Suspension feels "loose"

[DucatiRdr]

I am pretty confident in the engine bay but when it comes to suspension "stuff" I have little diagnostic ability. That being said, I just put a set of ponys with 225/55 up front and 245/50 out back. Looks MEAN but maybe that leads into my issue. Back in 1991 or so I installed FMS C-springs, adjustable Konis all around, poly bushings, etc. I am assuming the front end was aligned when they installed the Konis...I dunno...I don't remember that far back. I don't remember the car feeling loose way back when and there were a number of high speed runs on the highway that would have put me on the news if the suspension felt as jittery as it does now.

So fast forward to today, 14 years since I have really driven it last and I just changed from the OEM Eagle Gatorbacks to BFG KDWS. At street speeds, so under 70 it feels fine, hit a bump after that number and the car wants to wander. I can control it fine but it is not as sure footed as my Explorer, or the wife's Forrester. Do you think my Koni's lost their charge after 14 years of inactivity?

Speaking of Koni's, I installed those when I was 22 and had no idea how to adjust them. My local dealer just shrugs his shoulders and I found nothing online.

 

[hemi_fan]

When's the last time you changed your ball-joints? My car felt really 'loose' (almost like it had a flat tire) right before my ball-joint snapped in half and my wheel fell off the car. lol, if your ball-joints are old then i suggest you take a look at them. (mine only had like 80k miles on them) Otherwise, i dont know what would cause it. Tie rod ends?

 

[SVT32VDOHC]

My Cobra has the identical problem you described. My suspension in the front is all stock. I don't know what I will do, I need to do something though, cause it is scray.

 

[DucatiRdr]

When's the last time you changed your ball-joints?

Er...never. My car has 16,500 original miles. I just changed out the original dry-rotted Gatorbacks.

I'm thinking it's the struts, or a strut. Everything else has no mileage.

 

[tunedin302]

I doubt your struts are bad with such little mileage ... unless they have leaked over the years. The C-springs change the angle of your tie rods and lower control arms which in turn change the way your tire contacts the road. With that being said, do you have camber/caster (cc) plates installed? I would first check your struts to see if there are any obvious leaks. If not, then push down on the fender of both sides to compress the strut some. If the car "bounces" and is not dampened much by the strut then you likely have a bad strut(s). If th struts seem to be okay then move onto the next test.

If the car just "wonders" when driving then I would likely say it is due to having c springs and no cc plates installed. The car cannot be aligned properly when using just c cprings and no cc plates. If you have driven those 16K miles with the c springs then you should have noticed on your old tires that the fronts wore much quicker on the insides. This is because the c springs w/o the use of cc plates results in the tires looking like this from the front: / \ . Also, if the car wants to go its own direction when you go over bumps then you are also experienced bump steer due to the tie rod being pulled as a result of lack of travel.

As good maintenance, you should definitely check your balljoints but if they only have 16K on them then I doubt that is the problem. More than likely the car is not aligned properly because it has c springs w/o cc plates, as well as, bump steer b/c you don't have either offset rack bushings and/or a bumpsteer kit. The first thing I would do is put some cc plates in as well as a bump steer kit. Both of these are available from Maximum Motorsports. The only reason I know this is because I ran c springs for about 8 years and also had to cure this same problem. The best solution is do the above (cc plates and bumpsteer kit) and also switch out those c springs for some H&R or Eibach progessive rate springs. You will be much happier with the ride and performance. Good luck.

 

[DucatiRdr]

Tunedin,

Thanks for the info! The wandering is the most obvious at highway speeds, especially when hitting a bump or frost heave. Also when turning the wheel it seems to turn a little more than the input from the steering wheel.

I bought the C-springs ages ago when the only choices were the Bs and Cs and after driving lots of euro style handling cars (softish springs with lots of travel) since then I am definitely used to a different ride. The Cs are just too harsh for New England roads. Is there a particular Eibach that you recommend? How about alignment settings? Are the factory settings adequate or is there an alternate? I have a client who runs a service shop but they don't do any performance work, but can do alignments and will probably want to do the OEM settings unless I have other numbers.

 

[tunedin302]

That is exactly what you should be trying to accomplish - the factory alignment settings (for a street type car). Anyways, to accomplish that with lowering springs you will likely need some cc plates. When you put lowering springs in it changes the angle of the control arm, which in turn changes the angle of spindle which in turns changes the angle of the strut. To bring the geometry back to stock (except for the control arms) you need to get some cc plates. Once you do this then you will be able to get your tire patch more even and your steering feel will be much improved. I would suggest the Eibach pro-kit or some H&R springs, along with some MM cc plates. Do this first, on Monday give MM a call and ask for Matt. If he is not available then I'm sure some other very knowledgeable guy in tech will be. Explain you situation and see what they say. Those guys are really the masters at mustang suspension. http://www.maximummotorsports.com/

Keep us posted

 

[HISSIN50]

In addition to Matt's thoughts:

From the sound of it, tt's been 16 or so years since the last batch of installs, and 14 or so years since the car was driven with any frequency. That's a ton of time for seals to degrade, bushings to dry rot (unless you have delrin or something with no durometer rating ), etc.

If things are copacetic at lower speeds but get squirrely at speed, I'd consider the front LCA bushings and tie rods. You could be seeing some toe-out on one side or the other at speed (read unbiased load) when hitting bumps at such speed.

Also, plain and simple, some tires like to exhibit goofy characteristics like tramlining, and so on (and nothing more than a different set of skins is a fix). Have you swapped front to rears and seen if the symptoms changed?

It's really going to take a thorough once-over to see where you stand IMHO. As said, a call to MM never hurts. You might also be able to gleam some insight from the Cornercarvers forum.

Good luck.

 

[tunedin302]

In addition to Matt's thoughts:

From the sound of it, tt's been 16 or so years since the last batch of installs, and 14 or so years since the car was driven with any frequency. That's a ton of time for seals to degrade, bushings to dry rot (unless you have delrin or something with no durometer rating ), etc.

Good point ...

 

[Roland69]

do the steering boxs on our cars have a pre load adjustment like some others doo....They can become loose and make the steering feel loose

 

[DucatiRdr]

Awesome! Great advice. I just went to Stangsuspension.com and ordered a set of the MM caster plates and they were having a deal (no shipping) so not so bad. I'm wondering about the springs since now is the chance to deal with it so I don't have to get things re-re-aligned.

I'll call MM to see whether they think I need a bump-steer kit as well - hoping I don't...trying to keep the whole cost of bringing this car back to life as reasonable as possible.