misterZ Posted February 20, 2009 Share Posted February 20, 2009 When I bought my Z ~4 mos ago it drove exceptionally smooth and straight most of the time but I would pick up vibrations and a little shimmy from the steering wheel on certain roads. I opted to install a urethane steering coupler, strut bar and new steering wheel from MSA at the same time lowering it 1" with Tokico blues & 'matched' springs. This immensely improved handling and reduced most of the play at the cost of amplifying those periodic vibrations and shimmy. I've had two different mechanics tell me I have a nice rack ^^ and that it looks new. I have no record or information how old it is but the previous owner steam cleaned the entire car (engine/under carriage) before I purchased it from him last October. If its tie rod ends, I'm considering replacing them with these adjustable end links (?) but is there suspect to anything else I should be looking at? When a 'garage' replaces a rack do they typically replace the mounts or reuse the old ones? I intend to purchase a complete bushing kit in the near future as this car was entirely stock when I bought it. Any advice would be greatly appreciated and thank you for your time. http://www.designproductsracing.com/Z_Suspension1.html 224-1212 Steering Side Rod Ends These are adjustable tubular rods intended to replace the stock tie rod ends. They have 5/8" Teflon lined rod ends. Incl. hardware. $215.00 Btw - my sig pic is pre-lowered but hope to update soon. Quote Link to comment Share on other sites More sharing options...
lowrider Posted February 21, 2009 Share Posted February 21, 2009 I also have a similar problem. The steering wheel is the only thing that shimmys, and i dont feel it in the suspension. I bought a set of bump steer spacers, hopefuly those and an alignment will do wonders. Quote Link to comment Share on other sites More sharing options...
Savage42 Posted February 21, 2009 Share Posted February 21, 2009 To answer your questions, a good shop would replace the rack bushings with either new rubber or poly bushings. As for the tie rods, you can go that route, but make sure the inner tie rods are good, too! As for the vibration/shimmy issue, you said "certain roads" and I often drive on roads that make my BMW 540i feel like a wheel is out of balance, but it's the road. Solid bushings and tight suspension will transmit vibrations through the wheel more effectively. Some tire shops do lifetime balancing, so make sure they are balanced well, too. Just my 2 cents. Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted February 21, 2009 Share Posted February 21, 2009 I also have a similar problem. The steering wheel is the only thing that shimmys, and i dont feel it in the suspension. I bought a set of bump steer spacers, hopefuly those and an alignment will do wonders. Sounds like your tires are not balanced, or balanced right. Quote Link to comment Share on other sites More sharing options...
misterZ Posted February 21, 2009 Author Share Posted February 21, 2009 Took a friend to lunch yesterday that said the same thing so I'll get them balanced and rotated and let you know--14" AR rims w/ Goodrich T/A Traction radials looked new (3-5k) when I bought the car and I'm brutal so that's got to be it to resolve the $1000. question. Thanks! mister Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted February 21, 2009 Share Posted February 21, 2009 Took a friend to lunch yesterday that said the same thing so I'll get them balanced and rotated and let you know--14" AR rims w/ Goodrich T/A Traction radials looked new (3-5k) when I bought the car and I'm brutal so that's got to be it to resolve the $1000. question. Thanks! mister That has nothing to do with it, even if its brand new wheels with brand new tires, it always needs to be balanced properly or your wheel will shake. Quote Link to comment Share on other sites More sharing options...
misterZ Posted February 21, 2009 Author Share Posted February 21, 2009 Well, it took quite a bit of weight (7-8.25 oz on a couple tires) but the tires are balanced and the little bit of driving I did do, it seemed to have helped; however, while they had the car on the lift we checked the tie rods and they appear to be ok but it was tough to tell as the whole rack moved in unison--the bushings are shot! I got a good look at the sway bars and end links and all but the end links are dry and hard so a new (complete) urethane bushing kit is in order. What are recommendations to help correct over-steer now that the strut bar, coupler and suspension all but eliminated the push (under-steer); do I go with a stiffer rear sway bar? Thanks for all the input, I feel a little better now. mister Quote Link to comment Share on other sites More sharing options...
Savage42 Posted February 21, 2009 Share Posted February 21, 2009 That will make a difference and rack bushings will dramatically increase steering response. So, you say the car is now loose and oversteers? If so, you need to tighten the front sway bar (poly end link bushings will do that). If you have a rear sway bar, then you need to soften it up to get more rear grip (rubber bushings will do that). Of course, camber & toe changes will help with that, as well. It's also important to know what kind of driving you are doing to validate the no push characteristics. There is a huge difference in high speed/highway (track) setup, a street setup and an autocross setup. If you have the car neutral handling for one of those types of driving, you will need to adjust to make it work well in the other cases. Hope that helps. Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted February 21, 2009 Share Posted February 21, 2009 You sure its oversteer? For some reason with what you are describing Im imagining understeer. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted February 21, 2009 Share Posted February 21, 2009 Stock setup swaybars are for understeer (front slides out in corners). If you retain all the stock parts but change all the bushings to urethane, the car will feel tighter and more responsive but it will still be balanced for understeer. Not a bad thing on the street. When I bought my bone stock '76 20 years ago, the first mod I did was the urethane rack bushing kit, and sway bar bushings. Shortly thereafter, 225 tires. Open the hood and look down at the rack with a flashlight. Grab the steering wheel and force it back and forth. You will be amazed at the amount of slop in the rack. It should not move...but it does with the factory bushings, even when new. List all of your suspension parts and specs so we can guesstimate. Quote Link to comment Share on other sites More sharing options...
deja Posted February 21, 2009 Share Posted February 21, 2009 while they had the car on the lift we checked the tie rods and they appear to be ok but it was tough to tell as the whole rack moved in unison--the bushings are shot! One warning, new rack bushings might not fix that movement problem. I tried 2 different sets of bushings and the problem persisted. To "fix" that rack movement problem I made some spacers from 20 gauge steel and welded the on each side of both bushing flanges on the rack. I only needed to add a spacer to one side of the bushing on the steering box side. The bushings fit very tightly now and the rack movement is gone. I really don't understand why Datsun made these fit so loosely. Anyway I'm back on the road, vibration free and the steering in tight and as true. Quote Link to comment Share on other sites More sharing options...
misterZ Posted February 22, 2009 Author Share Posted February 22, 2009 I'm going for a pro street/autocross setup since its my daily driver. The nose goes where I point it now while the rear breaks loose but only takes a bit of over correction to bring it back straight--I'm half-way to a drifter right now (w/o using the e-brake :-Þ). Prior to this setup it did under-steer quite a bit under fast/hard cornering thru 60-180° turns. Maybe I should wait and re-evaluate after I tighten up the rack and replace all my rubber bushings. I guess roll is inversely proportionate to under-steer as I go in flat and come out flat--the stock set up was a boat compared to now. I pulled off new KYBs (no scratches) when I put the Tokico set on. Excuse my ignorance but can someone explain bump steer to me? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 23, 2009 Share Posted February 23, 2009 http://forums.hybridz.org/showthread.php?t=103886 Quote Link to comment Share on other sites More sharing options...
misterZ Posted February 23, 2009 Author Share Posted February 23, 2009 Very informative--thanks Jon! mister Quote Link to comment Share on other sites More sharing options...
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