• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Drive Shaft U-Joint

lmo1131

New member
rant.gif
How could they possibly have ever maintained the Thousand Year Reich, if they weren't clever enough to make drive shaft U-joints REBUILD-ABLE?!?!?!?
rant.gif
 
Same as the Brits when they manufactured a car with no replacement parts for the drive shaft, my old Ford Cortina. :laugh
 
I've heard of some people rebuilding the drive shafts. They ground away the tangs holding the u-joint in place, then tack welded the new ones in place. Finding someone to do this might be like finding a needle in a haystack. I think some people mentioned marine repair shops, but I have no first knowledge of this.

Oh, and yes it's very disappointing (and detremental to the wallet) that drive shafts were not constructed to easily replace the U Joints
 
Just curious how many fail versus the tinkering syndrome. I'm thinking not many, but that's not a good enough answer for the bloke on the side of the road with a failed one. :brow

What's the MTBF on them, anyone know? :dunno
 
This is from a pretty new BMW (R100GS Yr, '88):

driveshaft1.jpg


...at 67,000 miles. The sealed (!) bearings seized and split the metal claw which holds the bearings. At that time I was playing with the idea to have it repaired (e.g. http://www.brunos.us) but decided to go with a new one in the assumption that an OEM shaft is better balanced (wishful thinking!).

/Guenther
 
This is from a pretty new BMW (R100GS Yr, '88):

driveshaft1.jpg


...at 67,000 miles. The sealed (!) bearings seized and split the metal claw which holds the bearings. At that time I was playing with the idea to have it repaired (e.g. http://www.brunos.us) but decided to go with a new one in the assumption that an OEM shaft is better balanced (wishful thinking!).

/Guenther

Most Airhead driveshafts go a very, very long time. R100GS driveshafts were designed wrong and often fail within 30,000 miles. In typical trim the deflection angles of the U joint exceeds the prudent deflection angle which puts stress on the U joint and they fail early. There are specialist shops that rebuild them with grease fittings. This helps but they still fail too soon because of the excessive deflection angles.
 
Most Airhead driveshafts go a very, very long time.

Guess I'm a victim of statistics (like it's the first time.. . . ) :huh

Quite a few show up on eBay, IBMR Market Place and so on, but you'll never know what ya got until it's in your hands.. . .

But $615 for a new part. . . . ?!?!
 
In typical trim the deflection angles of the U joint exceeds the prudent deflection angle which puts stress on the U joint and they fail early. There are specialist shops that rebuild them with grease fittings. This helps but they still fail too soon because of the excessive deflection angles.

I've often wondered which angle is too much. Is it at the tranny, at the final drive, or both. Just curious.
 
The angle at the front of the shaft is too great an angle. They fail there often. The interesting thing I have observed over the years is that the really big folks loaded for camping around the world have longer driveshaft life. But that heavy load squats the rear of the bike downward and straightens up the driveline angles. A short shock does the same thing.

Ideally that shaft needs a CV joint but there really isn't room to use one - so they didn't. It's a wart. All models have at least one wart.
 
buy a spare

Buy a spare on ebay.I did,and save it for a rainy day 100 to 150 cheap as a fix and this is the complete swing arm unit.:violin
 
This is from a pretty new BMW (R100GS Yr, '88):

...at 67,000 miles. The sealed (!) bearings seized and split the metal claw which holds the bearings. At that time I was playing with the idea to have it repaired (e.g. http://www.brunos.us) but decided to go with a new one in the assumption that an OEM shaft is better balanced (wishful thinking!).

/Guenther

True enough, some of the GS bikes had issue but not that correlate to Lew's (the original poster) /5. sort of like comparing a Ford Pinto's horsepower to a real thoroughbred. They're both could be considered transportation...but completely different animals.

I think most 247 swingarm driveshafts have a pretty darned good record. Just pack a tube of Compound-W and hope you never need to use it on your wart. :brow
 
... just ranting... I've got a line on a replacement; odds are it will be in totally usable condition.

That said, I bought a LWB swing arm/drive shaft last summer for a sidecar tug project. I hadn't touched it since getting it and thought that there is my new drive shaft!!! Serendipity!! WooHoooo :dance

When I broke it down, the U-joint was perfect, but some hack had completely buggered the threaded end by using a chisel to get the nut off; first land of thread was gone, the second and third set of threads were flattened by the nut going on slightly off .. . basically rendering it scrap. :bluduh

But hey!!! I do have a spare swing arm!!!

AND IT WAS 83F here yesterday!!!!!
 
95% of the time I ride 2-up. I only go on dirt roads once-in-a-while - no jumps.

My shaft broke because the bearings were of poor quality and the flange that holds the U-joint bearings was of poor quality as well. The new shaft has 50Tmi and looks pretty good.

I do not 'support' the idea of GSes having this problem because of a wider swing arm movement. I think it's folklore...

/Guenther
 
The angle at the front of the shaft is too great an angle. They fail there often. The interesting thing I have observed over the years is that the really big folks loaded for camping around the world have longer driveshaft life. But that heavy load squats the rear of the bike downward and straightens up the driveline angles. A short shock does the same thing.snip

Pretty much what the Airhead guru at RideWest told me last summer. Keep the old sagging shock, my Jesse bags loaded and the shaft on my GSPD should last a long, long time. Since my unknown mileage shaft (bike is closing in on 97,000) was already shot, I sent it off to Hendersen Precision in California. They put it back together with replaceable joints and a grease nipple for periodic re-lubing.

While the bike was down I really hammered my maintenance budget and ordered up a Wilbers shock and front springs, but that is another story.
 
I sent it off to Hendersen Precision in California. They put it back together with replaceable joints and a grease nipple for periodic re-lubing.

Hmmm... Henderson offers that service for pre-'88 BMWs as well. I'm looking at a used OEM drive shaft for $200 in "excellent condition"... for what that's worth. Several others on-line for between $100-150.

The Henderson re-build for $170 sound like a pretty good deal. Thanks for the tip!

Anyone else have any experience with Henderson?
 
Anyone else have any experience with Henderson?

Not sure how relevant it is, but I bought a CNC'd exhaust nut wrench from Guy Hendereson. Very well made and had a brief conversation with him. Very knowledgable and knows the GS bikes very well. Not sure about non-GS things, but I'd expect he'd bring that up anyway. A standup guy IMO and the kind of place I'd love to hang out and watch 'em work. :thumb
 
Back
Top