RESTORATION

of AC's post-war 2 Litre Saloon

Page 6
Timber repairs (front half)

The rear half of the frame was difficult because of so many compound curves and few reference lines to measure from. The front half has plenty of straight lines making repairs easier. The main challenge is to get a good fit for the doors and the front wings, and I'll deal with these issues first.

Note that most of the photos on this page are of a repaired wood frame, and so repair pieces are noticeable for their pale colour.

Door fit

Traditionally, doors are built with a slight twist. This is so that as you shut it, the lower part closes first, resting against the rubber door-stop, and then a final push untwists the door until the latch clicks in. Changing the size of the rubber allows one to get the door fitting flush. The AC's door is slightly different because of its shape where the line of the wing flows into it. The rubber door stop is only a short distance below the door-latch, and this means that varying the size of the rubber won't help to untwist the door for a flush fit. There is also a second rubber stop near the top of the door.

The answer lies in the door roller under the door. When the door is closed, the roller slots into a cut-out in the main sill-board. With all trim and fittings in place, this roller presses against the sill-board and keeps the outer corner of the door flush with the wing and sill, and stops it from rattling against the door-step rebate. By "trim and fittings", I mean the roller complete with its rubber tyre, and the 2 layers of draft seals on the door: Sheet rubber and sheet leather-cloth. The cut-out in the main sill-board should be the right size to achieve this, but can be fine adjusted if necessary with extra layers of door seals or packing shims added to the cut-out.

The door also needs to have an equal clearance around all edges to the rebates in the body frame. With all panellng in place, and painted, the clearance is about 2mm. Panels are 1.2mm thick, and mostly in 2 layers around the door rebate on the main wood frame, and so about 4.5 to 5mm clearance is needed if you have the bodyshell removed. If adjustments have to be made to the depth of the door opening rebate, then one has to check to see if the bodyshell can be made to fit snugly around the altered outline. If adjusting the rebate along the door-step edge, you need to check that the bottom of the sill panelling (part of the main bodyshell) will line up perfectly with the wing.

The above photo shows the bottom front corner of the left-hand door and a repaired door-step. The outer sill rail is missing. Clearance between door flange and door-step rebate in this photo is 5mm.

The bottom of the door needs to safely clear the door-step plate. This is a very common problem, usually from doors sagging due to worn hinges or loose hinge bolts. Warping of the door-step can also be a cause of scraping doors. The first thing to scrape the door-step plate is usually the door roller-holder, after its rubber tyre has disappeared. The clearance is only about 1mm or so with good door-hinges, and so it might be advisable to raise the door roller another 1mm to improve clearance?

When test fitting the doors, the condition of the hinges is important, since worn ones will allow the front of the door to lower. If the hinge wear is largely in the steel pin, then you can tap the pin up slightly to tighten it up temporarily, although it is better to recondition the hinges first.

On the finished car - with door windows open - you should be able to close each door gently with one finger. When driving the car, the doors should not rattle.

Front wing fitting

The rear end of each front wing is supported by the wood frame. It rests upon the plywood "wing-panel" and also bolts to one of the small ribs between the bulkhead and screen pillar. For a good quality restoration, you will want the wing to line up with the door and the door-step in all 3 dimensions.

This part of the wood frame was well designed to make adjustments fairly easy. The vertical and lateral position of the wing is set by the plywood wing panel position. The lateral position at the top is also limited by the side of the scuttle, including that rib that the wing bolts to. Remember to allow for the thickness of panels and plastic wing piping: Two panels 1.2 and 0.9mm thick respectively and wing piping 0.7mm thick.

To move the wing fore or aft, the plywood wing panel needs to swivel forwards or backwards (using the slot that it fixes into as a 'hinge' for these adjustments until final fixing together). This latter adjustment means making any repairs to the door-step to the correct dimensions - as the plywood panel fixes to the front of the door-step. The bolts holding the wing to the inner wing and radiator cowl also influence the final position. The radiator and cowl tend to lean forwards until fully bolted to the inner wings. The inner wings rest upon sheet rubber seals on the chassis and only find their final position when you have persuaded all the bolts to fit. You might have to elongate the bolt holes on the wings to permit perfect adjustment. The vertical level of the front end of the wing also influences the wing's alignment with the door, as the two edges need to be parallel. The door-to-wing clearances in the above photos varied from 1.5mm to 2.5mm - mostly 2 to 2.5mm.

Scuttle assembly

Depending on the condition and nature of the wood rot, the bulkhead area is often a good place to start. The ribs that attach to the bulkhead should be repaired/renewed first, which then helps to maintain the correct position of the bulkhead when this is renewed (see Restoration page 4).

The upper half of each windscreen pillar (A post) can then be repaired. This is where removal of the bodyshell is essential, because one can't even see the level of damage - let alone fix it - as the pillar is almost encased in panelling at and just below windscreen level. The joint below the bottom corner of the windscreen may have rotted from inside and this is awkward to repair. It is fastened with 2 screws from the front, and if separated, the joint can be prised open far enough to get chisels into it.

About a foot (30cm) below the windscreen is another joint on the screen pillar that always rots (seen to the right on the photo below). This also tends to extend up into the depths of the panels. If this area is/has not collapsed, then it is best to attend to it at a later stage, because the slot for holding the plywood wing panel, extends up into this part of the screen pillar.

The close-up photo above shows a few details. The complex joint to the right on the screen pillar. The rib that has 2 bolt holes (inclined upwards) for securing the front wing. At the top-right is the plywood packing piece secured with panel pins, that flares the bodyshell outwards so that the door front edge is slightly recessed into the body. There is also a thin ply packing strip running up the side of the screen pillar alongside the windscreen. I suspect that this part is omitted from ACs with guttering that extends down to scuttle level (a minority of ACs have that type of longer gutter). In the photo below, you can see a tapered packing piece that I glued to the side of one of the ribs, because there was a tapered gap evident between this and the front wing during test fitting.

The joint between right-hand vertical pillar and screen pillar. The screen pillar rots at this joint and you can see my repair.

Front view of right-hand screen pillar. A gap had been left under the scuttle rail which I subsequently packed with timber.

Rear view of the screen pillar/scuttle rail joint showing another gap which needed to be packed with timber glued in.

Sill assembly

This will have rotted away near the front bottom corner of the door opening. The vertical pillar just in front of the door may also have rotted badly. This has the slot that holds the plywood wing panel, and will have rotted away around this. You might need to renew this pillar. You can use the panels around the door opening to help check the correct position to fit this vertical pillar.

When repairing the sill boards, there are a couple of details to be aware of. Firstly, the door-step top surface effectively extends into the main sillboard. That is, a narrow rebate is cut into the side of the main sillboard to accommodate the door when closed. This rebate is only about 6 or 7mm wide at the front end, and tapers to nothing roughly half way along the door opening. Secondly, there is a rectangular cut-out to accommodate the door roller when the door is closed. As mentioned above, this should be just wide enough to force the bottom of the door to remain flush with the external body panels (with seals fitted).

In the above photo, you can faintly see the body number stamped into the sill-board (top-right of picture).

Door step

The poor old door-steps have a hard life. Once the plywood wing panels - and the gusset panels under the door-steps - rot away, the door-steps are only held by a few screws driven into their edges. After being stepped on for a few years, the front ends of the steps will start to pull away from the sills.

The repair piece (ash) in the photo above appears thicker than the original (mahogany) step, because the latter had warped badly. I planed the top surface flat and deepened the rebate. There is a narrow cut-out at the front end of the step for the main bodyshell panelling to wrap around.

This area can be repaired even with the bodyshell on the car, as the side panelling can be pulled away from the frame without having to unfold any aluminium. The door-step can usually be repaired by splicing in a new section at its front end. Since this joint is end-grain to end-grain, it needs to be made as strong as possible. Ideally, the joint should run diagonally and be a halving joint (or any other equally strong type of splice).

Right-hand sill area after making repairs.

Starting work on repairing the doorstep.

Doorstep repair, vertical pillar and plywood wing panel being test fitted.

The door step is fixed to the sill inner rail with 4 no.12 woodscrews driven into its edge. Access to these is awkward when the body frame is on the chassis, and so I used this 90 degree lever as a screwdriver.

It is not unknown for the door-step to warp. Test fit the door with good hinges, and make sure that it will clear the door-step (with door-step panel, door-step plate, and door roller fitted). Also check that the door edges clear the rebate in the door-step with enough gap for the 2 layers of panelling (door-step panel plus main bodyshell). Warping of the door-step had lowered a rear corner of one of mine, and the photo below shows packing pieces glued on to level it.

When checking the rear end of the door-step, where it meets the hinge pillar, note that the rebate should not be flush with the rebate cut into the hinge pillar. With the door-step panel fitted, this will bring the rebate flush.

The outer sill woodwork, beneath the door-step, almost always rots away, since it is exposed to spray from the front wheels. There is a thin outer sill rail secured to the plywood wing panel at the front and to the wheel-arch at its rear. There are 5 wooden gusset panels that also secure it in place and these are fixed to the door-step underside by nails inserted at 45 degrees. I would recommend using screws and inserting them only from the rear side, so that spray will not hit them directly. The gussets are also fixed to the inner sills by screws.

The photo below shows the underside of the right-hand door step after removal of the sill components:

The following photos show the old and new sill components for my AC. Note that I have made the outer sill rail thicker than the original. The old ones were nominally of 19mm (3/4") square section, although roughly cut with thickness varying from 15 to 20mm. I have increased it to 25mm square section which more than doubles its bending strength and also makes it less springy when trying to hammer in panel pins later.

For the smaller of the wooden gussets, I ran the grain diagonally, since these parts tended to fracture in two along the horizontal grain.

Note that no steam bending is done for any wood frame parts, since this may reduce strength. The outer sill rail is cut to shape from an ash board (see above photo).

My AC had some skin-deep rotting in parts of the surface of the underside of the door-step. I glued on some repair pieces that are visible in some of the photos, including the one below.

The above photo is the view from underneath the right-hand door-step. In the foreground are the new outer sill rail and one of the gussets. The door-step itself has a thin layer of new ash to repair minor surface rotting. To the right of the photo is the inner sill rail, and note that there is a screw driven through this into the end of the gusset.

The above photo shows a make-shift screwdriver I made to fit the screws that go into the inner end of each gusset. The chassis obstructs the use of any normal screwdriver.

With the new sill parts fitted, I test-fitted the front wings again. The photo above shows the clearance needed from the edge of the wing, so that the panelling alongside the door-step can be folded over. Ideally, this should be achieved with little or no gap between bodyshell and wing.

Here are some more images of the repaired sill area:

And finally...

Some photos of the complete repaired wood frame:

The painted frame:

The previous page gives details of painting the wood frame.

The next page provides information on paints and painting chassis.

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Website started 29th December 2006