A TALE OF TWO SHAFTS

Our own 986 Boxster was in urgent need of replacement drive-shafts, but with only one readily available, and a used 987 Cayman component going begging, it was time to think laterally and try an imaginative modification. Story and photographs by Chris Horton

If you are a purist, with an unshakeable belief that your Porsche should be fitted with only brand-new, original-equipment spare parts, look away now.

If, on the other hand, you are a 986or a 996-owning pragmatist, with a limited budget, a yearning for the days when we all had to make do and mend, and are in possession of some basic fabricating and mechanical skills, then this is a story that should be right up your street. (And some of the basic principles apply to both 987and 997-model cars, too.)

Project Boxster ‘S’, bought just before lockdown, and then understandably idle until the beginning of August, clearly needed urgent attention in the drivetrain department. It was virtually impossible to let the clutch out smoothly and set the car rolling without generating some horrendous clonks and bangs, particularly when changing direction of travel from forward to reverse, or vice versa, and a quick exploration beneath the vehicle showed why. (To be honest, the problem wasn’t something we had fully registered during our somewhat cursory prepurchase inspection, but even if we had we would still have bought the car.) The left-hand drive shaft had a large amount of rotational movement within the outer constant-velocity joint, and an equally sobering degree of up-and-down play. The right-hand shaft was almost as bad, albeit without quite as much vertical and lateral slack. (And let the record show not only that the car had passed an MOT test just a few weeks before we bought it, but also that in 2009, with the gearbox out for replacement of the dualmass flywheel, it had been fitted with four new Cv-joint covers, which although now visibly perished, had not yet allowed the grease inside to escape.)

Simple. Or so you would like to think. Remove both shafts, fit two after-market CV joints – as you might for many other cars of the type and period – and the job’s done. But it’s like the Wild West out there, with prices ranging from suspiciously low to terrifyingly high – one well-known parts supplier’s website was showing a genuine Porsche shaft at nearly £850, or a fifth of what we paid for the entire car – and not least the problem that the outer joints cannot realistically be taken to pieces and serviced. (You fit a new rubber cover, where appropriate, by stripping down the inner joint, and sliding it on from that end.)

But then we struck lucky. Lancashirebased 9-Apart had in its ebay shop a used but apparently very good complete shaft for a (manual-transmission) car of exactly this type and vintage (Tiptronic shafts are somewhat shorter, due to the additional width of the automatic transmission), and at only £150 including shipping it didn’t take us long to decide to go for it. That, we thought, would do perfectly for the left-hand shaft – by far the worst of the two – and we could in this way buy ourselves some time and try to find a similarly good replacement for the right-hand side.

Cue Darren Gardiner, technician at Maundrell & Co in Oxfordshire. He is

already the star of several of these howto stories – and in the context of this one very much the man of the match. He had recently replaced a drive shaft on a 987 Cayman ‘S’ – not because of wear in the outer CV joint, but because its grease had been oozing out from the crimpedover seam between the two parts of the metal cover. The old shaft was effectively scrap, and would need the ABS ring from our car’s shaft, but he was confident it could be made to work. (The 987-model Cayman shaft also has a larger diameter than the 986 Boxster part, but logic suggested that would have little or no bearing on the outcome, and thus far so it has proved.) More on this in a moment.

Meanwhile, I had myself successfully installed that ‘new’ left-hand shaft. The original plan was for me to drive the car to Darren’s place for him to do the work while I took the pictures, but on the designated day I had travelled barely a mile before I chickened out. There was so much noise and vibration from the left rear corner of the car, even on a light throttle, that I had grave doubts the joint would last the distance. Back at base, then, and with phoned assistance from Darren, and also from Rob Nugent at BS Motorsport, I got the job done in just a few hours. Not too shabby a performance with the car ‘on the floor’ – although unfortunately I wasn’t able to take any worthwhile photographs.

It was relatively straightforward – if nowhere near as easy as on my E28 5-series BMW, which I had tackled a few weeks earlier. On that car you undo the

Best way to access screws securing inner end of each drive shaft to the transmission (main photo) is to reach in with a series of socket extensions with an 8mm hex key on the far end. Crucially, that key must be a snug fit in each screw to avoid rounding out the recess, so first clean away the dirt and then tap it in with a hammer. Photo top right shows fundamental difference between 986 Boxster shaft and 987 Cayman. Note latter’s lack of ABS ring, and also its tapered shape. Photo above shows 987 shaft (right) adapted to accept ABS ring from 986

First photo in this group clearly illustrates the ‘problem’. ABS ring from parallel-sided 986 CV joint (top) needs to be removed without damage, and then secured, in exactly the right place, to tapering 987 unit. Note also the differences in the two splined areas – although we had already concluded, correctly, that these would be of no significance. The joint at the inner end of the 987 shaft (top row, middle) is again slightly different to the 986’s, and the 987 shaft itself is a bit thicker, but neither factor appears to be detrimental to the fit or performance. First attempt to expand and remove ABS ring was using gentle heat from a hot-air gun, but it quickly became obvious that more drastic measures would be needed. Darren Gardiner made cutting through the ring and levering it off the old CV joint look easy, but it took patience, skill and not least a rock-steady hand

With the cut ends of the ABS ring reunited, Darren next cleaned the paint off the 987’s CV joint, and added four tiny blobs of weld to serve as mounting points, trimming them back, a little at a time with the anglegrinder, until they were just the right size. Note, though, that the ring must be positioned so that what will be its outer edge stands a few millimetres proud of the end of the joint. Accuracy is obviously essential, but by the same token the way in which the ring generates a pulse in the hub-mounted ABS sensor does allow for some degree of leeway