23 January 2023
Trevor explains the cutting and fabrication techniques involved in restoring a rusted bulkhead
Need to know
Time: 10 hours.
Difficulty: 4 out of 5
Models: Td5 Defender and Series.
Tools needed: Angle grinder 115mm with grinding and thin cutting discs, MIG welder, steel chisels, drill.
Parts & costs: LHS extended footwell repair panel, YRM Metal Solutions, £54.30; RHS extended footwell repair panel, YRM Metal Solutions, £59.40; LHS lower full door pillar, YRM Metal Solutions, £43.46; RHS lower full door pillar, YRM Metal Solutions, £43.46.
• Wear protective gloves and safety boots when handling heavy objects.
• Wear protective clothes, gloves and eye protection when cutting and grinding.
• Wear flame-retarding clothing, welding gloves and correct welding mask, when MIG welding.
• Be aware of the fire risk when grinding, cutting and welding. Ensure fire equipment is always to hand.
Contacts: YRM Metal Solutions. Tel: 01388 488150. yrmit.co.uk.
The story so far: After a customer bought the battered body sections from this 110 Td5 hard top, Trevor ended up with the remains including the wrecked engine and gearbox, rolling chassis, bulkhead and one wing. The mechanical parts have now been built up onto a new galvanised chassis with an ex-Discovery 2 engine installed. See also parts 1, 2, 3, 4, and 5 in our How to section. In this part 6, we turn to the bulkhead.
The bulkhead was sound and rust free in the areas that could be clearly seen. However, when the bulkhead was stripped of trim, door seals, dashboard and the engine bay assemblies, a few serious issues were revealed behind these parts. This is typical for Land Rover bulkheads: often the parts hiding the rust have created water traps that allow the rust to advance, unseen.
There are quite a few replacement bulkhead options on the market, made of new steel and hot dip galvanised. But it is always good to repair and save an expensive part where possible. And by refurbishing this original factory-fitted bulkhead, I can ensure it will be an excellent fit.
Cutting out the rust
A Land Rover bulkhead can be repaired by cutting new steel of the correct thickness and size and welding in place of the damaged material that has been removed. This is straightforward for flat areas and where the joins between two surfaces are fairly simple. The job becomes more difficult where the structure is more complex or where there are curved areas, for example towards the top of the door pillars. Clearly, it is important to get these curves just right, especially in the areas that are visible on the finished vehicle.
The good news is that there are many repair panels and other components on the market, for example pre-formed footwells, which make the repair job less complicated. YRM Metal Solutions has developed an extensive range of replacement and repair parts for Defender, including the bulkhead, so a pair of extended footwell repair panels and replacement full door pillars were ordered for this job.
Don’t want them to melt: The bulkhead has mostly been stripped. These last few plastic fittings are removed using a trim tool and can normally be used again after the repairs.
Typical example: This is the type of rust damage that needs to be dealt with, where the affected steel will be cut away and replaced with a new section.
A little more tricky: Areas of the bulkhead like this, where multiple surfaces are rusted through, will be more difficult to repair, but can be sorted with a methodical approach.
Help is available: This footwell centre panel, part of YRM’s set of footwell repair sections, can be fitted in its entirety, or cut into smaller sections for more localised repairs.
Versatile: The footwell repair sections are supplied as a two-piece kit (outer sidewall here) so that fitting them, or trimmed sections of them, is an easier task.
Readily available too: Replacement door pillars (or A-post sections) are also available and can be used whole, or a section cut to suit the extent of the repair area.
Hidden by paint: The spot welds are difficult to see, so each one that is to be drilled out is identified and spotted with a felt marker to mark the location.
Not too big: Each of the spot welds is drilled out using a drill bit that is just large enough to remove the weld – usually 5mm or 6mm.
Break them apart: A chisel is used to break any remaining spot welds and separate the door pillar from the other components, such as this bulkhead foot mounting bracket.
Best friend: After drilling out the spot welds, the angle grinder – when fitted with a thin cutting disk – is an invaluable tool for cutting out the rot. Hold it firmly.
Straight cuts: Each cut-line is carefully marked using a fine felt marker, so that the new steel
can be cut appropriately to be an excellent fit.
Keep it as simple as possible: This door pillar is not being removed completely, and is marked for cutting, to leave a relatively easy welded repair job.
Now it is free: The old door pillar, with a section of inner panel and the bulkhead foot, has been cut free and removed from the bulkhead.
Further surgery: With a section of the door pillar removed, the other main section that is rusted through is marked out and cut away using the angle grinder.
Measured and marked out: An identical area of new steel is cut out of the repair panel to replace the section that has just been cut from the bulkhead.
Preparing the door pillar
A bracket saved: The bulkhead foot has been fully liberated from the old door pillar and the holes created from drilling out the spot welds refilled with weld and ground flat.
6mm holes: The new door pillar section is being drilled in each of the approximate
points where there had been spot welds on the old one.
Copy it, recreate it: The bulkhead foot is now clamped to the new door pillar section, carefully replicating the position it had in the old rusted door pillar.
Similar effect to a spot weld: At each of the holes that had been drilled in the new door pillar, a puddle weld is made to bond the bulkhead foot bracket to the door pillar.
Use grinding disc: The puddle welds create a very strong component out of the door pillar section and the bulkhead foot bracket. They are now being ground flat.
Trim the excess: The new door pillar is cut to the required length (the upper curved section is not needed) after carefully measuring the void that we need to fill.
Correct order of things: The new door pillar section will be welded in place, only after the other adjoining sections that we cut away have been reinstated with the new steel.
Building onto the bulkhead
Getting the size correct: The new inner repair panel is offered up to the bulkhead and marked with a felt pen where it needs to be cut to size.
Trimmed and tacked in: Having been trimmed to the correct size, the inner panel is welded in place, again using the puddle weld technique that was used on the door pillar.
More than one technique: As well as the puddle welds, some seam welding is carried out where appropriate, ensuring as much strength as possible is built into the structure.
Bring it together: The door pillar is now aligned at the bulkhead and clamped in position using locking pliers or G-clamps, before a few tack welds are made.
Properly bonded: With the best alignment achieved, more puddle welds are carried out to permanently fix the pillar to the bulkhead from top to bottom.
Replacing the flange for the door seal
Badly corroded: The remaining original door seal flange lip is not in good condition, so it is decided to trim it off in order to replace it with new steel.
Clean the site: After removing the lip, the area is extensively cleaned of rust and paint using a grinding disc and a wire brush attachment.
Bend it, shape it: The new lip is formed by tack welding a little and then manipulating the steel to follow the contour, then repeating with another tack weld.
Repairing small localised areas
Careful cutting: Small areas of isolated corrosion are simply trimmed out, using the cutting disc, making sure that all of the rot is removed by cutting to clean metal.
Beware: This area is close to an important bracket on the inside, so we ensure nothing is damaged on the other side of the bulkhead.
Gentle heat: There is a lot of factory sealant around the area to be patched, so this is softened with the gas torch and carefully scraped away.
Cardboard cut-out: The aperture is prepared now, and a simple template is made which is used to cut and shape new steel to the size of the patch needed.
A deep clean: Following all of the repairs, all the factory sealant is scraped off before the bulkhead is sand-blasted to remove all of the paint and foreign material.
Final remedial action: After sand-blasting or manually preparing the finished bulkhead, additional small holes may appear, which need repair before painting or galvanising.
Next time: the galvanisers I use are extremely busy, but I hope the bulkhead is back in time to begin seam-sealing and painting, prior to fitting it to the rolling chassis. Additionally, the Discovery 2 gearbox that I’ve installed needs to be adapted for use in the Defender using a very clever part from Synchro Gearboxes. I might even fit its highly-rated Slick Shift at the same time. Suffice to say, there is lots to get on with, as the Defender 110 begins to really take shape.
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