I am going to media blast in a blast cabinet all my suspension parts. My half shaft u joints seem to be in fine condition; would it harm the u joints to put them in the blast cabinet as well to blast the half shafts for paint?

I wouldn't recommend sand blasting the half shafts with them being fully disassembled. The media will get into everything even if you think it is sealed.

The plate under the differential is a damper, and a good spot to jack the car up. It is stock on a 280z. The other plate in pic 7, is actually a rubber flap, backed by a sheet metal bracket. it is stock as well, not sure the original purpose but it's fabricated like a splash guard or something.

Remember the exploding Ford Pinto? I was told the rubber flap, backed by a sheet metal bracket was Nissan's solution to keep the gas tank from rupturing on rear end collision.

Who sells the OEM rubber suspension kit? I'm going with the original stuff all the way.

I went with OEM rubber suspension on my 1993 300zx. Only problem is that Nissan does not offer the rubber, only the complete part. So was kind of expensive.

Bought most of my parts from Courtesyparts.com. This is a link to their 1st gen z suspension. It's best to give them a call because not all parts are listed on the web site.

http://www.courtesyparts.com/240z-260z-280z-parts-s30-1970-1978/suspension/-c-7724_7762.html

Use Poly on the FRONT of the TC bucket, and rubber on BACK of them. This gives the needed flexibility to reduce the bending stresses on the TC rods, and gives you all the benefits of poly.

I disassembled, cleaned, and painted the entire underside/suspension/crossmember/drivetrain of my 240Z in about 2 months, on jack stands. I used all Duplicolor products. I got a barbecue brush with a scraper built into the tip, and brushed the entire undercoating clean. I then took the liberty to spray a very light coat of new undercoating under the entire car, and wheel wells. You might want to get new seals in the diff and the trans while it's all apart. Also consider, a new seal and o-ring for the speedometer pinion, and think about the ball joints if they are old. If you are dropping the entire suspension, there is much easier access to all those aforementioned things.

Edited October 18, 201113 yr by cygnusx1

All vertical suspension parts should be done with OEM rubber and horizontal parts done in polyurethane. Less squeaks, good riding car but a great handling car.

My '93 300zx I think of as more of a luxury sports car and the 280z more of a real sports car. Planning to do the poly upgrade on the 280z. Did OEM rubber on the 300zx.

What does everyone think about doing vertical suspension parts with OEM rubber and horizontal suspension parts with poly for the first generation Z?

Seems to make a lot of sense.

Edited October 18, 201113 yr by jkeese01

My '93 300zx I think of as more of a luxury sports car and the 280z more of a real sports car. Planning to do the poly upgrade on the 280z. Did OEM rubber on the 300zx.

What does everyone think about doing vertical suspension parts with OEM rubber and horizontal suspension parts with poly for the first generation Z?

Seems to make a lot of sense.

Doesn't make a bit of sense to me. Vertical and horizontal suspension parts? Are you talking about the direction of loads experienced by the parts? What is this going to accomplish?

I'm assuming Hunter260z was talking about the direction of the load. On rough pavement, wouldn't the rubber suppress more of the vibrations, and on curvy roads the poly would sharpen the handling? But I'm not an engineer or mechanic.

Plan to upgrade to poly on the 280z and looking at different options. Some people say the poly is too harsh and others love it.

Vertical loads are picked up by the upright and absorbed by the spring/damper. Lateral loads are picked up by control arm and steering rack bushings. Longitudinal loads are picked up by control arm and T/C rod bushings. Stiff springs with poor/improperly spec'd dampers will contribute to a harsh ride. I have no clue what bushings of "vertical parts" refers to.

Rubber will isolate the vibrations more, but you suspension will be better controlled due to less compliance (little movement at bushings). Like I said, springs and more importantly, dampers, will affect the ride more than bushings. I have poly, but I also have a stiffer suspension setup so I can't really comment on the effect of just the bushings. The ride is stiff but tolerable.

From your explanation, those unhappy with their poly bushings should first look at the springs/struts. I have KYB AGX Adjustable struts on the 300zx. The ride goes from standard feel to pretty harsh adjusting the firmness setting. I see your point here.

So rubber bushings would probably suppress vibration issues with the car itself. Road vibration tuning is the responsibility of the struts.

Edited October 19, 201113 yr by jkeese01

From your explanation, those unhappy with their poly bushings should first look at the springs/struts. I have KYB AGX Adjustable struts on the 300zx. The ride goes from standard feel to pretty harsh adjusting the firmness setting. I see your point here.

So rubber bushings would probably suppress vibration issues with the car itself. Road vibration tuning is the responsibility of the struts.

Bingo.

UPDATE: I completed this project and have driven my car some. Overall compared to my wore out suspension it feels much better. I have not heard any squeeks on my suspension whatsoever and the ride is not harsh in my opinion. Clearly my old Mulholland struts were wore out but with the combination of the KYB strut inserts and Eibach springs, the ride is compliant but not rough. I do only have 14" wheels so this could all change when I go to 16's. I would do it again.