This is from another post but though it applies to this. Please post how you get on, we are having this problem but not had time as yet to try this out
From VX forum , dont know if it works or not .
" The reason and cure for ‘wet foot well’ on both passenger and drivers side of the Vauxhall Combo van and the Corsa ‘c’.
The foam seal around the main electrical connection unit lid, in the near side corner of the engine bay degrades and lets water in. Remove this using the torx screws, push out out the foam seal with a flat blade screwdriver. I recommend using Wikes’s Acrylic Roof Repair. Product Code: 243816, Apply a thick bead in place of the foam and replace lid. Then use some more sealant to seal around unit. This should sort the problem.
If it persists to leak it will either be the electrical connection unit cowling to bulkhead seal, this is a rubber seal and you will need to disconnect the wiring loom plugs between the outside and inside beneath the lid. I recommend pulling the rubber seal out and cleaning it then replacing it in its groove then applying a bead of gunk on the seal then re fixing the cowling. The other reason may be the heater intake seal leaking. (Dough full though) remove the intake. The seal is foam tape. Spread a bead of gunk on this and replace.
The brake servo and brake fluid reservoir are mounted on a black bulkhead plate. This is secured to the bulkhead via 5 or 6 no. 13mm nuts within the engine bay and wiper bay area. The factory seal breaks down as its only thin. Remove the nuts and working inside under the pedals, lever the plate down. With latex gloves on use handfuls of sealant to thumb in and around plate, then refit. You could just smear sealant over the plate to bulkhead joint but this may not guarantee a fix as it is very awkward to get to the lower area under the brake servo unit. From the outside thumb in sealant over the join and where pipes ect. Penetrate the plate. All done.
Hopefull this should sort it. It did for me."
Posted on Friday 26th of August 2011Don't understand this? Ask a question