XK150 bodywork modifications

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Likely-required bodywork modifications

Each of these three modifications can be implemented after the T5 is in place.

Provide sufficient lateral space on the transmission cover left side for a connection to the reverse switch. After completion, this will be difficult to detect.

A section of the transmission tunnel is removed. The cutout is ~70mm (2.75") long, 15mm (0.60") laterally and 22mm (0.85") vertically. The cutout is then covered with an aluminium or steel cover,  and in turn the cover is padded with foam rubber strip to prevent sharp corners wearing the floor and transmission cover carpeting.

Provide enough width, left and right, in the gear lever cover cutout to allow the T5 first and second gears and the fifth and reverse gears to be engaged. After the cuts are made, the result is invisible from within the cabin.

This mod is achieved by cutting out a slender crescent of steel plate on each side of the original gear lever hole in the cover that forms the bulge at the location of the gear lever. Trial and error is the best way to determine how much sheet to remove. The amount to be removed is minor. A sabre saw is the ideal tool.

Cut out small sections of the left and right floorboards to clear the reverse switch connection on the left side, and possibly also to clear lugs on the T5 case on each side.

Optional bodywork modifications to allow the T5 to be removed without disturbing the engine

It is possible to remove the T5 gearbox from an XK140 or XK150 without disturbing the engine. This can be a real advantage for maintenance of the clutch and gearbox in later years. The T5 connection to the original bell housing is separated by removing the four 1/2" UNC capscrews that hold the T5 to the adapter plate. The exhaust pipes do not need to be removed.

These mods can be made later, with the T5 in place, if you have a need to remove the T5 for any reason, without disturbing the engine. However, it is much easier to do this work before the T5 is in place.

The first mod is to cut off three redundant mounting points from the T5 itself. Without these mounts being removed, it is not possible to remove the T5 from within the cabin.

The removal of these items will not affect the functionality of the T5 in any way. The items to be cut off are marked with an X in the photo. A sabre saw does the trick.

The next mod is to cut out a section of the prop shaft tunnel to allow the T5 to be moved to the rear sufficiently to disengage the input shaft from the clutch plate, and then move the T5 even further back so that the input shaft spigot is behind the clutch release lever plate (part 2472). Then the T5 can be lifted vertically, and eventually moved further back so that the input shaft is also clear of the bell housing rear face.

The cutting of the prop shaft tunnel is made in two steps.

First a 77mm (3.1") long section, 120mm (4-3/4") wide, is cut out permanently. Drill holes at the two rear corners to prevent later cracking.

Then a further 133mm (5-1/4") long, 105mm (4-3/16") wide section is cut, along with the handbrake mount plate that sits across the tunnel. Drill very small holes in the two rear corners, again to prevent later cracking. This section is later refitted to the tunnel when the T5 is back in place. To restore the integrity of the handbrake mount plate, a section of 38mm (1-1/2") x 3mm (1/8") aluminium or steel bar is used, held in place by four 1/4" UNF mushroom head sockethead setscrews and nuts. This bar is held to the removed curved section of the tunnel by, in my case, blind rivets. Making it all out of steel, and welding the parts together, is an alternative, except that the four 1/4" UNF setscrews would still be used.

When the prop shaft tunnel is modified in this way, the three 1/4" UNF captive nuts remain in place ahead of the handbrake mount,  enabling the rearmost part of the transmission cover to be bolted to the prop shaft tunnel in the normal way.



Cutout in transmission tunnel
to create space for
reverse switch connector

reverse swich floorbaord cutout

Typical floorboard cutout
for clearance at reverse switch


The lugs X that need to be removed
from the rear of the T5 case
to allow T5 removal via the cabin


Suggested tunnel cuts
(PDF version)


Parts used to restore
tunnel and handbrake mount


Parts now partially-assembled


Integrity of prop shaft tunnel
restored, and handbrake mount ready

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