Hi Guys. For the last 8 or so months I have been trying to figure out this strange shudder thats occurring in my Auto V6 VS (Live Axle Sedan on Superlows) I have this strange pulsating/shudder when traveling at 50-60km/h then again at 110km/h, but it doesn't happen all the time, sometimes it will happen on a dead straight road, sometimes it gets triggered by a mild incline. Now I am pretty sure its not the engine as I have let it roll at 60km/h in neutral and it still has the issue, I even went out into the middle of no where and rolled it at 60 with the engine off and still same issue (although not as severe as when the engine is running) It can be felt through the steering wheel and gear shifter and seats. It seems to be most predominant when the car has been sitting for a while. What I have done: * New Plugs, Leads, Coils & DFI to rule out an ignition/spark issue * New Tailshaft Center Bearing * New Transmission, TQ & Mount (Trans was due for replacement anyway) * Engine Mounts * Rotors Machined * All front end Nolathaned * Checked Radius Rods, Front Control Arms etc for play (the only front end bushes that seem to have any wear are the swaybar link pins but even then its only mild wear) * Checked all hoses for splits (e.g vacuum leaks) * Rear Upper Trailing Arms * Rear Swaybar Links * Rear Panhard Rod Bushes * 3x Different sets of wheels (stockies and alloys, all balanced and alligned by various shops just to be safe) Things That I haven't Done/Checked: * Lower Trailing Arm Bushes (worn but don't seem to have too much play) * Steering Rack/Tie Rods (how can I check these) * Being live axle and lowered I haven't installed an adjustable panhard rod so the axle/diff isn't 100% centered between the wheel arches (axle is over the left of the car by a few cm, could this be a contributing factor?) * Fuel Pressure (pump is only 6 months old, not sure about the regulator etc but once again I am fairly confident its not an engine issue) * Could wheel bearings be an issue? * Front ball joints, (they look ok, is there a way to check them?) * Inlet Manifold Gaskets are gone so the idle is a little rough, could a leaky gasket cause shudders (once again, really doubt its an engine issue due to my tests above) Any ideas guys, I am pulling my hair out here as I have spent a couple of thousand dollars on all this gear in the process of elimination but still can't figure it out, I am sure its probably something simple I have missed :hmmm: It's only really a minor shudder, a few people that have driven it can't even feel it but I am very picky/anal about these things so any minor imperfections just can't be tolerated :/ Thanks
Some cheapo ignition coils can be the cause of minor running problems such as small shudders etc.. A lot of the cheaper ignition coils getting around these days can start to fail after just a few months, Ive even seen them fail from new, so its always best to only use genuine holden coils, theyre more expensive, but the car will run properly and the coils will last a lot longer, and I havent come across a genuine one yet thats failed when brand new.
Hi Guys. Yes I have tried swapping wheels (3 different sets as stated in my first post) and I have replaced my coils, DFI etc (with factory genuine ones)
I'd check the tierod ends and rack ends - do this by jacking up the front (or each side) and try to move each front wheel side to side - there should be NO play visible or felt. It help when doing this to have someone apply the brakes so the wheel is locked. Good Luck.
Possibly Just jacked up one side, shook the wheel then the otherside and did the same thing. Its hard to tell if there is any actual play in the tie rods, because the car is lowered jacking one side up to the point where the tyre is off the ground also lifts the other side up enough to cause the steering wheel to move as I am shaking from side to side.....there is a bit of a clunk noise from either side as I am doing it but once again not sure if that is the tie rods or normal due to the wheels being partly off the ground. I am assuming if it the tie rods etc then I should get play and the steering wheel won't move
After doing some searching around JC it seems that others that have lowered their car and not installed an adjustable panhard rod have gotten shudders too due to the diff not being perfectly centered and causing the back wheels not to line up with the fronts. Maybe this is my issue?
I also seem to remember that on lowered cars you also need to sometimes alter the position of the centre bearing to keep the driveline as straight as possible.
No, but the problem was there before the bearing replacement, didn't make the issue any better or worse.
There should be 'no' clunk if teirod and rack ends are not worn. Turn the steering wheel to the lock position and this should hold it still or get someone to hold it while you move the wheels.
With the steering lock on the steering wheel still moves left and right about 10 degrees each way, is this normal or should I not be able to get any movement what so ever?
That's just play in the lock mechanism unless you mean the steering wheel stays still and the wheels move 10 deg? - you'll have to either get someone to hold the wheel still or use some sort of clamp device to hold it still (like they use in wheel alignment places to keep steering wheel straight ahead)
Thanks mate, old man is dropping up on saturday to help me with renovations so will ask him to hold the wheel for me then. I also ordered a new Adjustable panhard rod from Whiteline today which will arrive sometime before friday so I will fit that up and allign it to make sure its not the tailshaft and diff being off center. (have been putting the rod off for a while but this give me an excuse and it means the exhaust won't knock on the diff anymore so win win)
