From the factory, there are lots of soft bushings in the rear suspension. Like most, I’ve replaced the bushings with poly. However, for the bolt that holds the rear shock lower clevis, the lack of flex in the bushings can lead to the suspension binding somewhat if you use the factory torque spec of 8 billion foot pounds.
Folks have used various approaches over the years to alleviate this – replacing the M16 bolt with a pin, secured with cotter keys or snap pins etc. Hardbar has made some parts for this over the years as well.
I decided to go an easier route and source parts from McMaster:
- 130mm M16x2 socket head cap screw: http://www.mcmaster.com/#91290a848/=wk2iv3
- M16x2 castle nuts: http://www.mcmaster.com/#93760a328/=wk2iut
- Banski Motorsports shock bushings front and rear: https://www.banskimotorsports.com/Pin_Top_Shock_Mounts.html
The clevis on the Penskes is a bit wider than the OEM side – about 85mm, and since the bolt spec shows about 45mm of thread, 130-45 = 85mm of grip length, which the OEM bolts did not have. So, this solves two problems.