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frame back from welding!

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71tr

71tr

Jedi Warrior
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After stripping the car down to bare frame I found that I too had suffered the dreaded differential mount crack. Seems the PO had welded the cracked face of the passenger side front diff mount leaving a quarter inch bead sticking up. This was something undetectable until the differential was removed thus revealing the shoddy repair.

I had decided long ago that once down to bare frame I was going to have appropriate repairs and reinforcements completed. Finally all done; front diff mounts boxed, all mounts getting reinforcing plates on top, stiffening bars now connect the front and rear diff bridges, rear spring crossmember reinforced with gussets and front suspension mounts get stiffening plates welded to the steering rack.

I'm excited to get this thing painted and finally start bolting pieces back on. Also looking forward to a more confident driving experience knowing the frame should hold-up much better than original.
 

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Still have some sandblasting and grinding to remove remaining surface rust. Then a coat of primer followed by a coat of duplicolor truck bed liner. May sound unorthodox but I've been using the stuff on various frame parts, steering rack and inside of body panels and am very pleased with its durability. It dries hard as rock and leaves a semi-gloss textured finish. I believe it is vinyl polymer based product.
 
Looks like a great job. Do you have any feel for how much weight got added. My brother's 4a needs the same work.
 
i really don't think the weight change is significant. consider; added four pieces of 3/16 steel to box in the mounts, two 1" square tubes about a foot long each and a few misc strips of 3/16 to stiffen the front susp/steering rack and gussets for the spring towers in back. i'll guess 3-5lbs worth of steel.
 
I just finished the frame on my 71 TR6 as well. Have a competent welder look over ALL the welds on the frame. After I got mine sandblasted, I found about 6 or 8 cracked welds myself and the weldshop found another 6 just while we were going over the frame.

In addition to reinforcing the diffy mount, add gussets (kits available from the big 3) to the front lower A-arm mounts. Add a strap between the front lower mount and the steering rack mount as well since there's about a 1/2" long weld that is prone to cracking in this area.

As far as chassis coating, I used POR15 for a base coat and followed it with POR Chassis Black. The POR15 is fades if sunlight hits it so the black is used as a cover coat to protect it. This stuff is incredibly tough as I found out when I had to scrape through it for a ground strap attachment. One quart of each is enough to do the whole frame and suspension components although you'll have about a cup or so left over that will go to waste. Once the can is opened, the clock is ticking before the product sets up and becomes useless. Use a secondary container to work from and seal up the can immediately after pouring. A plastic bag between the lid and can helps when you have to open it again later. I believe POR offers 8oz six packs that make more sense since once the can is open. Use a respirator and a brush with lots of ventilation.

Good luck!

Ron
71TR6 (still in tiny pieces)
 
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