I bought my first z last week, so don't know that much about the running gear. It's developed a vibrating from the rear of the car dependant on the speed. It's pronounced at 40mph and doesn't stop when the clutch is dipped.

 

I had the wheels balanced, and swapped the wheels over as there was an 8j and a 9j on the rear axel. Then bought new tyres. The problem is now worse than before, maybe because of more grip?

 

I haven't checked the brakes yet for binding but is there anything else I should check?

 

Cheers

Prop centre bearing has probably let go, or the prop has been removed and refitted out of line. A lot of times when people take them off, they don't refit them the correct way (the way that they came off), so they become unbalanced. You can adjust them by jacking the car and changing their seating (between both sections) gradually until you find the correct location. But have a look at the prop bearing. It's not a solid bearing and is supported by a rubber sleeve that's sat in a metal housing. When the rubber sleeve goes, the prop drops slightly and you get the vibrations you experience.

 

Other things it could be, but are less likely are hicas arms and other associated bushing relating to the differential and rear subframe.

Edited May 7, 201411 yr by Funkysi

Proper centre bearing has probably let go.

 

Ditto.

I'll take a look when I get home. silly question, but best place to jack the z up, the sills aren't perfect. Also should I pack the bearing with grease?

Rear jacking point is under the diff.

I bought my first z last week, so don't know that much about the running gear. It's developed a vibrating from the rear of the car dependant on the speed. It's pronounced at 40mph and doesn't stop when the clutch is dipped.

 

I had the wheels balanced, and swapped the wheels over as there was an 8j and a 9j on the rear axel. Then bought new tyres. The problem is now worse than before, maybe because of more grip?

 

I haven't checked the brakes yet for binding but is there anything else I should check?

 

Cheers

 

Common, common problem with the propshaft, the rubber support for the bearing becomes hardened and no longer allows the prop to "float" into the correct position, for this reason the problem is often worse at cold start and gets slightly better as it warms up with use.

 

Save your self a whole lot of trouble and swap out the unit as below one of my previous posts:

 

The original 300zx one piece prop shaft supplier in the UK

 

 

Due to continued enquires, we have increased our manufacture numbers of the one piece propshaft, rotational weight saving and smooth operation:

 

 

So we can supply a newly fabricated single piece propshaft for both the TT and N/A auto or manual for £225 this with your prop in part exchange.

 

The new units are fully balanced and are super smooth in operation, no more centre bearing issues to worry about and at a cost similar if not less expensive than having a new bearing fitted.

 

All of the work is done by our own fabricator so no waiting for delivery from the US and no import duty, and fully warranted.

 

Jeff TT

 

 

 

 

 

 

Be wary of imitations

I must get me one of these!

one of the first mods I ever did. Aluminium shaft from Z1 Motorsports..

 

one of the first mods I ever did. Aluminium shaft from Z1 Motorsports..

 

[ATTACH=CONFIG]79198[/ATTACH]

 

Interesting. Had no idea Z1 props use a different forward joint.