Fresh Legs for the Z32

The reason for the 300ZX visiting my garage was leaking rear struts. Not surprising - they're the factory originals with 32 years on them. Only 38,900 miles, but time doesn't care about mileage. I decided it was time for a full suspension refresh with KYB struts all around.

I started with the rears in early November. Getting the strut assemblies out of a Z32 is a bit of a wrestling match - the suspension arms don't exactly drop down on their own. My solution was a ratchet strap to pull the arms down far enough to clear the strut for removal and reinstall. Worked like a charm.

One thing I noticed during disassembly was that the factory rubber strut mounting gaskets were completely shot. The OEM replacements are absurdly expensive, so I designed a set of gaskets and printed them in TPU. The flexibility of TPU makes it a great substitute for rubber - it'll handle the vibration dampening while lasting a lot longer than the originals did.

I came back to the fronts in late December. Same process - old struts out, new KYB assemblies built up with the printed gaskets, and installed.

The difference is immediately noticeable. The car feels planted and composed in a way it just wasn't before. Thirty-two years of slow deterioration means you don't really notice how bad things have gotten until you put fresh components in. The Z32 is riding like it should again.

I'll Take Transmission Fluid Over Eggnog

With the 300ZX convertible getting a full refresh this fall and winter, the transmission and differential were next on the list. Both still had their factory-original fluid from 1993 - 32 years in service. Christmas Eve seemed like as good a time as any to change that.

I started with the transmission. The drain plug is magnetic, and after pulling it the fluid came out looking about how you'd expect for three decades of service - dark, but not terrible.

The magnet on the plug looked normal - no concerning metal or shavings. That's a good sign for a transmission with only 38,900 miles on it. I refilled with Motul MT-90.

Next up was the rear differential. Same story - original fluid, same vintage. I drained it and refilled with Red Line 75W-90 GL-5+ Full Synthetic. I didn't grab any pictures of the diff work, but the process was straightforward.

Between the coolant flush, clutch fluid bleed, and now the transmission and diff, all the factory fluids in the drivetrain have been replaced. The only original fluid left in this car is probably whatever's still hiding in the power steering system. One less thing to worry about heading into the new year.

New Rubber for the 300ZX

The 300ZX was rolling on tires that were well past their expiration date - over 20 years old, and the sidewalls showed it. Dry rot and cracking all the way around. At that point it doesn't matter what the tread looks like; age is the killer and these were long overdue for retirement.

I ordered a set of Falken ZIEX ZE950 A/S Ultra High Performance All-Season tires in 225/50R16 from Tire Rack - my go-to for tires. They showed up quickly as usual. Once they arrived I mounted them myself, putting the tire changer to good use again. That machine keeps paying for itself.

The Falkens are a solid fit for the ZX - the Z32 isn't a dedicated track car, so an ultra high performance all-season makes more sense here than a sticky summer tire, especially at this mileage. Fresh rubber makes a noticeable difference on a car that's spent so long on cracked and hardened tires.

Pass the bottle!

The 300ZX has been getting a full fluids overhaul, and the clutch hydraulic system was next in line. I've been working through every reservoir on this car - most of it still running factory-original fluid after 32 years - and the clutch master cylinder was no exception. A look through the reservoir told the story pretty quickly.

I popped the cap to confirm what I suspected. The fluid was dark brown and well past its service life.

With the car on the lift, I got eyes on the slave cylinder for the first time. The NABCO unit is heavily surface-rusted on the outside - not surprising for a 32-year-old car - but the bleeder screw was intact and cooperative.

I attached a bleeder bottle to the slave cylinder and flushed the system from the master cylinder down. Fresh DOT fluid all the way through.

The clutch pedal feel is noticeably better. Hard to argue with fresh fluid after three decades.