So, I was getting a vibration in my 1995 coupe at high speeds. After a (much needed) new set of tires, that were balanced, the vibration was still there. After much further research and looking into it, I found that I was most likely looking at a u joint replacement. Here's where I need y'alls help:

I ordered four AC Delco 45U0400 U Joints to put in. Unfortunately, time constraints only allowed me to replace the driver's side half shaft u joints. In the process of removing my half shaft, it was extremely stuck, so it took a solid few whacks with a 2x4 and a mallet before the half shaft finally let go and hit the ground.
After that, my vice was not big enough to press the old u joints out, so I had to use the hammer and socket method. Well, the old u joints were so seized in there that it took me forever to get them out and I am nervous I may have done more damage than good in the process. Once one cap was out, I had to somewhat pry the other one out, which left a burr on my half shaft. I filed it down and finally got the new u joints in after much work.

Now I hear a clunk when driving and when it shifts gears. I know this has to be the u joints, so i'm wondering if I messed up the half shaft in the process or if I ruined new u joints by hammering them in? Any advice? Do I need to just order a new pair of half shafts and be done with it or do I try the whole thing again using a press instead now that they are free after what was probably 20 years of not being touched?

 

Hard for us to know without actually seeing the drive shaft and u-joint. You may have other issues going on and should check everything that moves i.e. wheel bearing, shocks and leaf spring mounts, etc. If you do have to get new u-joint do yourself a favor and get the Dana/Spicer without grease zerk.

 

You hammered the new U joints in? If you don't have a vise that opens wide enough, go to Harbor Freight, or other discount tool place, and get a C clamp big enough to do the job, Even gently, squeezing in new U joint's with plenty of grease to hold all those little roller bearings in place can be tricky; I don't know how hammering the u joint' caps together could do anything but jar and displace some of those rollers. Personally? I'd pull the caps again, I bet one or more little roller will be laying at the bottom of the cap; even though the U joint may have somehow, someway gone back together, a displaced roller can throw the geometry of the U joint off enough (I'm speculating) to cause a "thunk" as it now attempts to rotate through a less than perfect arc.

 

I have removed the u-joints on the half-shafts and main drive shaft with a hammer and socket also, with a 2x4 underneath, rotating the joints to get them to move. I had sprayed them with penetrant first. All this is aluminum so you have to be careful. I did not hammer them in, only tap them. U-joint shafts were pre-lubed before inserting. You may indeed have a roller out of place.

 

A tip for next time: Most auto parts stores will lend you a ball joint C frame press. They work great on U-joints too.

 

If one side was rusted solid - then the other side cannot be much better and the drive shaft may be a mess too. You kind of expected that you needed to replace them all anyaay so get them done. Rent the tools if needed to leave that hammer out of the deal. If it still rattles - jack it up and rock the wheel to see where the slack is.

 

My guess is you damaged a joint during assembly.
I have to agree about leaving the hammer in the tool box. Like the old saying goes you need the right tools for the job. Not picking on you, but you should never use a hammer for assembling the u-joints. They need to be pressed in. Hammers are for pounding in nails.
I always use Emery cloth where the cups insert to clean things up then apply wheel grease to the outside of the cups before pressing them in. Make sure they go in straight. Don't force them in if they start crooked. Im sure they are tons of videos on YouTube.

 

There is a lot of variation in universal cap dimensions. I used genuine Spicer ones last time in my 91 and they went in so easily. I used a hammer to tap them in, not because that was the only way to do it- it just went in so easily that I didn't feel like the hammer and socket was abusive at all. I did put the yokes and shaft up on 26 lb lead bricks I have so hammer blows are quite absorbed- but if you aren't working with oversized caps, it should be easy. even oversized caps can be pressed in, but it could be possible you marred the cap and roller surface internally...you would have to remove the shaft and give the movement a feel. It should have loosened up after a few miles and displaced enough grease to be able to rotate it through its arc to feel if it is good all the way around.
You could of course have an issue still with the side you didn't yet get to, or even the driveshaft. I have found d/s imbalance manifests itself differently- not a constant road speed vibe, but an oscillation up/down vibe at a constant speed (like a waah- waah- waah 2 or 3 times a second frequency).

good luck- it's just work, lol.

 

I appreciate all of the replies. I guess I didn't mean to sound like I abused them "hammering" them in. I used a mallet and socket and tapped it, but it did seem like more force was put in than I thought should be needed. It's sounding like I will pull both shafts this time and try again.

Unfortunately, I am a college kid with no garage, so I was pressed for time to get my car back up and running. I was at my parent's house and my vice was not big enough to press them in. I will make sure to either rent a tool or take it to a friend's shop this next time to have them pressed in. My main concern was that I screwed up the half shaft by beating a little too hard, but it sounds as if the half shaft is a little more rigid than I thought.

On the part numbers, I was looking at the Spicers and even called them to see what number I would need. The ones they said were the correct parts were nearly $60! So, I decided AC Delco has yet to let me down and I gave them a try. Can anyone verify the AC Delco 45U0400 part number as being a correct part for a 1995 coupe? From everything I've seen, they are. But I don't want to order another two if not. These are solid, non-greasable.

 

Pay the money and go with spicers. A hammer is cheap tool that will cost you the most. Good idea to replace the teflon washers while your in there. Your young and learning cheap and fast will always cost you more in the long run always listen to old farts. We made the same mistakes too.

 

I agree on all except don't rule out Moog u-joints in addition to Spicer.
Here's the best shop made tool for replacing U-joints

 

Two other possible causes of the "clunk":

1. Did not torque the hub nut enough.
2. Teflon coated washer. Either not reinstalled, replaced with a standard washer, or damaged and need to be replaced.

You might be able to determine the cause of the clunk by getting the tire off the ground, and listening while turning the wheel back and forth.

As far as the vibration, good luck with that. I've been trying to resolve that issue on my 95 for a couple of years.

 

This may be a dumb question, but bear with me. When replacing my driver's side half shaft u joints, I took the straps off of both ends and dropped the half shaft by lifting on the caliper. I did not pull a spline out with the half shaft. So would the teflon coated washer still be a suspect? I don't even recall seeing a washer in my procedure.

 

Yes, I beleive you are correct. If you took the straps of both end then obviously you did not loosen a spindle nut. I have never seen Teflon washers used in the u-joint area.

 

I broke out my service manuals as I too have 95. If you like I can email you some of the pages. I found this interesting :

 

2nd paragraph

 

 

2nd paragraph



And it goes on with how to balance. Lots of good info.

 

Not a dumb question, and you are correct. You won't see the washer removing just the half shaft. I forgot, but when I did mine, I replaced u joints and hubs at the same time, thus I removed the spindle nut. There are a lot of threads on here about the loud clunk issue you are having. Those that developed the sound after replacing the u joints or the rear hub typically narrowed the issue down the washer.

Have you tried to replicate the clunk by rotating the wheel?

 

I have not tried to replicate the clunk yet. I bought a used half shaft off flea-bay and pressed in new u-joints THE RIGHT WAY this time I am planning on putting this half shaft on the passenger side, pressing new joints into the passenger half shaft, and putting it on the driver's side. This will allow me to really inspect the driver's side half shaft and trash the u joints I had into it. Let me just say, it's a little bit of a chore to have a 20 year old Corvette as a daily driver and not having a back up car. But I absolutely love this car and the community it brings!