Cracked Rear Suspension Bracket Fix

[Trucker]

Cracked Rear Suspension Bracket Fix
      
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78invader440
   
post Mar 12 2007, 10:08 PM
IP: 68.188.237.116 | Post #1 |


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From: Dryden,MI
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O.K guys, I've finally got to this point of my restoration in order to show via pictures how I fix these rear suspension brackets. Mind you, this is not for the faint of heart. It is not an easy fix, but once completed, you'll never break a bracket again.
First of all, you need to understand what the failure mode is. A lot of people think it is the up and down motion of the rear suspension arms causing fatigue in the brackets. That is not the case. It is the LATERAL motion of the skid frame putting a sideways force into the bracket that fatigues them. Yee Haa power sliding around the corners is what kills them.

You must COMPLETELY disassemble the rear suspension. Right down to the point of drilling out the rivets that hold all the brackets on to the rails. Once you've got the brackts off of the rails, you have to sandblast them becuase you're going to be welding on them (see picture). A this point, you have to decide by inspection whether or not the brackts are too far gone for repair. If they're cracked the entire length, forget it. Find different ones.

The most time consuming part is making 16 "question mark" brackets (4 per suspension bracket) and custom fitting them to each suspension bracket (see picture). The material is 1/2 inch wide band iron available at most hardware stores in 3 foot lengths.

Once you've got all the question mark brackets made, weld them to the suspension brackets. Also at this time, you've got to repair your existing cracks. TIG welding is prefered here, because you can't have any weld come through to the inside. If that happens, the bracket won't slide on over the rail. Inevitably, you'll have some, so there will be some time spent with a small diamter round file trying to clean it up.

After that, sandblast again, and send the job off to the powder coater. Reinstall them on the rails using stainless steel socket head cap screws and nylon lock nuts.

I've done this fix on 4 rear suspensions now, and I've never had a repeat failure. BEST OF LUCK

[JDmatt]

Anyone ever find anything "off the shelf" to use to reinforce these brackets?  I'm going to take a set to my welder, but it would be nice if I could give him something to put on them. 

[jimvw57]

I got a replacement factory part from North Country up in St Paul MN he has listed a bunch of Kawi stuff on Ebay quite often

[ChaChi]

Also if you get yourself some good work gloves and a wire wheel, you can likely get away without the sand blasting (although it's nice if you have access to one), by wire wheeling the entire bracket and then either brushing on phosphoric acid or submerging the part in it, it will eat all rust and etch the surface of the metal to ready it for welding and/or paint!

You guys that are in the states can get the acid at various locations, it's used for concrete prep and also sold as milkstone remover at TSC for cleaning milk tanks... It's much safer to work with then muric acid because it's typically a food grade product and is actually in Coca cola and pepsi (you shouldn't drink that crap). Guys in Canada will have a much harder time finding it, pretty much have to order it off a bio diesel supplier or go state side...

I have now used over a gallon of the stuff on various projects and I can't say enough good things about it! It is acid tho so use proper PPE!

cheers

[Ken11487]

Phosphoric acid is available at greenhouse industry supply places if you have one near you.
May have to buy 5 galon size though.

[gixxer6]

Anyone ever find anything "off the shelf" to use to reinforce these brackets?  I'm going to take a set to my welder, but it would be nice if I could give him something to put on them.

I see these on ebay, I think I'd order a set if my brackets were cracked... 

http://www.ebay.com/itm/251201445396?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

http://www.ebay.com/itm/251201445389?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

[JDmatt]

Yep, ordered. 

[Mad Kaw]

heres my quickie fix i did... im pretty hard on this sled so we'll know if they hold up 

(not so much "quickie" as my brackets were completely busted and i had to swap out some from another skid)

12 pieces of 1/8" x 1/2" steel cut to 3 1/2" long...

1 piece welded to the top,,, 1 piece on the bottom,,, and 1 piece fully welded to the sides of the top & bottom piece

wont win any shows with the welds (welder was acting up) but what the hell