Last month’s theme in the Norfolk Garage was Lightweights: this month seems to be all about Defender bulkheads. As I write this I have just sent out a 1992 Defender 110 Station Wagon after a bulkhead swap, and have a secondhand bulkhead awaiting some minor repairs to the top corners prior to being fitted to a Ninety of similar vintage. A couple of years ago I wrote an article for LRM describing the common rust areas on Defender bulkheads. The bulkhead I used for the photos was taken from a running Mot’d Defender in daily use, and at the time I thought it was pretty rotten, to the extent that the vehicle should have failed the MOT on structural corrosion at least two years previously.
The bulkhead I have just removed from the Station Wagon is much, much worse. The vehicle has at some point been through the hands of a well-known rogue who is I believe no longer trading. I cannot be sure whether it was that person who perpetrated the outrage I am about to describe, but whoever was responsible deserves a lifetime ban from working on Land Rovers.
Both top corners of the bulkhead had rotted out, the rot extending along the top rail and around the ends of the air vents. This is a tricky area to repair to a satisfactory standard: to do the job properly the windscreen frame and most of the dash need to come out. The whole area forms a box section that supports the upper door hinge as well as the windscreen attachment bracket. It is possible to buy a steel patch panel which can be welded over the rotten area. Although not ideal (since the rot will continue to fester underneath) the patch panel will at least restore enough strength to stop the upper door hinge from flapping around, and buy you two or three years to source a better bulkhead.
It should be obvious that the patch panel will only contribute to the strength of the area if it is welded all round. However, that would have involved removing the windscreen frame, and why go to all that trouble with a vehicle you are looking to sell? That was presumably the thought going through the mind of whoever “repaired” this bulkhead: the patch panels were glued on with silicone sealant and plastic filler liberally stuffed into the gaps. With most of the upper corner structure having disintegrated, the windscreen brackets were bolted directly to the patch panels and the door hinges relied entirely on big lumps of plastic filler to stop them moving about. Sanded down and painted, this “repair” probably looked quite smart to the untrained eye – at least for the time it took to find a new home for the vehicle.
Removing the bulkhead revealed further bodgery. Both bulkhead outriggers had been replaced. The inner ends sit directly below the footwells and are very hard to weld properly without either removing the bulkhead or cutting holes in the footwells. Needless to say, the master bodger responsible for this job had done neither, and most of the welds between the outrigger sides and the chassis rails broke off when tapped with a chisel. Easy enough to sort with the bulkhead off. The sill rails were also in a rather distressed state where water had got between the rails and the seal retainers spot-welded to them. This is a fairly common problem on older Defenders, and was soon sorted by letting in strips of new metal, once I had removed the huge quantity of carefully shaped body filler that had been plastered over the top.
Given the various nasties I had uncovered I was just a little apprehensive about panel fits, in particular door alignment. With the new bulkhead loosely bolted to the outriggers I carefully measured the door gaps top and bottom. I normally look for something around 34.5 inches: the bulkhead can be moved forward a little to open up the gaps by adding spacing washers between the mounting foot and the outrigger, but on a five door Station Wagon the forward end of the side rails is fixed and cannot be moved without dismantling most of the rear body, so there are strict limits on how much adjustment is available. On this particular vehicle I found that two washers each side gave me acceptable door gaps at the base of the pillars, while still allowing the side rails to be bolted to the mounting feet without bending them too far out of shape.
I now needed to make the door gaps at the top of the pillars the same width as at the bottom. The bulkhead was a new old-stock Td5 item modified to fit a 1992
“When buying a Defender do some research into bulkhead rot”
vehicle. A few years ago the market was for a short time flooded with these Td5 bulkheads – I must have bought around a dozen at £200 each and now wish I had purchased a hundred of them. Although labelled Genuine Parts they were rather shoddily assembled (possibly the reason they were so cheap) and sure enough, this one was slightly twisted so that the door pillars were not parallel to each other. The alignment of the top of the bulkhead uses slotted holes in the bracket between the footwell and main chassis rail. I got one side aligned, tightened the bolts, then used a ratchet strap to pull the opposite top corner forwards before tightening the bolts on that side. It took two attempts but I ended up with nice even door gaps on both sides.
The wings went on with no problems and all the mounting holes lined up with those on the chassis and front panel, which is always a good sign. The first real test of alignment was when I fitted the bonnet. The striker plate on the front panel has only a limited range of adjustment, and a relatively small alignment error on the bulkhead can easily leave you with a bonnet that either will not shut, or worse, slams shut and will not open again. I loosened the two bolts that secure the striker plate, gently lowered the bonnet and found that with just a few millimetres of adjustment the bonnet pin sat dead central in the striker plate. I tightened the bolts, closed the bonnet, pulled the release and it sprang open. Things were looking good.
The second and more arduous test came with the refitting of the front doors. These were (unsurprisingly) rotten at the bottoms and (also unsurprisingly) stuffed with cardboard, sticky tape and body filler, artfully sanded down and painted to look like solid metal. I tend to steer customers away from trying to repair rotten doors as it is impossible to do a really satisfactory long term repair unless you strip off the skin, remove all the internals, blast, repair and paint the frame and then fit a new skin, by which time it would be cheaper to buy a new door. But in this case the customer had already bought bottom repair sections and was happy to accept the limitations of what I would be able to do with them.
With new door hinges attached to the bulkhead, each door was bolted to the hinges top and bottom and then gently closed, checking the alignment of each catch against its striker plate. The hinges have a small amount of adjustment at the bulkhead end via the J clips being able to move within the square holes, but the customer had supplied me with Pumatype hinges and metric clips, which have rather less scope for movement than the older Imperial threaded clips. If the door alignment was miles out I would be in a world of grief. Happily one door slammed shut and sat square in its aperture with no adjustment: the other needed the top hinge screws loosening and the rear edge of the door lifting to push the hinge forwards on the bulkhead before retightening the screws. End result, two doors that closed easily and didn’t look too far out of alignment.
That is not to say that the doors were perfectly aligned. The crease line at the top of the door pillar on the bulkhead was about 5mm lower than on the centre pillar, probably because the old bulkhead had sagged slightly on the chassis while the bulkhead outriggers were being replaced. There is no facility to adjust the vertical position of the bulkhead on the outriggers, so the end result was a slight misalignment between the trailing edge of the front doors and the centre pillar. Short of replacing both outriggers again there wasn’t a huge amount I could do about that, and I have seen much worse door alignment on vehicles which haven’t had the chassis bodgery that this one has suffered.
The book time for bulkhead replacement on a Defender is around 35 hours (plus painting) so it is not a job to be undertaken lightly. The message is simple: when buying a Defender, do some research into bulkhead rot and check all the weak spots in your intended purchase. The hardest area to bodge up for a quick sale is the metalwork around and above the windscreen frame securing bolts, on the top inner corners. You cannot see most of this area without removing bits of dashboard which most vendors are unlikely to permit, but if you can see holes or bulging filler in the small area that is visible, the bit you cannot see will probably be as bad. Whereas a new galvanised chassis is normally available off the shelf, Defender bulkheads are much harder to source at the moment, and you would be far better to buy a vehicle with a rotten chassis and sound bulkhead than one with a new galvanised chassis and a bulkhead made of Swiss cheese.