I developed a procedure for rebuilding the driveshaft that uses retaining clips to secure the u-joint. A trench is accurately cut in correct position as guided by the placement of the original u-joint cups. The driveshaft has seen a few miles now, no vibration has been observed, having gone up to ~80mph...
Please see and let others know:
http://mysite.verizon.net/vzerdcib/e34a/id9.html
A simple question which I'm sure you'll be able to answer but has my head scratching; Why wouldn't you do the groove cutting or at least be able to establish the start of one in the correct location before you actually drive out any of original assembly and the cups. I see you are removing everything before the cut. Seems the best time to mark the groove for cuting is where the original assembly and cups sit. The new circlip sits just above the cup so the original cup in its place shows exactly where you'd make the cut. Since a new joint and cups will be replaced, doing the cutting of the groove before dissasembly is better I think, you won't have to worry about marring the cups as they are the old cups and will be replaced anyway.
Just a thought. Thanks for the write up though.
'88 635, '92 325IC
The reason for this is inability to cut precisely at termination of the ujoint cup. The screw holding the cutoff wheel gets on the way, making extraclearance between the cup and the new groove. An alternative for this is cutting a cap off the cup for the screw head, alas, the visualisation of the cutting procedure in this case is not (as) convenient.
I am not following the point here. The original cup sits in place in either case whether one chooses to cut the groove from outside or inside of the yoke. In the second case it sits in its original place as the remaining collar, with the cap removed. For this matter it serves the same purpose...
I am sorry, I am not following here. Do you mean - cut the grove from outside, simultaneously taking care of the stakes, and then push the cups out by conventional method? I found challenging to do this at first, this was tried. First reason already mentioned. The second problem is grinding of the cup that has to do deeply enough to grind off the stake. It seemed greater risk of damage to the inner surface of the yoke is possible. I settled with shown method because in spite of being more labor intensive it provides greater neatness and hence accuracy to the final result. Having zero experience with driveshaft rebuild procedures and unable to foresee the result, I was pressed by idea of retaining balance of the driveshaft, so a way of achieving a neater result had to be used. As mentioned in the first posting, the procedure amazingly, yet justifiably provided a balanced driveshaft - first time.
Last edited by Rustam; 12-07-2009 at 12:12 PM. Reason: possible misunderstanding.
This is dependent on finding a replacement joint with exactly the same size of end caps as the originals, a little thiner or thicker on the end and it won't fit snuggly within the clips.
I would think any competent local driveshaft shop could do this at a lot less money than Drive Shaft Specialists, and it would be worth it to have done professionally and precise.
81 Euro undergoing total nut and bolt restoration
pictures at: flickr.com/photos/bertsphotos
I have a rebuildable driveshaft & just went through the rebuild. I ordered the u-joint from autohaus which were the Meyle/GMB. I found these were .035" too long. Took them to the local vocational school & got them milled. It's a teaching aid & something different.
Resurrecting an old thread here. When I first got my car it had a bad center bearing, guibo, and stiff driveshaft joints. I replaced the guibo and bearing and oiled up the driveshaft. Now it's giving me problems again. I need to have the DS rebuilt, there's no way the guibo and bearing could have gone bad so fast. I bought an extra one a while back but it ended up having bad U joints too.
I have a couple options:
1. Try this procedure on my own with my extra DS.
2. Have a shop rebuild the extra DS.(need advice on a price I should pay for this...)
3. Try my luck and buy another used one.
Recommendations?
Henry
Chief Inspector of the O.P.D.C. (Oil Pan Destruction Commission)
Your system failed out so fast because the u-joints had seized and they aren't serviceable from the factory. If the joints can't flex, then they just cause problems with the rest of the rubber in the driveline. You could certainly try this repair on your spare driveshaft, but using an imprecise tool on such a precise item makes me nervous. I would give a call to Driveline Service of Portland. They run a core exchange program, excellent service, and they replace the u-joints with a serviceable type, so you can just grease the joints later on instead of getting a new driveshaft. I think it was around $450 shipped, which is very reasonable.
Your second cheapest option to that might be a local driveshaft place. When I was researching mine (seized joints), I spoke to a local company, but since the BMW units are marked as non-serviceable, they were going to do a core exchange on one that had been rebuilt from a supplier in CA. The CA supplier was OEM, so the replacement unit would be non-serviceable. I don't remember what I was quoted from the local guy, though.
Probably your cheapest option would be to buy another used unit, but it will likely be nearing the end of it's useful life. I would worry that you might encounter this same problem again shortly if you just got another used unit.
Alex
Not every shop knows how to properly rebuild the BMW shaft, read the first link below for more in info on what is required.
This outfit rebuilds the drive shafts with grease-able, replaceable U-joints and the price includes return shipping of the core DS and a 5 year 50.000 mile warranty (everyone else is only 2 years).
Driveline Service of Portland
http://www.driveshafts.com/pages/bmw.html
http://bigcoupe.com/phpBB2/viewtopic.php?t=11155& (Scroll down to the 8th post.)
For my own edification, what is it about the BMW driveshaft specifically that some or most re builders have trouble with or no knowledge about when it comes to rebuilding these ?
edit: ok just read the link...but all i could see really is adhering to a balancing standard; ISO 1940 G16 grade. I would think that would be a requirement in any case and any driveshaft.
Last edited by carsnplanes; 04-04-2011 at 04:04 PM.
'88 635, '92 325IC
Personally, I think that their balancing bit is a bit hyped up. The issue is with the u-joints. Most driveshafts that I've been exposed to outside of the BMW realm use snap rings to retain the u-joints. Remove the snap rings, replace the fried u-joint with a new one, replace snap rings, and you're good to go. The joints on the BMW units have this pressed in cap looking thing that isn't readily removable or replaceable. That's what labels them as non-serviceable and requires a total replacement. Now, a competent machinist should be able to accurately remove them and cut a snap ring groove, and you should be able to source an appropriately sized u-joint for the application for future replacement. Whether this is cost effective or not I have no idea.
Alex
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