Clunk, shackle and roll
Having spent the last couple of months faffing about with the front of my A40, I decided it was time to investigate a slight knock from the rear I could hear when passing over one of the many thousands of speed humps that litter the roads in my particular area of South London. Having first thought it was a stray tool/ spare part or even a small animal moving around in the boot, a short trip with the boot completely empty – the tools were kept in the passenger footwell as I’m not one to tempt fate – revealed the noise to be still present.
A quick detour to a road I know to have the ‘button’ pad-type humps (you know, the sort that appear in threes and leave areas of the road flat for cyclists), revealed that if I kept the nearside wheel on the level, and just went over the hump with the offside wheel then the knock would occur, but not if I kept the offside wheel on the flat.
Returning to base, I jacked the car up and whipped off the rear offside wheel to investigate the springs and associated hardware. For a while now I’ve been aware the springs will need to come off for a bit of a clean and a good greasing as they have developed a very light coating of surface rust, so felt this should be the first area of investigation, followed by a check of the U-bolts, which sit over the axle and secure the plates and in my case a polyurethane pad. Next was to see how the bushes that sit between the spring and the shackle were fairing, so with the body supported on axle stands and a jack under the spring, I undid the nuts securing the shackle, slid it out and lowered the jack to drop the spring.
The truth is there was no real need to drop the spring away as it was soon clear it was the rubber bush itself that had perished, leaving a lot of play on the inner sleeve which I presumed was the cause of the knocking.
As I pondered the matter, I tried to recall just why I never used a poly bush at the rear of the spring when I replaced them about three years ago, as poly bushes are always my default when replacing any rubber bushes. I have half an inkling that I used bushes from a Moggie Minor in the rear, but why not the poly ones? A quick check on the Moss Europe website confirmed these items are available, so I can’t really understand why I didn’t buy a set.
With the spring loose I took the opportunity to clean up the pads and plate before reassembling them, but not before having to tackle the joy of getting them back over the U-bolt. It may be termed a U-bolt, indicating the legs of the bolt are parallel, but I’ve yet to encounter one that is not a little more V-shaped, meaning the refitting of the pads and plates requires a good bit of effort and ingenuity.
Personally I prefer to fit the top plate, both pads and then the bottom plate with a good amount of thread visible to fit the nuts. Next, get the pads and plates into place before undoing the nuts and fitting the larger plate to the bottom. Doing it this way provides a fighting chance of getting the larger plate back onto the U-bolt. Time to go online and order some new bushes I feel...
I tried to recall just why I never used a poly bush at the rear of the spring when I replaced them