Thread: defender chassis welding

Welcome to the Forum.
Just a few tips on welding chassis's, weld up the crack first, when fitting a fish plate avoid welding straight up the side of the chassis, angle the ends of the plate to give a longer weld run, avoid welding directly across the top of the chassis rail, angle the weld.
If using a long fish plate a few 50mm holes will allow you to weld the middle of the plate to the chassis,don't go overboard with fish plate thicness, usually same thickness or a bit more, Idea is to spread the load evenly over welds and fish plate, Regards Frank.

Where on the chassis is the crack? The chassis is double thickness in some places on that model. RR.

fix the crack first and if possible use a small drill to push a hole thru at the end of the crack then fill with weld to stop the crack progressing further.

when welding the existing crack do some weld preparation and grind out to about 2/3rds the thickness of metal.

normal mild steel filler is fine on landy chassis.

i always use flux cored .8mm gas less mig wire as it can handle dirty metal and a not so kind environment much better than gas welding. doesn't look as pretty tho.

make sure any fish plate has no square corners, use at least 12mm radius on any corner and weld prep the plate. i tend to use 5mm thick plates as a rule on landy chassis.

do not weld to hot as you will get undercut and that will negate the fish plate.

best of luck with it....

thks everyone for the comments - much appreciated

the crack is in front of the front tray chassis mount bracket and behind the rear cabin mount cross member- the defender is a dual cab with a tray. It has cracked from the top down and reflects heavy loads and heavy towing on ordinary roads and what is in effect a stress point in the chassis and is complicated by a land rover factory weld across the top of the chassis at this point

access is good for welding with the tray and exhaust system off - my main concern was needing to find high tensile steel for the fishplates and the right mig wire/gas for the weld - but the ability to use mild steel and normal mig wire makes the repair fairly straightforward. Will be plating top and bottom and both sides of each chassis rail. Quite conscious of fish plate design with curves and no welds directly across the chassis etc.

thks again for the suggestions

alanw

Alan while you are at it, have a good look at the tray mounts.
If its had enough load to crack the chassis Id be guessing the tray mounts have taken a beating too.

My 130 tray mounts need welding again, but as far as i can tell the chassis rails are still okay.

Any ideas on what rear suspension this vehicle is running... id be interested to know if chassis cracks are related to a higher spring rate (Similar to Patrol utes that crack out spring buckets and chassis at the flex point when heavy springs and heavy loads are combined) or if they are proportional to the random amounts of cheese in the british steel used in the chassis. Hmmm, maybe Solihull actually melted down old series axles to make chassis material???

Steve

Hello Steve,

Suspension is standard - so factory dual coil setup - which works very well. Never seen the need to make any changes.

Would put a 1 tonne pallet on the tray at times - and the roads I travel over are not very good. Also tow a tandem trailer at times - and the spare wheel and of course the fuel tank are under the tray at the back - so quite a load on the back of the vehicle.

No sign of any problems with tray or tray mounts or the tray supports which are factory welded to the chassis.

I built the tray myself - it has a much better mounting arrangement than any standard commercial tray. It does not flex and is far better supported along the chassis rails than 'normal'. Which may mean that the first place to flex is the chassis just infront of the front tray mount. And not helped by a factory weld directly across the chassis at this point.

In any event I have a welding job ahead of me.

Rgds

alan

Hmmm,
very interesting Alan. I would think my 130 has a similar use pattern, on stock rear suspension.
I have an alloy tray which only has two mounts at the front (just in front of spring towers) and three mounts along the rear cross member.

I have had to weld the chassis mounts one once and one side needs it again.

You may be onto something, my tray flexes heaps, enough to crack out the mounts obviously, but chassis is fine. I was contemplating beefing the tray support up when I next do the fix... but this has got me thinking!!!

Ive seen plenty of other dual cabs up on the cape roads banana-er-ing the chassis between cab and tray. I guess we may never know the real reason but certainly food for thought.

BTW good luck with the repair.

Steve

Pictures please. It will help us less familiar with the 130 configuration