The installation of the rear shock absorbers effectively started during the Rollbar install, when the top mounting bolt was removed. 

The top mounting bolts had obviously been installed before the chassis was painted by Caterham. My top mounting bolts were covered in overspray from paint coming through the bottom rollbar bolt hole, so I spent some time cleaning them.  I used a detailing clay and Isoproponal (also called isopropyl alcohol or IPA) to achieve the finish in the photo. I would have just replaced them if I’d had replacement bolts available.  

Shock absorber and fittings

I know from experience that the only struggle fitting these shock absorbers is the bottom bolt and its alignment with the hole on the de Dion tube; therefore I wanted as much free play in the shock absorber as I could possibly get before the install. To get this free play, I wound the spring platforms down to the lowest level, but not before measuring and taking not of the supplied setting. Once complete, I reset the spring platforms. I wasn’t looking for accuracy here, because I intend to have a flat floor setup performed once my car is on the road. 

To install the shock absorber, I started with the top, inserted the spacer into to the bush and fitted the top bolt. As usual, some alightment was needed with the pin punches until the bolt would pass through the spacer and into the thread on the other side. I applied Copper slip to both the bolt and the spacer. I also checked the bolt was through the shock absorber before tightning.

Bottom bolt fitted

Next comes the tricky bit: the bottom bolt. The problem here is the angle the shock absorber wants to hold; the bolt isn’t the same as the de Dion tube, so the bolt always feels like it’s going into the tube cross threaded. You really need to take care here that it’s only the bolt being pinched by the angle, and that it is not going in cross-threaded. A bit of slack at the bottom of the shock helps to align the bolt here. 

The bolt into the de Dion tube needs a Schnorr washer and some larger spacer washers either side of the shock absorber. This bolt is imperial, so time for the 3/4” socket to make an appearance. At this stage I didn’t torque the bolts, I will do that once the rear suspension is taking the chassis weight.

The new build manual (v1.2 and v2.0) calls for the rear brake hose to be connected at this stage, so who am I to argue. I found this task simple enough, but to get the flare spanner to fit the brake hose, I had to remove one of the tie wraps from the rubber protection hose. Another important thing to note is the gap between the brake line union and the nut holding the brake hose to the chassis: this ensures the nut is not preventing a good seal with the brake hose.

Tools Used

  • 1/2” flare spanner
  • 9/16” flare spanner
  • 14mm combination spanner
  • 3/4“ 3/8” drive socket
  • 8mm hex 1/4” drive socket
  • 1/4” drive extension
  • Selection of pin punches
  • Side cutters