Hot on the heals of our M3 Evo engine swap success, Ben, Robin and I decided to look for another challenge before the festive holidays were over. No need (nor time!) for anything as involved as an engine removal, but a challenge nevertheless. I’d been complaining about the M5’s clutch since I got it as it slips when upshifting under load. Over dinner on Friday a joke suggestion of trying to get the whole job, including sourcing parts, completed before Sunday rapidly became a plan we were itching to execute.

Come Saturday morning, Ben had successfully gained an MOT pass for the M3 and I woke the tractor from its freezing sleep to once again become support vehicle for the day.

I headed off to Wembley to fetch a clutch kit from ECP. I’ve been there before, but I’ve forgotten what a rancid experience it is – both the journey and the final destination. The LUK clutch kit was reasonable value at £260, but there were times this morning when I was wondering how much more I’d have been willing to pay to get the part from a BMW garage! While I was doing this, Robin took the M5 to the workshop and got it up in the air.

I think it’s important at this juncture to express that while we had done some research into the extent of the work involved in doing this job, we weren’t fully prepared. From this photo, taken at 12:41 Saturday lunchtime, we weren’t out of the workshop until 02:30 Sunday morning. As you know, we’re not inexperienced with the spanners, so here’s how it happened. Firstly, Ben ran away to play football, the big pansy! Then we tried to get the exhaust down.

For those who don’t know, the E39 M5 zorst is a single piece all the way from the join with the headers to the four tips. Here’s the usual view from the back of the car.

(Yes, I know I’ve got rather worn non-matching rear tyres. I will get around to fixing this, but Rome wasn’t built in a day!)

The photo to the left was taken at 14:02 – an hour and a half after the car was lifted onto the axle stands. How on earth did this take us so long?! Well, it’s a big exhaust system – probably as big as Diane’s 106! We don’t know, but we’d guess it weighs in at over 100 kilos (the M5 exhaust, not Diane or her car!).

After some experimentation with pallet trucks we ended up using our two faithful trolley jacks and some wood to support the mass while we worked on it. One of the studs on the exhaust headers snapped so we took some time considering how the hell we’d put it back together (more on that later).

Unfastening the middle section and lamda sensor connectors was fairly easy. Releasing the rear certainly wasn’t! Somehow we got into a right old mess trying to work out which of the three bolts to remove from each of the six mounts, we struggled to clear the bumper, and the heat shields proved to be a royal pain in the arse!

With the exhaust finally out of the way there were more heatshields to remove, then the propshaft was detached from the rear of the gearbox.

We got this far by around 15:00 – fairly good progress in the hour since the exhaust was removed (we British workmen need our tea breaks!). However, removing the gearbox proved to be the second major headache. Unusually, undoing the bolts that hold the bell to the block was all quite straight forward. Initially separating the two was okay, but after that they really didn’t want to come apart.

It’s all quite dodgy yanking a heavy gearbox rearwards when it’s supported on a trolley jack and you can only guess that the jack is supporting it on its centre of gravity – just think of the consequences if you get that wrong – you’re under there with it after all. Eventually much prying with a long bar got the ‘box off, but it wasn’t the kind of force I’d usually be happy using. I’m disappointed to reveal that including the removal of the bolts, removal of the gearbox took an hour and three quarters since the propshaft was removed; the below was taken at 16:47:

Even once free, getting the gearbox down to ground past the exhaust headers was a real chore. Here’s a view of the old clutch:

New clutch ready to go on:

Building up the gearbox side of things:

All nicely lithium greased. Next comes a comparison of the outgoing and incoming friction plates. At first I thought the outgoing one didn’t look too worn, until I noticed that like the replacement it once had grooves that had all but disappeared. Fortunately it wasn’t worn down to the rivets and there was no perceivable wear on the dual mass flywheel.

We aligned the friction plate with the pressure plate using our lovely clutch alignment tool purchased just days ago to do the Evo.

All nicely bolted up to the flywheel:

Now, here’s when the day turned really sour. The above photo of the clutch on the flywheel was taken at 18:09. We then had two giant problems. We should have seen both of them coming really, because like any DIY mechanics we’re extremely familiar with the mantra “refitting is the reverse of removal”. Removing the exhaust and removing the gearbox were both horrible jobs – therefore the refitting of both was no better.

We could get the gearbox input shaft through the splines on the friction disk easily, but we couldn’t locate it in the flywheel for toffee. The default reaction was to assume that we’d failed to align the clutch correctly, so after half an hour of precarious gearbox wobbling on top of the trolley jack, we lowered it again past the exhaust headers, removed the clutch from the flywheel, realigned it and once again attempted reassembly. No better at all. Eventually I concluded that moving the gearbox’s input shaft within the flywheel bearing was the trouble we’d had removing the gearbox, so we needed to winch it back in. Robin agreed and constructed an ingenious winching mechanism from some spare nuts and bolts we had.

Eventually it was in, so I turned my attention to the snapped exhaust stud on the headers. I wanted to angle-grind it off and drill it out. Was there an angle grinder in the workshop? No. Had I left mine at home? Yes. Out came the junior hacksaw.

With about 1 inch of blade movement available, 15 minutes and a set of knuckles later I’d sawn the bolt off. Half an hour later I’d bluntened three drills bits, snapped another and got about half way through what has to be the toughest material known to man! Yet the damn thing had snapped on us earlier!

I can’t convey how unpleasant it is to have a really sore back and shoulders from a week of car mechanics, to be lying again on your back on metal drillings, loads of crap in your eyes (safety goggles still seem to permit dirt in!), drilling relentlessly wondering if you’ll ever get your exhaust on again. Eventually I got the bolt out – fortunately we had some replacements in our BMW stock bin. When I say eventually I mean it – from fitting the new clutch for the first time at just gone 6pm, by the time we’d got the gearbox back on and I’d drilled out the bolts to take the photos below, it was 23:14.

Those five hours were the darkest of our day by far. It wasn’t even plain sailing from that point on – finishing up from this stage took another 3 hours! This delay was partially due to us both being incredibly knackered, but also the rear mounts were a complete arsehole – maybe Robin will comment on this later as he fought, and eventually won, that battle.

By the end of this we were thoroughly knackered, but it’s a results based business and I’m delighted to say that the results are excellent. The new clutch is lovely and light, with a nice low bite point, and it grips brilliantly – the car is transformed! Makes it all worthwhile, despite the expressions on our faces at 2:15 in the morning!