Corsa C water leak challenge. Jennie commented on my
original blog post and had been very unlucky with two garages trying to get this fixed. One mechanics solution was to drill some holes in the floor to let the water out! One tried to seal the bulkhead plate, but only around the accessible area, which get's them "close but no cigar" points. The problem was distance and timescale as this job would need completing over 2 days. That's interior out, dry and everything fixed and tested, which was going to be a good challenge. Perfect opportunity to write a better blog post on this issue...
Wet drivers footwell for the Corsa C explained.
Water in the drivers footwell is one of three problems:
1) Bulkhead plate seal.
2) Heater matrix. (you should notice the car using coolant and the water should smell of antifreeze)
3) Windscreen leak. (Would only be a problem if you just had a new windscreen fitted)
The bulkhead plate seal for the brake servo runs very close to a water drainage channel. Over years this drainage becomes full of leaves and muck which mean the rubber seal becomes constantly damp and wet. Over more time this causes it to fail and then water finds it's way in through the joint re-appearing inside above your pedals. The footwell has a thick foam insulation coated with rubber material, then a thin layer of carpet which makes drying this water tricky. It also means the carpet behind the pedals might feel dry but the footwell is wet which confuses some people. The fix involves the re-sealing of the bulkhead plate and the drying of the interior. You can't access the all important bottom right corner of the bulkhead seal due to the brake cylinder blocking access. The jobs a bit time consuming because of this and requires some mechanical skill.
Wet Passenger footwell for the Corsa C explained.
Under the battery tray located towards the front of the car is the passenger drainage flap. Water is designed to flow down these channels and out of the flap. Water should flow down the windscreen by the side of the relay box cover and then underneath it out of the drainage channel. However leaves and dirt cause it to linger around the relay box cover and over the years damages the rubber seal in the relay box lid. Once the seal perishes water can flow down access holes designed for the wires into the cars interior and onto the passenger footwell or carpet. The fix is to simply replace the relay box cover and clean the drainage channels. So what's the catch?... access with the scuttle panel and battery removed it's nice and easy to work on.
Scuttle Panel removal
* First job is to remove the wiper arms, but use a puller if they are stuck on. The masking tape on the windscreen is a habit I have of marking the wiper blade position for re-fitting. Puller can be purchased off ebay (Battery terminal & wiper puller).
* Scuttle panel is secured by three Torx 20 screws highlighted in orange in the picture.
* Pull off the rubber seal that runs across the engine bay.
* Remove scuttle panel insert.
* Pull up windscreen edge trim in bottom corners.
* Remove washer bottle by pulling it straight up. Hoses disconnect by simply pulling but but make a note for re-installation which nozzle is for front and rear. In this case upper nozzle for front washers lower for rear.
* disconnect battery
* unclip battery wires from scuttle panel
* lift up scuttle slightly where the rubber seal went across the width of the engine bay. Slide it towards the engine to release it from the windscreen. Be careful with this and do NOT pull up near the windscreen as you might damage it.
* Result!... the scuttle panel is removed and you can see part of the bulkhead plate seal where a failed repair has been attempted with tiger seal.
Removing battery tray and Pollen filter housing
* Remove battery completely.
* Remove pollen filter housing which has 4 Torx 20 screws.
* Remove battery tray and admire the leaves and dirt.
Clean all this out and hover inside the blower motor where the pollen filter was located. You don't want leaves inside the blower motor as it causes annoying noise when the blower is on 3 or 4. At this point my wet vac made short work of the mess and using the blower function you can direct air under the relay box to clear out all the hidden muck.
Attacking the bulkhead seal
* Onto the drivers side remove the wiper linkage (8mm bolts) and disconnect the electrical plug.
* Unclip the green brake line pipes from the plastic holders. This will give the pipes enough flex so you can move the brake master cylinder and reservoir.
* To avoid the need to bleed the brakes we just need to drain the brake fluid level below the grey corrugated tube on the side of the brake fluid reservoir. Depending on your type of reservoir you should be able to extract the fluid from the top using a syringe or spray bottle device. This particular Corsa(04 plate) threw me as it had a different type of brake reservoir than I had previously seen. Where you pour the brake fluid is solid it then flows up and through a small passage into the reservoir below. Not 100% sure why this is technically better but it means I had to think of another way of extracting the fluid. I would be using new fluid, so with kitchen roll underneath I quickly pulled off the grey tube and emptied the fluid into an old plastic milk bottle.
Took the picture after I had put the reservoir top back on but you get the idea. Normal rules apply for Brake fluid it's nasty, so wear gloves and wash any drips off straight away with water. once drained cover this connection with kitchen towel and tape to keep it clean and drip free.
* Undo the master cylinder bolts (13mm) and move it out of the way. I find it best to hold the battery cables and move it underneath.
* Keep the end of the brake master cylinder clean by covering in kitchen towel and taping it up.
* Tape up the servo to stop any bits falling in it.
* Tape up the grey hose and make sure the rubber end piece stays attached.
* Remove vacuum line out of brake servo. It's quite tough so a plastic trim tool comes in handy for this.
* Brake servo cylinder has two bolts (13mm). You will need to remove interior lower panel and accelerator pedal(10mm) to make some room. Use a universal joint and extension for this one and practice your finest yoga moves getting that socket in position. This is the view looking upwards in the drivers footwell.
* This is a nice picture of the extension bar setup to get to those tricky bolts. It also captures someone else's handy work at fixing this issue. When I say fix I mean drilling holes in the floor and removing that cover. Luckily they left the cover under the carpet and the rust was mainly fillings from drilling. I sealed the cover back in place and did the same for the holes.
The brake servo needs separating from the brake pedal with the following steps:
* Clip on the brake servo lifts up slightly then slides off.
* Unhook brake pedal return spring
* Remove pin and washer
* Lift brake servo out from bulkhead at front of the car. This picture shows the seal that people forget to replace when re-fitting.
Result!...you now have full access to the bulkhead plate and you can see where the seal has cracked and opened up in places. The tiger seal was from the previous repair attempts but nicely demonstrates how it's impossible to re-seal that bottom corner without all this removal.
Crack out your favorite old screwdriver, abrasive pad, plasters and swear-box for this next bit and scrape out the old seal from the joint. You should bash your knuckles a few times hence the plasters but the result is one bulkhead seal ready for sealant. Clean the area with degreaser or non corrosive brake cleaner whatever you feel is suitable. I dried the seal area using the blower of the wet vac which was quick compared to using a hairdryer on my previous fix adventure.
* Seal clean up and removal work in progress picture.
* Old seal removed and cleaned, ready for sealant
Sealant time now where you have a choice of 'Tiger seal' or 'Plumbers Gold'. Tiger seal is the proper choice but requires the area to be dry. For this reason I used 'Plumbers Gold' again in case tiny bits of moisture were still present. 'Plumbers Gold' specification resists the temperature extremes of an engine bay and I planned to coat it in under-seal for added protection. I applied sealant to the bolt heads in this area and bonnet cable grommet. This is a bit overkill but worth it just for peace of mind that nothing can potentially leak after this.
Let the sealant fully cure and mask up the area where the brake servo seal sits against the bulkhead plate. Cover the surrounding area to prevent over-spray and your ready to shoot some under-seal.
In true Haynes manual style 'Reassembly is the reverse of the above steps'. Points to note are the nuts that hold the brake master cylinder in place are meant to be replaced on refitting. I tired to purchase these though Vauxhall and they didn't have any stock in the country (3495607). I commented that obviously people weren't replacing them as the official procedure suggests. The parts guy told me they just use thread-locker which is what I did the first time around and again for this car.
You need to replace the seal on the brake servo cylinder with a new part (90447516). Ask the dealer to check that the seal is the correct one for your car registration before purchasing.
Replace the relay box cover with a new part (13132363) if you also have the passenger water leak. The picture shows the old one where the right hand side has rotted away.
Remember to add some new brake fluid and then with nearly everything back together it starts to look something like this.
Top Tip... The Scuttle panel is in two half's but it's easier to refit it as one whole unit.
Water leaks Fixed!
Interior Drying.
I choose to remove the full interior and again cut out the drivers footwell foam to dry it all externally. The wet vac worked wonders at this stage and sucked up an incredible amount of water from the foam. In brief the procedure is:
* Remove carpet fixings (2 drivers and passenger side)
* Remove door seat pocket trim. One Torx 20 screw and clips that pull.
* Footwell trims (torx screws and 10mm deep socket for plastic nuts)
* Disconnect the seat belt pre-tensioner wiring making sure you have the car battery disconnected. Plastic cover slides off, red bit pulls out which allows the green plug to be removed. Cut the zip ties and replace with new when re-fitting
* Remove the fonts seats (Torx 40)
* Remove rear seat bench which just lift up then unhook.
* Undo the seat belt mounts which need to be at this angle to unhook (Torx 45).
*Center console unscrews and lifts up slightly allowing you to cut the carpet joints. These wont be seen when refitting and save having to remove the handbrake and gear stick assembly.
* Pull the carpet out around the center console and cut the foam insulation (see photo).
* The carpet from each footwell now folds back and the whole lot can be removed and dried.
The weather was gorgeous the weekend I did this fix. Great for drying out the interior fully.
I cut out the drivers footwell foam which was soaking and re-installed it with small amounts of 'Gripfill'. You can just see the cut's if you look carefully in this refitted picture. The carpet was re-gluded to the foam using 'Ever Build Stick2 Adhesive'.
When refitting the footwell trims ensure you get the door seals over the trim and the center console ones can be a bit tricky. They have a locating peg that fits in the metal bracket behind the center console. Leaving the console loose and lifting it up slightly is the secret to getting these in correctly.
Job Done!
Conclusion & Testing
After test driving the car and re-checking all the brake lines in the engine bay for any leaks I asked Jennie to check the brake lights while I pressed the pedal. Unfortunately they were permanently on! Luckily she was able to pick the car up the next morning, which bought me some time to study this brake switch.
Turns out this brake switch operates on a ratchet, so I must have pressed it in when disconnecting the brake pedal from the servo. I manged to find some information on the internet where someone had written how they reset it (I can't find this now but thank-you!).
This is the brake light switch you don't need to remove it to reset it. Lying on your back half in the car with a torch and flat blade screw driver worked for me.
1) The collar extends out
2) Press the brake pedal down increasing the gap between plunger and pedal.
3) Use flat blade screwdriver to pull out plunger. It will click in my case twice.
4) Push the collar back into place
5) Release brake pedal which will reset plunger to proper operating position.
6) Press brake pedal and test lights again.
Enjoyed the challenge of Fixing this under the time constraint but the best bit was the weather. You defiantly need two sunny days to pull this off :-)
