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TR6 DIfferential and support damage TR6

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tr6web

tr6web

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All right everyone. After many years and now have time, I finally removed my brake drums to inspect the diff and everything around it. Geez...it looks like the support beam across the diff has damage to it. It's torn up almost in the middle. What the heck do I do now? EVerything else looks ok except the bushings which I can replace. Do I buy a new support and have it welded in? Does that mean I have to take everything apart? I'm dreading this...at least the frame looks ok. Any help would be appreciated, especially someone who had done this before. thanks.
 
First off, sorry to hear of your damage; how disheartening! Were there no symptoms? Would you explain "torn up" a bit more? It is unusual that the cross brace failed in the middle as it normally fails where the 2 mounting studs are welded in. I have not repaired this damage personally, but I'm afraid that you are looking at a body-off repair here. It's one thing to simply weld in the box reinforcements for the 2 studs with the body on, and something quite different to R&R the entire cross brace. Instead of buying a new brace (as if you could), just have the shop fab one from heavier gauge stock and reuse your studs. Get their opinion on attacking this job with the body on; they may suggest butchering your parcel shelf to access it instead of body R&R. Good luck.
 
Thanks for the sympathy, Rick. It looks like it was ripped apart right in the middle. It looks like a flower starting to bloom. The metal is pulled up so I have 3 jagged pieces sticking up. I'm so mad, sad, etc. There's no way I have the $$ to do this now...it may have to wait years.
 
Hello TR6web,
can you explain further, are you refering to the brace that bolts onto the front of the differential (the carrier) or the frame itself?, as you say there is no frame damage. "at least the frame looks ok".
If so, surely you can remove the differential and carrier and repair it in a workshop?

Alec
 
It looks welded to the brackets which you can see in the pic. The bolts I think are for the diff. I could be wrong.
 
Hello Mike,
OK, that is not the part I was thinking of, as it's part of the frame that puts a differnet perspective on it.
I would suggest dropping the differential out and seeing how practical an in situ repair is.

Good luck

Alec
 
Thanks, Alec. I hope my repair guy can do it with the body on as I can't afford to do it any other way. It's still going to be expensive no matter how you look at it.
 
Mike,

Besides the fact that this obviously needs to be repaired, the question arises, how did it happen?

The crossmember is welded to the towers just inboard of the rear springs. If I understand your description, the only cause I can picture would be that the front differential mounts have failed and allowed the pinion end of the differential housing to rise up shaply and come into contact with the crossmember. Repeated contact like this would cause the flowered out appearance you describe.

Are the front differential mounts solid? Can you see the drive shaft well enough to see if it displays any metal-to-metal contact, it may be hitting the cruciform plate as well.

With this type of damage, I would take a hard look at the rear mounts (on the second crossmember where the shocks mount) also as they are probably carrying a lot more torque load that designed for.

I just looked at the 2 body off rebuilds I am working on and do not think the crossmember can be replaced without removing the body. It does appear possible to get to it from the top by cutting out the parcel shelf. However, I think you would have to be satisfied with a repair, not replacement. replace the crossmember this way, just patch it.

I am sure finding this damage was not the best news you ever got, but on the other hand, no one was hurt as could have been the case if the crossmember failed while driving.
 
Hi Mike Had the same problem with my on going frame off 70.
I was able to repair mine (frame off) by welding all cracks and then welding a 3 x 3 x 1/8 th plate with a 1 inch hole in the center on top of each bolt. You may have another area of concern as mine did. I don,t know if you can see the front edge of the crossmember but mine was cracked on both sides of where it is welded to the towers. Inside on one tower outside on the other. The drivers side, (outside crack) was quite bad. About 3/8 gap at the bottom edge of the crossmember. The outside end of the crossmember is what supports the springs and takes tremendous stress. I was able to force the gaps back to normal, weld and then reinforce with 1/8 x 1 1/2 inch metal across the full width of the crossmember. Did the same to the back side of the crossmember. The rear crossmember (shock mount) was fine on my car. I have seen a kit that does basically what I did but also included the box pieces that go inside the crossmember.
While under there, also have a very good look at the trailing arm mount section. Look with a hammer and if it is soft at all, its frame off time. Good luck!
Brian
 
If I understand your problem right, it is not as bad as you may think. The diff. on my TR 6 was loose on one of the mounts. when we took of the mounts we found that it was the frame that had torn loose. It also appeared that this same thing had happened before as you could see where the frame had been welded. Before we put the new mounts on we wleded the frame once again and then had the welding shop make me four heavy reinforcements about 3 in.X 3 in. with a hole in the middle. These were then welded to the frame. Other than the differential, nothing else had to be removed to do the job. This should be the last time it tears loose from the frame. I hope this is helpful.
 
sorry to hear about your frame damage by the way I am a new member and am really enjoying this site. Your frame damage really hits home as i have been operating a part time welding shop for the past 15 years and have experience in many forms of automotive welding, most of has been on large american autos but of course my interest is in british cars. Too bad your not a little closer to canton, Ohio or I could swing by and take a look and give you some advice. from my point of view this repair job may take a little time but I know that I've tackled much worse. If you have any questions, I'd be glad to be of any assitance, again this is not as bad as it may seem, Take care , vince R
 
Its not easy

Watched mostly but its really not that bad of job. Just
takes some time. I worked the floor jack up and down till
he got it in. Takes some fanagling but get someone to help
you. He did it in one day.
If you need any pointers let me know my Mech. is on duty now
in the garage. betts
 
I've been postponing this repair, but I'm back now. From the responses on here, some say I can do it with the body on..some say body off. Any other opinions out there? If it's body off, do I have to remove the entire body or can I just remove the rear somehow? I also have a new deck and front sections to replace anyway. Any idea on cost to remove the body and to repair based on experience? Thanks.
 
Mike,
Removing a TR6 body is not that difficult. I removed my body tub with an engine hoist and a couple of tow straps. First you need to lighten the load a bit by removing your interior seats and maybe even the body wings which are simply bolted into place. This would also aid in replacing your deck sections. You must also disconnect everything bridging the body/frame gap; steering column connection, brake and clutch lines, engine bay wiring connections etc. If interested I have photos of my body lift I will share.
 
Mike,

I'm sorry to hear about your car. I'm just completing a frame off on a 70 TR-6 and it sounds to me like you need to take the body off to rebuild this rear cross member. I have access to a British auto salvage yard near me and I've helped my brother in law replace that entire cross member which was missing in the 73 TR-6 he bought! The yard has a few more frames that would be a good donor for that part, and whoever you get to do your work could reinforce the diff mounts when he welded that new piece in. Good luck and let me know if you need that part!!

Mark
 
There's a guy in PA who does a body on replacement of the frame members to which the trailing arms attach. He's got a system down where I think he puts the car on a jig, cuts out the old and welds in new. He does a good job. Here's the link https://www.triumphworks.com/
 
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