Chassis question please

Just got myself a 79 LWT, yay!

Ok, there's plenty of issues to keep me busy but help with my first issue would be really appreciated.

First issue is that I need a new rear cross member. The chassis rot goes up the rail past the spring hangers and so the best looking option I think is a galv replacement that has the expanded extensions that slide over the original chassis rails. The extensions are long enough to get past the rot. I'm not bothered about trying to hide the repair with perfect butt welds and think the sleeve over method might be stronger, maybe. Has anyone used one of these types and can rate them?

Thanks in advance,

Jase

It's the normal way to do it in fact the only way as if you butt weld you will have to plate over the joint anyway...dont bother with galve as the rest isn't just give it a good coat of chassis paint and rust proofing the inside before fitting...are you welding it yourself?...

Been there, dunnit!
Make sure you get the measurements right, then check again to be sure

kermit_rr said:

Been there, dunnit!
Make sure you get the measurements right, then check again to be sure

Click to expand...

+1^^ and check again and again resent thread on here replacement A bar cross member and tub doesnt fit now...

Shippers said:

It's the normal way to do it in fact the only way as if you butt weld you will have to plate over the joint anyway...dont bother with galve as the rest isn't just give it a good coat of chassis paint and rust proofing the inside before fitting...are you welding it yourself?...

Click to expand...

Yes, probably will do it myself. Have a stick welder and usually get neat results if the prep work is good.
So, should I try and fit the new crossmember with the tub in place so I can line it all up? I could at least get the vertical welds done in situ and then lift the tub to access the top seams for welding.
All comments appreciated.

Jase675 said:

Yes, probably will do it myself. Have a stick welder and usually get neat results if the prep work is good.
So, should I try and fit the new crossmember with the tub in place so I can line it all up? I could at least get the vertical welds done in situ and then lift the tub to access the top seams for welding.
All comments appreciated.

Click to expand...

Not done the job myself but re-building an S2 bulkhead just now and yes fit/bolt and make sure it fits tack weld then final weld...I would weld a tab on to chassis on both sides before you cut rotten bit off so you have a measurment from rear of cross member as well as a fit before you tack weld...

I did mine about seven years ago and it already needs another one. The Bearmarch replacement seemed OK but it has already rotted and holed. Waxoiling the inside was a job I never got to and it’s just fallen to bits. The next one I get will be galvanised but it’s going to take extra work to weld it to bare steel.
The rest of my chassis is in good nick mostly due to oil leaks and diesel spills so I’m so peed off I have to do this job again.
You can lift the tub on an 88 without completely removing it by removing the row of bolts behind the front seats, the row of bolts above the windscreen and the two braces in the rear wheel arches. That only leaves the bolts between the rear tub and crossmember. These can be lined up with the new chassis part to line everything up.

Jase675 said:

First issue is that I need a new rear cross member. The chassis rot goes up the rail past the spring hangers and so the best looking option I think is a galv replacement that has the expanded extensions that slide over the original chassis rails.

Click to expand...

It's not a good idea to weld galvanised steel as the zinc fumes are toxic. Breathing it in can give you a condition called metal fume fever. Someone who had it once told me it was the most ill they had ever felt.

Webley1991 said:

It's not a good idea to weld galvanised steel as the zinc fumes are toxic. Breathing it in can give you a condition called metal fume fever. Someone who had it once told me it was the most ill they had ever felt.

Click to expand...

Not an issue for me as I’m stupid.

Webley1991 said:

It's not a good idea to weld galvanised steel as the zinc fumes are toxic. Breathing it in can give you a condition called metal fume fever. Someone who had it once told me it was the most ill they had ever felt.

Click to expand...

It does look very pretty though (the fumes)

As I wouldn’t attempt welding through tin the galvanising would have to be flap disked off. In essence I wouldn’t be welding any zincy stuff. I’d also be doing it outside and not for any length of time. I’m all for those in the trade taking all precautions but as a DIYer I won’t have years of exposure to anything much.

Galvanised all the way, not to fit galv is madness if keeping the car.
Fitted galv one to my 90 about 10 yrs ago, looks just the same as the day I fitted it.
Just use a flap disc to grind off roughly an inch past the weld point, but still avoid any fumes just to be sure.
Mig will be way easier than a stick welder, especially if you come across a thin patch.

No matter how much you measure and double check there is a strong possibility that when it has been attached, it will be a few mill out. Id recommend taking some time to make a jig out of angle iron before you remove the old section.

Col

lynall said:

Galvanised all the way, not to fit galv is madness if keeping the car.
Fitted galv one to my 90 about 10 yrs ago, looks just the same as the day I fitted it

Click to expand...

Whats the rest of it like though...if the OP's has rusted up past the spring shackles the rest wont be much better in places...

I found this worked, If you tack a few bits of angle iron along the top of the chassis with the welder before you cut off the rear crossmember, weld small blocks to angle iron to fill the gap between it & the crossmember, it ensures the new 1 will go on in the same place. (take loads of measurements just to be sure tho ) the slip over's are great, but had to make a U channel section to reinforce the base of the rear chassis rail, I know it's probably overkill but it's strong.

Shippers said:

Whats the rest of it like though...if the OP's has rusted up past the spring shackles the rest wont be much better in places...

Click to expand...

No idea as its the ops car.
Just stating if he fits galv he wont have to do it again.

Bobsticle said:

I’m all for those in the trade taking all precautions but as a DIYer I won’t have years of exposure to anything much.

Click to expand...

It's not a long term illness that happens after years of exposure. It is short lived and can happen after being exposed to enough of it as a one off.

Webley1991 said:

It's not a long term illness that happens after years of exposure. It is short lived and can happen after being exposed to enough of it as a one off.

Click to expand...

Is it like Theakstons Old Peculiar.

At a place I once worked, we had a galvenised de-greasing tank that needed welding. The maintenance fitter refused to do it so the MD who was a bit impulsive said he would do it. There were clouds of whitish fume and the MD ended up in hospital and was off work for weeks. He was only welding for about 15 minutes and not in an enclosed space.

Col

I have just replaced the rear crossmember on my 90. I used a second hand one that was given to me. It was in good nick even though it had been previously fitted for seven years. It was a galvanised one.

The previous crossmember had already been replaced and I was very reluctant to fit a non galvanised unit. The black paint that they are coated with is like a rust enhancing formula specially developed to make sure you have to replace it again in around seven years or so.

I have welded lots of galv in the past. It can give you what we used to call "galv flue". It usually cleared within a day or two, though I am sure I would not recommend it. Definitely do it outside - the fumes off galv tend to float around and linger.

The thing to do is remove the galv before starting welding. Use a flap disc and slowly grind the galv away. You will know when the galv is taken off as the galv has a silver shine to it. As you get to mild steel it will be a greyer sheen. I would try to strip away about 10mm of galv from the edge as it will get hot enough to burn off the galv. Also welding on galv just won't work as it will contaminate the weld and make the weld porous.

Good luck with doing the job.