6GT Rear Propshaft Flex Disc (Guibo) Replacement

[Matthew]

During my last MOT, the tester identified a couple of cracks in my rear propshaft flex disc. The cracks weren’t bad and according to BMW’s workshop manual, it did not need replacing, yet. However, I don’t want to get caught out at the next MOT so decided to change it anyway.

 

The parts you need are:

Flex disc

1 x 26117610061 – Flex Disc (£161)
3 x 26117527475 – Hex bolts M12 x 71 (£4.46 ea)
3 x 37106789678 – Hex nuts with flange M12 (£1.66 ea)
3 x 26118607971 – Torx screw M12 x 55 (E14) (£4.15 ea)

Or, as I bought:

1 x 171174 – Febi Bilstein - Flexible Coupling Kit for propshaft, with centering bush. This kit includes all the bolts and nuts listed above along with the Flex disc. The flexi-disc is identical to the genuine BMW part except it doesn’t have the BMW logo and both are made by SGF.

In June 2024 I paid £80 for the Febi Bilstein set on eBay so around £110 cheaper than genuine BMW parts.

 

Exhaust

1 x 18308623284 – Exhaust Clamp (£27.14)
1 x 18307525607 – Hex nut M8 (A2 stainless)
4 x 07119904024 – Hex nut M8-ZNS3 (Chrome free)

Torsion strut – rear

3 x 07147413212 – Hex Bolt M12 x 40 (£3.60 ea)

Under Tray fixings

07149213164 – 8mm Head, self tapping screw with washer (from vehicleclips.co.uk)

Heat shield fixings

07146949380 – Wide Collared Metal nut (from vehicleclips.co.uk)

 

The exhaust needs to come off to give access to the propshaft which is covered by heat shielding.

I started by jacking up the rear of the car with my 2-ton aluminium trolley jack using the jacking point on the flat of the rear diff with a piece of flat wood between the jack and the diff.

Once in the air, I used my 3 ton Halfords axle stands with custom jack pads that fit the shape of the axle stands and into the jack points on the car, to take the weight of the car.

Remove the plastic under tray between the rear bumper and the exhaust.

Disconnect the exhaust valve flap electrical connection.

 

 

Remove the rear right under tray which is held on by multiple 8mm head self-tapping screws.

This gives access to the Torsion Strut which needs to be removed.

 

Then remove the connecting member for the rear tunnel which is held in place by 8 x E10 Torx bolts and 2 x 8mm self-tapping screws. I replaced the Torx screws into the chassis for safe keeping.

Connecting plate:

 

 

Use a 13mm socket to loosen the nut on the exhaust clamp at the front of the exhaust clamping to the cat downpipe from the engine.

 

Loosen the 8mm nut (1) attaching the front of the exhaust pipe to the body.

 

Support the rear silencer with the trolley jack and loosen the 4 nuts, 2 on each of the silencer where it is attached to the chassis.

As only the rear of the car was raised, I put a 3” thick piece of polystyrene under the front of the exhaust to catch it once it came free.

Wiggling the silencer and pulling backwards at the same time, it parted from the downpipe quite easily.

Out came the exhaust.

 

Starting at the back of the tunnel, remove the heat shield which is held on by numerous 8mm self-tapping screws and the wide collared metal nuts (some cars may use the plastic nuts instead.

Once the heat shield is exposed, loosen the 2 bolts holding the propshaft centre-bearing in place – Don’t remove them just yet.

Note: Mark the position of the 3-hole flange on the diff, the flexi disc and the propshaft. This is important to maintain the propshaft relative balance – the propshaft must go back the same way.

Remove the Torx screws that attach the flex disc to the 3-hole flange using an E14 x ½” socket and a ½” breaker bar.

Using an 18mm spanner on the nuts, and an 18mm socket on the bolts, remove the bolts attaching the propshaft to the flex disc. I used my Dewalt DCF891 Impact Wrench.

 

Now remove the bolts holding the centre-mount.

With a pry bar between the propshaft and the flex disc, push the propshaft towards the front of the car.

This will give just enough room to remove the flex-disc.

 

 

 

Transfer the marking from the old flex-disc to the new which just makes it a bit easier to align the holes.

Install the propshaft centre bearing but don’t tighten the bolts yet.

Offer up the new flex-disc and make sure the 3-hole flange, flex-disc and propshaft are in line with the marks you made.

I offered up the flex-disc to the 3-hole flange and screwed in the new Torx screws.

Issue: Then I tried to attach the propshaft with the new M12 bolts and Nuts but the holes between the propshaft and flex disc no longer aligned - out by around 5mm. As the car was up in the air with no exhaust, I could not start the car to get it into neutral and wasn't going to fiddle with the external lever on the side of the tranmission to engage neutral. So I used the well-known manufacturer diagnostic software on my laptop to release the parking brake allowing me to turn the rear wheels slightly which of course turned the diff allowing me to insert the bolts.

Tighten the Centre Bearing bolts.

Reinstall the heat shield with the piece closest the transmission first – All screws – 3 Nm.

Note: If I were to do this again, I would try assemble the propshaft and flex-disc first before attaching to the diff 3 hole flange to make it easier to torque the bolts and nuts and perform the final 90-degree angle as this was very difficult once the 3-hole flange, flex-disc and propshaft were attached to each.

Reinstall the Exhaust:

There is a spot weld connecting the old clamp to the exhaust pipe. Using a small angle grinder I removed the weld and the old clamp. (The new clamp does not need to be welded on).

 

 

With help and by sliding the front of the exhaust on the polystyrene slab so as to not damage the pipe, we put the exhaust in its installation position but on the ground.
Put the new exhaust clamp in position.
I put the rear silencer back on the trolley jack and lay two folded trestle tables, one either side to catch the silencer if it fell off the jack.

 

My helper was guiding the exhaust using the trolley jack and I struggled to mate the exhaust to the flex coupling at the end of the downpipe as I was now working under the front of the car that was not raised. With perseverance the exhaust went into the downpipe and we wiggled it into place.

Replace the 8mm flange nut on the exhaust bracket to chassis mount (A2 stainless) – 19 Nm

With the trolley jack, push the rear silencer into position and tighten the 4 x 8mm flange nuts – 19 Nm.

Reconnect the exhaust flap electrical connection.

 

Reinstall the Rear right torsion strut – using the new bolts – Torque 100 Nm + 90 degrees.
Reinstall the right under tray using the new 8mm self-tapping screws (the old will probably be very rusty) – 3 Nm.
Reinstall the plastic undertray between bumper and silencer – 3 Nm.

After 5 hours of work and climbing in an out from under the car to get different tools and sockets, that is how I got it done.

 

Torque settings:

Flex disc to Diff 3-hole flange	Torx screws M12 x 55	55 Nm	90 degrees
Flex disc to propshaft	Hex Bolts & nuts M12 x 71	55 Nm	90 degrees
Propshaft Centre Bearing		19 Nm
Heat Shield	Metal nuts - wide collared	3 Nm
Exhaust mounting nuts	Flanged nuts - 8mm	19 Nm
Exhaust Clamp		26 Nm
Connecting support to body	Torx screws	20 Nm
Torsion Strut	Hex bolts M12 x 40	100 Nm	90 degrees
Underbody panelling screws	8mm head self-tapping screws	3 Nm

 

Edited July 1 by Matthew

[Sir Anthony Regents Park]

I just replaced the front Giubo (pronounced joo-bow, not gwee-bow!) on my 05 120d, 19 years and 178,000 miles old. It wasn't bad but I was replacing the prop centre bearing and it was a bit cracked although not as bad as yours. 

It just shows how much component quality has dropped in the last 10 or 20 years. 

[Andrew]

15 hours ago, Sir Anthony Regents Park said:

 

It just shows how much component quality has dropped in the last 10 or 20 years. 

This!

I've replaced stuff on my F10 at 50k miles that was lasting 70k miles on my E60.

[Sir Anthony Regents Park]

I've not replaced either the rear beam bushes or the giubo on my 1989 E32.

 

Both are still good so they were either replaced before 2003 and 204k, or they really are 35 years and 316,000 miles old. I suspect they have been renewed but that makes them 112,000 miles and 21 years old. 

 

The exhaust lasted until 2007 and the clutch a full 312,000.