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?Waldo?
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Joined: February 22, 2006
Posts: 9752
Location: Where?
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 Posted: Tue May 26, 2015 7:11 am Post subject: |
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insyncro
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Joined: March 07, 2002
Posts: 15086
Location: New York
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| Posted: Tue May 26, 2015 7:23 am Post subject: |
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Great vid 
I have new OG, slip yoke and donut-less driveshafts here to work with.
I prefer a slip yoke, but have found the donut-less shaft to work just as well.
The question I have for the OP...why is your front diff so "off" that it needs shimming?
Most shim due to differing engine heights after a conversion, changing flange angles.
Post pictures of all the attachment points, mounts and sub frame if possible.
First it needs to be established that all parts are properly installed. |
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?Waldo?
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Joined: February 22, 2006
Posts: 9752
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| Posted: Tue May 26, 2015 8:31 am Post subject: |
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Watching the video I posted in my last post might help understand the physics behind the common driveshaft vibration issues.
I have little experience with syncro vanagons. I assume from this picture, posted earlier, that the flange shafts are not parallel, but rather the drive shaft u-joints are intentionally out of phase in order to cancel the accel/decel of the two 4° angles.
It's just a guess, but I imagine that the non-parallel shafts (out of phase u-joints) and the additional 1° angle are what make vanagons more prone to vibration than the other vehicles discussed in this thread. Considering that the driveshaft itself is constantly speeding up and slowing down regardless of whether or not the angles are correct and cancelling at the flanges, I imagine that also contributes some vibration to the vehicle. Some drivesahfts use CV joints at the ends. Seems like someone developing a CV equipped driveshaft for the vanagon rather than the u-joints might be a hero. |
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insyncro
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Joined: March 07, 2002
Posts: 15086
Location: New York
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| Posted: Tue May 26, 2015 8:56 am Post subject: |
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I own two of the driveshafts that use CV joints instead of UV joints.
Neither are being produced any longer.
One is much too heavy and the other doesn't hold its professional balance longer than 15k miles...I assume it is an issue inside the yoke.
The shaft I referred to earlier on Quattro Syncro has CVs IIRC.
My experience has shown that in the front, usual issues have been improper installation of parts that creates vibes and in the rear...transmission bearing issues or the use of the wrong engine carrier bar for a conversion and or failing motor mounts are the causes of vibes. |
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xoo00oox
Samba Member
Joined: February 11, 2010
Posts: 2672
Location: East Nassau, NY
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| Posted: Tue May 26, 2015 9:14 am Post subject: |
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| insyncro wrote: |
I own two of the driveshafts that use CV joints instead of UV joints.
Neither are being produced any longer.
One is much too heavy and the other doesn't hold its professional balance longer than 15k miles...I assume it is an issue inside the yoke.
The shaft I referred to earlier on Quattro Syncro has CVs IIRC.
My experience has shown that in the front, usual issues have been improper installation of parts that creates vibes and in the rear...transmission bearing issues or the use of the wrong engine carrier bar for a conversion and or failing motor mounts are the causes of vibes. |
That's right, CV on each end and universal in the center. |
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kustomizingkid
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Joined: October 16, 2014
Posts: 142
Location: Minneapolis, MN
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| Posted: Tue May 26, 2015 11:14 am Post subject: |
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That is a great video... True skill in teaching is being able to take a difficult concept and make it just that simple to comprehend.
Last edited by kustomizingkid on Tue May 26, 2015 11:26 am; edited 1 time in total |
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xoo00oox
Samba Member
Joined: February 11, 2010
Posts: 2672
Location: East Nassau, NY
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| Posted: Tue May 26, 2015 11:23 am Post subject: |
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| kustomizingkid wrote: |
| That is a great video... True skill in teaching is being able to take a dofficult concept and make it just that simple to comprehend. |
I agree, thanks for posting that Libby, that video is really interesting. |
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pedrokrusher
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Joined: July 11, 2011
Posts: 654
Location: Montreal, Quebec, Canada
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| Posted: Tue May 26, 2015 10:33 pm Post subject: |
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syncroflee, i feel for you, as I went tru all that too a couple years ago. If there was a cliff near my house, I would have pushed my ex-syncro over and have a malicious pleasure getting it destroyed.
Here are some suggestion for you, that i have done before...
1- Rubber bushings
The rubber bushings are new. Just double check with your own weight and pull and push the front diff and rear tranny to make sure all bushings have flex and moves around. It was difficult for me to install the plastic supports properlly around the rubber bushings. They have a certain way to go together. That can cause a rubber bushing to not flex properly (for some reason i believe your problem is here, at the rubber bushings not flexing properly).
Also check the engine rubber bushing supports if they ar not allowed to flex properly.
2- Balancing
I read again your posts and you have tried different known well balanced shafts, so i think you can rule the driveshaft out.
At this point you need to check if EVERYTHING ELSE is balanced. What i did is have the syncro on a lift with someone at the drivers seat and start the engine and roll the wheels as if you were driving it. Look everywhere for vibrations. This is very dangerous! Be carefull if you have long hair, or loose clothing that can get caught in anything that turns. You can loose an arm.
I had all wheels balanced, and guess what? My rear passenger wheel was off balance and it was going up and down. Got that wheel balanced again and that took care of a certan percentage of the vibration.
Check all driveshafts at each wheels if they shake.
Check your disk brakes and rear drums if they shake, with the wheels off on a lift.
Just as another double check. With the driveshaft out, with the rear wheels off the ground, have someone turn the rear wheels and you, you check if the flange at the trasmission stays balanced when it turns. Maybe the rear flange is out of allignment? Maybe a previous mechanic had it bent accidently? The front diff is rebuilt by AA, so i believe that one is ok. Your tranny is not rebuilt.
Its been 6 years ago now that I went tru all that. I don't remember right now what else to check... Maybe later something else will come back to mind...
The syncro driveshaft vibrations theory.
After dicussing with some other mechanics and the driveline balancers, here is what we believed what makes the syncro much more prone to driveshaft vibrations. First, the driveshaft is very long. And second the tubing is too thin. This would create the driveshaft to bend in the middle at higher speeds, and create vibrations much easier than any other vehicle. Having a driveshaft in two sections with a fixed middle part would most probably eliminate the syncro vibrations.
Another point is the lack of a big metal donught at each end of the driveshaft to have more rotational mass to stabilise the driveshaft at high speed. My jeep rubicon and my wifes jeep liberty has those big metal donuts at one end.
Just found this video on youtube regarding that donut, they call it a harmonic balancer:
Link
Ok its late now... Gotta go to bed...
_________________
Pedro
1989 vanagon Karmann Gipsy #652, TDI AFN
1991 vanagon westfalia conversion TDI ALH Silverfox
ex-1989 vanagon syncro passenger Syncrofox (Sold)
http://www.thesamba.com/vw/forum/viewtopic.php?t=598791&highlight=
http://www.thesamba.com/vw/forum/viewtopic.php?t=493964&highlight=speed+aap+trans
http://www.thesamba.com/vw/forum/viewtopic.php?t=496589&highlight=carrier+bars
http://www.thesamba.com/vw/forum/viewtopic.php?t=506025 |
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IdahoDoug
Samba Member
Joined: June 12, 2010
Posts: 10250
Location: N. Idaho
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| Posted: Tue May 26, 2015 11:13 pm Post subject: |
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When you do the Pedro test for vibrations up on a lift, be sure you are lifting from the suspension arms, not the frame only. If the suspension arms are at full droop, you have changed the vibration harmonics away from how they would be on the road. So, put the Syncro on jack stands - one under each suspension member so they remain at the same angle as they are on the road. This is safer as the vehicle is close to the ground....
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader |
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syncroflee
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Joined: October 11, 2013
Posts: 11
Location: Snohomish
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| Posted: Fri May 29, 2015 10:29 am Post subject: |
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Just an update on my saga here.
I added some spacers to the front diff (to bring it up closer to 2.5º down like the tranny flange. Things actually seemed worse. I had more pronounced vibration at lower speed in the 30-50 range. It did seem a little smoother at the 50+ range however. Pulling the shims out today...I am sure its not the answer.
If this problem does lay in the transmission like the main bearing as was suggested by one of you, is there a way to pinpoint it a little better than pulling the whole unit out? I am sure I'm close to needing a rebuild since its the stock unit with 170K on it. Problem is its almost summer and I am hearing AA transaxle is 2 months out on jobs.
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pedrokrusher
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Joined: July 11, 2011
Posts: 654
Location: Montreal, Quebec, Canada
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| Posted: Sat May 30, 2015 9:38 am Post subject: |
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Syncroflee, don't give up, you are almost there!
Believe it or not, the answer is in this very thread somewhere in a previous post. Which one is the answer now?
I think at this moment you need to start over and check everything.
Remember i said i had the wheels balanced, and in the end, one wheel, the rear passanger side was off balance and was causing a percentage of the vibrations? Well sometimes some work was not properly done, the machine was wrong, or the parts we believe was good turns out to be faulty.
Another thing i tried but gave no result for me (maybe for you?) is that i had also unbolt the 4 bolts of the driveshaft and turn the driveshaft a quarter turn. I did that the 4 turns at each end. 8 times in total. Very time consuming, but cost you absolutely nothing. Just lay a card board on the ground, slide under, unbolt, quarter turn, rebolt. Drive test. Redo. Write it down! And dont forget to mark the original position.
Just an suggestion, on the top of my mind, just like that... Maybe you should print this thread. Highlight with a yellow highliter all the ideas. When its done scratch it off. At some point one thing will work. But at least you really did each one! With a writen list you wont miss it... I guess...
Good luck my friend!
_________________
Pedro
1989 vanagon Karmann Gipsy #652, TDI AFN
1991 vanagon westfalia conversion TDI ALH Silverfox
ex-1989 vanagon syncro passenger Syncrofox (Sold)
http://www.thesamba.com/vw/forum/viewtopic.php?t=598791&highlight=
http://www.thesamba.com/vw/forum/viewtopic.php?t=493964&highlight=speed+aap+trans
http://www.thesamba.com/vw/forum/viewtopic.php?t=496589&highlight=carrier+bars
http://www.thesamba.com/vw/forum/viewtopic.php?t=506025 |
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IdahoDoug
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Joined: June 12, 2010
Posts: 10250
Location: N. Idaho
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| Posted: Sat May 30, 2015 9:59 am Post subject: |
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I just reread the entire thread and I'm puzzled. I could have sworn I read that you tried someone else's Syncro driveshaft that was smooth and it was rough in your van? Could not find that.
If the shaft being out smooths things out, then I think you still need to look at the shaft. Its an unfortunate thing, but some people do NOT know what they are doing with drive shafts. Most shafts are done for heavy power equipment where a crap job won't show up as the vibrations are lost on a huge machine. Or done for a 20 year old lifted F150 with 36" rubber that vibrates anyhow. So, perhaps you should borrow a known good shaft, or send yours to a specialist. I recommend my guy here absolutely.
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader |
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syncrodoka
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Joined: December 27, 2005
Posts: 12006
Location: Santa Cruz, CA
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| Posted: Sat May 30, 2015 10:07 am Post subject: |
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| A correctly speed balanced driveshaft should be smooth regardless of which position it is mounted in. |
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IdahoDoug
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Joined: June 12, 2010
Posts: 10250
Location: N. Idaho
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| Posted: Sat May 30, 2015 1:28 pm Post subject: |
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I did the exact same thing as Pedro did when my shaft was improperly rebuilt. I used a sharpie to mark each position in turn, and drove around in my coveralls with tools. A mile or so and I'd pull off and switch the shaft to try another position. I took notes on each position as to what speed it seemed to be best and worst. I was surprised that I found an obvious "best" position. This was still beyond acceptable to me, so I removed the shaft and brought it to my driveline guy. When I went to pick it up, he expressed anger at the driveshaft work I'd been sold and explained what he had done to correct their work. My kind of guy. I put it in and the Syncro had absolutely no trace of any vibration. Not even the slight vibration you think to yourself "Oh well - I'm just going to consider that tiny 54-58mph vibration acceptable. Crap." Nothing. And I used to evaluate cars for vibrations and noises.
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader |
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insyncro
Banned
Joined: March 07, 2002
Posts: 15086
Location: New York
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| Posted: Sun May 31, 2015 6:47 am Post subject: |
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| syncrodoka wrote: |
| A correctly speed balanced driveshaft should be smooth regardless of which position it is mounted in. |
Yup, any flange position and guibo front or back...it shouldn't make any difference when the shaft is "properly" balanced. |
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Zeitgeist 13
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Joined: March 05, 2009
Posts: 12115
Location: Port Manteau
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| Posted: Sun May 31, 2015 10:09 am Post subject: |
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Has anyone experimented with a guibo on both ends of the shaft?
_________________
Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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insyncro
Banned
Joined: March 07, 2002
Posts: 15086
Location: New York
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| Posted: Sun May 31, 2015 10:26 am Post subject: |
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| Zeitgeist 13 wrote: |
| Has anyone experimented with a guibo on both ends of the shaft? |
No but GW's donut-less units have surprised me and are very smooth  |
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syncroflee
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Joined: October 11, 2013
Posts: 11
Location: Snohomish
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| Posted: Sun May 31, 2015 1:31 pm Post subject: |
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Thanks for input guys:
I'll try the 1/4 turn method later this week when I get some time to mess with it.
All my front end bushings and mount bushings are new polyurathane ones and seem to have the proper amount of wiggle to them when yanking on the transaxle etc...
As far as the shaft being balanced I guess never say never but tried 2 different shafts (both new) the second on has been brought into Drivelines NW in Everett 2 different times with it basically needing nothing done. I asked if they spin it at high rev and I was told they balance their shafts at 3000+rpm. I also tried a known virbrationless OEM shaft early on in my quest for smoothness...
"new rear wheel bearings and I took out the shaft and had it checked and balanced 2 different times AND tried an OEM shaft out of a different syncro...I still vibrate. A Lot!."
Think I should try the goWesty donut-less shaft?
I'll keep chasing this thing down one way or another.....pulled my wheels and bringing them in for balance check today....they are new rubber so I pretty sure it wont yield results...never thought I'd wish for out of balance tires! |
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syncroflee
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Joined: October 11, 2013
Posts: 11
Location: Snohomish
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| Posted: Mon Jul 20, 2015 5:00 pm Post subject: |
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Update:
So when your favorite vehicle has issues that seem unresolvable what do you do....exactly, go on vacation! Wife and I went to Europe for a month which was very cool for a lot of reasons..one of which was all the vanagons still running around over there! Most of them work rigs...quite a few dokas and the like..but saw several Westies from Mid 80's to '91...very cool.
I digress.... prior to leaving town I drank too many beers and binge ordered the donutless go-westy shaft..it showed up 3 days prior to our trip so it sat in the garage for over a month. Today I pulled my troublesome rebalanced twice replaced back massaging vibrating slip yolk out and popped in the new shaft. Loosened up the diff bolts and...and ......
NO VIBES!
drove it around town for about 5-6 miles...cranked the diff back down and took it on a 75 mile loop....virtually zero vibration. Little bit in the 45 mph range but soooo minimal. I am ecstatic...I cannot explain why 3 other shafts shook the cabinet doors off and this one does not...but I am not going to temp the Syncro gods and ask questions. I am a big dumb ear to ear smile again!...
So...who wants to buy a slip yolk shaft? 
Thanks for all the advice and help...it really kept me from going nuts and just selling the damn thing...you Samba guys rock...
sincere THANK YOU!
Lee B |
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pedrokrusher
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Posts: 654
Location: Montreal, Quebec, Canada
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