Secondhand Coilover Shocks - Buying UsedPosted in How To: Suspension Brakes on January 22, 2014
Recycling someone’s pre-owned parts, and making them work on your rig, is a big part of how most of us make this seemingly expensive hobby affordable. As your build platform evolves, it’s natural to gravitate towards more performance-derived components. One of the most common progressions for those tuning-up their suspension is to make the leap to coilover shocks. So, in this edition of Buying Used, we are shelling out tips for what to look for when buying a used coilover.
Coilovers are not cheap, and even used, they can still fetch a premium. But, paying half-price is still better than buying at full pop. Since coilovers are typically valved from the manufacturer for a specific application, choosing the right shocks for your vehicle isn’t as simple as picking one that is the correct length. On enthusiast websites such as www.race-dezert.com, you might get lucky and find a pair valved correctly for your vehicle, but it’s safer to assume that you’ll need to have the shock revalved.
Fortunately, re-valving a coilover isn’t a big deal and virtually every piece on and inside a coilover can be replaced. Most off-road shops and shock manufacturers charge around $100 per shock to rebuild/revalve a coilover. If you are a savvy DIY guy, re-valving a coilover shock is something that can be done in your home garage, but it will take some research and a proper tool set. Coils are another part of the equation, but coil rates tend to be even more vehicle specific than the shock’s valving. For this reason, the shock bodies tend to be sold separately from the coils.
A. Examine the body closely for dents, corrosion, and damage to the threads. A large dent can cause the piston to stick, and damaged threads can give you trouble when adjusting your coils.
B. If the shock has coils, look closely for cracks. Chipping powdercoat is a common sight, so don’t let that be a deal breaker. Hopefully, the coils are separated and you can easily see if any are bent.
C. A bent coilover shaft is something we’ve seen a lot, so look closely. Rust and corrosion can also eat away at the important component. The shaft is not a cheap part to replace, and a damaged one can be a sign of internal damage. With the nitrogen charge removed from the reservoir, you should be able to completely cycle the shaft. Shock manufacturers list the shock’s collapsed and extended lengths. These will be good numbers to have with you to make sure what you are getting is as listed and the shock is cycling correctly.
D. Not all coilovers will have reservoirs. If you are looking at coilovers with an externally-mounted reservoir, check around the reservoir fittings, hose (if applicable), charge port, and the body of the shock for leaks. Any leaks, big or small, are signs that the shock will likely need to be rebuilt.
E. If the seller recently pulled the coilovers off of a rig, they should still have nitrogen in the reservoir. Ask the seller what psi they ran and then check the pressure with a gauge. Minimum psi is around 130 psi, but we commonly see shocks charged between 150-200 psi. Running too little pressure can cause cavitation and damage the shock.
F. Ask the seller if they have extra valve stacks and a record of what the current valving is. You can use this info to see if the shock will work for you and get a starting point if you decide the shocks need adjusting.
G. The shock mounting eyelets can wear the same as a rod end, so check for excess slop. The eyelet housing is another area we’ve seen cracked and damaged beyond repair.
H. If it is a dual-rate coilover, make sure the slider is in place and the stop rings (smaller threaded collars inside of the coil) are present.
I. Look for signs of cracking in the rubber seat that rests at the bottom of the shaft. These are not meant to replace bumpstops on a vehicle, but rather keep the shaft bottom and body from ever contacting.