Front suspension and steering, how do you know you need to rebuild the steering? |
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Front suspension and steering, how do you know you need to rebuild the steering? |
DRPHIL914 |
Nov 27 2019, 08:04 AM
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#1
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Dr. Phil Group: Members Posts: 5,806 Joined: 9-December 09 From: Bluffton, SC Member No.: 11,106 Region Association: South East States |
I am wondering this as I have been driving my car this week with the great weather and fall temps here in SC, and I have noticed something that just doesn't feel right, and I am not sure I can put my finger on it, or even describe what I am feeling but I feel like my steering should be super tight, since a few years ago we did all the bushings bearings turbo tie rods ball joints brakes etc etc, everything but the steering rack itself and I didn't replace the front strut inserts because the feel fine.
wheels are 16'x6" 205/55 Potenza AE11's. 4 years old about 5,000 miles of use, lots of good rubber on there yet, but regardless will have to replace in another year just due to age of the rubber... so with that, here is what I think it feels like, kind of like it wants to jump around or shift off track. no vibration , no rattle , and I can grab the tire/wheel with car parked and try to move it back and forth and don't feel any play like if you had a loose or work tie rod or ball joint etc., what I guess I am wondering is if it is time to pull the steering rack and replace it with a rebuilt one from 914rubber. if that hockey puck thing is getting old and worn, what would that feel like or how would that present itself? And can I remove it by just disconnecting the inner tie rod ends and not have to mess with my alignment? ive not done a steering rack on a 914 before.. as always , advice from those that have done this is appreciated. Phil |
Garland |
Nov 27 2019, 08:39 AM
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#2
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Restoration Fanatic Group: Members Posts: 1,370 Joined: 8-January 04 From: ......Michigan...... Member No.: 1,535 Region Association: Upper MidWest |
Could be a bad tire, try rotation and a test drive. See if anything changes, no cost diagnostic.
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DRPHIL914 |
Nov 27 2019, 08:55 AM
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#3
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Dr. Phil Group: Members Posts: 5,806 Joined: 9-December 09 From: Bluffton, SC Member No.: 11,106 Region Association: South East States |
Could be a bad tire, try rotation and a test drive. See if anything changes, no cost diagnostic. will do, but after being pointed in this direction, just did a search and watched a couple videos etc and I think we are on to something, I do think it is bump steer. if there is irregularity or a bump it pulls the car one side or the other , this is what happens. so now the question is why am I feeling bump steer? is it worn parts or just poor alignment? and how do we correct it. I have had an alignment done one time a few years ago when Bob Woodmans shop put in the new turbo tie rods and my new A-arms and bushings etc. that was when I had different wheels, 2 years later I switched from the 14" rims to the 16" rims I am currently running. wider tires etc might also be part of this and why I feel this now and didn't used to? (IMG:style_emoticons/default/idea.gif) sounds like I need full realignment and leveling. basically it has to do with the geometry of the alignment of the rack and the control arm and if they are lined up correctly and do they stay on a proper plane when now moving up and down with the strut as the tire hits a bump. not sure I exactly have it down but will study this more so I can comprehend it, not sure if I can fix it myself but someone can !!! I don't like feeling that bump jump at 60 or 70 mph!!!! |
Superhawk996 |
Nov 27 2019, 10:00 AM
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#4
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914 Guru Group: Members Posts: 6,469 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
Could be a bad tire, try rotation and a test drive. See if anything changes, no cost diagnostic. I had different wheels, 2 years later I switched from the 14" rims to the 16" rims I am currently running. wider tires etc might also be part of this and why I feel this now and didn't used to? (IMG:style_emoticons/default/idea.gif) Suspension geometry is complicated. 914's and McPerson struts in general don't have great bump steer characteristics (zero bump steer being the ideal case). You may also be feeling the effect of a changed scrub radius that occurred when you changed wheels & tires. Wider wheels and/or wheel spacers typically lengthen the scrub radius unless you changed the wheel offset to compensate for it's effect. That increased scrub radius affects steering efforts and how much distrubance is put into the steering system when you encounter a bump or surface irregularity. Lowering your vehicle below stock ride height will also have adverse affects on bump steer. This is where bump steer spacers come into play to raise the rack back up. BEWARE adding spacers will only compound the problem if your car is running ABOVE OEM ride height. There are no simple answers. Study up on steering geometry and it's effects. I highly recommend Carrol Smith's books Engineer to Win, Tune to Win, and Prepare to Win as a good starting point for the layman. Once you understand more about geometry, then decide what experiments to try. Only you can determine what makes you happy and what feels best to you. |
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