Essential - VEHICLE SPARE PARTS - to take on a foreign trip

You are about to embark on a foreign excursion, let's assume it's somewhere remote and the terrain can be arduous, Mongolia or the Sahara for example. What spare parts do you take with you?

The way I see it, there are a number of categories you have to consider when travelling:-

Vehicle spare parts.
Recovery equipment.
Camping/cooking equipment.
Vehicle kit (fire extinguisher, etc.)
Tools.
Personal kit.

Here we'll concentrate solely on Vehicle Spare Parts.

You can't take too much as weight (and to a lesser extent - space) are overriding factors, so that's a spare gearbox ruled out then! So ... what essentials do you take? I'll start the list, then add your suggestions to this 'Master List':-

~ A full set of hoses.
~ A full set of pulley belts - if a good Samaritan, also a couple of universal emergency pulley belts for helping out fellow overlanders en route. They are small, lightweight, but oh so essential for your engine - or somebody else’s engine in this case! Armed with one of these, you can make a friend for life.
~ Water pump.
~ Radiator sealant - two Radweld or whatever.
~ An assortment of fuses.

Depends a lot on vehicle type, and the conditions you drive in.

So true - exactly how long is that piece of string?

For many modern vehicles a crank sensor. Its small and light but one of the few sensors that if it fails will result in total failure and inability to start, unlike say maf or air pressure sensors which may result in a limp home mode. Also relays for essentials such as fuel pumps etc and some of those big breaker type fuses that no one ever has with them.
Unsure whether it falls into parts or tools but jb weld or similar liquid metal type resin. I've bodged many a repaired part with the aim to replace them when home only to forget about them because they work as well as the original and show no signs of giving up. 
Similarly hylomer type sealants, not masses but a tube to get you out of a fix.

I have carried sheets of gasket paper that can be cut at need. Often not as pretty or neat as a pre-cut gasket, but has worked for me with thermostat housings, hub seals etc.

In Africa I learned one of the really valuable items is old tire innertubes cut up into strips. Africans will tightly bind anything that breaks or comes loose with layers of rubber and tie it off. A bodge job but often got me home from the bush.

Probably on of the things I rely on most is a box filled with odds and ends of bolts, nuts, washers, small springs etc. Inevitably after long days bashing around or vibrating across corrugations, something has snapped or worked its way loose. So a nose round in my box usually turns up something that fits until I can get home and source the correct item.

Seemed to recall the box in question made an appearance at Donington.

I used to carry one like it on Landy Rally. It really came into its own one year when the overloaded roofrack of a team decided to collapse, so the assortment of nuts & bolts saved the day. Yep, a box of bits 'n' bobs is essential.