I'm getting a grinding, metallic noise coming from the left rear wheel of my 70 240Z. It starts out like a metallic clonk and then shrieking sound. My Haynes manual says this is the sound you will hear as a roller bearing starts to disentegrate...

It has something to do with load, as I only hear it staring off from a standing start in 1st and slightly shifting into second, then it goes away. I don't hear it at all at speed or accelerating while moving.

It's definately not the rear brakes. I think it's either the U-joint in the half shaft or the left rear axle bearing. So, any suggestions? Anyway to tell if it's the half shaft joint or the axle bearing? Wouldn't the axle bearing make noise pretty much all the time?

I've never taken the half shaft apart, could it be the half shaft instead of the u joints?

I can remember the same problem with my 71 about 33 years ago. It turned out to be one of the U-joints in the half shaft. The early cars had the off-set in the half shafts to the differential which put unusually hard loads on those U-joints. This would be the first place I would look. Hope this helps.

Dan

Let's hope it's a U-joint. Seems to me it could be a rear axle bearing. This is not fun to change out. The clonk then whine could also just be a tired differential. I've gone through several rear ends in mine.

You prob won't need to bother with taking a halfshaft apart. Look for a driveshaft repair shop in your town. In Orlando we have Advance Driveline. Shops like this can rebuild rear ends, install high quality U-joints and balance shafts after assembly. You need to bring the parts to mine though. They don't take'em out.

2c

Jim

Since the site was down, I had nothing better to do than work on the Z. Turns out it was the outside universal joint. You could see metal shavings coming out of it and it had a rust hole in one of the caps!

I had both joints replaced and put it back in, and the noise is gone. Only problem is the guy who did the work wasn't the greatest and bent one of the yokes. He says he got it "unbent" and tested it, but who knows.

Next, when I go to put grease in it thought the fitting, it starts coming out around the seal of one leg of the joint, pretty quick. Can I feel confident it's got enough grease in it?

Thanks,

Bob

If when the joint is lubed , do not push grease into the joint untill it shows. Stop when you see the rubber seal expand. If you are seeing grease , then the seal is out of it's seat and it will fling the grease out of the bearing cup as it spins . I must have changed close to 100 ujoints or more in my life time, and have never bent a yoke. What in the heck was he doing other than no paying attention . Gary

Kind of a long story, but the guy said that he didn't do as well when people talked to him, so I shut up (wasn't talking that much in the first place) Anyway, he then proceeded to talk non-stop to me (I wanted to just say, "Hey, Bob, no worries, you don't need to talk to me..." Anyway, you got it, he wasn't paying close attention and the piece on the bottom wasn't lined up properly, so it caught the old bearing and the yoke and bent the yoke.

Oh, the seal didn't expand, the grease just started coming out. Really!!!

This is exactly why I do all my own work unless I have absolutely no choice or any specialized tools are more then the repair. In my 40 years on this planet, I can honestly say that I have never paid anyone, ever, to do anything more than change the oil, tires, or balance the tires. Perhaps this is because I have always stuck with Toyotas, at least until now. Once I start building up my F54 motor I'll need to get some help.......those machine shop tools are probably going to be out of my budget.

I try to replace all the rear berings half shaftss & drive shaft every 3 years weather they need it or not.

bump

sorry to bump a old thread

but i was wondering ive got a similar problem in a C210 skyline same motor as a 240Z

now im a poor school student not 1 cent etc , and ive been getting a grinding sound my car is a auto 3 speed but im not to sure what gear it happens in but ive been babying it lately and ive been getting this grinding sound time to time not always probably about 3 - 5 times in a 20min drive, when i bought the car i had a mechanic drive it and inspect it and he said a uni joint or 2 is on the way out and a gear box mount , so was wondering is it possible for a uni joint to cause grinding sounds ?

please god dont be my gear box bearings / gear set the gears shift perfectly and do not slip etc only problem is when going from P to D it makes a clunk but meh and believe its the gear box mount making that sound , lately ive been feeling a bit of vibrations from the gear shifter but not to bad so i just prey its the gear box mount stuffing up more

Absolutely it could be a u-joint . If they are making this much noise you should be able to see and feel the play in the u-joint. Just lift the car and grab the half shaft and see if you can see any play. there should be zero play. The u-joints have vary small needle bearings in each of the four cups. When they fail the bearings just desintigrate and the shaft will start to wobble. When it gets to this point it is no longer wise to drive the car. If the u-joints are lubed from time to time properly they will last for years. Gary

ok please god be a uni joint

so the part which connects to the diff then the bottom of the shock / rear wheel assembly it called a half shaft?

are there any bearings in this half shaft apart from U joints

also will i have to drain my diff fluid removing the half shaft

found the busted joint its the one on the propeller shaft which connects to the transmition ,

so how hard is it to remove the prop shaft i see theres 4 or 8 bolts holding it to anther then would i just slide out if i removed them both or one ?