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Rear crossmember replacement


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We started the task of replacing my busted rear crossmember on Saturday. 8 hours later we had the old one out, and the new one resting in place but not yet welded.

 

I bought a replacement crossmember from Tony at Rat-co. People may be familiar with his replacement TR6 frames but he can supply other bits too. He send me a new crossmember that is much stronger than the original as well as some reinforcing pieces and gussets. The C channel wraps around the frame at the location where the old crossmember was mounted and generally strengthens that area.

 

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I did not have to remove the diff, just lower it to clear the front and rear studs. I did remove the rear section of exhaust to give us easier access. It is a stainless exhaust with band clamps so it comes apart easily.

 

 

My temporary repair to the broken crossmember had held up well despite the poor weld on the inner most fracture (could not get at it very well).

 

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That's some nice welding work. Was it welded with oxy-acetylene?

 

I'm almost ready to hire a mobile welder to come to weld in a proper TRF right-front diff bracket & side braces to replace this horrible repair somebody did.

 

Just wondering Mig, Tig or gas?

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That's some nice welding work. Was it welded with oxy-acetylene?

 

I'm almost ready to hire a mobile welder to come to weld in a proper TRF right-front diff bracket & side braces to replace this horrible repair somebody did.

 

Just wondering Mig, Tig or gas?

MIG welder should take care of that. My Lincoln 135 is barely able to weld 1/8th inch steel even when turned up to 11 but a pro will likely have a bigger machine than I do.

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MIG welder should take care of that. My Lincoln 135 is barely able to weld 1/8th inch steel even when turned up to 11 but a pro will likely have a bigger machine than I do.

 

 

Thanks.

Can the job be done by the welder working on his back, under the car, with the frame raised a couple feet overhead?

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Can the job be done by the welder working on his back, under the car, with the frame raised a couple feet overhead?



Depends how much they're getting paid! Previously in other welding tasks I've had a blob of splatter drop down between my sock and boot, I did some impressive dance moves.

Next task time, I made sure I had the works in protective gear but didn't consider a splatter dropping into my ear.... Not good, I was expecting it to come out the other side....... So, yes it can be done depending on the determination of the welder and choice of protective gear....


Regards


Bill

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Thanks.

Can the job be done by the welder working on his back, under the car, with the frame raised a couple feet overhead?

 

I did my upside down welding wearing a t-shirt and shorts (it was a hot day). Not something I would recommend though. A pro mobile welder will have all the gear including protective clothing that doesnt have openings on the front where bits of molten metal will find a way in. The inside of the front mounts are easy to reach, the other sides not so much.

 

Stan

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Thank you Stan and Bill for your insight.

When I contact a mobile welder, I was looking for assurance that I won't be asking for the impossible.

 

I'm going to remove the faulty RF bracket/pin with a drill & cutting wheel, and I have the new bracket, pin & side & base plates ready to be fitted.

I'll clean the area with a wire brush.

Hoping to keep the welder's labor time to a minimum.

 

Got the parts from The Roadster Factory, had to ream the bracket hole slightly (round file) for pin to fit. Other then that, the pieces fit together nicely.

 

Cheers

Walt

 

 

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Walt, a couple of tips:

Make sure the boxes that are welded are self-draining, by leaving a bit un-welded at the lowest point.

 

The pin: I warmed it up to 150 degr.C (pre-heat), to reduce potential hardness, since I was not sure what material the pin was made of. It does not harm if the pin is just simple steel like St37/Fe360/PH235 (old and newer and latest designation).

 

Make sure the distances between the pins is correct, there is some play in the rubbers to allow for error, but limited.

And that they are parallel.

 

Trial fit the diff before final welding.

Best to use a jack with a box for this.

Some have used polyurethane foam to create a mould for proper support of the dif in the box. I did without that, just a big trolley jack.

Waldi

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