check it,, i replaced the rear wheel bearings,(i would
advise others to do) tightens up the rearend big time.
but i've still got that vibration,it starts at about 35 mph
to 40 mph then smooths out,untill i hit 70 mph then it
sounds like the whole underneath of the car is going to
fly out,,it can be felt all over the car,,now what the ****?
over??remember,,,it just started out of the blue..the very same crap before i replaced the rear wheel bearings,,,,drive shaft ???front end ????u-joints ???
it ******* pisses me off,,it shouldn't be this diffacult to
find and fix this problem..i'm going to try this,,go down
to my mazda dealer and ask and bribe the service mgr
to take a ride with me and tell me what he thinks it is..

 

check your driveshaft.

 

Probably those carrier bearings. Doing mine Saturday oh what fun.

 

Also try rotating your tires if you havent done so yet. Universal joints on your drivesaft ? Good luck

 

I knew a Marc A. Perez here, I heard by his brother mike that he went to PR. I had a 79 rx7 that made that noise for ever and i sold it like that; never bother.

 

Sucks... I agree that driveshaft is likely. Hopefully it isn't your differential but that's possible. If you're gonna continue replacing things, obviously do the easier/cheaper things first. Incidentally, one time this happened to me because I somehow tightened one of my wheels on wrong... sounds pretty stupid but I did it once. Removing the wheel and putting it back on fixed the problem.

Maybe you should make sure your wheels/tires are not the problem, then worry about driveshaft, then perhaps your diff (I'm not sure what else there is...)

 

The goal is to,,not replace everything on the car,,thats
a trip about the wheels,,huh ? remember,,the vibration
just started while driving and is still there.,.,.pulling out
my hair on this one,,that P.O.S.

 

sorry to hear that mark...

man quick check, get underneath the car...check for play at the driveshaft u joints. Don't be replacing everything...but make sure the tires are balanced.

 

Yeah ,,tires are balanced,Got under that MF tonight,
and get this,,the yoke and the front u joint area on
the driveshaft were hitting the heat shields,,,i havn't
yet , but i need to pull those hitting ,and flaten some.

 

Hmmm... that sure don't sound right. Still have those heat shields eh? Maybe you just found your problem!

 

Heat shield rattle yes vibration I doubt

 

Push up and down on the driveshaft near the u-joints. It should not move.

 

Speed sensitive vibration = U-joints

 

just pulled my driveshaft. even thou it checked out fine on the car nice and tight when I got it out I noticed that the rear ujoint was flexing harder in one direction than the other. Looks like more$$$ to spend. Probably my noise.

 

It is...

 

what do you think,,pick up another driveshaft from
the junkyard = around $20.00... or buy new u joints
at $16.00 each,,,an 82 has removable u joints if i
remember right,,,i used to replace the u joints in my
1969 mustang all the time with a socket and hammer.
it used to explode u joints like water,,,imagine ,,at the
stoplight,yellow,,green,,wind that MF up and launch,,,
BANG!!!! all you could hear is all the needle bearings
hitting the car on the side of me,,and stick too,,untill
i bought some lakewood solid u joints=no grease fitting.
at $ 45.00 each...the mustang was(is)NHRA legal,
driveshaft safty hoop,castiron bellhousing,4 point,etc,,
thats why the driveshaft never hit the ground on the street...but i think get another driveshaft because my
driveshaft may be out of balance,hitting the heat shields
and all,,get it out of a car that has not been hit

 

Measure off all the critical length dimensions for the shaft in your car and get the junkyard piece if it stacks up to the numbers. Get a car whose engine died, not a wrecked one. Take it to get the U-joints over-hauled and shaft balanced by a Pro. This way you can use your car until the day of the swap and the piece going in will be all "top shelf." On top of that, if the Pro bill is kind of high, you can pay in installments and still have your driver until the wonderful day arrives when you get the shaft...

 

If you check the u jounts pull the shaft out and put it in a vice . Its the best way to be damn sure its them. Checked my ujoints while still on and no play but check them with driveshaft out clamped in a vice and you could tell that one way it flexed easier than the other way. Also was told that when you hear the noise while driving to put it in neutral and if its still there its driveshaft not rearend. probably won't hurt to put the clutch in too if manual. Also http://www.uneedapart.com found me driveshafts in minutes good search engine for all kinds of car parts

 

Today is 1/2 off everything at the boneyard,,yah,,
found an 82,5 speed, no body damage,the 12mm bolts
on the flange have never been loose,,i had to gorilla
those mothers off, scored a clean driveshaft for $ 7.00.
there must have been 300 people standing in line to
buy there ****....hope this gets it !! if it don't,,i'm gonna
shoot that POS,,,really !!

 

NAILED IT GUYS,,,front u joint = fried,,, car is happy again,, that MF does 110mph RIGHT NOW easy...
any smoother,,and it would be shaven,,smoothie,baby!
thanks all,,well done,,buy yourself a cold one.

 

sigh...

 

I don't know but check the pitman arm, idler arm..I was told if they are bad, the car will shake...I could be all wet though , just putting in my two cents since you really sound "pissed off"....cjf

 

sounds that way,,more frustration than anything. I don't
know if its just me, or the car gets to me.something
about how all of a sudden,,with these cars (my car)
when **** happens,,you know your driving,,and bang!
something new to repair..I just don't like the idea of
just pouring money in it, like water.

 

yeah, I hear ya, but you gotta expect putting money into it here and there, especially if you drive it for your main car. It is not that bad though, I bet you have it paid off!! If you had a new car, you would be making payments...and even with a new car, you do have to throw money at it here and there. Gotta remember also, that it is a old car. Face it , it is 20 years old. You have a cool car, it is "relatively " cheap to have, its fun ( except when you are having problems ) and you have a great sourse of information here at the rx7 forum. Don't fret......and....if you can , work on the car as much as you can "yourself"..you will save a lot of $$$$$. And if you run into problems, post it here and some one will try and help out...Be cool......cjf

 

and also, be patient...think, think and think...listen to what others say, look at those things and keep trying...