240z Vibrates

[NismoZ]

Hi All,

I recently have gotten this issue of vibrating yesterday..probably due to these L.A streets beating on my car .. anyway the vibration appears only around or above 50mph coasting but not under load.. also car has just recently got a clicking noise coasting to a stop while braking near the rear. Not sure if this is all related but it has all happened at once and in the last couple days. Any suggestions? Could this be U-Joint?

Thanks

[Walter Moore]

It could be a U-Joint. It could also be that you have a wheel out of balance. The clicking noise, I am not sure...

[BTF/PTM]

My own z has a light clicking sound that I hear during the last part of coasting/braking down to a stop. As Walter mentioned, it sounds like it's coming from the rear of the car and I suspect it's just one of the U-joints spinning. I can't move any part of the U-joints by hand, which tells me it's not severely decomposed, so if it's getting loose I don't think it's urgent.

As for vibration, anything that spins can cause a vibration, and its location and sound are the best things to use to track it down. If your steering wheel shimmies along with the vibration, it's likely a front tire out of balance. If you feel it coming up through your seat but the steering wheel is stable, it's likely a rear tire out of balance. Vibrations that come with a metallic hum can be a drive shaft noise, engine mount noise, rear end noise or any other part that connects one vibrating metal part to another. Check bolts for tight, check U-joints for slop, check the engine oil level (low oil can increase engine vibration that's normally damped out), check transmission/differential oil levels, get each wheel up off the ground one at a time and try to move them laterally/axially to check for wheel bearing slop, so on and so on.

For what it's worth, my own car makes a few different metallic hums and drones at various driving conditions, so either that means she's gonna do like cartoon cars do and just explode to pieces and leave me skidding along in a hollow shell on the highway or it means that old z cars are talkative cars and just like to tell their owners what's goin on

[NismoZ]

Thanks for the fast reply's guys, I gave it a look right now and it turns out 3 of the drive shaft bolts where loose! everything els looks tight no loose joints that i could find..

Since my car was up skyward I decided to have a look at the rear brakes and im glad i did those things should have been changed yesterday... Is there a pdf instructional on here for drum brake replacment? Ive done drums before years ago but not on a z car.

Edited June 5, 2010 by NismoZ

[BTF/PTM]

http://www.xenonz31.com/s30/reference.html

That's a link to a downloadable factory service book. Best to order an actual copy, I got mine from Mike McGinnis at Banzai Motorworks.

Drum brakes are pretty simple, read the manual to make sure you have all the right tools before you dig in and make sure to leave one side assembled so you've got a reference. That technique has saved me multiple times!

[NismoZ]

Thanks BTF/PTM.. turns out i need to replace one wheel cylinder or maybe just the dust cover? not sure.

Edited June 5, 2010 by NismoZ

[BTF/PTM]

Glad I can help, this forum has helped me tremendously as I've fixed various bugs on my z so I'm happy to return the favor.

If you see brake fluid anywhere on any part of the wheel hub/brake cylinder assembly, you have a leaking wheel cylinder and/or a loose bleed nipple or brake line fitting. Check all the fittings first, I found a couple that were just loose enough to ooze when I did my brakes recently. Cinch them down with the proper flare nut wrench and it may solve your problem. If the wheel cylinder or any part inside the brake drum has brake fluid on it, the problem is most likely the wheel cylinder seal. The dust cover is just that, a dust cover, it is not a liquid pressure seal. Fluid getting past that came from the wheel cylinder.