Features

How to fit polybushes - pictures

by: Auto Express team

27 Sep 2017

Go to: How to fit Polybushes: Disco 1 and 2, Defender, and Range Rover classic and P38A

Radius arms - All bolt heads, nuts and threads are wire brushed and soaked with easing fluid. These two hold the rear radius arm to the rear axle.
The rear radius arm’s chassis attachment bolt is treated similarly. This work is done first to allow the fluid to penetrate all threads.
Each of the radius arm to axle bolts are released using a 22 mm AF spanner on the bolt, and a 24 mm on the nut.
The rearmost bolt is drifted out using a small diameter steel punch (small enough to avoid distorting the end of the bolt and its thread).
The forward bolt attaching the radius arm to the axle won’t slide out because it contacts the anti-roll bar link bracket on the axle casing.
So Andy removes the bolt (22 & 24 mm AF again) holding the forward end of the radius arm to allow the arm to twist.
The radius arm can now be tilted inward slightly to allow that rear bolt to be extracted. The arm is then removed to the bench.
To see exactly what is being dealt with, the joints between the old bushes and the radius arms are wire brushed clean.
The axle end bushes are easily pushed out on the press, their nylon outer sleeves sliding easily through the bore of the radius arm.
The bush in the chassis end of the arm is bonded to an external steel sleeve which is an interference fit in the arm.
The steel sleeve of the chassis end bush is difficult to press out. The press pushes out just the rubber part, leaving the sleeve behind.
This hollow (51 mm O/D x 8 mm thick) mandrel has sheared the rubber from its outer sleeve as the press pushed it down.
The steel sleeve is removed by first cutting along its inner length with a hacksaw, keeping the blade level, and avoiding cutting into the arm.
The hammer and chisel is used to distort and finally cut the sleeve, until it folds inwards sufficiently to be driven out.
With the old bush sleeve removed. The arm’s bore is cleaned, any tool marks removed, then lubricated to help the new bush slide in.
The new Polybush is positioned on the radius arm, and a spacer (drilled to clear the bush’s inner steel tube) is placed over the bush.
The hydraulic press gently forces the bush into the arm, with alignment being checked all the way down, until the spacer contacts the arm.
The bush still needs to be further in, so the spacer is replaced by a socket of the correct O/D to push on the bush’s outer sleeve.
Each of the twin bushes at the axle end comprises a three piece set: the orange bush in two halves, and the centre steel tube.
The new axle end bushes can be easily pressed in by hand, after first cleaning and lubricating the bores in the radius arm.
With the arm turned over, the other halves of the bushes are pushed into place, and the central steel tube is pushed through.
Before refitting the arm, all bolts are treated with anti-seize grease, and this forward axle end bolt (see caption 5) is set in position.
Here, Kevin lifts the re-bushed radius arm into position and fits the restricted forward axle bolt first to secure the arm.
With that bolt pushed through, the radius arm can now be pivoted to align the rearmost axle bolt and the forward chassis bolt holes.
Finally, Andy fully tightens the bolts, torquing them to 230 Nm for this vehicle (check the torque value for other vehicle types).
Watts linkage to chassis: The bolt at the chassis end of the left hand link is removed (21 mm AF bolt head, 22 mm nut). Axle pivot linkage seen at right.
The inboard bolt at the differential mounting is withdrawn (19 mm bolt head, 21 mm nut) and the link removed onto the bench.
As with the radius arm to axle bushes, this Watts link bush also has a nylon outer sleeve, so it should come out easily.
Again, the arm is supported accurately, and a correctly sized mandrel or socket is used with the press to push the bush out.
With the old bushes removed from each link, it’s obvious that they are past their best, with one nylon outer sleeve breaking up.
The bore in the arm is cleaned with emery cloth and lubricated ready to accept the new Polybush and its steel centre tube.
This Polybush also has a tapered leading edge (right of picture) which must be entered into the bore first to make fitting easier.
These Watts linkage bushes can be fitted using the hydraulic press as pictured, or simply squeezed in using a vice.
With the bush fully in, the link is turned over to check the lip of that leading edge has expanded over the face of the arm.
The central steel tube can now be pushed into the new bush, squeezing with a vice and protective wood packing if needed.
The link is now refitted with greased bolts, and tightened to a torque of 140 Nm (chassis) and 155 Nm (axle end) for this vehicle.
Panhard rod: Here is the Panhard rod (arrowed) bolted between the chassis bracket (left of pic), and the bracket on the axle (right).
The Panhard is held at each end by a bolt and nut (24 mm AF). The nuts may be tight, and the bolts may need levering out.
Removal of the old bushes is a similar procedure as seen above, here pressing the bush out into a hollow tube underneath.
In this case, the steel centre tube is fitted before pressing the new bush into the housing – the procedure works either way.
The tapered leading edge is entered first as the bush is pressed in, and then checked to confirm it has spread out over the housing.
The Panhard rod is refitted to the vehicle with bolts well greased, and torqued to 230 Nm. That’s it, the D2 is rebushed.