A while ago I picked up an old caravan chassis for 20 quid from the guy who runs the caravan park down the road with the intention of turning into a trailer to pull the Caterham I will one day own around the circuits of the UK and Europe and also because it just seemed like fun project, not to mention a proper car trailer costs about £2000.
I chose the chassis because A) it was made of steel and I can weld to it, and B) it had independent suspension comprising proper swinging arms with coil springs and hydraulic dampers as opposed to the more modern (but slightly crappy) rubber torsion thingies. I stripped it down and could see that it was made by a company called B&B who specialised in caravan chassis between the 50's and 80's, did some research and found the old maintenance manual. you can see the bare chassis layout and suspension set up here.
We (me and my bro) decided we would need to widen it, so the overhangs on each corner were cut off and the the whole thing was chopped in two down the middle and the overhangs used to spread the four transverse members by about a foot, all of these joins were re-enforced with a strip of 25x25mm box section steel. More box section steel was used to weld on a sub-frame to support the main rectangle from beneath. It's worth pointing out that this was one rusty old caravan chassis, so the mind numbing task of wire brushing the whole thing (including all the larger and smaller suspension and brake parts) back to good metal with the angle grinder began in earnest (my brother was glad to leave this bit to me). a few weekends later it had had its first few coats of anti rust primer and was starting to look abit less like a lump of scrap.
I found it some new suspension bushes, as well as new bump-stops and brake expander's but the awesome, custom made, stainless steel, M16 suspension spring bolts are my favourite piece so far. I'm going to try to use new stainless steel to replace nuts and bolts, brake rods, clevis' etc where I can to give it some longevity and keep it looking smart.
Its upside-down in the garage at the moment after having its first two coats of paint and the newly refurbished and re-bushed swinging arms re-fitted, but its coming out to get flipped over and have the brakes and suspension properly re-assembled this weekend. Then I need to get the runners and ramps made up, re- fit the A-frame, make new brake rods and wire up the lights and electrics etc. It's still along way from finished but at least its going to look allot closer after this weekend. Sorry there's no picture's of the build but I'll take plenty from now on.