ok guys need some help in diagnosing this wicked front-end shake i've been having.. here's the symptoms: it only shakes between 42 and 50 or so also it will only shake if the steering wheel is on center or slightly off center I.E. making a gradual left/right turn. however, as soon as the front end is loaded lateraly left or right the vibration goes away also it seems to be more pronounced in straightline situations if i were to be accelerating fairly agressively and then let off/cruise once i reach about 45. My first thoughts were tie rods so i jacked up the front end and shook the crap out of each tire and couldn't find any play.... now i'm begining to think wheel bearings because i haven't replaced them since i've owned the car and i've had it for nearly 8 monhs and who knows when the previous owner did them last seeing as how she was a 30 year old woman that didn't own a single tool..lol...

so chime in guys and i'll take any advice i can get..

 

Well you could check the wheel bearings easily by jacking a tire up and grabbing it on the top and bottom of the tire and shake it to see how much play it has.
I think it would be a good idea to replace your steering idler arm, and check your brakes to see if they have anything to do with it. These would be the first 2 things I would do at least, Good luck!

 

Check for a slight bend in a wheel, or a tire that is starting to seperate. If the front and rear tires/wheels are the same size, swap them around and try it again.

 

dank: i did shakethe wheel there's maybe about 1/8 " travel either way from center also i did just replace the idler bushings and new front pads... also the vibration stays constant even when the brakes are applied..

rogue: I can't remember but i believe i rotated my tires when i did the pads..but i'll try again to see if it helps..and the tires appear to be in great condition i.e. no seperation visible and plenty of tread, but they are quite wide for an FB at 225/50/15

 

bump...anybody????

 

Have you checked any of the previously mentioned items?

 

Bad tierods usually cause play in the steering wheel, so will the idler arm, not vibration that I know of. You could remove the wheels and check the bearings for sufficient grease and pre-load, then while you're re-mounting the wheels, make sure the lug bolts are evenly and correctly torqued.

 

I had the same thing once, it turned out one of the balance wieghts from my tire flew off.
But what your saying it sounds to me like a dry or ruffed bearing.

Try when your going 50mph to swerve slightly left to right and make note it the wobble and or bumping changes from left to right.

 

I'm not a mechanic nor an RX-7 expert, but I have a similar problem.
I checked it all out at the dealer: UV joints, idler arms, suspension, drive-shaft and even transmission mounts. All good.
Then they balanced my wheels with the new surface test machines (? I don't know, they're the new balancers that check for road surface pressure).
I should say they "tried" to balance them.
Afterward the mechanic relayed to me the marvelous news that "your wheels are anything but round".
Two of my wheels were bent.
Hence, I'm saving up for some new wheels.

 

ok...rogue..yes i checked the above items and no change... just for refreshers... recent brake job..recent idler bushings...tires in good shape..haven't checked balance but shake is still present no matter which tires are on the front... also the shake is only at the above specified speed...if i slightly turn the wheel it disappears.. also the shake is present with brakes applied and not applied...also i've done the "shake the wheel test" and seems to be little to no play..... as for the wheels not being in round i don't know but if i can't fix this problem myself i'll be heading to the tire store to check balance...

any other ideas guys?

 

If the sound changes when you turn left or right its a bad bearing!!!!!
they may have not put a new cone or cap in when they did the brakes.
Get some new rotors and bearings and do it agian.

 

hey black..i'm going to check the bearings this weekend.hope that's it..beause it's getting REALLY violent...never had a car shake so hard...damndest thing...i mean below 45..smooth as silk.above 45 smooth too...but right around 45 it shakes so damn violently i think the wheel is gonna fall off... i'm so stumped

 

Possible the ball joints in the control arms are worn, also if you have custom wheels larger than OE, you need to make sure you have the right length of lug nuts, you will sheer off nuts that are too short and having only one or two tight lugs instead of 4 or 5 will cause vibration.

 

jay: i no longer use the old lug bolts i have studs and nuts...they seem to be fine in terms of length... theese wheels and tires have been on the car for the better part of ten years and nothing has sheered off...but here's an update..yesterday i went out and checked the brakes and it appears as though the pads had been dragging due to improperely installed pad springs ( little wire springs that insert into the holes on the top of the pads).. so i fixed that and the car seems to drive/steer/stop better..BUT the shake is even worse...the best way i can describe it is that the steering wheel shakes Violently back and forth to the point that if i don't have 2 hands on the wheel it would probably get ripped out of my hand...if i go a litle faster the problem seems to go away...if i pull the wheel to the left it goes away also...the right it goes away.. i don't here any bearing noise..grinding/squeelling when i'm driving or when i had it apart yesterday doing the brakes.... also i performed the "tire shake test" and there's little to no play... oh yeah also...if i apply the brakes the shake gets worse...any ideas?

 

This is beggining to look like a possible bad rotor. You said "recent brake job", did that include resurfacing or replacing the rotors? A brake rotor can warp or go out of balance while in use. Improper resurfacing can lead to a rotor that is not running true. Even a new rotor can be improperly machined.

 

rogue.. i did not replace or resurface the rotors when i did the brake job.... but here's more info of what i found out today.... the idler arm crown nut was a little loose from when i replaced the bushings and that was creating some steering play..fixed that today... rotated the tires, bought new lug nuts with a better seat design to fit the wheels a little better.. my wheels are also lug-centric and i was sure to torque the wheels properly ( no weight on wheels turn wheel and shake lug by lug until wheels are properly seated..) i also checked the front bearings and adjusted preload, it was pretty good but driver's side was a little loose.... now i just went and drove the car again and still shakes... i would buy new rotors but can't afford them right now...but it sounds as though it may be it... i mean everything else has been checked/replaced/tightened would just hate to spend 100 bucks on new rotors and still have the problem, so i come to the forum again to see if there's maybe something else i may be missing.....

thanks again for all the help guys...