QLex300

Thanks for the update!!!

CurlyG

Update: The shake is back at 70+ mph, intermittent.
Current configuration:

• New front rotors
• Caliper pins greased, but the rubber pin grommet will not fit back on the pins, oversized (shears off when the pin is slid back into the caliper). Both sides (L&R). New grommets on order.
• Same pads with %75 life left.

Same strong, heartbreaking steering wheel shake at about 15 Hz. My giant 16" tires were balanced about 1,000 miles ago, which did nothing to stop the vibration. They're running at 32 PSI (factory spec), but I can see the sidewall bulge on the ground in the front tires.
I just inflated the front tires to 38 PSI to see if it solves the vibration, which will be validated on my commute to work tomorrow.

Update: I increased the (OEM spec) pressure in my front tires from 32 to 40 psi. This alone greatly reduced the steering wheel vibration. It's like %90 gone, and only reappears momentarily. It's all about the balance of the rotating parts. It appears my giant balloon 16" tires have trouble staying round. At 32 psi and parked, the sidewall bulges out at the ground contact, which means the tire OD is smaller at the area, as it's pushing the sidewall out of plane.

Other symptoms: "Pop" noises at low speeds, pulling into driveways, coming from the front and rear. No pops at speed. All new or recent suspension components, which ran perfect and noise/pop free for about 10k miles. Maybe I'm breaking tack welds with the stiffer suspension?

Current suspension settings:
Tein Flex-Z coilovers with EDFC, ~1.75" drop
Figs Engineering:

• Front Upper Control Arms
• Castor Arms
• Front Stabilizer End Links
• Rear Lower Control Arms
• Traction Links
• Toe Links

Front Suspension, OEM: %100 new components, including inner/outer tie rods
PU Steering Rack Bushings
Original Spindle/Wheel Bearings (160k miles)
Rear Suspension, OEM: Upper Control Arms replaced about 50k miles ago

Custom 4-wheel multilink suspension alignment, with rear bump steer set to about zero (daily driver). About -0.5 degree toe set in the front and rear.
OS Giken LSD

Raven01750

Has anyone considered that it could be the driveshaft? Just saying.

Paul

CurlyG

No, the driveshaft vibration is felt in the chassis, especially on the armrest. This vibration is in the steering wheel, yet is barely felt in the chassis.
I've had my driveshaft out a few times to swap in different rear differentials, and somewhere in the process of reassembling it, it is no longer perfectly balanced (I once pulled it apart at the spline). I get a mild but annoying rumble vibration accelerating from 15-25 mph.

DMPesso

I’ve had brand new OEM tie rods go bad in 10k miles. Second time I went with moog and they lasted longer. How old are your ball joints? Popping noise is usually the ball joints and your coil overs will sure wear them out prematurely.

In my experience, if the alignment is staying in spec and the balance is good, and it’s still shaking, it’s always the tires! They must all be evenly worn and close to new. I’ve had shakes from having 2 brand new tires in the front with rear tires that only had 10k on them. Also have had shakes if the tires are not worn evenly.

Please put your psi back down to 35 max. 40psi cold is dangerous, I hope that’s when it’s already warmed up. You’re also making the ride way more stiff then it should be which will cause even more premature wear on the suspension.

CurlyG

I'm on the 3rd set of front lower control arm (FLCA) ball joints this year because:

• I installed MOOG ball joints that felt like they had crushed glass in them before I put them in. I put them in because I was in a rush, and made myself believe they would break in just fine. After 500 miles, the popping started and these ball joints now feel like they have chunky rocks inside.
• Installed the 2nd pair of non-name ball joints the night before a week long trip 500 miles away. I did not fully torque the ball joint nuts, which cause the ball joint taper to move in the LCA taper hole, and widen the taper hole in the LCA. I believe this led to the current popping sound condition.
• I'm installing the 3rd set of ball joints today, using non-name parts off Amazon. For $110, they came with new LCA's, which I needed because the ball joint taper hole in the former LCA's was damaged from improper torque. I also pressed out the rubber bushing, and installed super pro PU bushings in each LCA. The idea is to reduce the movement of the front suspension members, which may help reduce the resonant vibrations.

If you re-read my posts, everything in my front end is new. I can confirm that everything is also tight. From reading these threads, and my personal experience, I've come to 2 conclusions:

1. 2GS Front Ends are very sensitive to rotational vibration
2. Loose/worn suspension components contribute to the vibration problem, and are discovered during the search for the cause

Re: Tire pressure, yeah, I'm not enjoying the extra stiff ride at 40 psi up front. It is a temporary experiment to determine if the tire shape is contributing to the steering wheel vibration at 70+ mph.
I know now that warped rotors and stuck caliper pins (which often cause warped rotors) also cause the steering vibration problem. I finally got the new caliper pin grommets today, made in China, and installed on greasy pins.

DMPesso

you should just use an oem ball joint and be done with it. They have an updated design in the 01+ GS I think.

What about your tires you didn’t answer about that. That’s usually ALWAYS what causes my GS to shake.

CurlyG

I recently did a lot of work on my 2GS, and drove it 1,600 miles, which confirmed that I no longer have the chronic, soul-crushing front end/steering wheel shakes at highway speeds. Here is my recent post on 2 things I did to fix problems with my steering column (thread related), and also other mods that may have solved the vibration at highway speeds: Steering Column Rattle Issue - Solution
Here's what I recommend trying to cure your steering wheel and front end vibrations at highway speeds:

1. Have your tires balanced, wheels aligned, and ensure that the tires are properly inflated.
2. Visit the post linked above, and check your steering column bearing and clip.
   1. If you can see the clip sitting alone on the shaft, the shaft bearing has likely slid out of the steering column, leading to large steering shaft movement. Except for positioning yourself upside down, with your head on the floor, eyes looking up at the affected area, it may somewhat easy to push the bearing back up in the housing, and then slide the clip into the groove. You can then do a test drive, and see if that reduced or eliminates the front end shakes. Of course, without taking further action, the clip my again pop out of the groove, allowing the bearing to wiggle out of its seat (see the above post for more permanent solutions, if applicable).
3. Check if you have an adjustable per-tensioner on the steering rack, in iteratively increase/dial in the per-tension.
4. Heat up the upper U-joint yoke on the steering shaft with a heat gun (to re-melt the hardened OEM bearing grease), and then take the car for a test drive.
   1. This is short of pulling the shaft, and servicing the U-joint yoke, or replacing it entirely.
5. Check your transmission mount (car on jack stands, jack lightly supporting the transmission oil pan, unbolt the transmission mount bar, and then wiggle it, to check the condition of the rubber mounts.

Note:

• My old Riken Raptor tires have been flat spotting in the cold December weather. They vibrate like mad for about 5 miles, until they warm up and re-flow. They were balanced 3 times; each time the shop said they were %100 balanced.
• My current alignment has slight toe-in in the front (which is prescribed by the OEM manual, and most cars).
• I also just replaced the plastic wheel centering rings with aluminum center rings, which may have resulted in better centering of my aftermarket wheels.
• I cleaned and lubed the brake caliper pins with an orange high temp grease, and then removed enough extra grease to prevent the suction-lock condition that prevents the caliper from sliding.
• I installed new brake rotors, which have not warped in 2,000 miles, since I no longer hold the brakes after coming to a stop after hard braking. I believe that holding the brake at a stop can press the pads into burning hot rotors, sintering on material which creates a unique surface finish in this small region, and causes uneven rotor cooling, leading to rotor warpage.
• I now have about %90 PU bushings in the suspension, and recently all four of the differential and all rear subframe bushings are now PU, leading to:

1. Excellent handling.
2. High transmission of NVH, and possibly
3. Prevention of certain vibrations, as the suspension geometry nodes no longer drifts under load
4. Overall, changing the natural frequency of vibrations through stiffer bushing and mount materials can have a positive effect on damping or preventing vibrational modes, including the front end shakes.