Replacing a Classic Range Rover boot floor

Need to know

Time taken: 10 hours.
Tools needed: Slit disc, abrasive wheel or grinder, spot-weld drill, centre punch, straight edge, pen, drill, MIG welder, hammer, fire blankets.
Difficulty: 4 out of 5
Models: Classic Range Rover models (similar process on Discovery 1, using a Discovery floor).
Parts used: Range Rover boot floor, £420; Range Rover floor edges, £30. Supplied by Machinor Ltd.
Work Safely
• Use the right tool, for the right job.
• Be fire safe in the workshop and keep extinguishers and fire blankets to hand; always check for aperiod after welding.
• The fuel tank should be removed before grinding or welding in the area, and fuel lines sealed off.
• Get an expert to do the job, if in any doubt about what you’re doing.
• Never take risks working underneath a vehicle, or with welding.
• Wear appropriate eye, face and hand protection when you’re grinding and welding metal. 
Thanks to: Phil Holland and the team at TwentyTen Engineering, and Stuart Jay at Machinor for their help with this feature. twentytenengineering.co.uk, machinorltd.com.

 

The original Range Rover has a fearsome reputation for corrosion, mainly concerning the inner steel bodyshell which hides many areas and joints where moisture sits or flows, and where corrosion can really take hold. These areas include inner wings, scuttle panel, footwells, rear door apertures, rear crossmember – the list goes on.

One of the easiest areas to check, and most accessible to repair, is the boot/load space floor. Early models had aluminium alloy floors riveted in place, but in the 1980s the body became spot-welded and the boot floor was changed to a steel panel. Typically, these corrode along the edges and above the fuel tank filler pipe. Localised repairs are possible but, because of the spot-weld construction, the easiest and neatest fix is to simply replace the boot floor as one.

Previously, the Range Rover floor wasn’t available, so the shorter Discovery repair panel was used with a filler piece at the rear (or, for the fastidious, buy two floors and cut eight inches off one to use as a matching filler).

Thankfully, Midlands-based Machinor is now producing bespoke Range Rover floor repair panels. Made as the original, they drop straight in, making the finished job look great and taking less time to complete. Machinor also offers an option with boot floor sides fixed in place, making fitting easier still.

The conventional replacement procedure would be to drill the spot-welds from the original floor edge, tidy that edge, then spot-weld the new floor in. Range Rover restoration expert, TwentyTen, has developed a faster, and neater method – by laying the new floor (with edges attached) into the car and trimming the existing floor to the edges of the new one. The 1mm gap left by the slit disc is ideal to then fill with weld.

Here, we show how TwentyTen Engineering installs the new Machinor floorpanel to a car it is restoring.

 

Removing the old floor

The problem: This is a typical corroded floor that TwentyTen will remove. The sides start to rust through, but so too does the joint across the rear crossmember area.

Catch it quick: Ideally, you should stop the issue before it starts to eat into the side panels of the floor. These panels can be replaced, but the job rapidly escalates.

Removing the floor: Simon Taylor begins by running a strip disc over the spot-welds to help locate them, centre punches them, then drills them out using a spot-weld bit.

Alternative trick: Although the whole floor can be removed traditionally by drilling the spot-welds, TwentyTen runs a slit disc down the existing floor’s sides.

Rear crossmember: At the rear, Simon marks then cuts a line inboard of the crossmember. He is basically trimming inside the edge of the floor, leaving the outside lip on.

Detail saw: After teasing the edge with a pry bar, Simon cuts through any parts he’s missed, avoiding wiring, brake pipes and the two boot supports.

Helping hand: With the sides cut free, Simon props the edge of the floor on wooden blocks. This allows him to identify where the floor is still held in place.

Supports: The spot-welds across the two floor supports are located, punched and drilled out, then the floor should be free. Check for any remaining spot-welds.

Out it comes: Eventually, with some persistence, the floor is free from the car. Crucially, Simon has left the floor sides in place, which will be trimmed to suit the new floor later.

Whilst you’re in there:  With the boot floor out, you’ll never have better access to the rear chassis area. Consider rubbing down and repainting the top of the chassis, or any other job requiring access to the chassis, such as fuel lines, A-frame bushes or ball joints.

 

Installing the new floor 

New part: Machinor spot-welded new side joints to the new floor. TwentyTen used chassis paint to protect the bottom, and removed paint from the weld points.

In the car: Will Webb refits two floor supports, and places fire blankets around the work area. Fuel tank should be removed prior to the work. Consider painting the chassis.

Body prep: Will runs an abrasive disc down the sides of the body, to provide corrosion-free, clean metal to weld to. The edge of this will be trimmed.

Forward edge: The front edge, to be spot-welded onto, is cleaned and sprayed with weld-through zinc primer in preparation. If it is corroded, it must be repaired first.

Locate it: The new floor slides in, and the two side panel corners locate into the car by tucking under the existing floor joint, making sure both sides locate accurately.

More prep: With the floor now laying in the car, Will runs an abrasive disc down the top edges of the new floor joint to remove any primer or paint.

Crucial overlap: New floor edge overlaps the boot floor side panel (right). When a cutting disc is run alongside the edge of the new floor, this trims the existing side panel to match it.

Vital reference: Much time is spent making sure the front of the floor is fully flush against the vehicle. If it isn’t, the floor won’t fit squarely into the car.

First fix: Will begins pooling a few spot-welds through holes in the leading edge of the floor to the vehicle structure, checking alignment, and repositioning if needed.

Located correctly? Happy, he makes a few light tack-welds down both sides of the floor. The aim is to locate it in position against the car as a reference, and then cut out.

Slit disc: Without measuring, the existing floor is cut by following the edge of the new floor, trimming the existing floor edge to the new, avoiding parts and structure below.

Lined up beautifully: This is the result: old material removed from under the new floor edge. A gentle downward push lines up the new and old, leaving a perfect gap to weld.

Weld together: Short welds are then made, penetrating both sides of the joint fully. Will works in small sections each time, spreading the welds so the heat doesn’t induce distortion.

Long line: By repeating the welds, we end up with a continuous line of weld. Will checks for pinholes, filling gaps where required, until both boot sides are completely welded.

Front and back: Unlike the sides, spot-welds are used at the front and back, as they were originally from the factory. Will pools in larger spot-welds, tying together the crossmember and new floor.

Tidy the job: Finally, Will ‘dresses’ the side welds using an abrasive pad until the welds are flattened back level with the panel face. He goes steady, and works neatly.

What joint? The end result is a hidden joint and an appearance similar to how the original car was made at the factory. All done without any measuring whatsoever.

Ready for paint: The inside is now ready to move on or prepare for paint. Note the underside and weld joints will be protected by applying seam sealer and stone chip protection.

 

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