How to repair a seatbelt mount

Electrolytic corrosion can do a lot of damage to your Land Rover. One common area to rot is around the seat belt mounting points at the front of the rear body tub in commercial Defender 90s and 110s. The brackets are made of steel and bolted through the body to the chassis, so the aluminium structure of the body is sandwiched between the steel chassis and seatbelt mounting brackets.

Add moisture, and you have perfect conditions for electrolytic corrosion. In a nutshell, electrolytic corrosion occurs when two dissimilar metals are in electrical contact, in the presence of an electrolyte. One of the metals corrodes in preference to the other – in our case the aluminium corrodes, while the steel is largely unharmed. 

Assessing the damage

The first signs of a problem in this area are often where the rear body tub is bolted to the chassis’ tubular outrigger (in a 90) or to the four body brackets (in a 110). It’s here where the aluminium of the body is sandwiched between the outrigger and the seat belt mounting bracket, that corrosion festers. We will see in this example, just how far the corrosion can spread in a Defender or earlier Ninety/One Ten.

Prepairing for repairs 

All the work shown in this feature was carried out on a Defender rear body tub that had been lifted off the chassis to carry out a chassis replacement. Removing the body certainly helps with the access, and with the clarity of the photographs, but the job is still very achievable with the body still attached to the chassis. Clearly, the chassis mounting bolts would need to be removed but, otherwise, preparation is mainly about removing all of the seat belt mounts, and dealing with the excess flaky aluminium.

Fitting repair panels 

The repairs panels (underside seat belt mounting panels and inside tub repair sections) will bolt to the front of the body tub, with the original remaining aluminium sandwiched in between. Luckily, galvanised steel does not react with aluminium in anywhere near as dramatic fashion as raw steel does – so the electrolytic corrosion effect will not take place with the lower seat belt mounting panels.

The only tricky part of this job is to ensure that the inner aluminium repair panels are drilled accurately, to allow seat belt mounting bolts and studs to go through in the right place.

Time: 1 dayCost: £118.80

Contact

YRM Metal Solutions Ltd Tel: 01388 488150 yrm@hotmail.co.uk

Health and safety 

• Wear protective gloves • Take great care when working under a raised vehicle • Ensure the chassis and components are stable and secured before working • Always wear eye protection when drilling or working overhead

Click on the gallery below for our handy step-by-step guide…