Replace U Joints - Rebalance Driveshaft?

[SZR48207]

I can't seem to get a clear answer on this in my scouring of the web. It seems like, for the most part, you can replace u joints in your home garage with no issue, but I've seen a few places where someone says you MUST get the driveshaft rebalanced or the rear differential can be damaged.

What say ye?

Also, anyone see issues with using Precision brand or AutoZone u-joints (particularly AutoZone Gold non-greaseable) for a daily driver? It seems like Spicer are the best ones on the market, but I can't see how $80 for a u joint will be worthwhile on an 8 year old truck when you can very commonly find u-joints in the $10-$25 range.

 

[bluestream]

Yes, you can change them yourself, no need to balance anything. I used to use the socket in a vise method, but now I bang them out with a BFH

 

[Zaedock]

You do not have to rebalance your driveshaft after installing u-joints. Factory driveshafts are typically balanced without them.

I can't even count how many u-joints I've swapped out, both at home and in the field. I've found the Advance Auto "Brute Force" joints to be pretty good for the money. I will say though, that Spicer is hard to beat for top quality. I'm running 5-760-X in my front high pinion Dana 44 with 4340 alloy shafts turning 38's and they actually hold up well.

For a daily driver, the $15-$20 u-joint is perfectly fine.
I prefer the added strength of non-greasable joints, but either would be fine for your application.

 

[SZR48207]

Great! Thanks for the responses. Looks like I'm going to replace these soon.

 

[bluestream]

Reddy45, what vehicle are we talking about?

 

[andyd]

My BMW has "staked" U-joints on a 2 piece drive shaft. They have to be rebuilt by a machine shop set up to handle them. Or by a real clever mechanic using very basic tools, a grinder, a welder, and 7/8" OD wrought flat washers. Supposedly, they need to be re-balanced, but I have mixed front and rear shafts from different cars and had no problems.
On my Jeeps,I use U-joints from NAPA that cost about 20$ apiece

 

[97f150]

Just index your driveshaft and put it back on in the same orientation and you should have no problems.

 

[onion]

I might have some more specific info if I knew the year/make/model that we were talking about here... but here are some general guidelines:

Balance is a non-issue in 99% of applications.

The cheapest u-joints on the shelf will work fine 90% of the time. Unless you're doing some significant towing, or dealing with a poorly designed application (like a Jeep Wrangler).

Most u-joints can be changed in a reasonably equipped home garage- though some GM units (with molded plastic retainers) can be a real [censored] if you don't have a torch handy.

 

[SZR48207]

Originally Posted By: Bluestream
Reddy45, what vehicle are we talking about?


Ford F150 with the 4R70W and a single driveshaft with single cardan u-joints on each end (slip yoke and differential).

 

[97f150]

What year F150? My 2005 has staked in joints.

 

[Kruse]

Originally Posted By: Reddy45

What say ye?



Take a paint stick and mark how the yoke was attached to the driveshaft and also exactly how the driveshaft is connected to the rear end yoke and you will be fine.

 

[mechtech2]

There should be no need to rebalance the driveshaft.
Most of the mass of the actual joint is close to the center, and they are pretty symmetrical.

If you Do balance it, you probably will see some anomalies. But this was more than likely from before - they are not shipped perfect.

 

[SteveSRT8]

how true.

I've seen stockers that were WAY out from the factory!

The indexing is very important. But then again, looking carefully at anything before disassembly is generally a good idea.

 

[mechtech2]

When the new joints are installed, beat around the area with a hammer - it will seat and loosen them noticeably. Really... do this.The front U-joint and the rear should be the same angle. Shim the transmission or mount to do this [on level ground or a rack that raises the car by the tires.

 

[SZR48207]

Just reporting in that I got both switched out, although I learned the hard way that a ball joint press is worth every dollar (or no dollars if you rent one from AutoZone).

I actually broke my bench vise while trying to get the first u-joint out, so I had to resort to whacking it with a claw hammer. Took me 4 hours to get the first ones out, and then literally 15 minutes to do the 2nd set (with a press).

I noticed that with the rear of the truck jacked up, transmission in Park, i could rotate the driveshaft maybe 1/2" in both directions (and would see the rear wheels slightly turn forward/backward), but I wonder if this is normal slack since those splines have to catch?

The difference isn't as significant as I had hoped, but the ride feels smoother, or as smooth as it can be with a truck.

Next up is to drive a few thousand miles with some ARX in the transmission, then drop the pan, replace the filter, and do a coolant line flush of the fluid.

Thanks for the help, all.

 

[Kruse]

Originally Posted By: Reddy45

I actually broke my bench vise while trying to get the first u-joint out, so I had to resort to whacking it with a claw hammer. Took me 4 hours to get the first ones out, and then literally 15 minutes to do the 2nd set (with a press).


If you are absolutely, positively sure you have the proper replacements, you can surgically remove the old U-joints with a cutting torch. Cut through the U-Joint cross (not the cups) and when you have it in more than one piece, the cups can be removed by lightly tapping on them with a small hammer.
It beats having the pieces get deformed by excessive pressure from a vice or a press.