Fitting Guide for Polyurethane Bushes

This guide describes in general terms how to fit SuperPro polyurethane bushes in control arms (wishbones, radius arms, A-arms). It does not replace the vehicle-specific instructions supplied with the kit: if they differ, always follow the kit instructions. Fitting should be carried out by a qualified workshop.

Before you start: two types – and where grease goes

• Bush with metal shell: the polyurethane is bonded to a CNC-machined steel or aluminium shell. The shell is pressed dry into the arm, like an original shell bush. Everything where polyurethane meets metal is lubricated: the bore of the bush, the outside of the steel crush tube, and spacer or cone washers.
• Solid polyurethane bush: no shell, often with a flange on both sides for retention. The polyurethane also touches the arm itself, so the outside of the bush and the seat in the arm are greased as well.

Basic rule: wherever polyurethane touches metal, apply the supplied SuperPro silicone grease – generously. This is what prevents noise, vibration and a harsh ride. Use only SuperPro grease: it is silicone-based, does not dry out and is matched to the material.

Tools and preparation

• Hoist or axle stands, remove wheels; secure the vehicle against rolling.
• Hydraulic press with suitable press tools (avoid hammering).
• Wheel alignment before the job; note the values, especially caster.
• For eccentric bushes: photograph the orientation of the original bush before removal.

Step by step

1. Remove the control arm. Loosen related parts if needed (strut mount, anti-roll bar link). Undo bolts as per manufacturer; note bolt direction.
2. Press out the old bushes. Support the arm in the press and push the original bush (with shell) out completely. Clean the seat with brake cleaner, remove burrs and check for cracks or distortion.
3. Press in the new bush. Start straight and press in slowly until the shell (or flange) protrudes evenly on both sides. Grease the outside of solid bushes first.
4. Grease bore and tube. Coat the polyurethane bore, the outside of the steel tube and all faces of the spacer or cone washers generously with SuperPro grease.
5. Insert the tube. Push the steel tube into the bush. The polyurethane is intentionally sized tighter than the tube, so a hand press may be needed.
6. Fit the washers. Grease cone or spacer washers and push them on; the larger face points toward the bush.
7. Refit the arm. Fit all bolts finger-tight, lower the vehicle to ride height (or load the suspension) and only then tighten to the manufacturer’s torque. Over-tightening is a common cause of unwanted vibration.
8. Have the vehicle aligned and check the values.

Polyurethane bushes must always be fitted in pairs (left and right).

Eccentric bushes: setting caster and camber

With kits containing eccentric bushes (offset hole in the steel tube or bush), the position of the hole determines how the geometry changes. Orient them as shown in the kit instructions and check the result after fitting. Typical kit variants:

Practical examples: at the rear mount of a lower control arm, fitting the eccentric tube with the hole pointing towards the centre of the vehicle moves the ball joint forward relative to the strut mount – caster increases (in one example about 0.6° per offset tube). Kits for upper arms with camber correction change camber by a fixed amount per side (in one example 0.5°). The exact values are in the instructions of each kit.

Eccentric bushes do not adjust continuously but by a fixed amount. Background: glossary: caster and camber.

After fitting

• Wheel alignment and test drive; if there is noise, check all bolts and the amount of grease.
• Polyurethane bushes are maintenance-free – no re-greasing is required.

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