defender chassis welding

[alanw]

hello,

wondering if anyone has any experience welding up a cracked 130 td5 defender chassis?

In particular, what grades of steel to use for repair fishplates? and any preferences for type of mig wire/gas?

thks

alanw

[Tank]

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.

[Red Rocket]

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

[incisor]

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....

[alanw]

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

[roverrescue]

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

[alanw]

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

[roverrescue]

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

[slug_burner]

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

[lardy]

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

Hi Al,
Just an enquiry out of pure interest as I run my tub standard.
Did you consider the effects of extending the tray you made beyond the original length.
Just that i have seen alot of 130's with trays that are way beyond the standard tub length and was wondering if this adds to the stress that the chassis has to endure under load or is it purely that they are weak chassis parts under mass load and bad roads ?
Regards Andy.

[hagus]

G'day Alanw

My 130 cracked in the same place. I have seen a couple of others also. I have also welded up the front tray mounts twice. Last time I put in an extra support up the front taking advantage of the factory mounted supports nearest the cab. (they have rubber cushioning rivetted to them). An engineering mob in Kunnanurra welded my chassis for me about three years ago. One side looks like the apprentice did it the plate is fully welded, crappy job, the other looks much better with radius's on the corners and welds run off beyond the plate on a gentle arc. Both sides have held up to date.

Cheers

[alanw]

Just an update on the repair - and what is now an obvious cause of the problem.

The chassis rail that cracked first and worst had only half the steel thickness than the other side - it was that thin that welding was difficult.

Have used 3mm plate and have fishplates top and bottom and inside and out of each rail - and quite confident that it is now much sounder than when it left the factory.

As for andy's query about tray length - the tray is 6ft long - so not overly long. I have the spare tyre under the tray on top of the fuel tank and substantial tool boxes under the tray and behind the wheels - so this is an additional load behind the axle

The heavy loads which go on the vehicle are always at front of the tray - a 1 t. pallet is abt 4ft square - so the length of the tray is probably not an issue. But it would be hard to get that 'dense' a load in the front of a standard tub.

The tandem trailer we tow is around 3t. gross - so well within load capacity and the towbar is in the forward position so shouldn't be any issues there.

And finally, a big thankyou to the people who have provided advice, comments and suggestions - it made the repair much easier. And I suspect we have all learned a bit as well.

Alan

[roverrescue]

Hi Alan,

Thats interesting. What was the construction of the rear chassis.
I hacked an old ranga for its front spring mounts and was impresssed to see internal laminations within the chassis. From memory it had a 4 radius laminates inside each corner as well as a strip running along the top and bottom rail inside the outer skin chassis. Seemed a very strong manner to build a chassis. I guess the front spring mounts / engine mounts would be engineered differently but would be keen to know what you found.
I would also be keen to see any photos you may have of the repair, PM if you would prefer not show the world...

Regards,
Steve

[alanw]

Hello Steve,

As per request a few photos. The plates are top and bottom of chassis and inside and out of each rail. The top plate goes to infront of the rear cabin support bracket. On the outside of the chassis they go forwards to the lower link mounting bracket. This required a new bracket to be fabricated to support the rear cabin support rail - the factory bracket did not survive removal.

As for chassis construction - no laminated chassis here - just 2 bits of U shaped folded steel welded together on the top and bottom. And as mentioned previously a lot less steel on the LHS than the RHS.

Hopefully I won't have to do this again.

Alan

[broonski]

Hi Alan,

nice repair job! :)
I was wondering how this sort of repair affects rego and insurance... would an engineers certificate now be required?

cheers,
bryce

[rick130]

Hi Alan,

nice repair job! :)
I was wondering how this sort of repair affects rego and insurance... would an engineers certificate now be required?

cheers,
bryce

I've been told technically yes, it has to be re-engineered, this is why quite a few professional repairers refuse to repair a chassis in case of a come back, either from the RTA or insurance in case of an accident, but what do you do ? AFAIK almost every 130 suffers from the complaint in the same spot.
It's poor engineering on Land Rovers part, but they've never come up with a 'fix', they just blame overloading, which is crap, but that's another story.....