horrific vibrating at slow speed

[wrxkyle]

so my 93 240sx(sr20 coupe) rolls completly normal at very low speeds, but at around 25-35mph it vibrates in a way that shakes the whole car, seems like it is comming from the back. it's on coilovers(apexi) with 18" rims and is low to the ground, but i can't figure out what it is, once i get above 30-35 it's gone, only shows up at that speed. i'm really stumped on this one, as even at 90mph i don't get anything. almost feels like when you gas it at 1k rpms and the engine runns super rough till it picks up, but this is not the engine, i have the clutch in and the car in neutral and it's still vibrating, what suspension issue should i bee looking for?

also does anyone know the "correct" size crush washers for the turbo oil feed line banjo bolt on the block? that thing is leaking like a siv. i think that has been taped and helicoiled as well, anything i should know about those when it comes to torquing downs things? are they weaker than an original tap?

[MrSoutherland]

Get under the car and look for obvious signs of problems. Maybe as simple as a bushing is completly gone or a loose bolt. Maybe something is bent?Just look at both sides and try to compare and figure out what side the vibration is coming from.Don't know about your other Q though.

[wrxkyle]

i see the bars that seem to connect the frame to the suspension in the rear are pretty bent, would that be the cause? i might be able to pull them straight as they look pretty thin but i saw some aftermarket ones but now can't find them cause i don't know what they are called.

[greencar]

these?:

zerothread?id=428512

[OutToWinPAHC]

Tire balance, worn subframe bushings, loose subframe bolts, loose arm, worn arms busings, loose diff bolt, bad transmission mount, bad u joints.

Could be anything, go over it really well.

[liquid_cool]

you need to look in a few places first to rule out searious danger area's...

#1) drive shaft...if you dont have a 1 piece then you have that silly little mid bearing..and if that goes..it could spell disaster..

#2.)transmission mount&bolts!

#3) rear differential...you may have bearings failing and things starting to woble..

#4.) check your motor mounts...just to be shure...

#5) last but not least...rear rotors..they may be warped..or worse..cracked..

this is just a starting point bro..plus what is mention'd above about the subfram..check all the critical area's and dont drive it till you find your issue...

besafe..and keep us posted on what ya find.

[KennyV]

check the balance on your rear tires. =)

[BTP]

check your alignment and tires.

[blackandblue]

check your alignment and tires.

There is no better way to save yourself money than by giving your car a good inspection. To re-enforce, take the time to do a thorough inspection of the under carriage. You might be surprised. Tire balancing, tight lug nuts. If it's a really bad shake at low speeds 25-35, I would NOT suspect control arms or bushings. I would suspect lug nuts, tire balance, or a differential. I had a problem with a newly installed (junkyard) vlsd that had locked plates. The car shook and hopped horribly in turns until the plates loosened up. Check lower ball joints by using a pry bar to see if there is play in the LCA. If the tires are unevenly worn, compounded with worn lower ball joints, could add up to the problem you are having.

[wrxkyle]

yes those are the ones thanks a ton!

would a drive shaft issue cause the vibrating/wobble even if not on throttle? i don't think it's wheel balance, too big of a shake and only at low speeds, straight line, (maybe around turns too, it's from 19mph to about 21-22 mph, then smooth as butter(well as smooth as it can get with coil overs on full stiff)
Modified by wrxkyle at 4:22 PM 1/16/2010

[Klits562]

yes those are the ones thanks a ton!

would a drive shaft issue cause the vibrating/wobble even if not on throttle?

Modified by wrxkyle at 4:22 PM 1/16/2010

yea because the drive shaft is still spinning.

[sileghtychad]

I HAD THE SAME PROBLEM, IT WAS THE (U) JOINTS ON THE DRIVELINE!

[Klits562]

I HAD THE SAME PROBLEM, IT WAS THE (U) JOINTS ON THE DRIVELINE!

This.The U joint is the bearing in the middle of the driveshaft.Idk if the bearing can be fixxed lubed replaced or w/e but fix it cause if that breaks then your gonna have alot more trouble than just vibrating.

Friend told me about a corvette that had more HP than the driveshaft could handle and the U joint seized the driveshaft broke and dug into the road and made the car do a front flip at 150mph

[brokeded]

[QUOTE=Klits562]

This."The U joint is the bearing in the middle of the driveshaft." WRONG!!!!!!!!!

"Friend told me about a corvette that had more HP than the driveshaft could handle and the U joint seized the driveshaft broke and dug into the road and made the car do a front flip at 150mph " slap yourself for believing that BS..........what your talking about is the center bearing aka carrier bearing. the universal joints are the little cross looking things that connect your shaft to the rearend and to the tailshaft yoke

[nismoracingsx]

If your diff is having problems, you might hear a resonant sound at the speed of the vibration. I've only owned 2 240's so far, but when each had diff problems, they reared their head at the exact speed you're having problems, :p.

[wrxkyle]

hmm, nothing seems out of whack turning, but i'll pay attention, i'm going to have the shop that will be replacing the headgasket check it out when it's on the lift, cant get under it with it being so slammed on coils

[wrxkyle]

got under the car, and checking the driveshaft found the problem, therear joint to the mid joint connection had 2 out of 4 bolts left, and one could be turned by hand, and the other had backed out enough to wiggle around with finger pressure.

oh, and the friggin headgasket wasn't blown
Modified by wrxkyle at 10:53 PM 3/13/2010