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Strengthening a rear crossmember.

Les Henson

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Most, if not all new crossmembers need some kind of reinforcing if you are going to pull anything bigger than a medium-sized trailer. Strengthening can be as simple as a plate to spread the load, to making your own out of an RSJ. If you are going to use your truck off-road, then it's likely at some point that you are going to need either to recover someone, or be recovered yourself. Some situations are such that the rear crossmember will have to take violent jerks that will equal several tons, or a sustained pull that will equal twice the weight or more of your truck.

I decided to buy a ready-made (but pretty rubbish build) one from Bearmach. and strengthen it myself.

Firstthing I noticed was how it was put together - short bursts of weld, rather than a seam, poor build quility in general, and the usual in-built help that makes sure it'll rot away quicker than the old one.

The idea is to strengthen the crossmember, protect it from rotting away, and to strengthen the corners where they have a tendency to bend easily.

The thing as it comes. Judging by the odd holes it seems it's only suitable for a ball hitch (note no crush tubes or similar inside). I want to fit a NATO hook, so I'll have to alter the holes.

Note also the short bursts of welding.


I removed the top and bottom centre tabs so that the strengthening plate I'm going to use on the inside will fit better. I also joined all the welding up to add strength.


The spring bush mounts are a joke - they look like a child made them. Not too different fronm the design of genuine ones though, and no surprise a hole developes in the chassis.


Blanking them off not only makes them look better, but strengthens the bush housing.



The rear of the outer sections fill with mud that's thrown up from the rear tyres, so blanking them off is common sense and helps to reinforce them against corner damage.


As mentioned earlier, the holes are no good for a NATO hook, I need to make my own and reinforce them too. Fortunately the internal diameter of an old steering tube is a little bit bigger than the 14mm socket head bolts I want to use to mount the NATO hook, so this is what I'll be using as crush tubes.

One hole at a time, and care in making sure they are in the right place.


The two smaller holes are in the way, but I'll deal with what's left of them ones the tubes are in place and ready to be welded.


The tubes can be spot welded in position, but a complete weld is a better job I think.


Front face has to be done in a similar way.


make sure the weld has depth asyou need to level the weld with the face of the crossmember at the front and rear.


Test fit of the NATO hook shows that everything is in line.


I have some butch grabhandles that I want to fit in place of those tin standard items. I welded nuts on the inside before closing the ends of the crossmember.


Just got to paint it now :(

Les. :)

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As others have said Les a very nice job.

Out of curiosity what sort of garage/equipment have you got at home?

A couple of photos of that would be interesting for us mere mortals.



PS Nope not asking fo your post code!!! Not just yet anyway!!! :P:P:P

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Out of curiosity what sort of garage/equipment have you got at home?

Well I have what is basically a big shed. It's 19'6" long x 9' deep and 7'6" at the front and 6'6" at the rear. In the days when you could get cheap ready-mix, I put down a base 7" thick and then built the shed frame out of 3"x3" fence posts, and the walls are made from the old floorboards from a school that was demolished here in Swindon. An old iron-framed window of the type that coucil houses had at one time supplies natural light, and three 6' flouresecent tubes as well.

Work bench is 10' long and has a 6" engineers vice clamped to it and a large spreader plate to take the strain. The door is 4' wide and is seperate top and bottom. Mains electric via a RCCB in the house, seperate fused circuits in a ring for the lights and 10 sockets. That's it really, shelves all round the sides, my welding stuff and a second set of tools. No vehicle access though unfortunately, although I don't think my neighbours would like it if I did have :D

I have a crappo Clarke pillar drill, and bench grinder as well, but they are real rubbish. If I have a certain job to do I just try to figure out how to do it with what tools etc I have.

Les. :)

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Well done Les. Hope you keep that article well archived.

Must admit it was a better read then some of the 'technical' articles in the mags.

Tend tend to read," we bought/blag item x from manufacturer y was fitted in bigger dearler z well equiped workshop in a millionth of a second"

Its certainly given me food for thought.



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