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02-08-2012, 11:06 PM #1
03-04 Cobra A-arms worth the effort?
I got a deal on a pair of 03-04 Cobra A-arms for my 94 Cobra. Is it worth the effort to install these on my car? What changes can I expect to the car after the install? Any alignment problems? Installation hassles? Thanks1995 Cobra R #82 - Sold
1965 Fastback Track Car - Sold
1995 Chrome Yellow GT Coupe, SOLD!
1998 Cobra Coupe, Chrome Yellow, SOLD!
1994 Cobra Coupe, Vermillion Red SOLD
1994 Cobra Coupe, Rio Red Daily Driver.
02-09-2012, 05:17 AM #2
- Join Date
- April 2010
If you already have them through a good deal, just keep them around till your stock ones are getting old, or probably sooner; the balljoints take a dump. Then install them.
They're a nice upgrade, but more worthwhile as an upgraded replacement, not a mod that you would HAVE to do right now.
Install is easy, they're not very different from your stock ones. Allignment is always a good idea after suspension work, so combine the job with new tie-rods etc and do it all at once.
02-09-2012, 08:10 AM #3
Thanks. The balljoints and tierod ends are shot so the timing is right. Ordered a Steeda bumpsteer kit (car has Sportline springs)to take care of the outers and will get a pair of inner tierods to finish the deal.
Are there any complications with the alignment? I've read that unless you go with 96-98 spindles it limits the alignment spec. True? I'd like to have it aligned with some track use in mind.
02-09-2012, 09:09 AM #4
- Join Date
- April 2010
Bumpsteer kit and CC plates will give you all the allignment options you need. Spindles are changed in '96 because of the different R/P height, which was caused by the different engine.
Here's an interesting read:
The problem is no one seems to pay attention to the reason for the change with the '96-'04 steering arm height change. With the intro of the 4.6 the current location of the R&P would not work with the new Mod motor. The R&P had to be lowered 1" to clear the engine. In doing so, to prevent bump steer issues, Ford lowered the steering arm on the spindles to match.
This allowed acceptable geometry for the factory intended ride height of the Mustang.
The suspension is only at rest when parked on a level ground. Parallel to the rack, and parallel to the ground are incorrect assumptions of where the tie rods need to be located. The suspension moves up and down, tie rods included.
The tie rods and FLCA should be parallel to each other at all times to prevent bumpsteer. Both component pickup points allow the arms and tierods to follow each other congruently while the wheel is turned through suspension travel.
Change the pickup points of one component, in this case the 4.6 spindles steering arm, and the arcs that the two components travel in are different. They are not parallel. Although physically the tierod is not any longer, due to it traveling on a different arc path, it will become effectively longer. This will push on the steering arm with no input from the driver, causing a change in steering angle. Since alignments are done when the car is at rest, the change in steering angle(toe) will happen during bump. Thus 'bump steer'.
A problem with bumpsteer is, you probably will never notice having it. There is an assumption that bumpsteer can be felt through the steering wheel. NOPE! Bumpsteer is the change of the steering angle of the wheel through bump.
Point your wheels straight ahead, lock the steering column. Remove the front spring, unbolt the end-link, and loosen the FLCA bushing bolts to allow the FLCA to freely move through its travel. With all the other components still attached(strut, tie rod,) place that front control arm all the way up til it bottoms out with a jack. Release the jack and you'll note the change in toe from compression to droop. The geometry is not perfect on the Fox Chassis, the ideal factory height and normal travel that the engineers have to comply to and the minimum amount of bump travel is maintained in that range. Beyond that, full droop or full compression, maintaining minimum bumpsteer is not optimized as the suspension would rarely be at those angles(per factory design).
This is why with lowered(with springs) Fox-Chassis(F-C struts/spindles/wheels) the easy way to 'fix' bumpsteer is to install the offset R&P bushings, without resorting to a bumpsteer kit that replaces the outer tie rod with a rod end and spacer stack. This is just a bandaid. Unless the suspension travel is limited to the new 'lowering springs/bumpsteer bushing' range, there is still the issue of the steering angle changing when the suspension is in droop. Since the suspension is now optimized for your new ride height, when it falls out of range(droop) the bump steer effect will be even worse than from the factory.
With the '96-'04 spindles used on a stock F-C K member the bumpsteer cannot be fixed. The R&P needs to be either moved down an inch or more(on a factory F-C K member, this is not going to happen) or the FLCA K member mounts need to be moved up an inch or more(which may also be difficult to do). Trying to do either would be cost prohibitive, and even then the geometry may not be spot on.
(Yes, Mathis did change the pickup points on a K member, but he was optimizing the factory geometry for Slot Car Mustang. And he was NOT using(nor would he on a F-C K) '96-'04 spindles.
A stock F-C Mustang needs CC plates to take the stock suspension out of positive camber as is. The spindles will not help.
'96-'04 spindles should NOT be used on a stock factory Fox-Chassis K member.(period)
Do not install a 1996-04 spindle on a 1979-93 or 1994-95 Mustang fitted with a stock-geometry k-member!
Doing so will significantly increase bumpsteer because...
•The steering arm on the 1996-04 spindle is about 1.02" (26mm) lower (relative to the rest of the spindle) than the steering arm of any 1979-95 spindle.
•The lower steering arm forces the outer tie-rod end to a lower position.
•That new position is far too low for the steering rack location of any 1979-95 Mustang, and radically changes the steering geometry.
•It is impossible to correct the geometry with a bumpsteer kit because the outer tie-rod end needs to be raised so much that it would have to occupy the same physical space as the steering arm.
Last edited by dutch; 02-09-2012 at 09:12 AM.
02-09-2012, 09:25 AM #5
Make sure you actually measure and set the bumpsteer if you are going to buy the kit. Otherwise, just buy factory replacements.
02-09-2012, 10:19 AM #6
Valuable info guys, thanks. The 96-98 spindle question has been settled then, assuming MM knows what they're talking about. And they should.
Re setting bumpsteer - I'm relying on the alignment shop to do this for me. I've worked with them before but not 100% certain they did it correctly. Any tips or things I should look for or recommend to them?
02-10-2012, 01:54 AM #7
- Join Date
- August 2004
99+ spec control arms are considered an upgrade over the stock 96-98 parts. They are designed to have the control arm more forward, giving better caster.