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slider2828
02-27-2008, 10:55 PM
Hey everyone:

Here is I think what plagues most people on wheel shimmy. Here is the list you should do in order. Move on if check ok!

Wheel Bearing Check - 6 oclock 12 oclock shake. If ANY play its time to replace them. (Hub centric rings for spacers, eh... most people don't use them and are fine with it. So I don't hub centric stuff.)

Tension Rods Check - retorque bolts, replace bushings

Suspension check for blown

Tire Balance - go to a friends shop if possible and look at the rim while balancing for rim bent. Also look to see if the tire itself jumps up and down a little which is a check for flat spot check.

Ball Joints Check - check for lube leak, check with crow bar with excessive movent, also 6 oclock 12 oclock movement shake

Tie Rods and Tie Rod Ends - Check 3 oclock 9 oclock shake. Pull down on rod with elbow strength, should be 0 movement. Push toward front and rear of the car, should be 0 movement.

Rack Play - 3 oclock 6 oclock shake, should be minimal about 2mm movement at most

Check suspension all suspension bolts.

Check engine and tranny mounts.

Check DriveShaft bolts and differential output shaft bolts

Steering Rack Bushings - Replace if worn.

Subframe bushings - Use collars because I know most 240's are cracked if not worn by now.

Full Alignment - Weird tow can cause some vibrations. (But it is up to debate that is why at the end.

Here are some symptons: after mentioned checks above

Shaking at high speeds -

if steering wheel also shakes while braking - replace rotors. Also check for frozen caliper. Rotate wheel with brakes off, should be minimal friction front end, and relatively low friction when spining rear.

Preload spring - Nissan Tech Bulletin - I changed this too, but it didn't help too much

Shaking over bump - Here is the kicker, ok probably experiencing bumpsteer and need to get new tie rod ends with bumpsteer adjustment. BUT EVEN if you replaced your rack bushigs with NISMO ones, my problem was here. I FINALLY FIGURED IT out. My Rack was shaking.

What you say even with the Nismo bushings? YUP! I had my mechanic friend rack the car and I turned the wheel with 0 load on the front with the car on. The WHOLE rack was shifting with 0 load. I was like WTF? New bushings that have probably less than 6 months on them. So far I used a heater hose to shim just the top, it helped SO much , but I think you need to shim those rack bushings all the way around.

Just shim the center of the bushing not the sides which have the lip. I think over time with heat, the rack clamps have stretched or expanded and just not enough clamp load to hold the bushings. A large heater hose might be too thick, so find a nice 5mm tacky rubber strip from somewhere (rubber hose from Home Depot?) and shim the INSIDE of the bushing on both sides of the rack and crank the rack back down.

This helped a lot and I hope this helps other people as well.....

Note: I torqued all the rear end suspension links or arms such as the toe bar, traction rod, etc... Didn't move much nor change anything, so I don't think this helps....

MadMaverick
02-27-2008, 11:20 PM
Good write-up!

A few things to add

When checking tie-rods:

There are inner and outer tie-rods. To see which one it is, you must get under the car and feel them. Have someone shake the wheel and grap the outer boot (where it bolts to the spindle). You should be able to feel/see the movement there. If you dont, reach in and grasp the steering rack boot. Squeeze it and you will feel where the inner tie-rod enters the socket (it gets wider). Again have someone wiggle the wheel, you should feel the movement inside.

Wheel bearings:

This is similar to tie-rod check, it will feel EXACTLY the same as a loose tie-rod or wheel bearing, depending on setup. The difference is, you can see through the wheel that the spindle assembly is not moving. The wheel and brake rotor/caliper are moving, but the rack is not changing position. This is a wheel bearing issue. A really bad wheel bearing will exhibit a "propeller noise" while driving (sounds like a prop plane is flying under your front end).

Ball-joints:

Confirm ball-joint looseness with a visual inspection while wiggling. A blown boot doesnt mean the balljoint is bad, but its not a bad idea to replace it.

Alignment and steering vibration:

An alignment will not cause a vibration, unless it is SEVERELY out. I have seen cars come in with toe so far out that the tires squealed going straight down the road with ZERO vibration. Im talking about toe over 3 degrees out of spec that didnt cause vibration. That is visible from outside the car type of toe. Alignment can make a car do funny things, but a vibration is not one of them.

Common vibration problems:

The MOST common cause of wheel vibration is tire balance, and it should be the first thing checked. As slider said, watching the wheel on the balancer is critical to diagnosing the problem. A tire hop, flat spot, belt seperation and bent or waffled rims can still be balanced, if you dont watch the wheel spin, you can miss it.

After that its back to the list above.

Brake Vibrations:

Vibrations from brakes are felt when the brakes are applied, not when you are just cruising down the road. If it is speed related (gets worse with speed) and doesnt happen off-braking, guess what. Its not your rotors. Some regular front end vibrations can get worse when applying brakes because the weight is shifted to the front. Deal with these first before you blame your brakes.

g-via
02-27-2008, 11:36 PM
Wow this write-up kicks ass!!

I have wheel shimmy at 80-95 km/hr...

I'll see if I can get to the bottom of the problem this weekend

GSXRJJordan
02-27-2008, 11:46 PM
*** Sticky this thread! ***

All extremely good info! Most people have some of these symptoms, some people even have all of them ~ when you finally get around to wanting your 240 to drive perfectly, this is all the shit you have to check!

slider2828
02-27-2008, 11:50 PM
I structured this write from cheap and easy to expensive and harder. I feel its more complete and logical this way. MadMav covered some wholes and expanded on a couple of points, but it is pretty exhaustive. Following these steps I feel cover about 98% of most problems. I feel the key points of tires is covered very thoroughly explained it is the only thorough way to check rims, tires, flat spots. Please take note that look at the edges of the rim when on the balancer rotating, any wobbles, mean it is out of round either waffling or bent.

slider2828
03-06-2009, 01:04 PM
Sometimes cheaper tires have poor belt design and this is internal to the tire, I know kumho's had some these problems in their SPT models which I have owned. Federals Dunlops, Bridgestones I haven't had these problems can't speak about others.

handinpants
03-30-2009, 04:30 PM
i am sure someone here has done this;
what are the symptoms of using 30mm rotors with the 26mm caliper z32 brakes. contrary to popular belief this happens all the time, people get mismatched stuff... so slider please let me know.

sridings13
03-30-2009, 05:17 PM
sweet ...thanks man