irs trailing arm bolt failure

[beetle1303]

On Friday on my way to a tire shop i had to make a choice. Hit the idiot on the scooter, or go through a deep and wide pothole...Guess what?? i chose the second one and ended up with a broken trailing arm bolt on the right hand side on my 73 1303.

Rear suspension is lowered 1 notch on the inside and at the time the beetle was wearing its original wheels with 165/70 15 tires...

The car is being driven absolutely normally since im running a 1200 engine for two years now since my 1776 was stripped for a rebuilt (this will go on another thread) and driving about 65km per day to work round trip. no spirited driving for a long time.

Funny thing is that nothing seemed to be wrong at the beginning and i only realised something was wrong when i tried to enter a bend with a bit more speed than normal. since im not running an AR bar at the back im used o setting the car dynamically for the bend loading the suspension gradually and then following the curve. This time though the car had a weird feeling, as when i thought the setting was complete the rear outside (left bend that means right side) squatted a bit more, but nothing dramatic.
so in the next bend i tried it again and it felt that the toe setting was changing violently when the suspension was properly loaded and a ruined inner cv boot .

This was justified by being able to rotate the wheel along the toe axis by hand for about 1.5 to 2cm per side (changing the toe + and - about this amount) and seeing the trailing arm pivot moving freely.

after i was finished with new tires and wheels (update to follow) i when about 10 blocks down the road to the garage to check the problem with my mechanic. the outcome is the the bolt was broken and only the threaded end along with a tiny bit holding half of the bushing was still left.

The beetle had to stay in since last friday and work will start probably today afternoon. Pic to follow from the broken bolt.

Another symptoms that occurred is a metal thud while reversing.

Luckily ive scored a proper bolt and corresponding shims from a donor.

Chris

[vdubzack]

Dont forget to put some anti-seize on the new bolt to protect from corrosion. And while you are at it , check the other one too.

[spannermanager]

That's a first, for me anyway, the bolt must have been run loose to shear at that point, , its possible to buy uprated bolts, or eccentric camber adjusters, but I've not seen any need for these, as I've not broken one in years of trying, altho' i do take some precautions, for they will come loose in motor sports or off road use, where the norm is to re torque them every event, i prefer to drill the bolt head and lock wire them, others like to use loctite on the thread. once i almost ripped a rear wheel off with enough force to pull the torsion tube back a foot or more and tear the a arm almost off the inner pivot, but the bolt held, altho' it was banana shaped, my neck likewise after that. any pics yet?. good luck with it anyway.