Front suspension mystery, need help - Ford Mustang Forums : Corral.net Mustang Forum
 
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post #1 of 13 Old 11-20-2010, 08:37 PM Thread Starter
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Front suspension mystery, need help

I have an '81 Zephyr with these front suspension pieces: '91 Mustang K-member, SN95 spindles, Fox LCAs (new), a 1.3" sway bar and Koni yellow struts.

The problem is this: the front is about 2" too high, and won't deflect. You can bounce on the front bumper and the tires flex, but the suspension doesn't. The LCAs point slightly upward toward the wheels.

I have reduced the spring rate by going from a Moog 8606 spring with an installed height of 11" and a rate of 468 lb/in to a Moog 8600 with a 415 lb/in rate. No apparent effect, still no movement in the front suspension.

Should I change to a 9-1/2" installed height spring? Are the Konis to blame?

Anyone stepped in this one?

Tom

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post #2 of 13 Old 11-21-2010, 06:13 AM
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I had a similar situation with mine. Turned out to be the struts. They worked fine off the car, but installed, would not move up or down.


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post #3 of 13 Old 11-21-2010, 07:52 AM Thread Starter
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Dave,

Ouch!

In spite of the painful nature of the answer, it does make sense!

Maybe I have to send them to Koni for their evaluation....

Tom
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post #4 of 13 Old 11-21-2010, 11:39 AM
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Did you tighten the A-arm bolts while the arms were extended down?
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post #5 of 13 Old 11-21-2010, 12:44 PM Thread Starter
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Well, more research and speculation:

The loaded height and the free height for the two sets of springs I've tried so far are 11" and 15" respectively.

I had a buddy measure the free height of a stock Mustang spring he pulled out of an '89, and it was 12-1/4".

This would indicate I'm using the wrong springs....

Anyone have some free/loaded height data that could prove or disprove this?

I'm sorely tempted to cut off about 2-3/4" from the set that's in there.

Tom
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post #6 of 13 Old 11-21-2010, 03:59 PM
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As was mentioned, the rubber may be binding if the bolts were tightened with the suspension hanging.

Does it droop when jacked up, or is it frozen both ways?


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post #7 of 13 Old 11-21-2010, 06:31 PM Thread Starter
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Another chapter in the continuing stoooooory of the too-tall springs:

I put in a 2000 Mustang GT spring that I cut exactly one turn (one coil) off of. It seems to lower that side of the car about an inch, and lets me bounce it up and down more than the other side.

I'll do the other side Tuesday and report back....

Tom

PS to Terry: It can droop and deflect upward now. I plan to tighten both sides after I get the other spring in, with the car's weight on the tires.
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post #8 of 13 Old 11-23-2010, 04:32 PM Thread Starter
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Well, here's today's update...

I put in the 2000 Mustang GT front springs after I removed exactly one coil.

The good news = the car sits nice and level, exactly the way I hoped.

The bad news = the front tires rub the inner fenders horribly at the top.


Anyone know how to make more room at the Zephyr's front fender tops without significantly changing the appearance of the fenders?

I plan to use a small saw to trim the inner parts of the fenders as much as possible, but first glance shows it may not be enough. I'll also try some negative camber.

AAAAAAAAAAAAARRRGHHHHHHHH!

I do plan to try some "C" springs to see if the travel can be a bit less. The Koni struts should be OK with those springs.

Tom
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post #9 of 13 Old 11-23-2010, 06:43 PM
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You could try some older model fox control arms. I think the pre-86 cars had a slightly shorter control arm? Dial in as much negative camber as you can get, crack the fender bolts loose and have a fatass buddy pull out on the fender arch while you tighten them back down, maybe run a different wheel with more offset.
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post #10 of 13 Old 11-24-2010, 08:41 AM
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Quote:
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You could try some older model fox control arms. I think the pre-86 cars had a slightly shorter control arm? ....
This is not correct. All of the Fox Mustangs had the same length A-Arms (except the SVO). The SN95 A-Arms are 1.25" longer than the Fox A-arms.

However, the '85-'86 V8 and the '85-'93 I4 cars had the A-Arm mounting points moved 1/2" per side inboard compared to the '87-'95 V8 cars.



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post #11 of 13 Old 11-28-2010, 06:49 PM Thread Starter
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Well, I put the new Moog springs back in and they raised the front back to where is was before I started this whole mess.

I also removed two of the Koni spacer washers from each side, leaving one on each side, and, yes, I checked the hood clearance first and it's OK!

I drove the car gently for about a mile before tightening the A-arm pivot bolts with the car's full weight on them.

So I think I'll leave that end of the car as it finally is....

My next question: is there a way to raise the '03 Cobra IRS about 3/4" without too too much work or expense? This would level the car and give me a bit more fender clearance in the back.

Probably not LOL

Tom
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post #12 of 13 Old 11-28-2010, 07:39 PM
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Well, I put the new Moog springs back in and they raised the front back to where is was before I started this whole mess.

I also removed two of the Koni spacer washers from each side, leaving one on each side, and, yes, I checked the hood clearance first and it's OK!

I drove the car gently for about a mile before tightening the A-arm pivot bolts with the car's full weight on them.

So I think I'll leave that end of the car as it finally is....

My next question: is there a way to raise the '03 Cobra IRS about 3/4" without too too much work or expense? This would level the car and give me a bit more fender clearance in the back.

Probably not LOL

Tom
Without coilovers? Uh....possibly some spring isolators. Beyond that, coilovers are about your only option.

Actually....what springs are you running? The coupe springs are stiffer (600lb/in) than the convert springs (470lb/in). If you don't have them already, I'd try the stiffer coupe springs and see if they pop the rear up a bit.

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post #13 of 13 Old 11-28-2010, 08:40 PM Thread Starter
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what springs are you running?
I'll have to check - there seems to be a tag on the springs but I don't know if I can get close enough to read the tag if there is one. I'll try to look tomorrow.

Is there somewhere I can look up the tag if I do find the number to see if they are coupe or convertible?

I do have a pair of new aftermarket rear IRS springs. They are labeled Hypercoil FD001. RSA 127-03. Problem is, I don't know how they compare in installed height to the OEM ones that are in there.

I'll try to find out what's in there tomorrow!

Tom
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