Yet another thread for the dreaded 60mph shake, however I wanted to share my experiences and opinions with the countless other owners who may have come across at some point, and what steps can be done to get to the bottom of it. If you haven't experienced it yet, chances are you will at some point.

Here are a few quick details;

Car: Nov 1997 Plated RHD JZS160 GS300 (ADM) - the month/year is a fairly important detail, which is explained below
Symptom: Shudder/Vibration/Shake through the steering wheel, phaseing in and out from approx 80 - 130km/h (can also be felt at a much duller level at lower speeds above 50km/h. Varying road camber conditions and steering direction all play a part as to when it occurs, generally speaking when there is no "load" on major linked components such as tie rod ends etc



The SHORT version

To save you reading through the rest of the topic, I'll cut to the chase first. The definitive fix that solved my issue, after going through everything else (explained below) was tightening the pre-tensioner on my steering rack 3/16th of a turn CLOCKWISE. However it should be noted, performing this step without first checking/replacing other vital components mentioned below is NOT recomended, and would be considered a band-aid fix in the truest sense. For this reason, I recomend you set aside the time and read on below.

The LONG version

A bit more backround to my particular scenario, I have been battling this exact issue for much longer than my ownership of the GS300 (approx 18months at the time of this post) Having previously owned a grey import JZX100 Chaser, it too also suffered this exact fault for countless years, to the point where I had all but given up on ever finding the cause. I ended up selling this car with the fault still present but heavily dulled by the use of the factory 16" wheels. These two vehicles, along with a lot of others of the same era, share the same base platform, the Toyota N platform, so by the time I had bought my GS I was already well acquainted with the front suspension and braking setup.

Between the JZS160 and JZX100, here is what I replaced (in not particular order)

- Caster bushings (Superpro Polyurethane replacements)
- Replacement upper control arms (in the JZX100, Superpro inner bushings and new Febest ball joints were used on the original arms)
- Lower inner control arm bushings (Superpro Polyurethane replacements)
- Replacement OEM inner and outer tie rods
- Replacement OEM lower ball joints
- Steering rack mount bushings (Superpro Polyurethane replacements)
- New brake rotors all round
- All wheels spin balanced
- Wheel alignment performed to be within factory toe spec after all works completed (between 0 and 1mm toe IN)

A thorough list of these components and the associated procedures I have outlined here (parts specifically for the JZX100 but the procedure is common between the two chassis so should be some help)

In addition to this, on the JZS160 only I also replaced the following;

- Front sway bar D bushes (Superpro Polyurethane replacements)
- Front wheel bearings (Toyota OEM)
- Brand new BC BR coilovers all round, with factory spring rates (10/8)


In both cases the sway bar end links were in good condition still and didn’t require replacement, also the shudder was more prevalent when running larger wheels with low profile tyres (18" in both cases was as large as I got, so 40 profile tread) However in addition to this, the fault was still present on the factory fitted alloys (in the case of the JZX100, 16" with a profile of 50, JZS160 17" with a profile of 45) albeit dulled down.

After coming to the end of my replacement path on the JZS160 and STILL not having a solution, there was only one thing left to do, and that was to follow the advice of various topics within CL, and adjust the steering pre-tensioner. Threads used for reference;

Do you have a vibration at highway cruising speeds? Mines fixed!
Steering pre-tensioner -- how do you do it? (I searched)
60mph Vibrations - DIY Steering Tensioner Adjustment

In my case, being this particular car is one of the early builds, It didn't have the more common female hex bolt (which has an ID of 24mm) but rather a male bolt with a head size of 30mm, which actually made the whole process much simpler (not having to source the correct tool from Toyota/make the key from a threaded bolt and nut combo as mentioned in the above thread)

Firstly I marked out the bolt and corresponding rack area with a permanent marker (after cleaning up the surfaces of course) I marked out the "home" position which was a simple line from the bottom of the rack section onto the bolt


I then marked out the rest of the rack section in quarters, then halved again into 8ths, both clockwise and anticlockwise so I could judge how far the bolt was turned


Following all the advice given, I then used an adjustable wrench that reached to 42mm to break the locking nut ANTI-CLOCKWISE, which was holding the adjustment bolt (30mm hex head) in place.


Once this was freed up I used a 30mm socket on a breaker bar to slowly rotate the bolt CLOCKWISE until tension was felt, which in my case was at 1/8th of a turn.


At this point, I re-tightened the locking nut, put the car back on the ground and went for a quick test drive on the freeway. Low and behold, the vibration was DRASTICALLY reduced immediately, no low speed pulsating, high speed vibrations were at my guess 90% reduced, they were still very faint.

I then returned, got the car in the air again, performed the above steps again and rotated the bolt a fraction more to a total of 3/16's of a turn from the original position. After this next test drive the vibration was all but completely gone! A truly glorious moment after years of battling the achilles heel of a design fault for this platform. Further confirmation of the success was after about 500km of driving both city and highway. The steering is much heavier, firmer and smoother than ever before, feeling very E39-esque (V8 especially) which is superb on the open road, maybe not so much around town however turn-in is very commanding and precise.


Probably the one main disadvantage with this fix is the auto-return to centre is somewhat hindered, requiring some effort from the driver to re-centre the steering after taking a sharp turn, you DO get used to this, it may not be to everyone's liking , however given most of the driving this car does is on the highways/freeways it is not a big issue in my case. To resolve this, there are a couple of options;
- Back the pre-tensioner ANTI-CLOCKWISE until you find a sweet spot where the auto-centre starts to work at an acceptable level for your liking, the main drawback is you may have some vibration return of course
- Either remove your steering rack, or find a spare from a wrecking yard and have it rebuilt from the ground up with new internal bearings, bushings etc and reinstall into your car with the factory recommended pre-tension torque value



The Bottom Line

At the end of the day, by tightening the pre-tensioner, you are essentially removing the slack which comes from years of operation resulting in the wearing down of internal components within the rack itself. The "correct" way to fix this per the manufacturer would be to rebuild the rack, however this may not be the most affordable or time conscious solution. Theoretically, you could keep tightening the rack as it continues to wear down and vibration returns, but eventually you will probably be forced to fork out and set the time and money aside for a rack rebuild.

Also as mentioned previously, inspecting and/or replacing other faulty components should take precedence over this solution first and foremost, and it should be used as a last resort provided everything else checks out.

Other Potential Factors

Another angle worth exploring would be working through the rest of the driveline components which could be causing harmonic vibrations, ie; driveshaft centre bearing, trans and diff mounts, rear suspension balljoints and bushings. One thing I have been able to notice since resolving my steering wheel vibration, is there is a noticeable dull vibration from underneath the seat so to speak, again while at highway speeds. Whether this is linked at all is up for debate, until I decide to start replacing worn components again (of which pretty much consists of the entire rear end in my case) I will keep enjoying not having my hands shaken to insanity and worry about that at a later date!

Conclusion

I hope this helps put to bed any doubt you may have had from surfing around the forums and facebook groups for a definitive breakdown of this notorious fault. I will continue to update this thread as I continue to finally start enjoying driving this otherwise engineering marvel of the 90's, with any other things that popup and/or progress moving forward.

Thanks for reading!

The main reason I created a new thread was to summarise what a lot of threads go into in minor detail, and pull all the elements apart in one place. I literally was cross referencing between about 6 from many years ago to get my result so it would not have been viable to post replies in all threads, plus I also felt it worth noting that I’ve had the same issue on another car entirely (that shares the paltform
to some extent however) I did reference a few of the useful threads at the start of this one in case people wanted to see what others had weighed in on the ordeal. There were many more threads that I felt not worth mentioning as there was little to no useful detail.

Also no one from my searching had come accross the 30mm bolt which my vehicle has, I wasn’t sure it would adjust and could not find confirmation that it would even work, so there was that too.

ANYWAY, Minor update, I have also ordered sway bar end links this week as I was doing an online order. So will install those even though they seemed to check out and see if things improve at all.

Its a Lexus GS300 and no it doesn’t have AWS