BigBirdsZ

My 79 280zx bounces like crazy at low speeds, it doesnt do it in nuetral, but when i stick it in gear it startes to bounce. I was told it could be the diferential bushings. has anybody experienced this kind of problem? help please

Bleach

Explain in more detail what is going on. Are you even moving when this happens?

If you coast in neutral (moving at speed) it rides smooth, but when you put it in gear and drive easy it bounces? Is it an even bounce, up an down in the rear or forward and back like the engine surging?

BigBirdsZ

it starts about a minite in to the drive at low speeds when its in gear it bounces it feels like its in the back it not the engine surging in nuetral its smooth ride but once its in gear and you start letting off the clutch it starts to bounce it like it cant handle the power

Bleach

One idea is your wheels are actually hopping. To accomplish this without trying, you would have to have skinny tires maybe even bald tires and your rear struts would have to be blown or so worn out they aren't doing anything. Does the rear end sag like crazy too when you accelerate?

BigBirdsZ

actually i have 235's in the back the tires arent bald their in pretty good condition, but i did notice a little sag in the back as for the condition of my struts i dont really no how they are but they arent blown and i geuss its possible the tires could be leaving the ground but it really doesnt feel like it leaving the ground i want to know if you know anything about bushings?

Bleach

Maybe something came loose. Your differential could just be hanging there by one bolt and vibrating around. Actually it sounds like nothing I've ever heard of. Weak diff mounting bushings cause a clunk as you accelerate. The 280ZX usually always sags in the back, but excessive saging is usually caused first by bad shocks, send by weak worn out springs.

BigBirdsZ

thanks i been thinking of getting new shocks any way

BigBirdsZ

i'll be gettin some uerathane bushings also so i hope it works

RodMoyes

1. Shocks/Struts have nothing to do with ride height...

2. It's the rear springs wearing out that cause the "Z car Sag"

I think it sounds like he is describing a bad case of clutch chatter... or possibly a bad axle joint. Still not clear on the symptoms, but if it only happens under a load, it's probably the cluthch or the axles.

Rod.

Carl's Z

That bounce COULD have to do with really bad rear struts, and to tell you the truth, when I first got my Z, the rear struts were so bad, it sat low enough so I could'nt see the top of my 205/60/14s. Put on new struts, and it started sitting about 1.5 inches anyway above the rear tires. So, I don't really go with the shock/struts not having anything to do with height. Same thing happened on my wife's old '83 Chevy Caprice. Sat real low in the front, changed out the shocks, and regained the height and ride.
Also, when the struts were bad, if I let the clutch out too quick without enough gas, it started "hopping" until I pushed in the clutch and gave it a bit more gas. Did that once pulling into a car show. Boy, did I feel like a dork!

Bleach

struts on these Z do have some upward pressure when new. I swaped out only the struts on a friend's 280Z using the same old stock spring. She gained about a half inch ride height in the rear.

BigBirdsZ

i performed a bounce test and it shows the struts are fine the sag i said was very slight i checked my freinds z and hhis z was slightly higher barely noticible my opinion is that it a rear end drivetrain problem whats clutch clatter?

Skully

does it kinda...go and jerks back then goes and jerks back...or bounces UP and DOWN actualy???



when i had that bounce...my tire was so worn out from fooling around that there was a foot of steel wire showing and a big *** bulge on the insides...and every time i would go it would hop up