Failed guibo

wkohler · Post by **wkohler** » Mon Oct 22, 2012 2:05 am

The dealer won't have the slightest clue on that, but I agree with everything else you said. I've gotten to be a bit of a driveshaft pro, and you want to torque the bolts like you would a wheel.

Blaise · Post by **Blaise** » Mon Oct 22, 2012 12:16 pm

GripGreg wrote:Sorry to be so late, but, Don't forget to NOT remove the metal band that wraps around the guibo til you install & torque down every bolt. For some reason this adds mileage to the guibo job.
Also, a Grip trick; maybe alternate the bolt heads as you go; and, maybe tighten it like you do your wheel after the flat? Just a couple guess's there. Maybe inspect the position of the factory installed bolts before removing? Or, ask the stealership for some info? Remember, the factory guibo lasted 100k.
But, the metal band deal is a must!

I had installed mine carefully alternating the bolt tightening sequence and getting them up to torque before removing the metal band.

Blaise · Post by **Blaise** » Mon Oct 22, 2012 12:24 pm

I installed an E28 guibo with some machined spacers to make up the difference. The E28 guibo is fiber reinforced and does not use the temporary metal band. I figured that if they installed them stock in the M5, it should be fine in my application.

My car is now more quite and smoother.

Eddie in TO · Post by **Eddie in TO** » Mon Oct 22, 2012 12:26 pm

wow...nicely done!

wkohler · Post by **wkohler** » Mon Oct 22, 2012 12:41 pm

"I just whipped up these spacers..."

Wow.

Eddie in TO · Post by **Eddie in TO** » Mon Oct 22, 2012 12:59 pm

wkohler wrote:"I just whipped up these spacers..."

Exactly what I was thinking when I read the update.

Blaise · Post by **Blaise** » Mon Oct 22, 2012 1:04 pm

I guess my post was misleading. I do have a lathe and should have made them at home, but I did not have any stainless stock on hand. My office is surrounded by industrial shops, so I walked a few doors down to a machine shop and $40 later, had three perfect stainless spacers to my specifications.

Eddie in TO · Post by **Eddie in TO** » Mon Oct 22, 2012 1:28 pm

Blaise wrote:...so I walked a few doors down to a machine shop...

LOL...darn, wish my trusty machinist was as close. My project would have gone much smoother...double sad face for me...I know...

Anyhow, glad it worked out and your baby is back on the road.

janusz200 · Post by **janusz200** » Sat Nov 03, 2012 6:59 am

I've just found your post Blaise so my reply is late but helpful I hope. I've got the same problem in my 635. It's 1980 car so my guibo is the same design as yours before replacement with spacers. New guibo in my car had withstood some 6 kmiles and than had been torned off as yours. The misalignment between propeller shaft and gearbox's body was the reason. For more please read
http://bigcoupe.com/phpBB2/viewtopic.ph ... highlight=

Blaise · Post by **Blaise** » Sun Nov 04, 2012 2:49 pm

janusz200 wrote:I've just found your post Blaise so my reply is late but helpful I hope. I've got the same problem in my 635. It's 1980 car so my guibo is the same design as yours before replacement with spacers. New guibo in my car had withstood some 6 kmiles and than had been torned off as yours. The misalignment between propeller shaft and gearbox's body was the reason. For more please read
http://bigcoupe.com/phpBB2/viewtopic.ph ... highlight=

That's interesting.

Has anyone else experienced issues with the driveshaft centering bearing?

Mine felt fine when assembled and I likely will not jump in there to replace it right away, as it would take dropping the exhaust and the driveshaft. But I will keep an eye on the guibo and probably replace the centering bearing when the time is right.

Thanks again.

Zaider · Post by **Zaider** » Wed Jan 02, 2013 12:32 pm

I know its been a few months but here's what we got when the guibo on our 1975 530i race car failed going down the straight. Driveshaft came loose and destroyed the output shaft, tore off the exhaust and bent the shifter linkage in a U-shape.

https://www.revshift.com/shop/bmw/e30/f ... uplers.php

Freddy · Post by **Freddy** » Wed Jan 02, 2013 4:06 pm

I have wondered about this also. I have the later e28 style on my 81 528. I installed it about 50,000 miles ago to replace the previous one that was the same. Don't remember who made it. I don't have a spacer. Now I will check to see that there is no bumping for sure. Mine is 2/81 build date. Does anyone know if bmw switched to this one near the end of production?

Post by **John in Simi Valley** » Thu Jan 03, 2013 3:09 pm

Yea, I'm late on the reply too, but Greg mentions the metal band which is important. The e12 guibo is a bit complicated in that the metal band must remain on during installation. This is one of those designs that I'd really like to talk to the designers about in verifying what they were thinking.

As a mechanical design engineer, the most common job interview question I've had was "Why do you preload bearings?"
The purpose of preloading a radial ball bearing is to make the inner bore run concentrically, or on simultaneous axis as the outer bore; to center everything up. It also evenly distributes loads to add to component longevity.

This guibo is a tricky example of recognizing when preloading is intended. In the case of this guibo (I think) is to compress the rubber so it can be assembled with the bolts, then release the band so the bolt holes preoad against the outer bolts, centering the bore respectively. If that's true, then the radial bolts must be slightly loose to allow centering, then torqued to final seating loads (after the band is removed). Torquing beforehand will just bind everything and the rubber will fail in compressive fatigue. (Propagating shear forces, tearing the rubber over time because it's not quite centered and excessive induced vibration as a result thereof).

Like I said; it's a little complicated, presuming I interpret the design intent; which is why the E28 version was redesigned to a simplier joint.

Blaise · Post by **Blaise** » Thu Jan 03, 2013 6:13 pm

Interesting. Thanks

Mike W. · Post by **Mike W.** » Fri Jan 04, 2013 12:01 am

Zaider wrote:I know its been a few months but here's what we got when the guibo on our 1975 530i race car failed going down the straight. Driveshaft came loose and destroyed the output shaft, tore off the exhaust and bent the shifter linkage in a U-shape.

https://www.revshift.com/shop/bmw/e30/f ... uplers.php

Wow, that's an eye opener. And it should have quite a torque capacity. I, like usual, have something to add. On my E28 I had some drivetrain vibration and at one point installed an older guibo, the flat kind with fiber, that was somewhat stiffer than the one on the car. I got significantly more vibration, enough I changed back in short order to the "old" one. Given that it would seem part of the purpose of it is to correct minor misalignment I don't think the above would be good on a street car, at least not a daily or semi daily driver.

And the driveshaft shouldn't really come that loose, there is the centering pin on the end of the transmission that the driveshaft is supposed to go into which would prevent a catastrophic event. Except racing or a racecar that only looks like a daily driver.

It is impressive looking though.

Firstfives.org

Failed guibo

Later car with later Flex Disc