POWERFLEX FRONT LOWER TRACK CONTROL ARM INNER BUSHES PFF27-702

[iRS]

I've swapped out my Powerflex front bushes, so these are available to anyone wanting to upgrade for a bargain price.

https://www.ebay.co.uk/itm/192853891416

[J44EAG]

I have these fitted to my XJR 350, Roger. Indeed they were on the car when you drove it at Fareham a couple of years ago. I found the fitment useful as it stopped apparent scuttle shake when crossing motorway tarmac expansion gaps. I also found that the car became rather more directionally stable and more "pointy". They suit the car fine for me.

A word of warning regarding the fitting of these bushes on the lower rear control arm. Once the OE bushes have been removed and registers cleared of corrosion and burrs, the Power flex ones are just pushed in by hand then given a bonk with a hammer just to seat them. They are then given a couple of finger fulls of copper grease before the compression tubes are again pushed in by hand. I offer the following fitment advice.

Before fitting the compression tube within the bush, check that the tube slides easily into the cross member without resistance.Note that sometimes the metalwork of the cross member will have closed up due to the compression action of previously tightening the cam bolt and nut. On cars that have never previously been fitted with new bushes. Expect the old bolts to have issues as regards security location. The bolts were revised with much better design arrangements which offer improved location and security. So junk the old bolts and get the revised new items! These cam bolts are readily available from Jaguar. Moog also offer revised aftermarket bolt kits which are obtainable from the States. I fitted a set to my early V8 S-type before Jaguar came out with the similar revision idea.

The second issue which I took up with Powerflex was that the two part bushes were about 2mm too long which made them jam up when pushed into the cross member. The fitted bushes once within the drop arm should allow the compression tube to protrude from each end of the complete fitted bush by about 1mm at each end. I suggested that Powerflex alter the design slightly in the light of my experience. One hopes that they took the feed back advice on bush production following my findings. I got around the issue by machining off a tad of bush at either end to allow the compression tube to protrude. That stopped the bushes binding on the cross member when the cam nuts and bolts were tightened.

Once the drop arm has been fitted and tightened, it is imperative that you work the drop arm up and down to ensure full and free movement. It is not necessary with the Powerflex bushes to torque up with the car weight on the suspension. Torqueing is best achieved with the car still on axles stands and support blocks. The position of the drop arm is unimportant. Bolt torque loads though are high and if working on hands and knees rather than on a proper garage lift ramp, the tightening is best done by two people. One holds the cam bolt perfectly still whilst the other tightens the nut. A sizable torque wrench is needed to achieve manufacturers torque settings. If working on axle stands and blocks, ENSURE THE CAR IS SUPPORTED ADEQUATELY TO ALLOW HIGH TORQUE TO BE PULLED WHEN NUT TIGHTENING. Under such loads it would be all to easy to pull a car off axle stands alone.

Note that with Powerflex bushes, they operate differently to standard OE items. The PF range allows the bush to revolve around the compression tube. Hence the need to fill the bush void with copper grease.

OE bushes have the compression tube bonded to the rubber internals which in turn are bonded to the outer case. The OE bush relies of torsional "wind up" within the bush as the suspension moves in up and down motion. Eventually OE bushes will break up and require replacement. The concept is totally different from the workings of the Powerflex units.

Personally, I like these PF poly-urethane bushes as they are well neigh indestructible and offer a very long lifespan in service. They come with a lifetime warranty which operates whilst the car is still in the fitting owners hands. If a bush were to fail, you would let Powerflex know and a replacement would be in the post within 48hrs. PF hold only a small stock of bushes and each one is then custom made overnight once an order is received and paid for. I`ve found their service to be excellent and the product range reliable and only a little more expensive than OE parts.

Mike K

[iRS]

Now sold for a bargain price via eBay