Installing Shocks & Bump Stops
A critical part of any cars suspension is the dampers also known as shock absorbers. There is wear and tear placed on the dampers from towing the car on long stretches of road between race tracks, not to mention the hard work they perform out on track. All of this motion and heat eventually wears out the seals compromising the fluids necessitating a replacement or rebuild. The dampers used by Spec Racer Fords are a sealed unit that must be serviced by a SCCA Enterprises approved vendor to make sure they meet performance specifications. The dampers/shocks on our car were long in the tooth having endured multiple years of action and needed a rebuild. Unfortunately the rebuild time was going to be longer and later than our next race weekend as Sonoma Raceway. The condition of the shocks and timeframe meant we needed to buy new replacement unit. Whether you are rebuilding or replacing the steps are the same for removal and installing into the Spec Racer Ford.
Tools and Equipment
New Penske Racing Shock bodies - Enterprise Part Number 280396
Spacer Upper Shock - Enterprise Part Number 280588
New Bump Stops - Enterprise Part Number 280407
1/2, 9/16, 5/8 inch Wrenches / Spanners
1/2, 5/8 inch Sockets
3/8 Drive Ratchet
Jack / Wooden Blocks
Degreaser / Cleaner
Microfiber Towel or Rags
Simple Green HD Purple (Aluminum safe)
Replacing the Rebuilt Penske Shocks
The Spec Racer Ford can use either Koni or Penske Racing Shocks. The advantage of the Penske’s is that they can be adjusted for rebound without removing them from the car. Very handy on a test day especially if you are both the driver and crew.
To remove the shocks from racecar, start by jacking up the car in the air and putting it on low jack stands.
Use blocks of wood or a jack to support the weight of the wheel and upright assembly. You can disconnect the sway bar using the 1/2 inch wrenches, socket and ratchet or impact driver.
To unfasten the shock top use the 5/8 inch wrenches, socket and ratchet/impact driver to remove the bolt. Be careful as the Upper Shock Spacers might fall out and you don’t want to loose them.
Then undo the lower mounting point of the damper using the same set of 5/8 inch wrenches, socket and ratchet you likely won’t have the space to use a cordless impact driver. Then you should be able to slide the damper off the lower chassis mount. Make sure to put the spacer and nut back on the mount so you can find them easier later.
We bought fresh new Penske Racing Shock bodies for the racecar. Here you can see the difference between an old and new unit.
The Spec Racer Ford dampers are sealed at approved vendors and they have a glued SCCA Enterprises seal in place to prevent tampering.
The new bump stops are Enterprise Part Number 280407. These are required in 2020, so we decided to install them while swapping out the Penske Racing Shocks.
The previous owner of my car had drilled out the upper shock spacers and rockers to a 10mm metric bolt. I love the metric system, as I grew up with it in Australia and use it in my engineering work but this made my car non-standard and so slightly more difficult to swap in replacement parts trackside where there is limited time. To return the car back to the original design, I bought a full set of Upper Shock Spacers (Enterprise Part Number 280588) as we were already swapping in the new Tubular Rockers.
Before we could get the new Penske dampers installed into the car we had to strip off and clean the parts from the old shock bodies. Parts include the top eye, upper and lower spring perches and the o-rings.
The lower spring perch just unthreads from the main body. To remove the upper spring perch and various parts you might need to hold the top eye in the bench vise and use a 9/16 inch wrench on the machined portion of the shock shaft.
Some aluminum safe Simple Green HD and scrubbing brushes made quick work of the years of built up grime and dirt.
With all the parts cleaned up it was time to install them on them onto the new Penske Racing Shock damper bodies. First slip the Bump Stop over the shaft, unfortunately I placed the bump stops upside down in the photos and had to go back to correct it after the fact. Those eagle eyed readers probably already noticed.
Then slide on the top spring perch, followed by the O-ring. Place a little blue thread lock on the threaded portion of the shock shaft and then screw on the Upper Shock eyelet. Put it back in a bench wise and use a 9/16th inch spanner to tighten into place.
With the upper assembly complete you can now slide the coil spring over the main body and thread on the lower spring perch to set the initial spring pre-load and ride height.
Here you can see the complete assembled damper units for the rear of the car. On the lower spring perches you might note the numbers stamped into the coil wrench steps used for helping to set the rear ride heights and keep track of any set up adjustments.
Here you can see the detail of the new Upper Shock Spacers installed.
Slide the shocks into the lower mounts, insert the lower spacer and tighten the nut into place.
Getting the upper spacers into the rockers might be a little tricky but once in place, slide the bolt through and tighten the nut in place. Make sure the adjustment openings are facing the front otherwise you will regret. Don’t ask how I know this.
With the new or rebuilt dampers installed on the car you will need to reset your ride heights and then do a full setup to check your alignment.
The brand new Penske Racing Shocks installed on the rear of the car looking fantastic and ready to hit the track.