Repair your rusty door frames

9fc1e5f0-8c72-49b0-b65b-e82fc3196121

By Trevor Cuthbert

01 April 2019

Fix_rusty_doors : credit: © Trevor Cuthbert

Replacement Land Rover doors are expensive, but rusted door frames can be repaired. Trevor Cuthbert explains how

Models: Series, Ninety, One Ten, Defender
Time: 4 hours
Cost: £50
Difficulty: 3/5 stars
Tools needed: Angle grinder with thin (1 mm) cutting disc and sanding/flap disc; MIG welder; trim removal tools; general workshop tools.
Parts: Door repair section £23 each by YRM Metal Solutions Ltd.; grey spray primer paint, £4 from local hardware store.
Work safely: Wear face protection and protective gloves when using a drill and angle grinder; ensure a fire extinguisher is available and close by when using an angle grinder and welding equipment; wear protective gloves, clothing and appropriate mask when welding.
Contact: YRM Metal Solutions Ltd, yrmit.co.uk, Tel: 01388 488150

 

Land Rover doors come under attack from two kinds of corrosion. The inner frame is made from mild steel which can and will rust, and we have all probably seen the brown flakes pushing and bubbling the paint away along the underside of the door bottoms. In extreme cases, the bottoms of these steel inner frames crumble away, often leaving the outer panel loose at the bottom and depositing a shower of rust each time the door is slammed shut.

The steel frame is covered by the aluminium door skin, which is folded around the edges of the frame, at the sides and bottom. This introduces the second type of corrosion that we’re more familiar with, often appearing as bubbling through the outer skin on the bottom edge of the door. When it becomes advanced, this electrolytic corrosion caused by the close proximity of steel and aluminium, plus moisture, will turn your aluminium door skin to a white powder in the affected areas. Little can be done about this problem, other than replacing the door.

However, if the outer panel is reasonably good, the rusted inner steel door frame can be repaired to a good standard, given a little time and effort, plus the right materials. Here’s how to do it...

 

Exposing the inner frame 

On the doors shown here, the outer door skin is in quite good condition with no signs of significant electrolytic corrosion. There are no major dents or creases either, so the door skins are well worth preserving. 

The door skin is bonded to the frame with an adhesive substance, and folded around the frame along all four edges. Prying back these folds to expose the frame and breaking the adhesive bond needs to be carried out with care, so as not to damage the skin and spoil the outside finish.

Clearly, removing the doors from the Land Rover and handling them during the job also introduces risk of damage. A second pair of hands helps with this, and will hopefully get the doors safely to the working area.

Each door to be repaired has been removed and carefully laid out on a suitable working surface, taking care to protect the outer skin.

The bottom of the inner door frame is heavy corroded, as is typically seen in many, if not most, older Land Rovers and some not so old.

This frame is so disintegrated that the fixings for the inner door trim no longer have any metal to attach to – it has totally rusted away.

The inner door trim needs to be completely removed, by first taking off the door handle, window winder and inner door pull.

The factory-fitted plastic shield is pulled back from the frame to allow access to all of the rusty areas of the inner door frame.

It’s surprising how far the bottom corners of the steel door frame can corrode, yet the outer skin on this door remained in serviceable condition.

Knowing the outer skin is in good condition, we begin to unfold the lower edge from the steel door frame, very carefully using a trim removal tool.

Here, a screwdriver is used to carry out more precise unfolding of the outer door skin – any tool appropriate that causes minimal damage is employed.

Pliers can also help with easing the skin back from the inner door frame, as well as straightening up any kinks that are inadvertently formed.

Here, the lower edge of the door skin has been successfully unfolded, as well as about 100 mm up both sides, exposing all of the rusty frame.

 

Removing the rusty steel

As with any metalwork job, the key to a long lasting repair is to ensure that all of the damaged and corroded material is cut away, leaving only good sound steel to weld onto. Most of the lower frame has rotted away on these particular doors, and the bond to the outer skin has long since broken down, so removing this will not be difficult. 

The rust has affected the side frames of the doors in a fairly typical and expected way, so the first few inches at the bottom on each side also need to be cut away. These areas are more likely to be still bonded to the skin.

Using a fine 1 mm cutting disc on the small (115mm) angle grinder, the bottom section of the frame is cut away from the side sections.

The door frame is also attached to the outer skin with an adhesive, so the lower rail may need to be eased free by careful insertion of a scraper tool.

Side sections of the frame have significant corrosion on the lower parts, which also need to be cut away, leaving the remaining good section.

Before cutting the rot from the side section, the outer skin is eased back away from it, and held clear by inserting a piece of soft timber.

Now with the side frame section clear of the outer skin, the rot can be cut away without causing any damage to the door skin.

All of the rusty metal has been cut away and consigned to the recycling bin, leaving good quality steel, which the repair sections can be welded to.

 

Welding in the new metal

The new steel for repairing these doors is in the form of a special repair section manufactured by YRM Metals Solutions Ltd. It is a profile made from two components that have been spot welded together. The sections are made from 1.2 mm thick zinc-coated mild steel, which will provide a good degree of rust resistance.

Each repair section is 1.5 m long. That’s enough to replace the lower door frame and up to 300 m up along each side. The repair section is cut to length for the lower frame and for what is needed on each side.

The door frame repair section is supplied in standard lengths and is formed of two pieces of folded steel, spot welded together along the length.

Short pieces are cut to replace the rusted lower side frames. Being short, their length includes only one of the spot welds, so extra tack welds are added.

By making the first two spot welds opposite each other, the opportunity remains to fine tune alignment prior to adding a spot weld at the top.

Our repair sections, which have been cut to correct lengths, are tack welded together to reinstate the lower door frame with the side sections.

The other side is treated exactly the same with a new short piece connecting the side frame to the lower frame section, initially by tack welds.

The sides and lower frame are normally mitre jointed together but we opted to butt-join them to keep the side channels open – thus not creating a water trap.

Once happy with the alignment of the new frame, the tack-welded sections are fully welded. Excess is trimmed off the lower side sections, leaving just the flange.

Any raised sections of weld are buffed flat with a flap disc on the angle grinder and the side sections cut to match and blend with the profile of the lower frame rail.

After cooling, a coat of spray primer paint is applied, getting as much paint in to the open channel as possible, as well as the underside.

When given a top coat and reassembled, a little time and effort will have given this Land Rover door a vastly extended service life – and saved money.

Repairing multiple doors

All Ninety, One Ten and Defender doors tend to rust and corrode in similar ways – and if one door needs to be repaired, the others will also have suffered rust damage. They can each be repaired at different times, causing less disruption to the Land Rover. But, if new paintwork needs to be applied, it may be preferable to repair them together, especially the outside finish paint.