MK III corroding front wheel arches

[Steve@CCR]

you're looking at a MKIII front wheel arch mud flap. good at stopping mud
splattering along the side of your clean van, but dirt and water get
trapped between the inner wheel arch and the mud flap a long time after
the rest of the van has dried out. my van had a big hole behind the near
side mud flap which was hidden. check this out and the rest of the
front arches before buying.

[FredTransit]

I always though that the mudflap was there to stop the water/salt/mud getting on the step, that's what it does with the Mk2, and it works , stopping the steps rotting. Would it better to got rid of them, despite having mud up the side of the van?

[Luke]

I think the problem with the mudflaps is when there new they work great but after a time they become loose and allow water/dirt down the back!
What i'd do to prevent this happening to a van i allready own is remove the mudflaps, paint the area behind them with an thick underbody paint (after removing any rust i'd found) and then re-fit the mudflaps

[Steve@CCR]

correct Luke. and you can seal around the edges of the mudflap
with pur-flex or the scotch 3m version!!!

[Gunslinger]

bad move ... the more little sealed areas you have, then the more areas for water/damp to get trapped,

best thing you can do is the following ....

1) never screw them into the box section or arch (causes water to get in)
2) dont try and seal the gap, but make it bigger !!

here is what i did ...
1) repair the knackered sections !
2) get 4 nuts and bolts (about 2 inches long)
3) get 4 valve step seals, top hat ones (i think mine came from a vauxhall)
4) weld the bolts head first to the box section in the reqired places, creating studs
5) slide the valve seals on (narrow end first)
6) fit mudflap and fix in place with the nuts

this will increase the gap around the back of the mudflaps, it will not decrease its efficiency much and will allow the mud/water to come out easier ... and when you wash it the hose will flush all the crap out nice and easy

this i did on a mk2 ... but should be fine on a mk3 if you dont mind seeing the small gap

[WINDSCREENGUY]

the big hole is already there on my mk5 its large round hole but its made that way its a factory thing on mine

[Gunslinger]

oops ... my bad ... i read "hole" and immediately thought "rust" .... now i see what your on about, there is a round hole in the end of the sill behind the mudflap .... these are present on many vehicles, and to be quite honest are a real pain in the ass ... weld it up, youll never need it, i think it has something to do with access for painting (not really sure) all i know is that the plastic bung they fit never does squat but add somewhere for water to hang around and cause it to rot

[Steve@CCR]

you underestimate the power of Puflex. when that stuff
is applied properly no water or damp will get in and it looks
neater than having a gap. it's used to bond and seal
front window screens, so it's the business.