MONTHLY TECHNICAL
Jigged for accuracy
1 The bulkhead components are assembled on a rotating jig to maintain dimensional accuracy. Here, in the horizontal position, cab side sections have been welded together.
Easy access
2 Here, the jig and bulkhead have been rolled to the upright position to gain best access to other weld areas. The assembly is easily revolved to allow good access and good welds.
Heavier gauge than original
3 The bulkheads are manufactured from new 1.6mm steel. The jig ensures all elements of the structure are held in exactly the right place for welding.
One for every Land Rover
4 Shielder Chassis Ltd manufactures new replacement bulkheads for all models of Defender and earlier coil-sprung models, as well as Series II and IIA and Series III trucks.
Optimum working levels
5 At the workshop the new bulkhead is raised on the pallet stacker, which allows the height to be altered to suit preparation work in different areas.
M8 fixings required
6 As the fuel filter will be mounted on the bulkhead, a pair of Rivnuts will need to be fitted in place in these predrilled holes.
Get the angle just right
7 The appropriate Rivnut is screwed on to the riveting tool by the correct amount to allow the handles to be operated with relative ease and effort.
Just about right
8 If the handles were too far apart, at a wide angle, it is very difficult to squeeze the Rivnut correctly, and control is more difficult.
No damage done
9 The mounting points are in place and 9 an M8 bolt is trial fitted in them to check the threads have not been damaged by over squeezing.
Polyurethane sealer
10 A seam sealer compound is selected that can be painted over and has flexibility when set, to keep the water out for the life of the Land Rover.
If in doubt, seal it
11 A bead of the seam sealer is applied to every possible joint in the bulkhead. Taking time to do this properly at this stage will pay dividends.
Steady finger action
12 Each bead is then smoothed and squeezed into the joint at the same time, to ensure that the sealing action is as complete as is possible.
All will be unseen
13 In particularly vulnerable areas It is better to be generous with the sealant, rather than sparing, to make your Land Rover as watertight as you can.
Belt and braces
14 After the engine bay side of the bulkhead has been sealed, it is turned over and the cabin side is fully treated in exactly the same way.
Trestle and beer keg
15 The paint shop has painted many bulkheads and has developed this method of standing them so that they will not need to be moved during the process.
Access all areas
16 The position is optimum for painting the surfaces of the bulkhead that will be visible in the finished Land Rover but allowing everything to be painted.
Copper grease
17 The vent flap hinges had been packed with grease to prevent molten zinc from clogging them – this is cleared using a small drill bit.
Sort it before painting
18 A compressed air jet is then used to blow any remaining deposits of grease to ensure the hinge is completely clear for use.
Clear them out
19 Using a tap of the appropriate thread size, all threaded holes are cleared of excess zinc so that fixing bolts will fit during the build up.
Clean it off
20 The bulkhead will have invisible deposits of grease and debris, so this Tetrosyl pre-wipe degreaser fluid is used for the first time on the whole structure.
A “green” solution
21 This type of blue tissue roll is used because it is fully recyclable and does not leave any lint or fibre deposits on the surfaces.
Right grade for this job
22 The bulkhead will be sanded using an orbital sanding tool fitted with this 80-grit sandpaper, which is coarser than expected for bodywork.
Air powered
23 The orbital sander is excellent for the larger open areas and makes short work of smoothing down the rough zinc surfaces.
Remarkable transformation
24 Comparing the ‘before and after’ by touch, really demonstrates why the coarse grade of sandpaper is right for the job on galvanised surfaces.
Get them all prepared
For the areas where the orbital
25 sander cannot reach, a scratch pad is used to key the surfaces in all of the nooks and crannies.
Degrease and blow
Dust on the
26 bulkhead is now all blown away using the air line, before being completely rubbed down again with the degreaser solution.
Chemical action
27 With the preparation complete, the bulkhead is now painted with an etch primer, which bonds to the metal finish of the bulkhead.
Paint every square inch
28 One single coat of the etch primer is applied to every part of the bulkhead and this will ensure that the subsequent paint coats will not peel off.
Leave it for an hour
29 The etch primer needs to be completely dry throughout before the next stage of the process can take place, including areas where primer may have pooled.
A coat of grey
30 We can now begin applying the 2K (2 pack) primer paint to the bulkhead. This is sprayed on in up to four thin coats throughout the bulkhead.
Fast process
31 As we’re using a wet-wet process on this bulkhead, the 2K primer only needs to dry for 10 minutes or so, before we can apply the 2K finish coat.
Dramatic change
32 Now the bulkhead begins to be really transformed, as the final colour is applied – in this case a lovely rich red colour of the early 1990s era.
Resplendent
33 The finished job is excellent and superior to refurbished and galvanised bulkheads we’ve fitted in the past – new steel always galvanises better, in our experience.