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-   -   Trailing Arm Project (https://67-72chevytrucks.com/vboard/showthread.php?t=600268)

low&slow 10-13-2013 04:57 PM

Trailing Arm Project
 
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 10-13-2013 11:30 PM

Re: Trailing Arm Project
 
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 10-14-2013 01:21 AM

Re: Trailing Arm Project
 
What's the reasoning behind your answer on number 3?
Why skip around with the welds?

70shortwide 10-14-2013 03:05 PM

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

Captainfab 10-14-2013 11:35 PM

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

Quote:

Originally Posted by 70shortwide (Post 6314673)
too much heat in one place will distort the metal. So when you jump around it gives that area time to cool.


vin63 10-16-2013 12:03 PM

Re: Trailing Arm Project
 
Quote:

Originally Posted by 70shortwide (Post 6314673)
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 10-17-2013 03:21 PM

Re: Trailing Arm Project
 
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 11-26-2013 01:28 AM

Re: Trailing Arm Project
 
3 Attachment(s)
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 11-26-2013 07:29 AM

Re: Trailing Arm Project
 
Thanks for the heads up. I'll be sure to check them thoroughly.

chevy_mike 11-27-2013 12:15 PM

Re: Trailing Arm Project
 
Here's what I did with my arms.

http://gallery.lisaandmike.org/album...k/PICT2938.jpg

eldogg 11-27-2013 09:33 PM

Re: Trailing Arm Project
 
I stitch welded mine.

RockTonka 11-29-2013 03:31 AM

Re: Trailing Arm Project
 
1 Attachment(s)
Stitched welded mine also and made plates for just the outside of each arm...

low&slow 11-29-2013 03:34 AM

Re: Trailing Arm Project
 
Quote:

Originally Posted by RockTonka (Post 6393579)
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 12-05-2013 08:21 AM

Re: Trailing Arm Project
 
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 12-05-2013 10:01 AM

Re: Trailing Arm Project
 
Quote:

Originally Posted by PGSigns (Post 6402681)
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 12-05-2013 11:21 AM

Re: Trailing Arm Project
 
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 12-06-2013 08:56 PM

Re: Trailing Arm Project
 
Quote:

Originally Posted by 70shortwide (Post 6402884)
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 12-06-2013 09:56 PM

Re: Trailing Arm Project
 
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 06-27-2014 03:03 AM

Re: Trailing Arm Project
 
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 06-28-2014 12:40 AM

Re: Trailing Arm Project
 
I can't speak for the GM engineers but triangulation helps resist side to side movement

SCOTI 07-10-2014 07:25 PM

Re: Trailing Arm Project
 
Quote:

Originally Posted by Captainfab (Post 6739136)
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.


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