Sills LH and RH were rust damaged and required replacing. The castle rails, inner sills, and outer sills were replaced and the side member was repaired on both the left and right hand sides of the car. The restoration of the sills were accomplished one side at a time. The car was stripped and placed on the modified engine stand rotissorie. Bracing of one inch square tubing was added across each door and behind the doors from side to side providing additional support.
The doors were left in place on the hinges so that alignment can be periodically checked during the restoration process. Occasionally the doors would be in way when cutting, grinding, or welding, but the end result is worth the slight inconvenience.
Sills LH and RH were rust damaged and required replacing. The castle rails, inner sills, and outer sills were replaced and the side member was repaired on both the left and right hand sides of the car. The restoration of the sills were accomplished one side at a time. The car was stripped and placed on the modified engine stand rotissorie. Bracing of one inch square tubing was added across each door and behind the doors from side to side providing additional support. The doors were left in place on the hinges so that alignment can be periodically checked during the restoration process. Occasionally the doors would be in way when cutting, grinding, or welding, but the end result is worth the slight inconvenience.
Tools and equipment used to complete the work were a sawsall, air body saw, air chisel, angle grinder with 36 and 50 grit disks, rotary tool with carbide cutting tip, air hole punch, big hammer, tape measure, square, vise grips, c clamps, MiG welder, auto darkening helmet, safety glasses, gloves, ear protection, and dusk mask.
Before cutting any metal, take a pen, paper, and measuring tape, and record measurments. Take measurements of the door opening, the distance of the gearbox to the side member at several points, the distance from the cowl down to the bottom of the sill, and other points that will be benefical for reference when fitting and welding.
The repair was started by cutting the lower portion of the rear wing using the repair panel as a guide to determine the amount of metal that could be removed. The front wing was removed when the car was stripped for the rotisserie. At this point the entire outer sill is exposed. Remove the outer sill spot welds by drilling or grinding with the rotary tool. The outer sill area behind the A post, B post, and behind the dash side panel will be more difficult to remove. There are a few ways to address this area, one is to cut and remove as to replace the outer sill as the original. Drill or grind the spot welds along the top of the sill in the dash side panel. Drill or grind the spot welds in the three flaps at the bottom of the A post. All the spot welds in the outer sill are cut through or weakened except behind the A post and B post. Cut the outer sill with a saw around the A post. Care must be taken not to cut the three flaps at the bottom of the A post. Cut the outer sill with a saw at the B post along the seam and behind the B post. Hand or air chisel the remaining outer sill until it is removed and exposing the flat inner sill. Usually the inner sill will be in worse condition than the outer sill and come off at the same time. The only pieces of the outer sill left is under the A post and B post. Take the outer sill pieces under the A and B posts and bend them down to give access to the area behind. Drill or grind the spot welds and remove what remains of the outer and inner sill.
Next is the castle rail, which was attached to the outer sill and below the side member. The castle rail starts inside the front wheel well and continues back to the rear wheel well. The castle rail is the thickest metal piece of the sill and will not require replacing in most repairs. If the part is in good condition clean and prime the area proceed with replacing the inner and outer sill. The castle rail on this project is very rusty and need to be replaced. The outside edge of the floor is attached to the castle rail and one must be carefull cutting if the floor is not being replaced. In this case the floor is rusted so removal will be less complicated. Spot welds or welds are removed from the castle rail at the front flap the bends up into the front wheel well. The welds attaching the cross member are removed best with the rotary tool. A saw or chisel can be used to cut the welds between the castle rail and side member cutting more into the castle rail to save the side member flange.
The last part is the side member. The side member and castle rail maintain all of the structural support on either left or right side of the car. When one or both of the parts are severly rusted, the structural integrity of the car is compromised. The side member rust damage if found will be in the front near the foot area. If there was any more rust damage the car would not have been repaired by a sane enthusiast. The rusty section is removed by cutting the spot welds along the bottom of the dash side panel, grinding and chiseling the tab folded over into the front wheel well. The side member section is cut to the point where rust is removed and sound metal remains.
Side Member Repair. The side member repair panel is available in a full length or a three quarter section. The three quarter length section is less the curved part from the B post and back. The panel to use depends on the amount of rust damage found in the side member. A full panel is more difficult to replace because it spans and connects the front of the car to the rear. In this project, a small section of the side member from the front wheel well to the cross member will be replaced. The LH side was a small 3 inch by 12 inch patch in the forward section. The RH side had more rust damage and required a larger repair section. The replacement panel was trimmed to fit. The new piece was clamped into place and checked several times with a straight edge spanning the old and new sections to ensure correct alignment. If the door was removed, put it on and check the spacing at the upper rear of the door and rear wing. Measurments were taken and compared to the original measurments also to check the side member position before welding. The repair piece was welded with a continuous weld where it mated with the original side member panel. The lower dash panel area was welded an 1/2 inch every 2 inches on the inside edge in the interior side footwell.
Castle Rail Install. The castle rail is the thickest piece of metal in the side member box and is the base for the floor, inner sill, outer sill, and front wing. The cross member which runs from the LH to RH sides of the car attaches to the castle rail. The carefull fitting of this piece will make the remaining steps very easy to complete. Before installing this piece, check the middle section for straightness. This piece should run straight a few inches from the front until it starts to curve up after the B post behind the door. Get the big hammer and strike it a few times or use other methods to make it straight. Next find you C clamp collection and fit the castle rail to the side member. To aid the alignment, make three spacers to place inside the side member and castle rail. The spacers are 4-1/2 inches in height and 2-3/8 inches wide. These temporary spacers will square the outside edge of the side member at the top and the castle rail along the bottom while keeping the top to bottom distance uniform from front to back. The outer edges of the side member and castle rail will measure approximately 5-1/2 or the height of the inner sill panel. Clamp the cross member to the castle rail and at the back end clamp the castle rail to the rear wheel well. Before welding check the fit and door alignment. Weld the castle rail to the side member with one inch welds spaced about 1-1/2 inches apart.
Jack Support. Install the jack support before installing the inner sill. The jack support is placed against the side member above the the crossmember. Weld the piece at the castle rail and side member. This piece provides the structure additional strength to support the car when using the jack.
Inner Sill Install. The inner sill completes the box section of the side member. This box section is the primary side structure of the car. The inner and out sill can be installed separately or together. Welding time can be shortened by installing the inner and outer sills together. Test fit the new inner sill panel to the car. Some cutting may be required at the A and B posts depending on how the old inner sill was removed. Drill or punch 3/16-1/4 inch holes one inch apart where the inner sill contacts the side member and castle rail. The section behind the front wheel well and in front of the A post can be installed two ways. The first is as originally fitted under the dash side panel or second over the dash side panel. The inner sill panel fitted using the original method requires the existing spot weld holes in the side dash panel to match the holes in the inner sill. Clamp the inner sill to the side member, castle rail and plug weld. Weld the rear flange to the outer wheel well arch. Flatten the plug welds with the grinder to prepare for the outer sill install.
Outer Sill Install. The outer sill is the finishing panel of the sill. Test fit the outer sill panel to the car. Check the door bottom alignment and the front fender rear edge alignment with the outer sill. Some cutting may be required at the A and B posts depending on how the old sill was removed. Drill or punch 3/16-1/4 inch holes one inch apart where the outer sill contacts the inner sill. Clamp the outer sill to the inner sill and plug weld. Weld the rear flange to the outer wheel well arch. Flatten the plug welds with the grinder to prepare finishing. The outer sill filler piece is installed at the rear of the sill. A few tack welds will hold this piece. Finish the filler piece by using seam sealer to prevent water and dirt penetrating the outer sill. Next step is to install the dogleg or rear quarter panel.
MGB Guide to Purchase and DIY Restoration by Lindsay Porter