Flex-Disc (Guibo) DIY

[willscam]

Recently, there has been some discussion about the difficulty of changing out the guibo. This is my experience (and DIY) on the guibo. First of all, yes it can be removed (at least in an S54 roadster) without removing exhaust or anything else. There would be much better access with the exhaust removed. So, if you don't mind taking down the exhaust - that would be the recommended approach. Also the bolts are on TIGHT. Be prepared to use some force. Otherwise, I found no surprises.

Tools:
18mm open wrench and 18mm socket wrench.

Parts:
Flex-Disc (26112226527)
Six 18mm self-locking nuts (07129900047)
Molykote Longterm 2 grease

1) Elevate car for access to underside.

Guibo-tranny mount DIY 004.jpg
(There's the guibo)

2) Remove six 18mm bolts by counter-bracing the front 18mm nut with open wrench, while torqueing bolt with socket wrench (long handle would help). With the car in neutral and the emergency brake off, you'll be able to spin the driveshaft to get access to each of the bolts.

Guibo-tranny mount DIY 043.jpg
(counter-bracing with open wrench (left). This is actually the opposite of what you will do when tightening the bolt back on after replacing guibo - You'll want to torque from the metal flange side, where the open wrench is in this picture)

3) With bolts/nuts removed, push driveshaft back an inch or so and swing free from transmission. Work the guibo out.

Guibo-tranny mount DIY 050.jpg
(driveshaft swung free of transmission. Guibo removed. Grease the center sleave)

Guibo-tranny mount DIY 046.jpg
(old guibo - crack apparent)

Guibo-tranny mount DIY 048.jpg
(old screws - if in good shape, they can be reused. Also, there should be six )

[willscam]

Guibo-tranny mount DIY 036.jpg
(new guibo, 6 nuts - got two new bolts, just in case)

Guibo-tranny mount DIY 039.jpg
(note arrows that should point towards flange arms when installed)

Guibo-tranny mount DIY 044.jpg
(new guibo (left); old guibo (right)

4) Clean center sleave and apply Molykote grease.

5) Reinsert Guibo, align arrows with flange arms.

Guibo-tranny mount DIY 051.jpg
(guibo maneuvered back in - not aligned yet, the driveshaft should be rotated so that the flange arm lines up with the next bolt hole)

6) Torque nuts to 75 ft/lbs. Torque from metal flange arm side while counter-bracing from rubber guibo side.

[PbFut]

You were lucky the drive shaft slid on it's spline. Some will not side back far enough and require the center support to be removed which requires the exhaust to be removed.

[willscam]

You were lucky the drive shaft slid on it's spline. Some will not side back far enough and require the center support to be removed which requires the exhaust to be removed.

And I'm not the lucky type.

[sideslip]

What is the part number for the bolts?

What do you mean by torque from the metal flange side? You mean tranny or nut side?

[willscam]

What is the part number for the bolts?

What do you mean by torque from the metal flange side? You mean tranny or nut side?

The bolts are part #26112227195. My bolts were all inserted by the factory in the same direction, from the driveshaft side towards the transmission. The driveshaft and the transmission each have 3 flange arms (look at the pics, you'll get my drift). I inserted the bolts back in the way I found them. On 3 bolts I torqued on the driveshaft side (the flange arms) while counter bracing from the opposite (rubber side). On the other 3 bolts, I torqued from the transmission side (with the flange arms) while counter bracing on the rubber guibo. So, the bolts you torque will alternate from transmission side to driveshaft side depending on where the flange arm is. If the car is in neutral and the emergency brake is off, the drifeshaft will spin (I'll add that to the DIY). I hope this has made it more clear.

[willscam]

It's kind of odd. The way the guibo has arrows pointing towards the flange arms, you would expect the bolts to follow the directions of the arrows, alternating direction every other one, but there's no easy way to do this - short of dismantling the transmission housing. I wonder if the way the factory installed them, with all of them inserted in the same direction (and probably all torqued from the bolt side) is responsible for their premature failure.

[critterxl]

Thanks for posting the tutorial!

[Doctor M]

So I have this right, your last pic of the unmounted guibo shows it NOT lined up correctly, yes? When mounted it will need to be offset from the picture by one hole, so that the metal flanges (on either side) always get bolted to the rubber, and not to the matching metal flange on the other side.

Do I have this right? If I was to use the picture exactly I would have 3 bolts going from flange to flange, and then 3 bolts that were only sitting in rubber. I just want to make sure I have this sorted in my head before I take anything apart.

Great post -- many thanks!

[willscam]

So I have this right, your last pic of the unmounted guibo shows it NOT lined up correctly, yes? When mounted it will need to be offset from the picture by one hole, so that the metal flanges (on either side) always get bolted to the rubber, and not to the matching metal flange on the other side.

Do I have this right? If I was to use the picture exactly I would have 3 bolts going from flange to flange, and then 3 bolts that were only sitting in rubber. I just want to make sure I have this sorted in my head before I take anything apart.

Great post -- many thanks!

Yeah, sorry about that pic. I thought it might cause problems, that's why I put in the caption that it was not aligned yet. Should have aligned it, then shot the pic. You are correct. The flange arms do not line up to one another. One bolt per flange arm, either transmission-side flange or driveshaft-side flange. It's always a good idea to take a picture of the item you're working on before you start (especially serpentine belts), that way if you get confused you can refer back to the picture of it's original state. The second pic of the DIY shows the correct orientation; the open end wrench (left) is on the bolt head going through the transmission-side flange arm. The socket is on the nut on the guibo. Just below the socket is the driveshaft-side flange arm. Note: It doesn't matter how you take the guibo off, you can torque it off from the easiest side (driveshaft), because the used guibo is going in the trash.

[sideslip]

Great stuff here! Thanks for posting.

Is the grease anything special or is it a common product at auto stores?

[willscam]

Great stuff here! Thanks for posting.

Is the grease anything special or is it a common product at auto stores?

I used the closest thing that I could find, which was a lithium, molybdenum, graphite grease from Autozone.

[SoCalDan]

I have to replace my Guibo in the next few weeks. I noticed a crack in the rubber when it was in for an oil change. But 120K miles I need to replace the center support bearing as well (just to be safe and for preventative maintenance), which isn't such a simple DIY job. Bought everything from Turner Motorsport, and figure I'll let my trusted mechanic handle this job, since I don't have access to a good lift.

Great post...would like to see more of these.

[Vinci]

Glad to see that the job went well.

[rjcoston]

Thanks for the write-up and pictures.

[djb2]

Was that flex disk actually failing? Did the crack show broken fibers? The fibers are the important part -- the rubber just encapsulates the fibers.

The pictures I've seen of failed flex disks show very obvious destruction.

[willscam]

Once fibers are splayed, the disc is on the verge of failure. Do you wait for your tires to show no tread before replacing? It's maintenance. I also replace belts when they begin to show cracks and wear.

[QuestMCoupe]

Nice DIY, thanks for this.

[jackool]

Thanks for contribution and your concientious approach. You've been a great help to me in the past and I truly appreciate it.

[mrnvgtr]

Thanks to the OP and thanks for the bump. I'm doing this soon and I'm happy to find out its not absolutely necessary to remove the exhaust and possibly even the CSB.

[2kredz3]

Any noticable difference in driving? your guibo doesnt look as bad as i have seen some look.

[putyoursoxon]

Thanks, this is very helpful, I was trying to figure out what this was since everybody was talking about it, but this is my first BMW and I have never heard of it on any of my others , seems like a not to difficult job. I'll check mine out now

[bluefire]

Appreciate the explanation and all the pics! Thank You!!

[willscam]

Any noticable difference in driving? your guibo doesnt look as bad as i have seen some look.

No difference in driving that I could appreciate. Before I replaced it, I posted pics of the old cracked guibo on this forum and the overwhelming consensus was that it should be replaced. I was somewhat surprised that it looked as good as it did after it came out. Just the one crack. But it wasn't too bad a job (couple of hours - taking pics, etc) and the parts are pretty cheap. Hopefully, I won't have to worry about the guibo for another 30,000 miles.

[sideslip]

I noticed a very subtle difference after replacing mine @ 46K miles. However, my quibo was in worse shape than willscam's.

After the replacement, the driveline felt less "rubbery" on clutch engagement if that description makes sense.