Removing the seatbox
Assessing the issues
1 Localised repairs can be carried out in situ, but as I am rebuilding the Ninety, I set about removing the seatbox. Not really a difficult job, though
Previous riveted repair
2 The seatbox end on the left-hand side had a patch riveted on. It’s obvious as to what it’s hiding. Let’s drill out the rivets and take a look . . .
Removal of the seatbox
3 Whoever patched over this corrosion could have replaced the section with part 013. To remove the entire seatbox, I start undoing nuts and bolts from the sill rail.
Removing the floor
4 Working my way round the number of floor bolts and large crosshead screws, I could then lift out each floor panel. I also disconnected the handbrake lever.
Nothing seized – lucky day
5 Surprisingly, they all came undone without too many issues, such as seizing into their plastic inserts. A good soaking of penetrating oil beforehand helped here.
Just a row of bolts
6 With the row of M6 bolts connecting the seatbox to the rear tub (positioned behind the seats) undone, the old seatbox was soon on the workshop floor.
Exposed to the elements
7 The steel battery box suffers from rust as it’s exposed to water, mud and road salt. It is also in direct contact with the aluminium frame.
Not as bad as some
8 This one is still not so bad as many, given its age. I’ve seen them so bad the only thing holding the battery in is the earth strap!
Untidy repair
9 But someone has tried repairing it in the past with a scruffy welded patch. It’s had its day and it’s now time for the scrapyard.
Battery box
10 If you wanted to replace only the battery box and fit to your original frame, drill the spot welds and rivets and remove. More on how to re-assemble later.
Multiple holes
11 My old seatbox had several holes drilled over the years for various seat frames. While you can purchase individual parts, the decision to replace the entire seatbox was easy.
Complete kit
12 Laid out on the floor, supplied flat-packed by YRM Metal Solutions. Seen here are part numbers 336 which corresponds to the entire kit, and 021 the battery box.
Starting at one end
13 Each part comes marked up, so assembly couldn’t be simpler. Part number 148 is offered up to the front panel. The basic frame takes just minutes to assemble.
It’s all lining up
14 The accuracy in the parts is superb. The smaller holes require a Type-a pop rivet. The larger hole has a rivnut ready to accept your seat frame.
Now at the back
15 It’s now worth riveting part 148 to the back angle. You don’t need to rivet the outer holes yet – you need to offer up the end panel first.
End panel 014 offered up
16 Now rivet the outer corresponding holes from the top of 148, front and back, which go through the front panel, back angle and into the end panel (three layers).
Starting to take shape now
17 Moving along, you can rivet home the middle seatbox panel (part no. 147). There’s only one place this can go, and it’s marked up to indicate the front.
Before going too far
18 At this stage it’s time to assemble the battery box. You’ll need the frame to be flexible and be able to rivet through the frame and into the box.
Getting your head around it
19 The battery box is made up of three parts: a bottom, side and back. They are marked up on the protective coating as 1, 2 and 3.
It’s a numbers game
20 Helpfully, YRM marked up that number one meets up with the opposing number one. Similarly for two and three. Just don’t remove the protective film too soon!
Knowing where it all goes
21 Once all is in position, remove the protective film before finally riveting. If you don’t, you’ll be picking out the plastic from around the rivets for hours!
Back to the frame
22 Now you have the battery box made up, you’ll need to offer it up to the underside of the frame and line everything up. It’s made to fit!
Ensuring a tight fit
23 With mate Darren helping, we work out that the battery box needs to sit flush at the top. A couple of clamps hold it in place for now.
Checking the alignment
24 We double check the front edge and side for alignment. This is bang on. We’re now ready to drill some more 5 mm holes. We’re getting there.
Measure and drill
25 With Darren being an engineer by trade, he insisted on measuring between rivets for accuracy – it’s definitely a continuation of the way YRM design their parts.
Flip back over
26 Now that the holes have been match drilled from the underside, we turn the seatbox over and fit eight more rivets. It now feels a lot more rigid.
More accurate measuring
27 We now need to secure the front panel to the battery box. A marker pen is used to mark out perfect spacing. A metal rule helps, too.
Home straight
28 We’re match drilling the front panel into the folded lip of the battery box. We drilled eight holes in a line here. Should be more than enough.
Rivet along the bottom
29 And the final row of rivets fixes the battery box in place. You won’t see these rivet heads if you choose to refit the matting back in the vehicle.
Final task for now
30 We match drill the 10 mm holes on the edge on the battery box side of the seatbox where it will finally bolt through to attach to the sill rail when fitting to the car.
Finishing off
31 The front panel will be drilled for the handbrake mech. After painting, we’ll rivet the original seatbox lid clasps back on (new ones available from YRM, part 250).