Can a Guibo look fine and still cause a vibration?

[Gearhead]

A while back I started feeling a vibration at certain speeds under acceleration. This will come and go depending on temperature...wose when cold, almost non-existent when warmed-up. This is definately not related to tire balance, etc. Anyway, soon afterward a rythmic squeaking started and it directly correleated to the vibration I'm feeling.

I went and replaced the center carrier bearing myself taking care to mark and re-align everything the way it originally was. I also made sure to preload the carrier bearing when re-installing. Now the squeak is gone, but I still have that vibration.

I've have looked at this guibo a number of times hoping to see any evidence of cracking or notible failure, but I'm seeing nothing. Is it possible that perhaps the rubber has just gotten so hard that it's causing a vibration? Has anyone had a guibo go bad that didn't look bad?

Any help is greatly appreciated!

John

[stargazer_61]

John,

Most likely the U-Joint on your driveshaft is going bad. Similar experience at low-speed acceleration produced a bad vibration and replacing the carrier bearing & guibo did not fix it. A worn U-Joint will destroy that new bearing in a hurry. If you can find a shop that will machine in a serviceable U-Joint, great, do that. Otherwise you must replace the entire unit new.

Good Luck!

[Gearhead]

Great.... Helga wants more money. I'm beginning to wonder if the ex-wife was cheaper. Maybe should have kept her around.

Anyway, how does one check the u-joint proof-positive to make sure it's the culprit? Do I just call local BMW (independant) and drive-line shops to see if this is something they can "machine" in? RealOEM.com isn't showing a part number for that joint so I'm guessing this is one of those non-servicable parts. And in checking on the more expensive route, BMA isn't listing a replacement driveshaft assembly.

Any experience/help in this alternative route is greatly appreciated!!!!

Thanks Guys!

[mattyb]

you are right. this is one of those non serviceable parts.

In oz getting hold of an entire tailshaft is expensive, probably like any where else perhaps. id go for pulling the guibo,(Flex disc as we call it here) off and having a look to double check. I have done this as well as the centre bearing myself prior so im not talking out of my arse.

when you did the centre bearing did you remove the guibo? if so did it go back on right?

How are the engine mounts? unlike our six cylinder brothers theres a heap more weight up front to shake things about and often mounts dont show their ugly heads till u look.

how are the tranny mounts? cheap and easy to do, part of the elimation process, guibo, engine mounts etc before heading to the expensive options.

Im not saying it isnt the uni, but these going are rarer than the others and are the last thing you would want to be spending money on if poss. your car hasnt done that many K's so id be hesitant to focus on the uni for now.

hope this helps

reegards

mattyB

[Ross]

The squeeking might indicate a dry u-joint. Have a look at the joint(s) around the cup seals, rusty residue is a sure sign of a dead u-joint.

[stargazer_61]

Yes, as MattyB suggests, check the engine and trans mounts for deterioration. Leaky PS fluid will ruin the driver side mount, which in turn can wreck things further down the driveline. And as Ross suggests, have a look at the joint itself for signs of rust.

I had posted basically your same question about two years ago and was told the same by the experts here that my u-joint was the culprit. Upon removing the driveshaft I found some resistance on one of the pivots. Not much, but appearantly enough to cause enough vibration to rip the carrier bearing apart.

There is a shop in Raleigh, NC that will take a non-serviceable u-joint and machine it into one that is serviceable. However, this cost about the same as a remanufactured unit from Oliver's Drive Shaft service in Winston-Salem, NC. Given time & distance issues, I chose a reman. for about $375. Old shaft had about 150,000 on it when it went bad.

[Qube]

I vote for u-joint and center bearing. Machine and balance. Mine went at about 320000 KM. I thought guibo too except I changed it half a year ago.

[mattyb]

Gearhead, make sure you let us know how you go, casue results and the fix,, your contribution in this fashion is whats keeps the board going and the knowldge flowing not to mention the love! best of luck

[Gearhead]

Will do mattyb.

Quick follow-up...
1) I've already replaced the center carrier bearing. That fixed the squeaking, but did nothing for the vibration.
2) I've noticed that the vibration seems to be temperature-centric, meaning it's usually more noticable when cold and almost non existent when the warmed-up. This point tends to make me think it's the quibo as rubber flexes more when warm.
3) I never removed the quibo from the trans output flange when I yanked the driveshaft, so it's still aligned properly (plus i've triple checked that)
4) The quibo looks fine (no cracks) for what that's worth, hence the title of this thread
5) I've changed a number of u-joints in in american cars over the years, so I know how to spot a bad u-joint. While I didn't notice anything loose when separating the shaft to install the carrier (getting to that bolt was a pain), I honestly didn't even consider that the joint could be the culprit with such an obvious carrier bearing failure (the squeak). That said, I can't say I actually "checked" that joint. My bad.

At this point I'm just going to have to drop the exhaust and the underbody heat shield and really check that joint. If I can't find any rust, or torsional/ lateral play, I'm going to gamble and throw a new quibo at it. At the same time I've tracked down a rebuilt shaft through my local Bimmer Indy shop for about $450.

Thanks again all for your feedback!

John

[stargazer_61]

I didn't think that my u-joint was bad either. I went so far as to pull the shaft & take it to the dealer to have it checked. They were no help. There was no end-play, it felt nice and tight, but the resistance was there. It didn't feel like much but when I put in the new shaft the problem was gone.

PS: Easiest way to get to that 18mm bolt holding the shaft together is to leave it in the car and break it loose with an 18mm gearwrench, as it's thin enough to get between the two pieces.