Have a few drive shaft/guibo/CB questions

[brtele]

I finally got an opportunity to remove my drive shaft to replace the Guibo and Center Bearing. The car has been slightly shuddering on moderate acceleration in 1-2 gear right around 2200-2400 rpm.

Once I removed the drive shaft (the next time/2nd time I remove it will be much faster/easier), I inspected the Guibo/CB and didn't really see any obvious signs of failure. Also, prior to removing the shaft, I really tried to get movement on the shaft, but it was firm in all directions.

Questions:
1. The new Center Bearing is a Febi. Does it need to be packed with grease similar to a wheel bearing or is it pre-packed?
2. My U-joints were not bound at all, but one direction was easier to move then the other. Again, both directions felt smooth, just different. Can I spray a lithium/lubricant on the joints or is this ill advised?
3. In the pics the U-joints had a black build-up at the "joint-seam". It flaked out when touched and what is left is red. Is this normal?

Thanks for any assistance,

Brandon

[Ralph in Socal]

The guibo is the rubber coupling at the rear of the trans. Take that out (note location with paint mark if re-installing) and inspect. Put a couple of long bolts in the holes and deform it to see if you can find cracking of the rubber.

Same for the center bearing. Move the mount around to see if you can find cracks in the hard plastic/rubber.

Be sure to follow instructions on installation of the assembly. Preload of the Center Bearing is essential to preventing vibration and ensuring long life.

No packing of the new CB is necessary. It is a sealed bearing. The u-joints really will not lubricate from the outside so it's futile. Maybe some fine oil but that won't last long during use anyway. The flaking old grease buildup is normal but your u-joints are wearing and could be adding to your vibration.

Ralph

[brtele]

Thanks Ralph. After damaging the brand new CB trying to mount it on the shaft, I'm seriously thinking about purchasing a rebuilt driveshaft. I'm at 140K miles and I'm somewhat worried about the joints.

It looks like the going rate for a rebuilt DS is approx $400. Anyone have great experience with a rebuilder that they would recommend?

Thanks,

Brandon

[brtele]

Going to call Driveline Service of Portland tomorrow to see what the pricing looks like.

[Ralph in Socal]

Going to call Driveline Service of Portland tomorrow to see what the pricing looks like.

They are highly respected but I've never bought from them. Let us know your firsthand experience please.

Ralph

[brtele]

After a little bit of research and calling around I went with Driveshaft Specialist (San Antonio, TX). Craig was very helpful over the phone and explained the "red stuff" coming out of the joints was rust and should probably be scheduled to be replaced. So I took the dive and purchased a reman.

$383 + $80 (core) = $463 (shipping both ways is included and it should arrive no later than this Friday)

Fingers crossed this weekend that I get rid of this slight shudder. Craig (along with others on this forum) recommended it could be the Diff Mount causing the shudder on accel. I have a new Diff Mount ready to install, but 1st want to see if the new DS eliminates the shudder prior to replacing (just for future reference of what certain parts failing feel like from the wheel).

Thanks again for assistance,

Brandon

[conez0]

Good call on replacing the driveshaft.

I'll add in my two cents here. I had a BAD and EXPENSIVE experience replacing my center support bearing (CSB).

1. Make sure you have a quality part. I'm not sure how to quantify quality really, brand isn't everything. Make sure the rubber isn't hard...but extremely rigid. You should have a pretty hard time flexing the bearing more than 5 mm in either direction just by hand. I will say that I ordered an OEM BMW center support and it performed just as bad as several others (I went through like 5 of them before I got one that was stiff enough)

2. Make sure your exhaust heat shield is in place and working properly. The catalytic converter site right under the CSB and its gets hot, very hot. If the converter is actually touching the heat shield it will increase the amount of heat on the driveshaft side and soften or in extreme cases burn the CSB.

3. When you preload the bushing, it should feel like you're really having to work to get the 10mm or so of preload needed. If pre-loading is as simple as just holding the bushing to the side a little while torquing the bolts I'm going the venture your thumping problem is still going to be there.

For installing the new CSB, I found using a couple PVC pipe coupler fittings and a mallet worked very well for installing the new CSB onto the shaft. If you're buying a rebuilt shaft though it will most likely just come with a new CSB. Pay a little attention and make sure the CSB on the new driveshaft meets the items in point 1 above. I got my driveshaft rebuilt from Driveline Service of Portland and unfortunately had thumping still even with the brand new shaft and CSB.

I'm getting dangerously close to going on a rant about my 2 year long CSB "replacement" experience so I'll stop here.

[brtele]

Conez0, thanks for the tips. All points well taken and will try to take of pics and record the drama of installing a new driveshaft.

[brtele]

So I received the rebuilt DS from Driveshaft Specialist (TX) on Thursday. Packaging was good and the DS was well protected for shipping.

The job wasn't too bad. Removal of the rear shaft and replacement of the new shaft took about 5 hours. If I had to do it again, I could easily cut it to 2-3 hours (1st time always sucks).

After reviewing the new DS U-joints against my existing ones, I realized the existing ones were shot. They were not smooth moving and felt somewhat "sandy" inside.

The existing Guibo looked alright at 1st glance, but when I would pull at it, stress cracks easily appeared all over it (pictured).

Everything went back together pretty easy. Tightened it all up, turned the motor over by hand a few times to make sure I hadn't skipped a cam tooth (thanks Da Hose for the constant paranoia I have) and went for a quick drive. Success!! The 1st and 2nd gear shudder was noticeably gone and the acceleration was very smooth. I really believe it was the U-joints creating the shudder. The existing CB looked pretty good on inspection.

I did hang the exhaust a little too high and had it hitting the heat shield. When I got back to the garage the car was smoking a little. It might be PB blaster that was on the exhaust, but I pushed a little on the heat shield and the exhaust sizzling went away. I'll drop it 0.5" to accommodate.

All in all, I would do this job again.

This weekend is the Diff Mount!

Thanks again for all the help throughout this site.

[hornhospital]

Well done, sir!