Bench Testing Half Shaft U-joints

[Hardway]

I have the rear suspension apart on my '72. It has a R200 diff in it and factory half shafts. I did not get to drive the car very much prior to pulling everything apart. The half shafts need new boots which I plan on replacing but question is there a way to tell if the u-joints are bad? They are grease-able units which leads me to believe they have been replaced at some point in the cars life. If there is no way to bench test them should I replace them with some solid brute force joints for assurance or just pump them full of grease, drive the car, and go from there?

[madkaw]

Not only U-joints, you should check the condition of the spline and ball bearings. probably not using the proper terminology, but anyway, ...

put the halfshaft body in a vise securely, then extend the inner shaft out and try and work it up and down. There should be no play, if there is, you need to find some better shafts.

Someone might have a good method for checking U-jonts off the car.

[Lazeum]

Been working in half shaft & steering company (Delphi), I can tell you the only good way to check is a bench with torque actuator to measure lash. In our garage, the only way is to check for lash by hand but it is not always easy to feel. If you had no noise before, there's no need for anything else.

Anyhow, getting half shaft out of the car is a matter of lifting rear wheels, remove them, remove half shaft bolts & pull apart shaft. It's an 1h job if you take your time. Bottom line, don't spend time redoing them if they feel tight, you can do it easily whenever you'll need it.

Make sure anyhow that boots on spiders are fine, if you have dirts going into needle bearings, they failed quite shortly. You might also be able to add some grease since you're at it.

Wear on them will most likely be fatigue so no deflection might occur before they fail eventually. If you don't launch your car & you do not have crazy power, you should be fine otherwise they'll fail without any notice.

Do I what I say, not what I do : I've replaced mine while I was working on them, you need a press (I used 25t), some fixtures to hold them up & some time. I have redone them also because I've shortened the driver side to avoid bottoming issue due to R200.

Edited February 6, 2013 by Lazeum

[Hardway]

Thanks for the info guys. I plan to open them up, clean out any dirt, check the condition of the splines and balls, re-grease, and put back together with a new boot and straps. Part of me wants to replace them as getting a socket on the side of the flange where the zirk fitting is located is a PITB. I will be dropping my rear hubs off at a Z shop in town to put in new bearings and I may have them put in some new u-joints in to the axles as well. That way everything should be good for many years to come.

[EuroDat]

Its hard to feel if a U-joint is good by hand. The spigots get fine lines in then caused by the needle rollers. This is generally on approx half of the spigot caused by the driving force. The side where to force comes during de-acceleration does not get this that much. The lines can cause noise under strong acceleration. If you have any doubt, I would change them.

Check the bearings and the spacers for wear by checking the end play. Clamp the large section of the shaft in a bench vice and used a dial indicator to check the up and down movement. Should be less than 0.1mm. It will be hard to find parts for this. Datsun/Nissan sold the shafts as a complete unit. Only the boots and U-joints were sold apart.

I have heard of people swapping half shafts from left to right/right to left. That way the accelerating force is then on the good side of the spigots and balls. Its not my preferred way to fix it.

Chas

Edited February 6, 2013 by EuroDat

[Mike W]

If you are not sure if they have been replaced recently, then I would just replace them while you have them out of the car. That's what I did when I refinished my rear end suspension. Everything got replaced, regardless. You know how it goes............. while I'm at it....... Admittedly the half shafts are not that difficult to remove from the car, but it is still work and they are accessible right now.

In any case, dealing with the boot replacement is much more of a PITA than replacing the u Joints in my opinion. I completely disassembled the half shaft sections so I could slip the new boot on. My old ones were in bad shape and so needed to be replaced but I could not find a way of getting the new one on the shaft without disassembling them. If you decide to do this be very careful as there are both roller and ball bearings that will easily fall out as you remove one part of the shaft from the other. There is also a C clip you will need to remove from one end in order for the inner shaft to be removed from the outer. Finally getting all of the balls and rollers back in was tedious and time consuming. I used lots of grease to help hold the bearings in place as I re-assembled and this did help but it was still a lot of work.

I have pictures of this operation if they would help you out. Just let me know and I will send them to you or perhaps this is the reason we have been looking for in terms of trying to get together one of these days.

Let me know if I can be of some assistance.

Mike.

[Zed Head]

They are grease-able units which leads me to believe they have been replaced at some point in the cars life. If there is no way to bench test them should I replace them with some solid brute force joints for assurance or just pump them full of grease, drive the car, and go from there?

Whoever put the R200 in probably installed the R200 half-shafts also since the R180 had bolt on half-shafts, the R200 half-shafts bolt up to a clip-in flange. I think that the R200 shafts came with threaded holes for Zerk fittings, so that wouldn't be an indicator of stock. Look for Japanese writing on the u-joint caps instead to see if they're stock.

Also, examine the dust seals on the u-joint caps for red dust (rust) or dryness or just cracking and falling apart. I've found the stock u-joints are very durable and of high-quality. If they're still lubricated, I would just refill them through the Zerks and run them.

I did have one half-shaft that wore out on the telescoping body of the shaft. I don't know if it got shocked or dried out but it wouldn't telescope freely any more. So they do wear out sometimes. There's a procedure in the 280Z FSMs for testing play on the R100 half shaft. Download 75, 76 or 78 (77 is too bulky) and look at the Rear Axle chapter.

[Hardway]

My half shafts bolt up on each side to a 4 bolt flange. After doing some reading to determine exactly what I have I came across the site and article below. My driver side rear wheel bearing is shot as I can hear what sounds like a ball or two is missing when I turn the hub by hand. Other sites indicate the driver side half shaft should be shorter than the passenger side to make up for this. It is possible mine were not installed correctly by a PO. At the very least I think I will be replacing the u-joints and continue researching exactly what I have and ensuring it is installed correctly when I put it back together.

Beta Motorsports, LLC Bench Racing

[Zed Head]

The rear wheel bearings are kind of noisy in general, with no load on them, up in the air. Mine also sound a little rough, but I've put almost 40,000 miles on them since I noticed.

Did you read the link at the end of Lazeum's post #3 (hidden unless you notice the blue font)? He shows one way to shorten the shaft. The problem with the R200 in the 240Z's seems to be that the distance between the wheel flanges is (must be) shorter on the 240Z vs. the 280Z, unless the body dimensions changed. The wheel axles and companion flanges are different, 25 spline versus 27 (I think), and unless the body dimensions changed that must be where the difference comes from. Some trivia, I've never actually seen a measurement.

My post #7 didn't make sense as far as "bolt-in" shafts. I meant bolt on flanges. And it's irrelevant anyway, I think that the half-shafts are actually the same. But the half-shafts that I do have, from R200 cars, all have the Zerk fitting hole, for greasing, no solid u-joints.

[cajunz]

Very good info in this thread. I have a quick question about the half shafts out of my '78. I noticed that on one of them, when you extent the inner shaft out to full extension, it doesn't retract itself like the other half shaft does. What would cause this and is this gonna be a problem? It doesn't make any noise and there isn't any play between the inner and out shafts. Thanks for any help.

[EuroDat]

The only thing that will retract the shaft is the rubber boot. If it doesnt retract doesnt mean something is wrong with the bearings and spacers. Most likely a differance in flex in the boots or the bearings grease is starting to dry out and requiring more effort to retract.

You can inspect them by carefully removing the retaining clip on the big end of the rubber boot. This way you can pull the boot back and check the grease and the balls. Slide them in and out to check them.

If you have to grease them, you need to remove a circlip to get them apart. Be carefull, the bearings fall out and go everywhere if you are not carefull. Clean all old grease off and use high pressure bearing grease. They can be a pain to get back together. You just dont seem to have enough hands to hold everthing at once.

Replace the retaining clip by using vice grips to grab the band and a screwdriver as a lever. Thats a bit of effort and practice, but keep at it and you will get it tight and secure.

Left and right shafts are the same, but I would not mix the parts. Keep all the parts match.

Chas

[EuroDat]

Double post