Toyota design fault can cause RUST
Vehicle? 1993 Australian spec 80 Series GXL wagon – turbo diesel.
Other models? Most likely all 80 Series wagons.
Fault? Rust can develop on the left and right hand firewall.
Where? Around the inner mudguard mounts.
History? This vehicle is not garaged and does not do much beach work. Due to a lack of rust elsewhere, it would appear that these factors probably have little bearing on the fault anyway.
Cure? Read on…….
After spilling some milk in my 80 series, I removed the carpets in order to clean them and remove that incredible smell that milk manages to make after a few days in a hot vehicle in the sun.
I had removed the carpets and was doing a general clean up of the painted metal surfaces inside the cabin, and there it was, the dread of any vehicle owner ….. RUST. It was just to the left of where the front seat passengers feet would be when normally seated with legs stretched out.
When I got under the vehicle and had a look and feel around it didn’t take long to realise that I had a small problem. Looking straight up, I could see the rust around the lower edge of the inner guard mount. My panel beater referred to this panel as the skirt. The skirt mount is on the sloping part of the firewall. The next photo is what I could see when looking straight up. It even still had a dribble of moisture visible.
You cannot see the firewall above the skirt mount, although you can get your hand up there, I had a feel around and could feel large flakes of rust. In the middle of the mount on the bottom edge and just left of the above shot there is a hole about 10mm diameter which has a rubber bung in it.
Next day I was off to a panel beater I have used before for tidying up the vehicle paintwork. A few hours later he had the bad news for me – the rust was more extensive that I had seen and it was on both sides of the vehicle, in similar positions. The bad news was that the mudguards would have to come off, which meant all components inside the engine bay mounted to the mudguards would have to be removed. The exhaust would also have to be removed to provide access to the offending areas.
With the mudguards removed this is what was visible:-
Those two bolt holes are where the skirt is mounted.
The drivers side wasn’t quite as bad. Note the nice flutes pressed into the top edge of the mount. I am guessing the designer at Toyota was having a bad hair day the day he designed these mounts and put the drains on the top edge instead of the bottom. They therefore became water collecting flutes instead of drains. The rubber bung and a good dose of body deadener around the bottom edges of the mount ensure that any water that gets in there is likely to stay for quite a while.
The panel beater cut the affected areas out and welded in new plates – 1.6mm zinc anneal sheet. This is the drivers side again with fireproof curtains visible.
The panel beater then fabricated and welded on some simple brackets which will not hold any moisture. The plates and brackets were then zinc painted and treated with a dose of Tectyl rust preventative and then body deadener..
To give you an idea of the size of the sections that were removed see the 375ml Coke can. This is the passengers (left ) side mount.
I had a look at a couple of other listers 1997 80 series vehicles and we removed the rubber bungs. One vehicle had no water but had a slight rust coloured weep mark on the edge of the seam, but the other vehicle dumped 100ml to 150ml of water out of the bung holes of both of the skirt mounts. The disturbing thing was that this vehicle had not been wet for about three months and had held the water since then or before. Thankfully there was no sign of rust in the water, nor inside the chamber of the mount.
My panel beater believes the best preventative measures to overcome this problem before the rust starts are:-
1 Remove the rubber bungs.
2 Drill additional holes in the bottom face of the mounts.
3 Spray plenty of slightly thinned Tectyl rust preventative into the chamber. Do not replace the bungs. He uses Septone brand and only recommends thinning with mineral turpentine.
All up, the repair cost me a bit less than $2000, and I hope the information I have provided above may help others prevent this unnecessary cost.
If only Mr Toyota had not been having a bad hair day that day…..…
Stuart McMurtrie
Brisbane
Might have to take the D40 Navara instead 
its completely stuffed!!!! it will take a bit more then a little bit of wind and rain to keep me away from fraser 
we're in a house so we'll be up there reguardless