Rust points

One of the reasons that the tens of thousands of R4's in the UK and other wet northern climes have disappeared is rust. The chassis is created by means of a series of fairly light gauge flanged pressings, spot welded together, and where extra strength is required, doubled up in multiple layers.

It is a masterpice of economic design, but there are numerous mud traps, especially around the rear outer suspension mounts and any water that gets into the box sections gets trapped between layers, or within flanged joints and starts to rust out.

Renault recognised this and in the seventies, injected foam into key areas, which, to be frank, didn't help at all, and you could find yourself with structural polystyrene in these areas.

So, any car that you are contemplating buying or are assessing, needs inspecting in a series of key places.

Obvious ones first.

The floor:

Front floor can rot out from the inside out, due to leaks from around the bulkhead, the heater, and water penetration through poor door seals, etc. Lifting the mats will reveal this and if insulation is present under the mats, this will have accelerated the process by holding the damp in place.

The toe boards, ie the canted up sections behind the pedals and in the passenger footwells can also rust from the inside out, and since these are a hollow triangular box section, any water that gets trapped in here can rot out both upwards into the car and down through that part of the front floor pan that forms the bottom. If rust really gets going in these areas, it can also set to work on the front chassis members which are built into this area, albeit you will need to get underneath and probe to find these.

Front Corners of Floor Pan, External:

Look inside the rear of the front wheelarches. These take a bashing from road debris thrown up by the wheels and are often patched and plated up. If it doesn't have a horizontal flange visible along its bottom edge, then it has been plated.

Front Cross Member

Look at the extreme ends where the bumper brackets bolt through and in the centre where the bolts fixing the gearbox mountings are visible.

Rear chassis.

Hot spots here are:

The outer chassis around the outer suspension mounting. This is a mud trap and can rot from inside, it also is a water trap under the C Pillar of the body tub and so can rot both down into the chassis and up through the base of the body tub at the bottom rear corner of the rear door aperture. Any rot here, or signs of patching, show that it is likely that more serious rust is under way out of sight. A decent repair is virtually impossible without removing the body tub.

If you look inside the wheel arch, you will see a casting which forms the inner rear suspension pivot mounting, bolted through the inner rear box section. Again this rots, usually from the inside out, (due to open ended chassis members). There are numerous double skinned sections here that rust and eventually blister outwards. A proper repair in this area is at least a rear suspension off job, and again, preferably a body off, since there are numerous stiffeners and reinforcement webs that need to be exposed and repaired.

After this, have a general good look around. The joint between the floor pan and the vertical box member that forms the primeter of the floor pan unit is a typical rust spot as are all of the external horizontal flanges that are visible below the cills. When buying, look for any areas that have been patched over with a plate, or have new underseal on them. My car had two or three layers in some areas around the front corners.

Body Tub

Not load bearing in the main and therefore not quite so critical, nevertheless the tub can rust in some key places. Surface rust is not so serious and a car that has been stored may have quite a lot present on the roof and side panels, but check out any seams that have expanded and are opening up, especially around the roof gutters, etc. Bear in mind also that these cars are very light in construction and even surface rust can serious thin the gauge of steel used if it is well established.

Most common rotspot is the double skinned section around the rear seatbelt mounting under the rear wheelarch, visible from inside by peeling back the rubber mat on the wheel arch.

A Panels in front of the doors can rust along the line of the spot welds to the inner flange that sits on the chassis, as well as along the welded joint to the front bulkhead. This damage can be masked on GTL's with the plastic side trims, as can rust in door bottoms.

The very rear cross member which is welded onto the rear edge of the boot floor collects mud and may rot.

The front bulkead may rust under the wheelarches, especially around the mounting bolts for the accelerator pivot brackets.

Doors rust along the edge of the folded over section of skin, where water sits, and the tailgate fails similarly.

Rust along the top edges of all four wings is common but is not serious since they bolt on, and new wings are still available. However the front inner and the mounting flange for the rear wings can also rust and are slightly more involved to repair, requiring the welding in of a repair panel.

The bonnet is more likely to be dented than rotten, but trouble spots occur around the sidelight positions and in the stiffening box section along the lower front edge.

Clementines Renault garage website has an excellent series of photos of typical rust spots on a GTL.

Follow this link.Clementines Renault Garage Buyers Guide