How to Grease Polyurethane Bushings? | Silicone Grease Steps

Use silicone-based PTFE grease on polyurethane bushings. Apply to the inner sleeve, bushing ID, and every metal-to-poly contact surface.

For the full breakdown, see our best Grease for Polyurethane Bushings guide.

Squeaking suspension and premature bushing failure are almost always caused by the wrong grease — or no grease at all. Polyurethane bushings demand a specific lubricant, and petroleum-based options will crack them within months. The only proven choice is silicone-based synthetic waterproof grease with PTFE. Here is exactly what to use, where to apply it, and the step-by-step process that keeps bushings moving smoothly without damage.

What Type of Grease Works Best?

Silicone-based synthetic waterproof grease containing PTFE (polytetrafluoroethylene) is the recommended lubricant for polyurethane bushings. PTFE lowers friction between moving parts and is completely waterproof, keeping moisture out of the joint.

Several common lubricants should be avoided entirely. White lithium grease liquefies under heat and runs off, leaving the bushing dry. Petroleum-based greases are strictly prohibited — they chemically attack polyurethane, causing it to dry out, crack, and fail structurally. Penetrants like WD-40 and any spray-style lubricant are also unsuitable. Never mix different grease types on the same bushing.

For a hands-on comparison of the best products available, see our tested roundup of the top greases for polyurethane bushings.

Where to Apply the Grease

Three distinct surfaces on a polyurethane bushing setup need different treatment. Surface A is the inner diameter of the bushing where the metal sleeve rotates — this is the only moving surface and must be thoroughly greased for proper articulation. Surface B is the outer diameter where the poly contacts the control arm metal; this acts as assembly grease that ensures proper seating and prevents water ingress and surface rust. Surface C is the inside of the metal tube and the through bolt — this surface does not move, so use anti-seize compound here instead of grease to prevent seizing and corrosion.

A reliable rule: apply silicone PTFE grease to every metal surface that contacts polyurethane, including knurling, bracket ends, end washers, and the bushing hats. This prevents squeaks and eases final assembly.

Step-by-Step Greasing Procedure

Start with a dry pre-install: seat the bushings into the control arm pivots using a mallet. This initial fit lets you verify alignment before adding grease. Then grease the inner diameter of each bushing generously, making sure all internal grooves are completely filled. Prepare the metal inner sleeves by coating their outer diameter with silicone PTFE grease, then install them into the bushings using a mallet, arbor press, or smooth-jawed vise.

Use excess grease on the bushing hats — the outer contact surfaces where the poly meets the plated end washers or the control arm pocket wall. This prevents squeaking during articulation and makes final assembly cleaner.

If your bushings include a Zerk grease fitting, clean the top of the threaded hole so the threads catch properly. Tighten the Zerk until snug, then rotate it to a position that gives your grease gun clear access. Before anything else, verify that a small gap exists between the bushing halves aligned with the threaded hole — if the gap is too tight or poly covers the hole, grease cannot be injected and the fitting is useless.

The single most critical step: loosen the bolt holding the bushing halves together before pumping grease. This opens space for the grease to expand. Pumping with the bolt tight traps internal pressure that mushrooms the bushing outward, ruining it instantly. With the bolt loosened, pump grease into the Zerk until excess bleeds out between the bushing hat and the end washer — that visible bleed confirms the joint is full. If the bushing deforms at any point, stop immediately and push the ball on the Zerk fitting with a pick to release pressure.

FAQs

Can I use WD-40 on polyurethane bushings?

No. WD-40 is a penetrant and solvent, not a lubricant for polyurethane. It washes away existing grease and dries out the polyurethane, causing cracking and premature failure. Use only silicone-based PTFE grease.

How often should I grease polyurethane bushings?

Can I use lithium grease on polyurethane bushings?

Standard white lithium grease is not recommended. It turns to liquid when hot and runs off, leaving the bushing dry. Stick with silicone-based PTFE grease for reliable long-term lubrication.