Bump Stops/Bellows for KYB shocks -- 84 AE

  • #1

    Bump Stops/Bellows for KYB shocks -- 84 AE

    Greetings folks,

    I need a recommendation for strut bump stops for front KYB shocks. I read that the ones in the KYB kit are not very good and end up falling apart. I also read somewhere on here that it was possible to get some good quality urethane ones, but have been unable to find any for the KYB.

    I must note here that after finding out that the Tokico aluminas are no longer available at the Z store and have been temporarily discontinued for the turbo car, I have decided to settle with KYB and currently my car has KYBs in the rear already (from PO) and my right front OEM shock is completely shot and bottomed out. This must be repaired. I do not care to pay the outraegous price for a new set from Nissan and I never use the adjustable suspension option anyway.

    According to KYB, their struts should only be used with stock springs. My car has some crap off-market lowering springs that I want to replace with Eibachs, as the former currently make the car sit way too low for comfort. I read a few posts over on zcar.com that KYBs can be used just fine with lowering springs as long as proper strut bump stops or bellows are used to keep them from bottoming out. supposedly people tend not to use these or install their suspension incorrectly and they end up having issues later on. I just want to make sure I can get a quality bump stop that will last. Also planning on getting the rear upper and lower spring inserts from the Z store. I haven't found any for the fronts, however.

    Can I use any aftermarket urethane part that will work on KYBs, or am I stuck with only the ones in the kit?

    I've also read that an adapter kit and or strut mounts must be used for the front adjustable struts when using the KYBs. Anyone have any experience with this?

    Note, the car is a daily driven street car. not raced or drifting or track, even though it was lowered previously. My target goal is to correct the blown strut and replace the unknown crappy springs in an effort to make the ride sit just a bit higher so that it is not hitting everything down low everytime I drive. Also to give some more comfort to the ride. It actually feels really good, smooth and tight, however I feel every little bump. Its not fun. And road dips are a major problem when driving high speeds.

    Appreciate your suggestions. Thank You.

    Bon
    Last edited by bonfire79; 08-26-2018, 03:52 PM.
    • 1 like
  • #2
    I used KYB stuff on my 87z a year ago. Everything seemed to be good quality and I haven't had any issues.
    https://z31performance.com/forum/soc…762#post536762

    I also used KYB stuff on my 89z which has lowering springs and it's doing fine so far. The lowering springs are taking some getting used to, but they look so good!

    KYB has a conversion kit to convert from electronic. KYB KIT108A. https://tinyurl.com/y7u3h8td I haven't used it.
  • #3
    One time I replaced the adjustable shocks with KYB gas shocks. I ordered it from Rock Auto. One of the rear shocks blew a week after installation. I got it replaced under warranty. I can't say how they held up after that because I sold the car. However, this got me thinking about other shock/strut options. I actually like the original adjustable shocks. Sure, everyone knows they aren't the best for handling but if you wan to keep the car original, they are the way to go. That said, aren't the adjustable shocks and struts rebuildable?
  • #4
    Originally posted by jdmlegends View Post
    That said, aren't the adjustable shocks and struts rebuildable?
    From what i can tell if they are, they require special tools. I've disassembled the fronts before to understand how they work and ended up cutting them open.
    There is a flat kapton flex-circuit (like a ribbon cable) that connects the connector at the top of the strut to a stepper motor in the bottom. That motor rotates
    a choke to adjust the bypass between the two sides filled with fluid and in-turn, adjusts the stiffness. The assembly of baffles and o-rings is pretty complex.

    iirc, the rears are a sealed unit like a standard shock absorber.

    Also, the hydraulic fluid used was reputed to be hazardous and NLA.




    84 AE/Shiro #683/Shiro #820/84 Turbo
  • #5
    Originally posted by Z_Karma View Post
    Also, the hydraulic fluid used was reputed to be hazardous and NLA.
    Thank you. I remember someone else had mentioned that now. It often seems like the engineers never intended for these cars to last more than 15 years. Many of the parts are like the shocks and struts probably aren't practical or are impossible to rebuild. Other parts like the IACV aren't available but you can get some parts like the Auxiliary Air Control Valve.

  • #6
    The non-adjustable struts were, you could just replace the fluid. If it was leaking, you replaced the o-ring.

    Adjustable struts you replace the cartridge.
  • #7
    I found this kit. It looks like it comes with everything you need. Not sure if you still need KYB KIT108A if you buy this. This may be the choice kit for our Z31s over Koni or coilovers.

    http://www.usautoparts.net/details/N…0819-06-A.html
    Last edited by jdmlegends; 08-29-2018, 05:28 PM. Reason: Added link

    Comment

    • Dunkine
      #7.1
      Dunkine commented
      08-29-2018, 08:30 PM
      Check rockauto.com too, they usually have them for cheap too. They also have the bump stops and mounts. Don't forget to use the discount code if you get them from rockauto,

      5% Discount Code: 3E5F069487D6C3
      Expires: November 12, 2018
  • #8
    Thanks guys for the responses.

    Dunkine: I had KYB's put on my 87 2+2 along with new bushings and it greatly improved the ride. the only thing that bothers me it they seem to have jacked the car up higher than it was with stock. still has the OEM springs. but I won't complain about the feel of driving. So, though I would rather have the aluminas, I'm not against getting KYBs again. Will check them out. I always have good luck with rock auto… my 87 is full of their parts. Appreciate the code reference too.

    jdmlegends: i saw that kit as well. as far as I know only the rears are needed since mine still has the stocks (or should) as I am sure since if I open the hood, and look at the strut mounts, the OEM electrical plug mounts are still intact and connected, which tells me its not aftermarket. I'll be looking into it for sure. Also, are the Koni's worth it and worth the price for the a daily driven-lowered car?

    Thanks,

    Bon

  • #9
    I read that the KYB bumpstops are garbage on Tom's 300zx Z31 website. Is that also where you read that from Bon?

    http://300zx.tombeauchamp.com/service.shtml#012104
  • #10
    Originally posted by jdmlegends View Post
    I read that the KYB bumpstops are garbage on Tom's 300zx Z31 website. Is that also where you read that from Bon?

    http://300zx.tombeauchamp.com/service.shtml#012104
    thats is where I read it from hehe

    those bump stops are actually part of the adapter kit that is needed to install the KYB springs on the adjustable shock system. I haven't been able to find another suitable replacement, so I will probably use those. I have to get the adapter kit anyways. there are alot of other urethane bump stops available but they are the ones that bolt on to the chassis to keep metal from coming down on metal.
  • #11
    They will have to make do until us Z31 owners can find a better quality replacement. Tom's write up is rather old so perhaps KYB has improved their product. I can't see why they would deteriorate so quickly unless they were exposed to oil or some other chemical. Maybe his shock was leaking and the bump stop became contaminated or maybe it was just a batch of defective ones.
    Last edited by jdmlegends; 09-01-2018, 06:42 PM.

    Comment

    • Dunkine
      #11.1
      Dunkine commented
      09-02-2018, 12:11 AM
      Or his rear springs were junk.