Parts for your 2018 Toyota Mark x-Bump stops

2018 Toyota Mark X bump-stops: what they do and when to replace them

Yes, the 2018 Toyota Mark X uses bump-stops (also called jounce bumpers) on both axles. This is shown in Toyota’s service literature for the GRX130/GRX135 series—Front/Rear Shock Absorber with Coil Spring procedures depict a spring bumper integrated with the dust boot—and in the Toyota Electronic Parts Catalog, which lists “Bumper, Front Spring” and “Bumper, Rear Spring” for the model. Major damper manufacturers’ catalogues for the Mark X likewise specify jounce bumper/dust boot kits, confirming fitment.

On the Mark X, bump-stops act as the last line of defence when the suspension compresses hard—think big potholes, speed humps, heavy loads, or spirited driving. Made from micro-cellular polyurethane or rubber, they cushion the final part of the stroke to prevent metal-to-metal bottoming, protecting shocks, top mounts, control arms and even body structure. Because they’re progressive, they also work like a secondary spring, helping the sedan stay composed when loaded up or cornering on coarse-chip roads common around Australia and New Zealand.

They’re small parts that do a big job, so smart servicing includes giving them a look whenever the shocks are inspected or replaced. If a bump-stop is cracked, crumbling, permanently compressed, oil-soaked from a leaking damper, or missing its mating dust boot, it’s time to swap it. Replacing in axle pairs keeps handling even left-to-right. It’s also good practice to install fresh dust boots at the same time—UV, heat and grit are tough on these components, especially near the coast.

Typical inspection intervals are every 40,000–60,000 km, or sooner if the Mark X regularly sees rough rural roads. Tell-tales of tired bump-stops include a hard “thud” on sharp hits, harsher ride at full compression, and accelerated wear of top mounts. If the front assemblies are removed, always compress the springs with a quality compressor, torque fasteners with the suspension at normal ride height, and book an alignment afterwards.

Considering lowering springs or coilovers? Use the kit’s specified shorter or re-calibrated bump-stops, or OE-equivalent items matched to the new travel. Avoid trimming factory stops unless the manufacturer instructs it—maintaining correct engagement height is key to preserving both ride and grip.

Popular questions about 2018 Toyota Mark X bump-stops

How long do the bump-stops typically last?

On a well-kept Mark X, bump-stops often last 8–10 years or 120,000–160,000 kilometres. Climate, load carrying, and road quality matter, coastal environments and corrugated roads can age them faster. Inspect them whenever shocks are serviced to avoid surprises.

Can worn bump-stops damage other suspension parts?

They can. If the suspension bottoms out without proper cushioning, shock seals, top mounts and even tyres can cop extra stress. You might notice a sharp knock on big hits, reduced control over repeated bumps, and faster wear of related bushes and mounts.

Do they need changing when fitting lowering springs?

Usually, yes. Lowering reduces available travel, so a matched, shorter or re-rated bump-stop helps maintain progressive support. Follow the spring or coilover maker’s guidance, check clearances at full compression, and finish with a wheel alignment.