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Steering will not self center
My Mk4 donor build is now two years old and I have one problem I cannot figure out how to fix. The problem is that the steering will not self center. It comes most of the way back, but if I don’t correct it, it will keep going a little to the left or right depending on which way I turned.
Alignment is: (Power Steering)
Camber = -.05 LH -.06 RH
Caster = +7.8 LH +7.8 RH
Toe = .11 LH .13 RH Total toe = .25 Toe IN
Cross SAI = 0.2 degrees
1. I had to cut the adjusting nuts to get 7.8 degrees caster.
a. Should I cut some more and add even more caster?
2. Would switching to the new FFR two piece spindles solve my problem?
a. I see in posts the guys with the Complete kit have self-centering and tramlining issues too)
3. If I could find a set of Whitbys SAI mod and install it, would it fix my self-centering problem?
4. Any other ideas on how to solve this problem?
Here is what I have: Mk4 with donor hydroboost PS (1996), and donor spindles (1996), FFR upper and lower control arms, red Koni shocks, 9 inch 300 lb front springs (replaced 500 lb ones), 4-link rear axle with FFR control arms, 245x45x17 Goodrich tires on front
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I would check for a defective or over tight ball joint.
Mike
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Senior Member
First I would disconnect the tie rods from the spindle to check if any of your ball joints are too tight as Mike mentions. At the same time check the steering column/rack by turning the steering wheel a bit. Then would look at the rack itself. Pretty unusual but it could happen that the friction adjustment is too tight.
PS rack adjuster by craig stuard, on Flickr
not sure why the illustration shows a pie piece cut from the nut cause the real one is 360 deg. But you have a big jam nut and a 3/4 (I think) bolt head down inside. The bolt pushes on a compression spring which pushes on a rubbing block inside the rack. There are inch pounds specs to adjust this nut they are a pain. I make a small adjustment and then drive it. At 20-25 mph, if you move the steering wheel 1/8 turn and let go, it may not return to center fully. At 40-45 mph it should return to center on it's own. You can fudge that a little so it will return at a little lower speed than I mentioned, but the rack must have some friction. Otherwise you will have almost constant small steering wheel shimmy.
FFR MkII, 408W, Tremec TKO 500, 2015 IRS, DA QA1s, Forte front bar, APE hardtop.
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WIS89 thanked for this post
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Also check for tight or binding steering shaft u joints.
Mk4, Moser M88 rear end, Eaton truetrak, Craft Racing 461 Windsor, MMR pro trans, Glenn’s 1,000 hp cobra fuel system and lots of other parts.
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Senior Member
In addition to what others have posted -- (1) Yes, the Factory Five 2-piece spindle is much better than your donor spindles. Can't say that it would specifically solve this problem, but they are way better. I've had both. I would go that way before going down the path of trying to improve the donor ones, e.g. SAI mod. (2) I'm assuming your ".25" total toe is degrees versus inches? Needless to say, that would be way too much if inches. 3/32 inches of total toe in seems to be about right for these. More or less can make a difference.
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Thank you for all your replies!
Yes, I will check the ball joints. I replaced the lower ones a few months ago because the blue boots that came with the kit squashed so badly the grease leaked out. The new ones were very tight so I will check to make sure they have loosened up properly.
Yes, I will check the tie rods too and lift the front wheels off the ground and check for any binding anywhere in the steering. I’ll save messing with the friction adjustment as a last resort.
Yes, And I will buy the MK4 spindles and install them.
Thank you again for your responses.
CamrCobr
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I always thought. Excessive positive caster doesn't not make the return to the wheel return to center. Hence the heavy feel.
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Senior Member
Originally Posted by
Jcdata
I always thought. Excessive positive caster doesn't not make the return to the wheel return to center. Hence the heavy feel.
I've experimented w/ as high as 10 deg caster. I have never had a return to center problem but the effort definitely increases w/ more caster.
FFR MkII, 408W, Tremec TKO 500, 2015 IRS, DA QA1s, Forte front bar, APE hardtop.