Spring pivot bolt broke

[2old2fast]

So yesterday , 10 miles from nowhere , for the 2nd time in 40K miles , my left front spring pivot bolt broke. This is the bolt welded to the tube that the shackle/batwing connects. In both cases , the bolt has sheared at the head. I can't see any mis-alignment that would be over-stressing this bolt although , by design there is alot of strees on it. the first was a component purchased from speedway , the second was 1 I welded. In neither case did the weld fail. Anyone care to venture a theory as to why this is happening ? Fortunatley , in both cases , we were traveling at low speed so nothing "bad" happened.... but there's always next time .
dave

 

[Francis Blake]

I can't even guess why a spring pivot would break like that. The pivots made in the last several years are forged steel and very strong, I would replace ti with one of these

 

[2old2fast]

I see RPM still sells the welded type....Ron , have these been a problem ??
dave

 

[Lee_in_KC]

Been there, done that...

 

[RPM]

I see RPM still sells the welded type....Ron , have these been a problem ??
dave

Knock on wood I have not had a problem. I weld them up about 40 at a time. What kind of a bolt are you using? I use a grade 8 with no coating.

Are your bat wings on at and angle causing a bind? The bat wings on my axles are 90 deg to the axle tube. So there is no bind in the pivots. What are you using for a bushing?

 

[choppinczech]

Are those hangers typically 3/8" or 1/2" thread?

If 3/8", that seems awfully small to support all of the front end's weight.

When I made my hangers I used grade 8 - 1/2" bolts with a long shoulder. But I can also see where thinner steel of bat wings wouldn't support the hanger's bolt as much as these 1 1/2" wide bones.

 

[2old2fast]

1/2 -20 x 1 grade 8 uncoated....batwing "ear" bent to 90* to the axle..... if you mean shackle bushing , the hard plastic that speedway sells..... Lee , how many miles before yours broke ?? maybe this should be a bi-anual replacment ....
dave

 

[butch27]

My shackles are like 7 degrees from paralell or something like that (from Total). Because the batwings are angled like that.

 

[choppedtop]

I wonder if the stainless steel units are any better? Got me concerned with mine now.
Lee

 

[choppinczech]

These have a 5/8" stud.

http://www.speedwaymotors.com/Garage-Sale-Total-Performance-Angled-Spring-Pivots,81083.html

 

[RPM]

How about trying something like this? By doing it this way, you won't heat the bolt from the weld.

 

[choppinczech]

That's a better design.

 

[2old2fast]

The stainless offerings from speedway are "investment cast "... wasn't impressed w/that....the ones Ron shows still put the threaded shank of the bolt in "shear" plus I'd need to widen the batwings or shorten the spring.... IDK , but there has to be a better way ?????
dave