nismo542

iTrader: (2)

i posted this in the clunking noise thread but i figured i would make a thread so it would be more easily found by members searching for a way to fix the suspension clunking sound that can occur with our Zs.

i noticed this clunk coming from the rear of my z around the shock area of the driver side and more recently the passenger side also.

well today i finally got around to a little inspection to see where the noise was coming from. i have stance gr+ coilovers and didn't notice any noise for months after i installed them.

i have read a lot of posts about how the shocks and other parts have been replaced under warranty but the noise still comes back sooner of later.

well i think i have found the cause of our problems and why it comes back and why it can also effect aftermarket shocks.

i started by removing my shock from the driver side and noticed that the hole that the lower mounting bolt goes through had the paint worn off and left an "oval" where the bolts had been rubbing up and down when i went over bumps. the bolt was still pretty tight, but the problem is that the bolt hole in the shock is a little larger than the bolt that mounts the shock. you can also see the wear on the inside of the hole where the bolt was hitting the top and bottom of the hole when i went over larger bumps in the road.

the noise from the bolt hitting the shock would travel up the shock to where it mounts to the body and then would be amplified by the sheet metal of the shock tower. if the shock is replaced the noise goes away because the lower bolt is removed and re-torqued when the shock is installed. if the bolt loosens at all from fully torqued then this problem can reoccur. the root of the problem is that they had to make the hole bigger since they needed to have some tolerance there because the nut is actually welded to the other side of the shock. if they just didnt weld the nut to the shock and left it seperate like all the others then the hole and the bolt could be the same size.




so here is what i came up with.... i needed some kind of bushing or spacer that could fill in the difference between the size of the bolt and the bolt hole. i took at trip to the hardware store thinking i was going to get some washers and cut them down, but i ended up finding some pvc pipe, 1/2" sdr 11 cpvc 4120. I.D. 1/2". O.D. 5/8", that worked perfect. the inside diameter of the pipe was exactly the size of the bolt and the outside diameter is the exact same as the hole. no modification was needed. i just bought the shortest piece they had, 4', for $2.50.


i checked my stock nismo rear shocks that i have boxed up and they had the same problem with the hole being too big for the bolt. the hole is slightly smaller but the 1/2" cpvc pipe i mentioned will still work, but it may need to be sanded a little to make it fit.


i just had to cut a little piece, about 3/16", to fit in the hole in the shock.
you can see how good of a fit it was on the bolt and in the hole.







while i had the shock out i decided to make a gasket for where they mount to the body since there wasn't a gasket there any longer. i used a sheet of valve packing that you can get in the plumbing section at lowes for $1.25.





after i finished the install on both sides i took it out for a spin in places the clunking was unbearable before.

NOW THERE IS NO CLUNKING, NO NOISE!!!!

i hope this will help any of you that are having this same problem. sorry for the crappy iphone pics.

tylerxfire

iTrader: (15)

cool man congrats. awful lot of work though

JasonZ-YA

iTrader: (60)

Great info!

-J

stevezcar

iTrader: (1)

Thanks for the info. Great write up.

JasonZ-YA

iTrader: (60)

Do you still have your factory rear shocks to check its hole size?

-J

Chris@FsP

iTrader: (4)

Nice job.

Rodizzle

iTrader: (27)

Man that's amazing. I has retighten that bolt just yesterday because it was clanking like crazy. I need to go ahead and do this.

davidv

iTrader: (2)

That's all well and good but what color wheels should I get?

JasonZ-YA

iTrader: (60)

I say keep a close eye on this spacer as well......its pvc, which is a quite brittle material.

I wouldn't put it past it to crack and break to smaller pieces and be gone one day.

Thinking about it more now, i would have a local shop tig weld a plate and redrill the bolt hole (M12 or 15/32" hole and wiggle it a bit) and get a longer bolt if the plate thickness was great enough to require a longer bolt.....

That bolt is an M12x1.25 bolt iirc....which is why a 1/2 ID pvc pipe worked.

M12 =.472 inch

-J

nismo542

iTrader: (2)

yeah this was a quick fix to see if it worked. if the PVC fails I still have 3'11.5" left. if it happens I might go ahead and weld on a plate in the future. we will see how it goes from here so far so good.

nismo542

iTrader: (2)

the stock nismo shock hole was basically the same as the stance shock. so this should work for stock also.

jalejune

iTrader: (2)

Dude this is it! Doing it tomorrow. That noise is killing me.

cellude

iTrader: (3)

Does anyone have the exact dimensions for the stock suspension? I am going to have aluminum spacers machined at a machine shop, but if someone already has their shocks off it could save me some time.

JasonZ-YA

iTrader: (60)

If your gonna go through the trouble of that, you might as well do what i posted in post #9 and tig weld a plate with a pre drilled hole the exact diameter needed....

machine shop time on making spacers is gonna be more costly then tig welding a doubler plate "sized to match the lower shock lug flange.

have the plate made and hole drilled.......use a bolt to mount it up and tig weld it on. replace the factory M12 bolt at that location with a longer one "if" the added plate thickness welded on is too much or not enough thread engagement is possible with the factory bolt.

done and done..

much better than a spacer you would have to keep an eye on and possibly loose, break, etc....

-J

nismo542

iTrader: (2)

i do like the idea of the welded plate but the only concern in any warranty voiding of the shocks or coilovers that will happen from modification, especially if they are stock shocks still covered under nissan warranty. nissan has been replacing shocks all over the place under warranty trying resolve this issue, but have failed to realize the true cause and the noise always comes back. a spacer is the most benign way of going about this.

any spacer that is used will not be able to come out and get lost due to the fact it is sandwiched between the bolt and the bushing in the shock mount. the pvc one i used, if it ever cracks, will still stay in place until i take the bolts out and remove it.

an aluminum spacer would be great and i did think about that at first but i was just looking for something cheap to test out my theory. i was first going to use metal washers that have the correct diameter hole in the middle and just grind them down to the diameter i needed for the hole in the shock. i still may due this if i run into an issue with the pvc spacer.

cellude

iTrader: (3)

Well my work has a machine shop in-house, so I can just pretend it is a part for work . Just need to throw it into Solidworks and I am good to go. I doubt that 6061 Aluminium will wear, and if it does I can switch to a harder steel.

JasonZ-YA

iTrader: (60)

nice.............

-J

JasonZ-YA

iTrader: (60)

i figured you were thinking warranty...

i understand its trapped....the pvc i just see cracking to smaller pieces and falling apart out of the hole. but well see....

Get ^^ to make a few extra for you!

-J

EddieBingo

What about something like this?

http://www.mcmaster.com/#drill-bushings-and-liners

I've got the same rattling problem... I'm really interested in a permanent fix. They have a piece that's 1/2" inner diameter / 5/8" outer diameter, but 3/8" in length. It could be cut in half to make two spacers, or maybe just used as is...

LaoSiFu

iTrader: (97)

Does anyone remember if the front hole size is exactly the same as the rear? Also what is valve packing used for? I tried looking for it one time and no luck.

~Robert