Expert suspension tech Gareth Court helps us avoid costly mistakes when buying used suspension

Purchasing second-hand shocks can be a big gamble. You never really know what you’re getting until they’re in the car and you’re going for a drive. There are a large number of second-hand coilovers available on the market that have been removed from imports going through vehicle compliancing, where the importer/seller does not want to have to get a low volume cert for the vehicle, as it’s easier and normally cheaper to replace the coilovers with standard shocks and springs, and sell the coilovers. These kits may not be available locally, which can make parts or servicing hard to find — so it pays to do a bit of research on unknown brands before purchasing.

Just about every coilover can be rebuilt, however there are some unknown brands out there, where the cost to rebuild them will make them dearer than brand-new locally available products. The cost to rebuild a shock can vary quite dramatically depending on what’s wrong with it and whether the internal componentry is off-the-shelf locally, or has to be custom-made.

Most of the kits will have been cleaned well, so spotting any signs of leaking will be hard or impossible. Over the years I have found sets that looked good, but started leaking within a few days, weeks, or months. Some of the second-hand kits available may have been sitting around for extended periods and seals may have degraded. Be wary of freshly painted bits that don’t come with a receipt from a reputable repairer, as the paint could be masking hidden problems.

There are also some new and second-hand kits available in New Zealand that are made from inferior materials and/or inferior manufacturing processes — most of these kits will not pass low volume certs. But with that being said there are definitely some bargains out there, and some really cool hard-to-find relics that are actually worth spending some hard-earned cash on repairing so you can reap the benefits of finely tuned, well made adjustable suspension.

If you have the time do the research, ask around, make sure the kit you are buying will be legal, and ensure that there are people out there that can service them at a reasonable cost. To get the best rest results from your intended purchase, make sure you get your vehicle set up by someone who knows what they are doing, there’s a lot more to it than just setting heights and a quick wheel alignment. Also, there have been recent law changes in New Zealand surrounding how much camber you can legally run … but that is a whole other topic in itself. 

Here are a few simple things to check for, to help you score a good set. Starting at the top of the coilover, check for the following:

Top strut mount

• Play in spherical bearing or seized bearing; this can be an expensive repair job on some brands
• Cracks or deformation in top plate
• Broken studs

Seal assembly

• Play where shock shaft meets seal. This the most common reason for WOF/cert failure, and will require a rebuild of the shock
• Visibly damaged seal
• Loose seal assembly
• Signs of tool damage from incorrect disassembly
• Leaking (if you can, compress and extend the shock, and look for oil seeping from the seal)

Shock shaft

•    Make sure there is a bump stop
•    Shaft damage comes in many styles. Look for rust, pitting, scratches, gouges, tool damage and bends. They are all bad, and all of them will destroy seals

Shock body

• Check all threads thoroughly, as rust and damage are common
• Spring seats and lock rings can also be expensive, as odd-sized threads or seizing can mean you have to get new ones custom-made

In general, rust, ugly welds, accident damage, and play in any bearings or bushes can all be signs of abuse, and may mean a cert or warrant failure at best. Remember, the items you are about to purchase are the main components that keep your tyres firmly on the road. Failure of almost any part of the coilover could mean a crash.