Drive Shaft

[art1]

 Was wondering if anyone could share some insight on a wreck I had last week. As I was heading down the straightaway I heard a loud noise come from the rear end of the car and lost control and hit the wall. My question is when I inspected the car the pinion yoke was completely broken at the rear end. Do these break on their own? or did something else cause it to break? The rear end spins freely with no issues.

Thanks,

Art

[VMS Motorsports]

Assuming there was other damage...my guess would be that you broke a right side trailing arm bolt, forcing the right rear back, which, can break the yoke, as it would be the next stress point. Noise you heard was  the driveshaft banging around at a few thousand RPM in the tunnel.

Of course this is a guess not knowing any of the other damage. I have never seen a yoke just break by itself without other contributing factors

[s10custom]

What Jim said. happened to us last year and cost us a front and rear clip. Added the double shear tabs to the trailing arms to help prevent this.
 

[art1]

 I think you are right on the money, went out and checked the RR trailing arm and the bolt was broken where it attaches to the frame. I took a big hit when the car backed into the wall damaging two rims, left rear shock, rear panard bar and suspension parts on the right front. This is the second time this bolt has broken in six races, any idea why it is breaking. All bolts have been grade 8 and the rear end is a double shear.

Thanks for the feedback,

Art

[s10custom]

Are the trailing arms double sheared on the chassis also and not just on the rear end?

[art1]

They are just on the rear end, are you referring to the double shear brackets that came out a few years ago?

Thanks again,

Art

[s10custom]

Yep. You weld the tabs onto the chassis where the trailing arms mount to the chassis. It helps support the bolt that is holding it on.

Robert

[Legends57x]

See link below.  I purchased the kit from my USLC dealer for less than $10.  Well worth the investment.

http://www.uslegendcars.com/inex/tech_tips/legend-car-rear-trailinge-arm-double-shear.html

[justfreaky]

I bought mine though Randy at RPM.
Double shear is the only way to go (front and rear).

Wanted to pitch in and say most folks tend to run Grade 5 bolts because they bend or break before causing damage to other parts in most cases.
I am onboard with the grade 8 from a strength standpoint.

Steve

[knoxracing]

We install a locking nut and a bolt long enough to accept the nut in all areas like this. The key is nutting and bolting the entire car weekly. We never broke trailing arm bolts after we did these things.