Trailing Arm Project

[low&slow]

I heard a lot of you guys welding your trailing arms together in the middle by either yourself or buying plates from various companies. My questions I have:

1. Can I remove the trailing arms from the truck without removing anything else?

2. Should I cut the plug welds, separate both sides, and clean out what rust may be there in the middle? Or not worry about it?

3. Can I just weld right down the middle on both sides of the trailing arms and grind it smooth?

4. After the welds are done, do I need to box it in or can I just leave the sides open?

I'm building my truck to maybe see some track time again. Not looking for low numbers and high speeds, but I know I'm going to end up welding the trailing arms sooner or later. Just trying to find projects I can do to the truck at home without having to buy pieces and parts.

5. Also, along with the trailing arms being out, what gauge of metal should I use to make drop blocks?

[Captainfab]

1) You should be able to.

2) I wouldn't go that far unless there is a lot of flaked rust between them. At the very least I would have them sandblasted if you can. That will reveal any hidden issues.

3) You don't want to just weld each side continuesly. You will want to skip back and forth from one side to the other, only welding 3-4" at a time. Also don't just start at one end and start welding. Also skip around on a side from end to end.

4) Boxing them would be optional, depending on just how much power you are planning on subjecting them to.

5) I would use 1/4".......or 3/16" at a minimum.

[low&slow]

What's the reasoning behind your answer on number 3?
Why skip around with the welds?

[70shortwide]

too much heat in one place will distort the metal. So when you jump around it gives that area time to cool.

[Captainfab]

This is why you want to skip around. Otherwise your trailing arm will end up looking like a banana.

Originally Posted by 70shortwide

too much heat in one place will distort the metal. So when you jump around it gives that area time to cool.

[vin63]

Originally Posted by 70shortwide

too much heat in one place will distort the metal. So when you jump around it gives that area time to cool.

Yep, the few sets I've fixed and reinforced for friends and customers, I've only really done stitch welds...I did not completely weld the seam on either side.

[low&slow]

This all makes sense. I think I may just break the plug welds anyways just to make sure they are good on the inside.

[RexDodge]

Be sure to look closely at the rear for stress cracks like these I found in mine. Clean them or have them sand blasted to be sure you find any issues...then repair!

[low&slow]

Thanks for the heads up. I'll be sure to check them thoroughly.

[chevy_mike]

Here's what I did with my arms.

[eldogg]

I stitch welded mine.

[RockTonka]

Stitched welded mine also and made plates for just the outside of each arm...

[low&slow]

Originally Posted by RockTonka

Stitched welded mine also and made plates for just the outside of each arm...

That's a really nice arm you got there. That's how I hope mine come out.

And thank you all for the info and the pics so far.

[PGSigns]

I have a set of the NASCAR truck arms under mine. The stock ones were not so good so I started to look around for a new set. I got a very nice set for a $100 from a local racer. Heavier gage, stitch welded and with ball swivels in the front. You can find them on ebay also.
Jimmy

[low&slow]

Originally Posted by PGSigns

I have a set of the NASCAR truck arms under mine. The stock ones were not so good so I started to look around for a new set. I got a very nice set for a $100 from a local racer. Heavier gage, stitch welded and with ball swivels in the front. You can find them on ebay also.
Jimmy

That's not a bad idea. You have any pictures?

[70shortwide]

I used 2x3 tubing and used a ladder bar cross member to bolt them too. one of the problems with the stock arms is the angle in the back and if your using a stock rearend the pinion angle will get to be too steep if you go real low with it.

[low&slow]

Originally Posted by 70shortwide

I used 2x3 tubing and used a ladder bar cross member to bolt them too. one of the problems with the stock arms is the angle in the back and if your using a stock rearend the pinion angle will get to be too steep if you go real low with it.

I was thinking about the pinion angle as well. For now I'm sticking with the original rear end, but when that goes out I'll be upgrading.

[JJLT1]

heres a pics search.. i'v been looking for/at options too.. keep the thread going..

http://www.bing.com/images/search?q=...ms&FORM=HDRSC2

[low&slow]

One other question on the trailing arms, Why are they layed out to be like a triangle and not just straight like the frame?

[Captainfab]

I can't speak for the GM engineers but triangulation helps resist side to side movement

[SCOTI]

Originally Posted by Captainfab

I can't speak for the GM engineers but triangulation helps resist side to side movement

Parallel to the frame (rectangle) wouldn't allow as much articulation vs triangulated.

The combination of triangulated mounting, I-beam construction, & rubber lined metal sleeves allowed the solid mounted rear some amount of flex for typical driving.