In my previous post, I mentioned that I wouldn’t be doing any more work on the E39 until after Easter. I really shouldn’t say things like that, because yesterday I found myself underneath the car again.
Very soon after I bought the car, I became aware that the centre support bearing on the propshaft was on its way out. The initial clue was an occasional pinging (metal to metal) sound when I set off from a stop. It wasn’t something that needed to be done right at that point, though, as there were no other symptoms and everything was smooth. But in recent months, the pinging has gotten worse (it has been doing it all the way up through third gear), and I noticed increasing slack in the driveline and some minor vibration, particularly at higher speeds. A day off had been marked in my diary, so I decided it was time to rebuild the propshaft.
This post won’t be as detailed as the last, because I was on a schedule and didn’t take as many photos, but if you want to know the procedure I used, you can view it here (propshaft removal) and here (propshaft rebuild).
To access the propshaft, you need to drop the exhaust. You don’t need to fully remove it, but instead just disconnect the hangers and it will give you sufficient access (you’re guaranteed to break the bolts connecting the exhaust manifolds to the down pipe anyway). There is one by the back box, one just in front of the offside rear suspension, and then a bracket in the middle of the car. Once you’ve lowered that, with the gearbox in gear and the handbrake set, loosen the bolt holding the two parts of the propshaft together, and remove the fasteners connecting the gearbox flange to the propshaft and the rear CV joint to the differential. Then disconnect the centre support bearing, and pull the propshaft out.
You can see below the two main causes of the problems in the driveline. The flex disc is cracking, and the centre support bearing is very loose.
And the centre support bearing is worn. pic.twitter.com/DBjykuifzZ
— Jake Belder (@jakebeldercars) March 10, 2017
Once the propshaft is out, the rest of the job is simple. Mark the two sides of the prop shaft carefully, because it needs to go back together exactly as it came part so that it remains balanced. Then separate the two pieces, cut away the rubber bit around the centre support bearing, and use a puller to remove the bearing itself.
Then install the new bearing. You don’t need to press it on, as it will get pressed into place when you reconnect the two pieces of the propshaft.
You can see here that the centring bushing that fits over the shaft coming out of the gearbox is very worn as well.
Next, use brake cleaner to help remove the old grease from the CV joint, and repack it with new grease. At this point you’re ready to reinstall the propshaft. Back underneath the car, install the CV joint first, then set the front coupling in place. Loosely connect the centre support bearing bracket, and then you can tighten everything down at the front and back. The final step is to pre-load the centre support bearing about 5mm towards the front of the car.
I was pleasantly surprised at how straightforward this repair was. The only difficulty I encountered was removing the old centring bushing, which required a lot of work with a hammer and punch. It is also an inexpensive repair, the new parts – the centre support bearing, flex disc, centring bushing, and gasket for the CV joint – costing only about £60. That’s more than worth it for a quiet, slack-free driveline.