A long-time-ago thread I know, and perhaps covered in a slightly different way before (apart from REIDALPINE above), but I couldn't find anything very similar so below is my simple take on a DIY rear wheelarch mud-protector.
Over a year ago I bolted in some rear flexible wheelarch liners/ splash-guards which still seem to be effective, and require almost no cutting or templating! I used 2 metres of clear flexible PVC 200mm wide 3mm thick used for industrial cutains /doors (the type one drives through in a fork-lift truck in a warehouse, for instance) . I found 4 metres was just right (2 metres each side), fixing the PVC strip up to the inner wheel arches with big washers & 6mm nuts/bolts, and rivetting it to a small aluminium angle-bracket which is then rivetted to the bottom of the suspension pivot at the front (see photos!).
The strip seems to cover the inner wheelarches, the rear suspension catastrophe and other mud-traps quite well. It has drooped slightly where I have bolted the strip near to the edge across the top section, but still stops the mud getting above. It doesn't protect the fuel filler-pipe but it was simpler to go around it at the time.
The tell-tale stripes of flung water & mud show that the guards are doing their job.
Small mud-flaps at rear an added bonus!
I may buy non-clear PVC next time (I bought the clear from here, and this is the coloured options:
http://www.ebay.co.uk/itm/Coloured-...hash=item3a903e12fb:m:mlA_f1pBxJuMTvqvt4UOwRw ), as looks a bit odd from the rear. As you can see, the van is spotlessly clean all the time, ha ha.
The mud at the front of the guard (below) is of course from the front wheels:
Front of offside wheelarch, showing suspension mud-trap protected
and rear flap as the 2 metres of PVC comes to an end:
Looking backwards up into the offside rear arch, with the outer wing on the left (is that cracking underseal?), showing a bit of droop in the flexible PVC as it travells horizontally, and three of the fixing bolts (the heads of which are easily accessible for inevitable angle-grinder-removal in the future!). The water/mud spray-striping on the PVC also shows that it is still stopping most spray & mud reaching the inner wing:
