What's the general consensus on the ball joint, replace or rebuild. The manual says replace if the dust cover is damaged, however the dust covers are still available from Nissan. The specs for testing the ball joint are also in the service manual.

I've managed to disassemble, clean and rebuild my original ball joints, any reason for not using them with a new dust cover and fresh grease?

Aside from replacing a part that meets Nissan specs, another factor to consider might be that used Nissan is probably better than new aftermarket.

13 hours ago, SpeedRoo said:

any reason for not using them with a new dust cover and fresh grease?

If there is more than 1 mm of play in the balljoints i would replace them, i believe nissan still have them? just look up the last part number and the dealer has the orig. part.. (If the balljoint comes apart.. someones life ends, would you take that risk?)

9 hours ago, dutchzcarguy said:

If there is more than 1 mm of play in the balljoints i would replace them, I believe Nissan still have them? just look up the last part number and the dealer has the orig. part.. (If the balljoint comes apart.. someones life ends, would you take that risk?)

I have no idea what you are talking about, there is no way the ball joint can come apart, it is a enclosed joint. The nut would have to shear off the shaft but even then there would be no catastrophic failure. How can you say someone's life ends if this happens? My question was if I should keep using the original balljoint if it meets all of Nissan's tolerances as @Zed Head said.

I would say yes, if it's not sloppy

Thanks @Patcon and @Zed Head for answering. I have stripped both joints down, they are the early 11mm type. I have lapped in the ball section to the parts it mates with using valve grinding paste, polished everything up with a brass wire wheel and reassembled. Will paint it in black satin as per original and grease up before removing the grease nipple and fitting the original plug @zspert mentioned should be in place.

Hi SpeedRoo

Please post some photos when you are done so we can see how they turn out.

On 7/29/2025 at 7:47 PM, SpeedRoo said:

I have no idea what you are talking about, there is no way the ball joint can come apart

If the ball wears out it can come out of the sleeve and make the car completely uncontrollable, never seen that happen in reality? Over here in the Netherlands we have strict rules about them, over 1mm play (around that) means new baljoints! It's just for safety.. but hey in the Usa.. no problem offcourse..

On 7/29/2025 at 10:20 PM, SpeedRoo said:

they are the early 11mm type.

What do you measure to determine if they are 11mm or 14mm?

G'day @26th-Z ,

easiest way to check if you have the 11mm 40160-78500 or 14mm 40160-A8610 is by the diameter of the thread on the ball shaft. The early ones measure 11mm. The early steering arms 40052-E4101 R and 40053-E4101 L also have the smaller diameter tapered hole to match the 11mm shaft.

The original ball joint is peened on the body to lock the lower cap into position. Careful grinding away of the peen allows the lower section to unscrew without damaging the threads. The parts are then degreased in the ultrasonic cleaner followed by corrosion removal in the cleaner. A brass wire wheel is then used to polish them up. The ball is lapped into the housing and bushing using valve grinding paste. I've managed to find four of the early 11mm ball joints and steering arms in my parts stash and have rebuilt them all.

Everything is cleaned, re-greased and assembled. The tolerances and loading are checked per the data in the service manual. Once it passes, it's then painted in VHT satin black, a new dustcap fitted, the grease nipple removed and a OEM filler plug 40189-7300 fitted. They are now ready for fitting back to the car.

The beauty of many of the parts on the early 240Z is that they were designed to be serviced or rebuilt rather than discarded and replaced. I've been fortunate to find many new old stock parts to rebuild my May 1970 240Z with.

Edited 29 minutes ago29 min by SpeedRoo

9 hours ago, dutchzcarguy said:

If the ball wears out it can come out of the sleeve and make the car completely uncontrollable, never seen that happen in reality? Over here in the Netherlands we have strict rules about them, over 1mm play (around that) means new baljoints! It's just for safety.. but hey in the Usa.. no problem offcourse..

What a load of rubbish, there's no way the ball can wear out that much! The Japanese engineers that designed that part knew enough about metallurgy to design the part so that never happens. The cheap stuff now coming out of some countries may be a different case, but not the originals.

Edited 25 minutes ago25 min by SpeedRoo