engine and drivetrain Driveshaft fun and games

[wagnerf15]

Can't get a BMW driveshaft cut and welded and balanced in STL, I found out today. No jig because no business...they told me to look at cali. I did find out, however, that the reason they can't even do the work is because of the center u-joint. Apparently, they can't even get this off without destroying it and it is required to center the 3 bolt flange properly and then balance. I'm fairly certain I want this job done properly, so onward ho.

Many internet searches and phone calls later, I settled on Driveshaft Specialist, Inc in San Antonio. They seemed to know what I was talking about and asked germane questions, which I found oddly comforting. It was almost like being on this forum. Anyway, I centered the diff in the slotted holes and measured flange to flange (minus 1 1/16" for the guibo) and came up with 59 11/16", which was largely in-line with previous posts. They asked me 2 questions which I didn't expect....

1. Which size 3 bolt flange did I have on my transmission? Didn't know there was more than one. Figured that out.

2. Distance from back of guibo to center of bolt holes for center bearing. Huh? Oh, I can measure it, but WTF does that have to do with anything?

I decided to ax a few questions myself. You guys aren't gonna cut the shaft aft of the center ujoint are you? No. Well, if that stays the same, and I give you a flange to flange length of the final driveshaft, why do you give a shit about this measurement? The slots are like 1 1/2 - 2" long, how accurate is that measurement? Anyhoo, armed with a LOT of previous postings and the PDF of the BMW manual, I felt like I held my own in the driveshaft wars. $470 for a *new* driveshaft (including shipping to my home and shipping the core back) was more than I planned to spend, and I now have a center bearing and 3 bolt flange for sale, but I'm hoping I have this bitch whacked. I'll let you know

[thehackmechanic]

Had a similar experience a few years back. Wanted to have a shaft shortened and balanced. No one here in Boston will do them because they look at those non-rebuildable U-joints and say "oh we don't touch those." I was told that the trick thing to do was disassemble the shaft and simply take the front half -- without a U-joint in it -- to a machine shop and have them shorten it. I did. It was cheap. I thought I was smart.

Then I put the shaft back together with a new center support bearing, put it in the car, and it was horribly out of balance. I took the whole driveshaft into the shop who shortened the front half, asked them to balance it the whole thing, and they couldn't deal with it.

It's for these reasons that I no longer screw around with shortening driveshafts, and instead send them to Dave Varco at Aardvark Racing in Cali, who sends them... wherever he sends them.

[PatAllen]

the driveshaft world seems to be very wacky.

i never been able to find a shop to do mines, so i did them on my own. I ended up buying one from driveline specialist in portland, for my E36. It turned out to be totaly out of balance, so i had to make some tooling to balance it on the car...YEAH !!!!

no one seems to realy know what they are doing. After some discussion, the guy told me they have them balanced by a third party company...wow, and you pretend yourself the specialits ???

i dont understand.

I am still under the impression that BMW, for the newer vehicles, they balance them while it is on the car. I found some interesting patents on the internet that belongs to zf iirc, to do this.

just removing it from the car and installing it back messes up the balancing, up to a point.

See, on my E36, i finished the "fine" balancing with tie-wrap heads, because i was using a vibration analyser...hehehehe...

http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/start,0/t,310494/topic_view,flat/

[conkitchen]

It's for these reasons that I no longer screw around with shortening driveshafts, and instead send them to Dave Varco at Aardvark Racing in Cali, who sends them... wherever he sends them.

Well it's a little late to the party, but Jeremy at IE sells a rebuilt shaft for $395 plus core. Total value given the stress of doing it with unexperienced machine shops. BTW, I believe Dave @ Aardvark sends his shafts to the same place as Jeremy. They hook each other up on the 5 speed parts for their customers.

[TobyB]

Driveline Service of Portland (Orey-gone) has been 2- for- 2 on the

5- speed re-shorten-spider-weld-balance for us. And I've used the

Seattle shop for other work, and while not a polished bunch,

they do know what they're doing.

Next, I have a custom thing for them, so I'll re- port when THAT goes

through their doors- and comes back out...

t

[02Les]

Many internet searches and phone calls later, I settled on Driveshaft Specialist, Inc in San Antonio.

As they are only 20 mile from me (when i'm home!) I contacted these people about shortening a driveshaft. Agree they appear to know what they are doing, but they told me they send driveshafts out to a place in California to be shortened/balanced etc. I never did get a round tuit, so cannot say how good, or other, they are.

[finkbuilt]

Many internet searches and phone calls later, I settled on Driveshaft Specialist, Inc in San Antonio.

As they are only 20 mile from me (when i'm home!) I contacted these people about shortening a driveshaft. Agree they appear to know what they are doing, but they told me they send driveshafts out to a place in California to be shortened/balanced etc. I never did get a round tuit, so cannot say how good, or other, they are.

Oh, the shadowy, secretive world of custom BMW driveshafts!

I have read and heard from various sources that the well-known California shops send theirs to Texas to be done, and now I hear that the Texas place send them to California. This is sort of a sad commentary on the state the country's industrial infrastructure.

I can just see this big whirling vortex of bmw driveshafts circling around and around in the mail, getting more and more expensive with each stop before finally landing in Nebraska.