Steering wheel shakes

[Jetfuel]

Guys I need some advice about my steering wheel shaking left to right when hitting a bump at moderate speed.
The car does not leave the track that it is on just the steering wheel shakes.
I have searched the forums and the only place I found any mention of this condition was an old thread titled “De-powering the steering rack” where someone made a comment of a magazine article describing this issue as a violent shake and not bump steer
At highway speeds / smooth surfaces and hands off the wheel it will maintain heading for a long time.
I has the Baer bump kit.
Any help in troubleshooting and finding a cure will be appreciated.

Jet

[J R Jones]

Jet, there is a lot of historical discussion here on bump steer. The Baer kit has been mentioned often. My project is not at the bump steer correction stage yet.
Being inquisitive I will measure existing bump steer and find a geometric solution. If you have not measured bump steer with the Baer kit, this is a good time to do it. Trust and verify.

I assume you have looked for loose tolerance between the steering wheel and tires, IE rack and pinion gear play, coupler, universals and tie rods? Wheel bearings?
jim

[Jetfuel]

Thanks Jim
The car will up tonight for a full inspection of suspension y steering components.
From this thread.
https://thefactoryfiveforum.com/show...rx-parts/page5
Post 194 it kind of describes my issue
With 10k miles on the road I will suspect wear and tear since it has been getting worse.
Thanks again.Appreciated

Jet

[J R Jones]

Jet,
I had not seen that thread before.....yikes. I never heard of that weld-up concept.

Brainstorming here, looking for a loose tolerance:
I think the steering stops (in my 2002 donor) are in the steering rack, not on the upright/steering arms. You can not test the parts outside the rack by cranking against the rack/stop.

If you can find a way to clamp an upright/steering arm in place, you could crank against that to see if there is play between the steering wheel and upright. If you have an assistant, they can help you identify the source.
You may have to do both sides.

For instance, put a wood or aluminum block between the steering arm and frame and securely clamp or strap it place. Then crank the steering wheel both ways. Play???
jim
BTW do you know about scrub radius? Wheel offset outside "0"scrub radius can cause the steering wheel to jerk to the side on bumps. Google it.

[Jetfuel]

Big thanks.
I'll post my findings.
google it is

Jet

[taco20]

Hey Jet

I had a similar issue with my car at speeds above 100 when hitting a bump. The worst was at the drag strip with a bunch of bumps at the end of the track. My fix was to ad caster which helps the car go straight at speed. I was running FFR spec for a 818S and switched to more of an 818R spec by trying to get as much caster as I could. I have no issues now and have been above 140 with no issues still. I hope this might help and good luck with the issue.

[aquillen]

Jet, we need to get together with both cars and compare. Mine will shake moderately going down the road, but only if I let go or very lightly hold the wheel. If I grip it normally with either hand, the shaking is gone. It also tracks great like yours. Not that comparing is a fix but interesting to see if is the same. Depowered and did a bunch of checking back then to make sure there was zero slop in the rack & pinion when assembled. 5K miles or so.

[Jetfuel]

Thanks for the input guys
All suspension and steering components show no signs of wear
Found several hardware items loose or below specs
The clamp down bolts of the steering shaft universal, 2 flats movement
The steering rack hold down bolts 1 flat
Both upper A arms pivot shaft. These are supposed to be a slight interference torque but I was able to turn the nuts quite a bit before resistance was established
Test drive was a great improvement, I’ll say 80%
The wheel is harder than before and when hitting bumps at 70/75 mph the wheel displacement is about 1/4” and very subtle hands off
Accelerating to and braking from 100 is straight with very little to no correction with 3 fingers on the wheel
I’ll live with it until winter when I’ll check/do the depowering mod that I still believe could make a big difference

Jet
PS Art, yes we can get together and compare
Taco20, thanks for the info, easy and quick to try out.

[J R Jones]

Jet,
Excellent trouble shooting and scofflaw road testing. BTW where were the other seven fingers?
My 2002 steering shaft has a rubber damper between the universals and I question how beneficial/detrimental it is. Rather than just eliminate it, I may put a high load SS hose clamp around it and torque the pizz out of it. Make it stiff.
With castor comes steering effort.
jim
BTW front wheel balance OK? Excellent? Wheel bearings?

[Jetfuel]

Thanks Jim
About .050” from the wheel …lol
The rubber damper is new and no signs of deterioration
Balance was done in January after the wheels got painted
Bearings was a feel only without the calipers or disk, no end play or roughness felt, only 10k on them

Jet

[aquillen]

Jim, FYI sent you a PM. Thinking Jet and I both come up and kick tires in your shop sometime. I know he is always up for a drive and I never stop thinking about another trip in mine.

[J R Jones]

Jim, FYI sent you a PM. Thinking Jet and I both come up and kick tires in your shop sometime. I know he is always up for a drive and I never stop thinking about another trip in mine.

PM, how quaint.
My memory from racing at IRP is about 400 miles, not the least of which is the Chicago obstacle and the Milwaukee obstacle. My recent experience is IL stopped manning the toll booths so unless you have an I-Pass, yer fornicated. They will find you and make you pay. Neighborly ehh? I have been detouring toll sections and Chicago traffic is a......joy.
BTW the bridge from KY to IN is a toll trap as is the Austin TX (COTA) by-pass. Guess how I know.

I never kick tires here, the footing is too treacherous in the FRP/filler dust, besides I can not get enough distance for a cathartic swing.
I'll send you my waiver by PM.
jim

[DMC7492]

Hi Jet, look into this thread post 47! I had slop in the lower steering column mount where the big grommet goes when hitting bumps the whole column would jostle around. I made this bushing reinstalled the grommet and now the lower mount is tight!!

https://thefactoryfiveforum.com/show...teer-kit/page2