vibration at 65mph+ (1991 240sx)

[zinger_usa]

hello all,

checked through 25 pages of posts and couldn't find one that directly related to my problem, or it was something i had already checked. anyhow...

almost anytime i am on the highway i get a vibration that seems to come from different parts of the car. sometimes it seems to be from the back, others the front and sometime right under my seat. my passengers can feel it as well in the foot wells. it doesn't seem to change with road surface. it isn't rpm related as i have put transmission in neutral at speed and the vibration remains. when i break it seems to amplify, but i get no pulse to the break pedal. often times i feel it in my steering wheel but the intensity varies. (question: should there be any play in the lower steering column shaft where it comes thru the firewall? i can move it about 1/2) i did hit a huge pothole a year or so ago that was bad enough to bend my stock aluminum rim, but have since had a 4 wheel alignment done.

my automatic transmisson was recently rebuilt completely and they said driveshaft looked okay for wear and wobble. i recently replaced the tension rod bushings with solid polyeurethane's from whiteline. i replaced outer tie rod ends. i have two sets of wheels and it does it with both, one set that came high speed computer balanced straight from the dealer. its got brand new brake rotor's and pads all around.

hoping you all can help me out with this. thanks so much.

[NISTECH]

this is a complicated problem obviously. when i started reading your post I wanted to say wheels but you covered that, I also wanted to say driveshaft but you said it was checked, you covered tension rods, I have a precise method to figure out what is causeing your vibration but it is gonna require you to run to your local lawn mower repair shop and pick up a tuning tool. it is a plastic disk that has a steel wire in it that you can rotate outward by the top of the disk. when you get that tool take your car out have a buddy with ya. when you get to the point it does it. note your speed , your engine RPM (which wont really be relevant but need it for the formula) the gear you are in (either auto or manual). then have your buddy hold the tool firmly against the dash and rotate the wire out ward till you get the most movement out of the wire(the wire will vibrate drastically when you hit the point of most vibration) go beyond that point then back below that point till you have pinpointed the highest point of movement in the wire. then note the number on the wheel the arrow is pointing to. after you get this done come back and post all your noted info and i will pull out my book with the formula in it.

but if what you are saying about throwing it in nuetral and engine rpm dropping to idle the vibration is still present and as severe.It leaves only a few things, drive shaft, drive axles, and wheels&tires.

[zinger_usa]

hiya nistech,

thanks for getting back to me. paid alot closer attention to it today on the highway and can feel it start around 50 and it seems to get the worst at 70-75 but continues up past that. and that is independant of the gear i am in.

had mentioned the lower steering column shaft and the play it had in my first post and hoping you can tell me if thats normal play due to the multiple joints and rubber bushings involved in it.

had the car in the shop today to get an exhaust hanger fixed and asked them to look at front end and see if it was as solid and tight as i thought (tie rods, ball joints, etc..) they agreed it was, but while handling the front tires found something of a high ridge on one and some odd wear on the other. i am gonna have new tires put on (need them for the winter anyhow) and see how things go. it was doing it on my new tires and rims i just recently took off, thats why i still mentioned the new stuff above.

thanks again!

[NISTECH]

the rubber dampner in the shaft will have some play but it is difficult to say weather or not it is excessive with out seeing it first hand. that is why i really didnt comment on it. I also forgot to mention that for my formula to work the vibration has to be harmonic(steady repetative feeling) in order for it to work. you said you swapped tires so i am thinking replacing your current tires is not the problem unless it didnt exsist on the other tires. it does not matter weather it is irrelevent to the gaer its in i need it to figure the formula.

[NiTeRiDeR]

this may be really simple but i had the same problem except mine was accompanied by horrible steering drift to the left

got new tires... and a balance (didnt even need an alignment but that might be a good idea) and the problem was solved... riding smoothly again... except for some shake from weakened engine mounts

[Avatargsr]

I kind of have the same problem. It didn't start until I had my car in the air for a week while I was doing my SR swap.

The car drives perfectly until about maybe 65mph...then these crazy vibrations in the front end will start. But it's not constant. They will come and go. And sometimes above 70, they don't come back severly at all.

I thought it was wheels/tires...but I put the stockies back on and it does the same crap.

I have a full bushing kit, so I think I'm going to start replacing bushings up front to see if that does anything. I'm starting to thing it has something to do with the steering rack...because at it's worst, the wheel is jerking back and forth pretty bad.

[Avatargsr]

Does anyone have any idea what might be causing this?????

[rogoman]

when i break it seems to amplify, but i get no pulse to the break pedal. often times i feel it in my steering wheel but the intensity varies. (question: should there be any play in the lower steering column shaft where it comes thru the firewall? i can move it about 1/2) i did hit a huge pothole a year or so ago that was bad enough to bend my stock aluminum rim, but have since had a 4 wheel alignment done.

i recently replaced the tension rod bushings with solid polyeurethane's from whiteline.

To begin with, there should be NO play in the steering column with the ignition switch in the unlock position; either the universal joint is worn or the rack is not adjusted correctly.

Check the wheel bearings for wear which could possibly cause a vibration at all speeds. The easiest way to check for worn wheel bearings is to remove the brake pads. Now spin the rotor by hand and listen for any noticeable rolling or grinding sound coming from the hub which indicates that the bearings are worn.

By replacing the tension rod bushings with solid polyeurethane bushings, any problems with the front suspension will be more amplified; the OEM silicone filled bushings are designed to absorb a lot of suspension. vibrations.

You also mentioned that there is abnormal wear on the front tires which indicates possible incorrect alignment; something else to check.

[SPEEDingMoNK-S13]

soo i have a realy good / simple idea that i did not see ANYONE mention. now im not a mechanic, i do work at a car dealerchip (honda, i dont like hondas they just pay me) as a lube technician.. we have had several cars come in w/ this problem.. simply balancing the tires will solve this problem. you already said you hit a HUGE pothole which bent your rim well.. im willing to bet that you need to replace that rim, atleast balance all the tires. ill bet e-money that will solve your problem. this is the first thing i would do. peace and gl please reply w/ the result

[0wn3r]

soo i have a realy good / simple idea that i did not see ANYONE mention. simply balancing the tires will solve this problem.

got new tires... and a balance (didnt even need an alignment but that might be a good idea) and the problem was solved... riding smoothly again...

honda people lol

my first thought was full alignment then look at wheel bearings...

[babowc]

my car does the same thing..anywhere past 70, the car randomly vibrates hard and wheel jerks up to an inch of turning at times.

i just recently put on some coilovers.. so i think my problem is the coilovers?