Jump to content
Sign in to follow this  
Stanley

Balance driveshaft after installing new U-joints?

Recommended Posts

I was advised to have the driveshaft (propeller shaft) balanced after putting new U-joints, which is scheduled to happen this week.

 

There's a new vibration last few weeks that may or not have to do with the U-joints.

 

No vibration previously, and the driveshaft hasn't been altered or dropped, so balancing seems unnecessary to me. But maybe I'm wrong.

Share this post


Link to post
Share on other sites

Balancing wouldn't hurt, but if the vibration wasn't there before you changed the U-joints, something is out of alignment since the change.

Did you check the clearance in the U-joints? There are Snap rings available from 2.00 to 2.06mm to get the clearance within specs. If the clearance is excessive then the propeller shaft be of center and vibrate.

 

TWhen I did the u-joints they were delivered with standard 2.00mm snap rings. After fitting them I put the yoke in the bench vice and tapped the other side with a rubber mallot to get all the cups out against the snap rings. Measured the movement with a dial indicator and divided that by two. They ended up at 2.04mm on both ends of the propeller shaft and the diff flange. The transmission yoke needed 2.06mm IIRC.

It doesn't sound like much, but it could be enough to cause the vibration.

post-25317-0-36984600-1438119301_thumb.j

Edited by EuroDat

Share this post


Link to post
Share on other sites

What year Z, and what speed do you notice the vibration.  The early ones had a shaft vibration at speeds over 55.  the old joints might have dappened the vibration.  The speeds the vibrations start and sometimes stop give clues to the issue at hand. 

Share this post


Link to post
Share on other sites

Cheap u-joints and or excess clearance can affect the balance. If you installed quality u-joints, the problem is probably lateral movement as described by EuroDat in #2. In my experience, driveline vibrations have occured at higher speeds, 80 mph + and the front joint has been the cause. With the car on stands, grab the front of the shaft and try to move it horiz. and vert while watching the u-joint. There should be NO visible movement other than rotational. I've not encountered a balance problem with OEM or a quality brand. Spicer has been my choice and was recommended by our local primo drive line shop.

Share this post


Link to post
Share on other sites

73 Z. Vibration is noticeable after 35 mph and gets worse with more speed. I'm staying off the freeway until it's fixed. Sounds like a tire going flat at 50 mph plus. Got the wheels rebalanced; tire shop said they were balanced ok anyway; made no difference. 

The new U-joints haven't been installed yet. A few weeks ago I had a shop put new front wheel bearings. Supposedly they also installed new lower control arm bushings and greased the rear wheel bearings. This was after I reported various noises that started after they installed new front pads and turned one rotor. The noises just got worse after they worked on it again, and the vibration started soon after.

 

A different shop is doing the new work.

Share this post


Link to post
Share on other sites

I'd be real suspicious of any shop claiming to have greased the rear wheel bearings. Given the effort required to get there to do that, unless they charged you for 2-3 hours for that item, they didn't do it at all. I see you've already had your BS detector tripped and went to a different shop. Very wise.

Share this post


Link to post
Share on other sites

Have you checked the condition of the mount for the diff? Mine was all torn up from the diff being moved up and down due to rotation from the driveshaft. i would double check that. 

Share this post


Link to post
Share on other sites

Yep, They are servicable per Aug 75 type. The snap rings are on the inside and hard to see. If it was the non-servicable type you would be able to see the spurs pushed in on the outside to hold the cups in place.

 

post-25317-0-44254300-1438194211_thumb.j

Share this post


Link to post
Share on other sites

OK, picture worth 1000 words. But the new Moog U-joints I bought have the snap rings on the outside. Will the still work?

Share this post


Link to post
Share on other sites

External clip u-joints typically have the groove for the clip machined in to the yoke.  The Nissan type, internal, have a flat machined in to the yoke fro the clip to sit on, but the groove is on the u-joint bearing cup.  So they're not interchangeable.  Stole a picture from the ZStore below.

 

I'm with zKars, I think that your first shop may have sent you off on a wild goose chase.  May also have screwed something up.  Probably started here - 

 

"This was after I reported various noises that started after they installed new front pads and turned one rotor. The noises just got worse after they worked on it again, and the vibration started soon after."

post-19298-0-89654900-1438199066_thumb.p

Share this post


Link to post
Share on other sites

Ordered a new driveshaft with oversize Spicer's. This is getting expensive, but it's probably not a bad idea to replace those old parts.

Share this post


Link to post
Share on other sites

I think that most of us were recommending that your drive (propeller) shaft wouldn't be the cause of the vibration.  But, who knows.

 

You're caught in the morass of many changed things, and a problem.  Have you had the front end rechecked?  Who turns just one rotor?

Share this post


Link to post
Share on other sites

The noise and the vibration sound like at least two separate problems. Maybe there's a loose bolt somewhere. I'd like to fix one thing at a time and test the car before doing anything else, but I'm not telling them to do that, it would take way longer. A lot of the work is stuff I've been planning to do anyway, like brake upgrade and heavy duty U-joints.  There's still more left for someday.

Share this post


Link to post
Share on other sites

Keeping the yoke and shaft orientation one to the other should keep vibration from returning. The shaft was balance that way so putting it back that way should be fine.

I agree with the guys in thinking you have other problems here.....

Share this post


Link to post
Share on other sites

I agree with Jim, also in the future instead of buying a new driveshaft. We have a local company that rebuilds shafts and balances them. It's a pretty common thing for heavier trucks and racecars. I am sure you have a similar service in your area. Cheaper than a new driveshaft. Like $60 for 2 u joints and a balance

Share this post


Link to post
Share on other sites

Got the driveshaft and diff mount installed today. Also new rear wheel bearings. Noise (the ratcheting noise that I posted about, a month or so ago; it was occasional at first and got worse and frequent) and vibration are gone.  Also the car feels smoother somehow on the road. Old wheel bearing were loose,  mechanic reported. He found  some new grease smeared around but none in the bearings. Diff mount was worn and weakened but not totally shot, think I replaced it when I bought the car.

 

Silky smooth now, feels faster, but probably imagining it. Brake upgrade next week.

 

Heard the mechanic telling other mechanic cause of the noise. Forgot to ask him later but heard something about "needle bearings". I first thought the noise was coming from the left front wheel. But I duct-taped a little recorder under the fenders, one at a time, and test drove it. I wasn't coming from there, but I never could hear where it was. Thought the vibration was from right rear wheel, also wrong on that one.

Edited by Stanley

Share this post


Link to post
Share on other sites

Great news. Nice to hear you have an excellent result too.

 

I might have gave you some bad advice in the second post. I misunderstood you post and thought you already replaced the U-joints and then had the vibration.

 

Chas

Share this post


Link to post
Share on other sites

So I was wrong to blame the first shop for the noise and vibration, and they mentioned bad U joints. But zKars was correct, they lied about greasing the rear wheel bearings, and took some shortcuts. If they had R&R'd them, why not put new ones?

 

Chas, thanks for the side by side U joint photos.

 

The boss at the new shop said to turn the new aluminum drums. "...they're probably from China...".

 

Charles, 2nd shop sent me to a driveshaft place in Gardena. $125 to install my (incorrect) new U-joints, $275 if they had been non-replaceable type. But they don't work on cars, and 24 hours to get  it done. Needed the car this weekend. I'd have had to R&R anyway, plus I'd have had to rent a car. So got this aluminum one I wanted anyway. Some bling no one can see unless they're under the car. The head suspension mechanic was pissed at MSA for the packaging. They could have stuck some wadded newspapers in there at least. Glad it only had a short ride from Orange.

post-23057-0-83387000-1438537781_thumb.j

Share this post


Link to post
Share on other sites

MSA is known for packaging problems, and not caring about it.  Only game in town, too bad.

 

I started a thread for MSA.  Linked this thread.  Hope you don't mind, let me know and I can edit it out.

Edited by Zed Head

Share this post


Link to post
Share on other sites

Stanley

That makes perfect sense and the lighter driveshaft is always good.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.