Phil’s Lightweight Land Rover (Air‑Portable) site

aka — Truck Utility, General Service, 1/2 Ton, 4x4, Rover Series 3


Making a hard top for a military wide track Sankey trailer

Trailer with new Hard Top
Trailer with new Hard Top

Most of the small images will display full size if you Click on them use your browser ‘back’ button to return here.

Trailer with canvas cover

Trailer
Trailer with hard top

Trailer
I decided to replace the canvas cover on my wide track sankey/GKN military trailer with a hard top. My reasons included:
If you want to do something similar the following might be of some help.

The issues

I wanted the end product to look right when it was towed behind my ex-military Land Rover Lightweight, so I decided to make a hard top based on a Land Rover roof rather than just folding a lip around a sheet of checkerplate. The trailer is wider and shorter than a SWB series Land Rover, so I need to cannibalize two 88in roofs to make one trailer hard top. The frames on Land Rover roofs are not flat at the back, they have a cut out for the top of the back door which I chose to fill in, another option would be to alter the tailgate to fill the gap. The roof from a Defender would have been harder to use as it also curves up at the front to accommodate the taller windscreen.
I've opted for a permanant fixed hard top, which does limit my ability to carry tall awkward loads in the trailer. If you need a 'quick release' top you'd need to use different hinges (like those on a Land Rover bonnet), and reconsider the gas struts mechanism.

The stuff you'll need

Tools

Materials

The only task I farmed out was the welding, you may be able to do that yourself.

The cost

The Construction tasks

First acquire two series 2 or 3 Land Rover roofs, get plain ones, no double skinned safari roofs, no sun roof, no alpine lights and preferably no stuck in headlining or insulation. Then clean up the roofs removing any fixtures, light fittings, aerials, door seal retainers, hinge brackets for drop down (cat flap) rear doors etc, if the screws are rusted grind them off, it'll be good practice using the angle grinder! I used SWB (88") roofs but I expect you could use LWB (109") ones, you'd just have to cut a longer piece off the back.

Trailer
Trailer

Measure the width of your trailer then draw a line along each roof to give you a right and left piece, each half the width of the trailer. I used an electric jigsaw with a hacksaw blade to cut each roof into two parts. I wanted to keep the transverse stiffener that runs across the underside of the roof, so I cut out the spot welds from above on the waste side of one roof and carefully cut the section of roof above it with an angle grinder rather than the jigsaw, which would have sliced through the stiffener too. I removed the remains of the stiffener from the other side by cutting the spot welds out from below. The buttons of metal left from the spot welds were then carefully removed with the angle grinder.



Trailer Roof

Test fit the roof pieces on the trailer, you really need your hinge at this point, I had to allow the roof to overhang the front of the trailer by 25mm so the hinge would bolt into the roof frame clear of the alloy roof panel and its rivets.



Trailer
Trailer

Measure how far the roof frame overhangs the back of the trailer, then measure that same distance forward from the end of the roof top, draw a line across both the roof halves and cut the back of the roofs off with the jigsaw.


Trailer

You now need to separate one of the waste roof parts from its frame, I ground off the rivet heads from under the frame and knocked the rivets through with a hammer and pin punch. The long side piece of the frame has to form the new flat rear frame rail for the hard top, keep one of it's rear corners in place and for the other use the rear corner carefully removed from one of the roof backs that you have just cut off.


Making the new hard top frame needs careful measuring and cutting in preparation for welding up, I ground off 3 rivets either side of each place where the frame needed welding and peeled back the alloy so the frame pieces could be welded without melting the alloy. I jigged the frame up by screwing through the frame into pieces of timber to hold it square, flat and straight while the welds were made. The two roof halves were supported by pop riveting the transverse strengthening rib into place.
Trailer

Trailer
Trailer
Trailer

I used one of the long strengthing ribs (top hat section) from a waste roof part to join the two new hard top halves. So I cut out the spot welds from underneath to free the rib and then ground off the weld buttons.


I re-used the original roof back pieces, separating them from the piece of roof cut off in the shortening process by drilling out welds and grinding off rivets. I used the jigsaw to cut off the lip that had attached to the frame around the door opening. I then pop riveted these back pieces to the new back edge of the hard top.

Trailer
Trailer
Trailer Trailer

I filled the arched gap using a piece of alloy cut from a waste roof panel, I got a local sheet metal works to fold a 15mm lip on the bottom edge so I could rivet it to the frame - they charged me £2.00.

Trailer
Trailer Trailer Trailer
Trailer

Trailer Trailer
Trailer Trailer

The long rib was pop riveted on to the top, but first it had to be shortened by drilling out the spot welds where the back section joined the front at an angle, cutting it short and riveting it back together. curved plates were cut from the waste roof sections and used (both inside and out) to join the very front of the roof.


Trailer
Trailer

You're left with open ends on the 4 strengthening ribs that were sliced through when the roof was shortened. I plugged the two inner ones with wood but the two outer ones cover joins in the roof panels and I decided to tidy them up by cutting them off short and using the rib ends from the cut off roof section - another job for the spot weld drill and angle grinder. I pop riveted some alloy inside the ribs at the join to strengthen them.


Trailer
Trailer
Trailer

I used a heavy duty continuous stainless steel hinge (piano hinge) at the front of the hard top, the sort used on security doors. It had countersunk fixing holes and I used Stainless steel countersunk socket head set screws and nuts to fix the hinge to the hard top and to the lip at the front of the trailer frame.


Trailer
Trailer Trailer

The new hard top is quite heavy to lift and needs to be supported when open, I used a pair of gas struts (gas springs) placed one on each side behind the wheel arch to provide lift and support. This kept them out of the way, but the multiplier effect due to having them so near the hinge meant that they needed to be rated at 300 Newton each to exert enough force.
I used a pair of over center clips to hold the lid down and a neat padlock to fasten the hard top to the drop-down tailgate - keeping the trailer secure.
The top is never going to be hermetically sealed but I glued on some strips of closed cell foam (cut off an old camping sleep mat) to help bridge the gaps along the sides etc.




Trailer with new Hard Top
Trailer with new Hard Top

You'll notice that I also moved the trailer number plate to the new hard top, that's not necessary but I think it looks better there. The wiring for the number plate light runs inside the centre strengthing rib (which I then filled with builders expanding foam filler).


I hope you found this useful.

Drop me an eMail with any questions or comments about this page. Phil