Bad U Joints on Drive Line?
 

I get a vibration in 3rd and 4th gear when under a load. It also seems like it vibrates at certain speeds. This happens on my 94 with the 5 speed. Last weekend, Brian Steel drove it and was not sure what it could be for sure, but thought it could be U joints on the drive line.

I was wondering if any one had had the U Joints go out or were bad on your car and what the symptoms were. If you think of something else it could be, let me know as well.

I am going to take the car to Small Car next week to have them check it out and find out what this could be.

I also have found out the at front end is out of alignment as well and have to get the fixed. I don't think that has anything to do with the vibration though.

Thanks in advance for any feedback. :)

Sounds like u-joints.

My SVX is fine but my 4wd Justy suffered that problem. Vibration really started around 80kph/50mph. The u-joints weren't designed to be replaced. My dad did something to the driveshaft on the Justy so it would accept "Toyota something" u-joints with grease capability so whever it starts vibrating we add another shot of grease.

That is what I had heard. Replace the drive line because the U Joints were not to be replaced. I will check on this. It hasn't gone very many miles since the new (different) drive line was put in during the conversion. It was a used one, so Brian may have some ideas. I hope that is the problem. :)

I had a vibration in my '95 SVX at about 90+ mph that I thought may be due to an imbalanced driveshaft. When I took my driveshaft out to get it balanced, the shop foreman inspected the u-joints and promptly said that both the end u-joints were bad, and there was no way he would be able to get the driveshaft to come into balance with those u-joints. I was a bit surprised at his conclusion, so I asked him to tell me the criterion for judging the condition of the u-joints, and it was very reasonable. Nevertheless, I had my local repair shop inspect it. He also said the u-joints were worn. Both guys said that if a u-joint pivot is not smooth throughout its range of travel or if it has any changes in stiffness when articulating it, that indicates a u-joint pivot is worn. By this criterion, 3 of the 4 inspectable pivots were worn out.

So, I went looking for a good used replacement driveshaft. I got the chance to inspect 5 different SVX driveshafts, one of which had only 27k miles on it, and by the wear criterion I described, every driveshaft had at least 2 worn pivots. I ended up buying elninoalex's driveshaft from his murdered black '92 SVX. The early SVX's have a CV joint at the middle rather than a u-joint. The driveshaft has about 100K miles on it. Two of the pivots were perfect, and two others were "worn". I'm not sure if it was the u-joints, the CV joint in the middle, or better balance, but elninoalex's driveshaft eliminated the high speed vibration.

During this entire process, I did a bit of reading on driveshafts. One key piece of info that I read was that a u-joint needs at least 1 degree of tilt to cause the needle bearings in the u-joints to spin and wear evenly. When I put driveshaft back into the car, it appeared to me that there was virtually no tilt in the driveshaft u-joints. This makes me wonder if this is not the cause for the premature "wear" in the u-joints that I inspected.

The straight shot from the tranny to the diff also made me wonder why Subaru is using a 2-piece driveshaft. I would think that a 1-piece driveshaft would fit just fine. Anyone have any insight on this?

drivelines
 

Earl,

I am also experiencing a vibration. I am currently having the center cv rebuilt (this is what the driveline shop decided to do though I question whether it will fix the problem).

Did you find your reason for the vibration?


Oh and the reason for the two peice driveline is because drivelines have a maximum length. I forget the number but any driveline over (42"??) must be supported in the center or there will be a vibration. This is what an instructor in diesel school told me though I have seen some pretty long drivelines since.

I have not checked out my drive shaft yet, because I am right in the middle of aligning the front end of the Blue 94. It was way out of allignment and wore out my front tires. They are totaly worn down to the belt on the inside. I didn't see it until I took off one of the front tires to have a screw taken out of the tire. It has been aligned twice before, and the previous owner said that he was not happy with the job they did. I am not either. The tires he took off of the car before he got the 17" wheels and tires show some wear in the same place.

I took the car to the Subaru dealership here in Burlington. They have a guy who really know SVXs. He can not break the nuts loose on the tie rods, and will let it sit over night to see if they can break them looose tomorrow. If not, they say that they need to replace the tie rods. $500 - 600!!! I want to find some used ones if that is the price. I have stock wheels and the older tires that I bought from the previous owner. Good thing I have them. I have to get all 4 tires replaced if I am going to use the 17" wheels again. The back tires are about 1/2 worn and new would be too much difference between them. :(

I just remembered that (I think) cbx-man has a carbon fiber drive line in one of his cars. I will check with him about that. :)

Check out this thread for replaceable u-joints.


http://www.subaru-svx.net/forum/show...light=rockford

Did the alignment shop tell you what settings were out of spec? From your comment on the seized tie-rods, it sounds like front toe-in is out of spec. What about front camber? I would think that if the wheels were heavily worn on one side, that would indicate camber is out of spec (too much camber?). Is the car lowered? If the problem is camber, and you can't get it to go into spec using the stock camber bolts, a company called "Specialty Products Company" makes a camber eccentric that may allow you to dial in the proper amount of camber.

http://www.specprod.com/

part # 81260

Many shops can order it for you. Its about $25.

This is a Subaru dealership. They have someone there that knows the SVX and does the work on them. They are trying to get the tie rods broken loose first, and I will talk to them today.

Thanks for the information. I will keep that in mind. :)

Tie Rods
 

Earl, I would be glad to give you a set of used ones for the price of shipping. Let me verify that I can find them.

Mike

staked u joints
 

Just ordered them. Thanks CBX-man. I NEW there was a way to replace them. Cost was about 50 bucks total.

getting my U joint replaced now
 

Timely for me to report, but I noticed a
shuddering when starting off with power,
coming from the rear. Put the FWD fuse it and it was gone. Nice smooth starts. Also noticed sounds
and vibrations that weren't there before. Lo and
behold the drive shaft U-joint was REALLY worn. Lots of slop and play when viewed on a lift, so that's being done now. Hope that's all, as I
also have this for sale (here and Ebay). It is a
great car, and i am honest. I also just replaced the A/C belt tensioner and belt. That bearing locked up and threw the AC belt. No idea when that happend but it was unusual to see no A/C belt.

Um...aren't tie rod ends only $40??

subaruparts link

Vibration gone
 

Repairing the driveline CV joint ALMOST eliminated the vibration. The car is considerably better now, though I can tell that there is some very small vibration still. So small that someone unfamiliar with the car would not notice it.

Initially the vibration was still there, then after a short distance it nearly dissapeared. This tells me that the CV had to work in a bit and eventually the vibration might go away for good.

Anyway I thought I should post this for anyone else that may run into the problem. I think it was related to changing the angle that the CV was used to working at.:cool: