HOW TO: 964 SUSPENSION UPGRADES

Barn find 964 Targa gets a suspension makeover with Bilstein dampers and Eibach’s new range of classic roll bars and springs

There can be little doubt that the most appealing and interesting aspect of any 911 project – the sexiest, if you will – has to be that iconic flat-six engine. Ultimately no less important, though, is the suspension – and the brakes, of course. Follow us, then, as with the help of renowned specialist Center Gravity we embark upon the ambitious chassis overhaul and upgrade of a barn-find 964 Targa. This month: assessing the scale of the problems, and taking some vital measurements. Story and photographs by Chris Horton

If a job is worth doing, says the old aphorism, then it is worth doing properly. I couldn’t agree more. That’s why it was such a pleasure to watch Center Gravity’s Chris Franklin and Peter Leason hard at work, carrying out a full suspension overhaul and set-up on reader Chris Howell’s 964 Targa, centred around the increasingly sought-after combination of Bilstein dampers and Eibach coil springs, and the same latter company’s recently developed anti-roll bars. Quick and efficient the pair may have been, but that was a speed born of knowledge, experience and, above all, natural competence.

The scale of the task was such that it occupied a non-stop working day – and several hours more, as I alluded to in The usual suspects in the June edition of the magazine – so it is probably no surprise that I came away from Center Gravity’s Warwickshire premises with several hundred close-up photographs. And because I, too, like to do things properly (and since on this occasion I have only three pages available to me, instead of the usual four), what you see here is just the first of what will in time be several instalments to the story.

As ever for these how-to features, we cannot hope to duplicate the level of terse but comprehensive information that you will find in the official Porsche workshop manual (written for trained technicians), or instantly to pass on the skills that come from years of hands-on experience. But what we can do is take the time and the trouble – and the column inches – to show in as much detail as possible what is involved in a project such as this, out there in the all too real world of rusted fixings, broken brackets and possibly bent chassis legs, and let you

decide how best to proceed. To have a go yourself, perhaps over the course of a rather more leisurely timescale, or to pass the task to a professional – but in which case with a far better understanding of what you are actually paying for.

The car was literally a ‘barn find’ for owner Chris Howell, and it must have been standing in said barn in rural Wales for some time – hence the extensive rodent nest that we found inside the central underfloor tunnel. Much of the hardware that would have to be dealt with was markedly corroded, although luckily a significant amount would by definition be replaced with brand-new components. There were signs that the car had led a hard life before its incarceration, too: worn-out bushes aplenty – most, if not all, to be replaced with the excellent Australian-made Superpro items; more on these in due course – and not least a possibility that one of the rear suspension’s trailing-arm mounts had been repaired, perhaps after some unscheduled interaction between the wheel and a kerb.

Shown here, then, are just the preliminary stages, with plenty more to follow in the months ahead: taking the ‘before’ measurements that would be vital in ultimately setting up the suspension geometry; the visual assessments required to determine what other parts might have to be replaced; and not least laying out those gorgeous new springs, dampers and antiroll bars to give us – and you – both a visual treat and a goal to work towards.

Bear in mind, too, that although nominally a runner, the car was still very much a work in progress. It was delivered to Center Gravity on a transporter – the brakes, like those of many a laid-up 964, had partially seized, making it predictably hard work to move around the workshop – and it would later be taken away in the same manner.

For Chris Franklin that was hardly the ideal scenario – unsurprisingly, he needs to drive customers’ cars both before and after working on them if he is to deliver optimum results – but he is pragmatic enough to know that sometimes you just have to go with the flow; to deal with whatever circumstances the job happens to throw at you. In any case, I have no doubt that, in the fullness of time, Chris Howell will return to Atherstone for further minor adjustments to be made, once he has put his beloved Targa back on the road.

Anyway, lots to get through, so I shall let the photos and captions begin to tell their fascinating story. Enjoy! I certainly did. PW

Replacing 964 Cabrio dampers and springs – and much else – is something for future issues; here the emphasis is on an initial assessment of the barn-find car, shown above as it arrived at Center Gravity premises in Warwickshire (centregravity.co.uk). Thanks to proprietor Chris Franklin (also above) and Peter Leason (left)

The first test any car undergoes at Center Gravity is on this damper assessment rig (top row, left and middle); in very simple terms a device that oscillates the two wheels on the same axle up and down, and measures their response times. This car’s, needless to say, were past their best. Work is carried out on a scissor-type lift which doubles as the geometry-setting platform (far right). The 964 was a bit of a struggle to position thanks to the common problem – in cars that have stood, like this one – of seized brakes. That would have to be dealt with later. Tyres were legal in respect of tread depth, but in age terms well beyond their use-by date; four-digit code (2705) shows they were made in 2005. Needless to say, any car to be set up MUST have correct sizes, front and back – and the correct pressures, too. If not, any adjustments made essentially meaningless. Crucially, all data is collected and carefully noted

In most Porsches – and the 964 is no exception – before any assessment or adjustment the steering must be centred by removing this plug (top row, far left) and inserting a special screw, whose pointed end engages in a recess in the internal rack. Car requires front-end ballasting, too, here with a bag filled with sand. Having very accurately noted initial ride heights, Chris and Peter hook the car up to their geo machine, which unsurprisingly comes up with plenty of red (ie wrong) settings. Obviously there is no point making any corrections at this stage, before the renewal of springs, dampers, anti-roll bars and not least suspension bushes; it simply gives a datum point, potentially also highlighting any more serious hidden problems. Thereafter it’s inspection, inspection and more inspection. Are the steering-rack bellows full of oil? (No.) Are the anti-roll-bar rubbers worn out? (Yes!) Will the fuel lines need replacing before the car goes back on the road? Will the front wishbone bushes and not least the bumpstop mouldings on the struts need to be renewed. Yes and yes!

Comparison of the two trailing-arm mounts suggests that the one on the left side of the car (middle picture, upper row) might have been repaired after some sort of (minor?) accident. Front wheelarches show evidence of tyres rubbing on metalwork on full steering lock, but that has a relatively easy solution. Red paint on the end of one drive shaft suggests it has never been disturbed. Similar marking on a couple of the wheel studs – rarely seen these days, especially on cars of this age – indicates the heaviest area of the hub, such that the wheel can be fitted with the tyre valve directly opposite