If you want something done right, ...

[Rosso Pintura]

I don't know what "Well Documented" means, but BMW started installing the bolts all heads on the rear side at some point, but not until the late '90s at the earliest, when Guibos got much beefier. In our early cars, especially using the small four bolt Guibo, nuts go on the flange. there is no argument against it that works. Tightening a nut against a steel sleeve that is molded in rubber makes the rubber twist, effectively creating a stress point and shortening its life. BMW doesn't, but if you get an aftermarket one, like Febi, there are instructions in the box that specifically say, nut on the flange. Kind of like the reason you preload the CSB forward a few MMs. There are reasons that the engineers want it that way, and it's easier to just do it as they say to, rather than wonder what you may have done wrong after it fails earlier than it should have.

 

Edited May 31, 2022 by Furry Camel

[JohnS]

The thing that worries me is that since they made these type of rookie mistakes.  How do I know that they torqued the output flange on the transmission to the correct spec?  Or that they properly set the preload correctly on the center support bearing?  I've already lost sleep thinking about it.  To me there's no excuse for leaving the metal band on the guibo.  That's pathetic ?

 

And if what Furry Camel says is true, then the possible damage to the Guibo has already been done.

Edited May 31, 2022 by JohnS

[JohnS]

I had to laugh.  I was looking at the Walloth Nesch web site at their complete driveshafts that come with the guibo pre-installed.

 

['76mintgrün'02]

 

 

The reason some people prefer to make all the bolts face forward is because a bolt coming loose will just fall out, as opposed to having a 50% chance that it will beat the crap out of the back of the transmission.

 

I've read posts in the past about giubo bolt orientation and one detail that they mention is that if you're installing all the bolts facing forward, it is important to hold the nut still while rotating the bolt head, to keep from twisting the rubber.  I'd undo/redo that step while you have the car up in the air, since they may not have paid attention to that detail.

[AceAndrew]

Yep, when done properly (twist at flange, period.  Doesn’t matter if its a nut or bolt).  It works great and offers a little piece of mind that you aren’t going to tear up the back of the trans should a failure happen (something I’ve seen too often).

 

…but if you’re one who prefers the alternating method, more power to you!

[Lorin]

12 hours ago, Furry Camel said:

I don't know what "Well Documented" means, but BMW started installing the bolts all heads on the rear side at some point, but not until the late '90s at the earliest, when Guibos got much beefier. In our early cars, especially using the small four bolt Guibo, nuts go on the flange. there is no argument against it that works. Tightening a nut against a steel sleeve that is molded in rubber makes the rubber twist, effectively creating a stress point and shortening its life. BMW doesn't, but if you get an aftermarket one, like Febi, there are instructions in the box that specifically say, nut on the flange. Kind of like the reason you preload the CSB forward a few MMs. There are reasons that the engineers want it that way, and it's easier to just do it as they say to, rather than wonder what you may have done wrong after it fails earlier than it should have.

 

The important aspect to follow is to turn the end of the fastener that is on the flange, nut or bolt. 

[Son of Marty]

5 hours ago, JohnS said:

How do I know that they torqued the output flange on the transmission to the correct spec?  

Hate to say it but you don't know, the only way to tell for sure is to take it apart and do it your self.

[JohnS]

Yes, it's a miracle that my tranny survived.  Here's the damage that happened when my Guibo gave up the ghost at around 70 MPH.  I'm going to hang the flange in my garage as a reminder to jack up my car every once in a while and inspect things...

Hey, at least I know I've got a fine splined output shaft on the tranny.  Gotta look at the bright side ?

 

Does anyone know whether the driveshaft can be fixed? i.e. a new flange welded on?

Edited May 31, 2022 by JohnS

[Lorin]

2 minutes ago, JohnS said:

Yes, it's a miracle that my tranny survived.  Here's the damage that happened when my Guibo gave up the ghost at around 70 MPH.  I'm going to hang the flange in my garage as a reminder to jack up my car every once in a while and inspect things...

Hey, at least I know I've got a fine splined output shaft on the tranny.  Gotta look at the bright side ?

 

That guibo had failed a long time before the 70 mph incident. That’s a lot metal removal ! 

 

Yikes! 

[JohnS]

7 minutes ago, Lorin said:

That guibo had failed a long time before the 70 mph incident. That’s a lot metal removal ! 

 

Yikes! 

Just goes to show what a dumb ass I've been for not inspecting things periodically...

[Jdddrigot]

I had a well respected mechanic in Fort Collins rebuild my engine. Now I’m well below the title of “hack mechanic” but I did notice the two pistons looked different. 

[jgerock]

3 hours ago, Jdddrigot said:

I had a well respected mechanic in Fort Collins rebuild my engine. Now I’m well below the title of “hack mechanic” but I did notice the two pistons looked different. 

Guess he wasn’t a Billy Joel fan …

[Einspritz]

Either way, unless you're adamant about saving weight, I suggest you check the torque of the nuts.

 

[JohnS]

On 5/30/2022 at 9:36 AM, ray_ said:

... How close would you have been to buying a lift if you hadn't spent that money on labor?

True Dat

 

Especially because I'm paying twice to have the first rookie mistakes corrected because my back is still f'd up.  ? I can rebuild shift knobs though... Ha Ha

Edited June 1, 2022 by JohnS

[JohnS]

Sorry folks.  This is starting to resemble Carl's "Friends and their mechanical skills" thread.  But, it gets better.  So, I took the car into Nate Smith's Optimal Auto to have all of the rookie mistakes corrected,  Around 3:30 I get a phone call.  "Mr. Sieraski, we found something that we think looks sort of hackish and wanted to ask you about it.  It seems that when they connected the new driveshaft on the differential side they replaced the special bolts with some grade 8.8 bolts and used a grinder to make them fit.  The special bolts have a sort of half circle head on them to keep them from spinning.  They also used regular nylock nuts instead of the proper all steel lock nuts.  Let me send you a picture.".

 

I said Okay, I know the correct bolts were in there before.  So, I went out to the garage and looked at the old driveshaft.  Low and behold the correct grade 10.0 bolts with the half moon heads were still in there.  So, I lightly tapped them out with a hammer.  Then I made the hour round-trip drive in bumper to bumper traffic from Watsonville back to Nate's shop in Santa Cruz and delivered him the proper bolts and 4 brand new steel lock nuts that I happened to have in my parts stash.  I'll get the car back tomorrow.  Nate and his mechanics were laughing.  A grinder!  Too Funny! Fail #5

 

 

 

Edited June 2, 2022 by JohnS