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How Suspension makes a difference to your Classics

Bush Whacked Published: 27th May 2011 - 0 Comments - Be the first, contribute now!

How Suspension makes a difference to your Classics
How Suspension makes a difference to your Classics
How Suspension makes a difference to your Classics
How Suspension makes a difference to your Classics Suspension arms will have to be removed
How Suspension makes a difference to your Classics Bushes come with installation lubricant
How Suspension makes a difference to your Classics Ensure mounting eye fits properly
How Suspension makes a difference to your Classics Pullers (such as this one) can be hired
How Suspension makes a difference to your Classics
How Suspension makes a difference to your Classics Impact wrench makes life a lot easier
How Suspension makes a difference to your Classics
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Can’t seem to make your classic handle like new? Could be that you’ve overlooked its innocent looking suspension bushes…Replace them now with modern poly alternatives

If there’s one thing that differentiates a good classic from an old banger it’s the way it drives, and this is never more highlighted than by a car’s handling. A motor can look factory fresh inside and out, and a rebuilt engine will make it perform like new, but unless the suspension is brought up to standard it will always be an old clunker to drive. It’s amazing how many enthusiasts overlook the suspension when rebuilding their classics. Sure, they may replace the dampers if they look past it or are leaking and even the springs, but that will have minimal effect if you don’t renew the unsung hero of any running chassis – the mounting bushes. Many people think that if they look okay and the car passes the annual MOT, all is well. But these bushes do gradually wear out and replacing them will instantly give any classic that ‘as new’ feeling we all long for. We were amazed in the Classic Cars For Sale office recently when we read in a club mag about an enthusiast who was restoring his car. Even though it was almost 40 years old and hadn’t turned a wheel in over a quarter of a century, the car’s owner checked the suspension bushes and declared them okay… Is he serious?

What’s their purpose?

Insulating bushes (sometimes referred to as compliance or void bushes) are fitted to a car’s steeringand suspension assemblies to provide a degree of ‘padding’ between various linkages and joints for comfort and quietness. Without them, refinement would be minimal but the chassis would prove very positive and sharp – rather like a racing car which canlargely do away with these rubber bushes for something much more unyielding and positive. Originally these bushes are made from rubber and as a result they perish and soften over time, leading to sloppier handling. Trouble is, like aging shock absorbers, the process is so gradual that a car’s owner hardly detects the deterioration taking place. Also, many home mechanics give them scant thought and overlook replacing them until their condition warrants an MOT failure. But according to one classic specialist we spoke to, in his experienceMOT examiners will only fail the car if they see a bush virtually falling out of its housing…

The racer’s edge…

Competition cars have long used uprated suspension bushes to improve handling and feel. Chief areas for upgrading are the antiroll bars to aid steering precision and rear axle location bushes to help combat rear axle steer (particularly prevalent on cars fitted with trailing arms and coil springs). This is achieved by fitting either roch hard standard bushes or by rose-jointing; both unsuited for road use due to their lack of refinement and increased noise. But since the 1980s a new medium has been available: polyurethane. Born out of motorsport, this man-made material offers many advantages over conventional off-the-shelf rubber replacements. It is tougher than rubber and more resilient to oil contamination and perishing, so it lasts longer as well as performs better but without hurting a car’s inherent NVH: noise, vibration and harshness qualities. There are two leading companies who deal in ‘poly’ suspension bushes, Poly Bush and Superflex, who between them have the classic market covered, (though Deflex have introduced an extensive range for Fords and more modern Vauxhalls). Superflex, for example, markets a range of bushes for road and track use, coming in four different firmness grades: 70, 80 90 and 95 ‘Shore’. Superflex claims that unlike conventional rubber bushes, its poly design acts more like a proper bearing for added precision while the impregnated lubricant instilled during manufacture means that they can absorb friction better throughout their working life, which can be six times the span of normal rubber bushes. Many experts give the life expectancy of rubber bushes a mere three years or so, meaning that for many owners, replacing them with a ‘poly bush’ would be a one-off job. Poly Bush offers two types of bush hardness: ‘Touring’ for road use and red ‘Performance’ for competition or extreme road use. Most experts reckon that competition quality bushes are too unyielding for most tastes and besides, for the purist, sportingbushes are usually flamboyantly coloured which will affect concours judging. Normal classic style bushes are usually a very dark blue/purple that virtually passes as black. Whatever the car or colour, you will enjoy the rewards at the first corner!

Planting new bushes

We recently fitted a complete set of rear suspension bushes to our project Vauxhall Viva HB using Superflex products. This car, along with later Ford Cortinas, Vauxhall Victors and Hillman Avengers (as well as most moderns now) was equipped with a simple but effective live axle rear suspension using four-link trailing arms for its location. Fine when new, but the bushes were prone to wear quickly and spoiled the handling as a result. As we are restoring this car and have already fitted new dampers, it seemed lunacy to neglect these items even if the total bill came toalmost £100 for the eight replacement bushes. Fitting them was fairly straightforward and took around a working day. We’ve heard stories that polystyle bushes are harder to install as they provided less ‘give’ than rubber, but we found no difficulty. The biggest hassle is raising and supporting the car properly to remove the suspension arms, plus ideally you need a proper bearing puller. These are available from all good tool shops or can be hired (try your local owners club, too). One additional tool we used was a professional impact wrench, which we must confess was heaven sent to ‘power the puller’.

Without its added muscle we reckon that we’d still be there now using a conventional spanner or socket set…Again these heavy-duty tools can easily be hired for a reasonable enough sum. Our fitting strip sequence shows how the job is done: a couple of the old bushes looked pretty shot, but we reckon that some have certainly been replaced during the car’s 35 year life – probably more than once we wager too… The results made the job well worthwhile. Before, the car’s rear felt a bit queasy at speed. Now it feels nice and taut, although it has to be remembered that new dampers were also fitted at the same time. Still, fitting uprated suspension bushes was a popular Viva mod in its time and we can see why. We only wish that we’d replaced the steering front control rod bushes (top left), which look well crazed with age. At £18 each it’s the next job on our list, although certain bushes cost just a couple of quid so they are by no means exorbitantly priced when compared to their original equipment rubber alternatives. Void bushes are the most common replacements, but there are others to contemplate too: anti-roll bars, damper mounting points, crossmember ‘top hats’, leaf spring eyes and so on.

Speak to a specialist

Before you go poly-bushing, speak to a marque specialist as not everybody is a fan of such advancements, reckoning that it spoils the authentic feel and can make the ride harsher (as in the case of MGs for example). However, if you are uprating the chassis to make the handling more suited to today’s tastes, then they are certainly worth fitting as part of the upgrade. So if you are unsure speak to an owners’ club or a good specialist for advice.



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