6th Jan 2012, 07:11
Finally found the source of the water leak in the rear passenger floor on my 2004 Mondeo TDCi. Water travels down the glass onto the window support bracket, which is screwed to the inside of the door, which has a hole above the screw, and allows water to bypass the waterproof membrane over/through the membrane, along and into the rear footwell.
Remedy is to pull back the membrane, and fill the hole with mastic. I used guttering sealer from B&Q, made sure water dripped into the door and out of the drain holes, reseal membrane. If car is parked upwards, water travels along the inner seal into the rear. If parked downwards, into front footwell. Obviously this can apply to the nearside and offside of the car.
16th Nov 2011, 14:21
Hi, I also have a mk3 ST220, which has recently developed a water leak into the rear footwell. This is very annoying, as the car itself is in fantastic condition, and the last thing I want is a pesky water leak. Will try removing the door cards as you recommend and resealing the membrane; fingers crossed it will cure the problem... Thanks for the tip.