steering wheel shake w/M II

40cpe · May 22, 2009, 02:28:03 PM

Quote from: "Mikej"Have you tried different air pressure? If you have bump steering issuses, you should fix those.

No, I haven't thought of that. Does more or less pressure help it?

enjenjo · May 22, 2009, 04:01:28 PM

Email me the pictures, and I'll post them.

Picture posting instructions here http://www.roddingroundtable.com/forums/faq.php#46

40cpe · May 22, 2009, 04:45:15 PM

Quote from: "enjenjo"Email me the pictures, and I'll post them.

Picture posting instructions here http://www.roddingroundtable.com/forums/faq.php#46

I'll try to post a picture. Excuse the dirt, it's a driver

wayne petty · May 22, 2009, 06:41:14 PM

the reason that many people are saying to try a different set of tires... is once in a while... when you cannot get rid of a problem... the only thing that you have not changed... is probably the problem...

those look like steel rims with significant tires on them...

do they fit tight on the hub??? hubcentric??? or are they centered by the bolt circle???

tire balancers are hubcentric.. they center on the hub... if your wheels bolt on and are centered by the studs and nuts... and you really really really cannot find another set of rims... even to try for a dozen miles ...

i have had f250 vans with factory rims that could not be balanced with a hub centric balancer.. only with a bolt on flange adaptor could those be balanced... a friend who puts over 1,500 miles a week on his van... mostly freeway miles... found a shop with the proper adaptor.. so he would pay extra for the balance every few months.. until the new store manager came in ... and sold the adaptor .. my friend ended up with new aluminum rims...

i don't think 1/16" run out is really going to affect most cars... but with yours suspension.. you need to change the weight of the rims and tires to change the harmonic resonance of your front suspension...

got a 7 inch grinder.. or polisher.. you can put a stack of grinding discs on... so you can jack up that wheel... and use the grinding discs against the tread to spin the tire up to speed...

just an idea....

Harry · May 22, 2009, 10:43:51 PM

Would putting balance beads in the tire help?

Many new tires are out of round and need to be shaved.

enjenjo · May 22, 2009, 11:10:05 PM

I suspect you have a bad tire. It may even be a rear one. From the pictures, the rack/tie rod angle is not off enough to make problems. I would look for a ruptured belt, or something else like that.

Pep · May 23, 2009, 04:11:09 AM

I think you might have missed what I am on about so I pinched this pic off another site. Look at the upper and inner pivot line between the control arms. See how it intersects the pivot point on the tie rod. That is the position you are trying to achieve. If it is not right, you may be able to raise or lower the rack to achieve it.

Charlie Chops 1940 · May 23, 2009, 07:55:44 AM

Dang, this steering wheel shake is exactly what I have been putting up with in my '40 Chevy convert for 20+ years. I had it licked for awhile with new front tires but it had gradually come back. It's more of an irritant than anything else. At first I thought it was cowl shake but eventually ruled that out.

Haven't had it on the road for a couple seasons and when it comes out it'll be on new tires and wheels. I'll drive it a bit then checks the alignment. It hasn't been adjusted in many miles so I suspect it may need tweaking.

Charlie

40cpe · May 23, 2009, 12:26:06 PM

Frank, I've been thinking the * of the steering wheel when I hit a bump at lower speeds and the shake at higher speed are connected, or the same problem. Maybe they aren't and I have two problems. I'll play with the tire pressures as suggested earlier, then beg or borrow another set of front tires/wheels and see if it makes any difference.

Pep, your point is well taken. At first I considered that the rack was mounted too low. The Heidt engineer said the upward tilt of the steering arm was attributed to the rake of the spindle caused by the 4 1/2 degree caster setting. That makes sense. Another variable that I hadn't thought about until you brought this up could be an incorrect rack length putting the inner joint of the steer arm too far out toward the wheels. I'll do some checking of the imaginary line between the pivot points. Are there other rack and pinion applications that would bolt to the M II cross member that have different rack lengths? Anyone know?

Wayne the pilot hole in the wheels are larger than the hub, so the wheel nuts are centering the wheel. Keep in mind these are after market hubs/rotors too, so they could be off or out of balance. But they don't show to be out of round or warped much with the pointer. I'm beginning to see why some folks like to stay with the OEM stuff.

Thank you all for your suggestions

wayne petty · May 23, 2009, 12:38:37 PM

Another variable that I hadn't thought about until you brought this up could be an incorrect rack length putting the inner joint of the steer arm too far out toward the wheels

are the tie rod ends adjusted so the rack is centered... not turned to one side... this will really make bump steer...

so how much thread is sticking out of the tie rod ends..

? an equal amount on each side?

just a thought....

40cpe · May 23, 2009, 01:13:02 PM

are the tie rod ends adjusted so the rack is centered... not turned to one side... this will really make bump steer...

Good point Wayne. I hadn't thought of that either. I'll check on it.

wayne petty · May 23, 2009, 10:46:21 PM

one other thing.... see if there is any room to put spacers between the rack and the cross member... and room in your steering column lower rods to make up for it...

with the rack so close to the cross member... it might get better leverage if it was moved forward...

i seem to recall that there are also offset bushings available... to move the rack up or down on its mounts...

trying to change the natural harmonic frequency response is what i am planning... think of putting a bend in a tuning fork... or changing its length...

with spacers moving the rack forward.. if it does not help.. you can always move it back....

got a plumb bob?

some masking tape?

measure the distance between the centers of the lower control arms... 4 places... lr, lf. rr. rf...

the center of the lower ball joint... the center of the tie rod end... and the center of the rack shaft...

in looking at your rack placement.. it looks like the arms rack might be mounted behind the centerline of the tie rod ends.. just a little bit.. moving it forward of the tie rod centerline will change the tuning... i don;t know what it will do with the ackerman angle without the measurements that you might supply...

reborn55 · May 24, 2009, 12:35:46 PM

Had the same problem on my 47 Chevy ragtop when I got it. Same set up, Mustang2 etc. Came to find out the spindle mounting bolts were loose. retorqued them and the car drove great for over a 1000 miles, then on the way to Louisville vibration started to come back and has got gradually worse. On the way to the trim shop was pretty bad. Don't know where to look now. I agree--I would drive almost anywhere if someone could fix vibration problems.

wayne petty · May 25, 2009, 01:59:18 PM

hmm.... offset rack bushings.... to reduce bump steer here is a shopping link.... so everyone can see the many options...

http://www.google.com/products?hl=en&q=offset+rack+bushings&um=1&ie=UTF-8&ei=sdsaSr7RApi8swOa482SDw&sa=X&oi=product_result_group&resnum=1&ct=title

more info for the fire...

i don't know if there is room for something like this on a MII rack... but if a later rack was installed... they should fit...

Coupen · May 28, 2009, 11:47:28 AM

PMFJI,

Have you checked the play in the lower steering column bushing/bearing? Excessive play tends to allow movement in the linkage and abnormal movements at the steering wheel.

Regards,
Ron . . .