust Beater
Then apply 2 coats of silver hammerite, and you end up with this
Then with new rubber hoses and clips i fitted the part back into the tank. Job done. Now you just have to get the tank back in
