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Author Topic: 1965 fastback (Shelby Clone) dives, squeals  (Read 2059 times)
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ITHERTZ
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« on: October 25, 2011, 08:55:01 AM »

I think the UCAs and LCAs as well as the front sway bar are original V8 Mustang on my car.  Pretty much everything else in the front suspension has been recently replaced.  I have manual steering and brakes / discs up front.  I'm running standard V8 springs and medium duty Gabriel gas shocks (KYB too stiff for my street tastes).  Recently, the car has started to feel a bit unpredictable up front.  It goes straight down the road at all speeds easily, but any wheel ruts or things like that during lane changes cause the car to pull/dive strongly requiring correction on my part as the driver.  It is a little nerve racking.  Also, I've noticed that when hitting small bumps and such on the road, the car makes a hard clunking at times.  Regular ride comfort is very nice, however.  The rear leaf springs and shocks have been replaced recently.  When turning while decelerating (off ramp), I notice the tires barking a bit at times, which is also strange to me.  I also have newer tires, and tire inflation is correct.

I am thinking I need to replace the UCAs and LCAs.  I'm also wanting to add a better front sway bar.  I don't track this car or race it.  I want it to be a comfortable street car, but not drive like a Lincoln Town car either.  I want a performance feel, but not so much that it is uncomfortable to drive in town.  I have a one piece export brace and monte carlo bar as well.  I assume I don't need a rear sway bar?

I am also considering doing the 1" UCA drop. Any reason why I shouldn't do this if I'm replacing the UCAs anyway??  I understand the front may drop a little (maybe 1/4" inch?), but in general I LOVE the way my car presently sits and don't want to stray from that too much.

What should I look for as far as alignment specs when this is all done?  I assume the stock specs in all the alignment computer databases are pointless?  I'm running 15x7 wheels with 205/60 tires front and back.

Thank you all for your input and assistance.  I'd like to get this done soon so I can safely enjoy the car again.

Troy

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iamcanadian
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« Reply #1 on: October 25, 2011, 10:04:58 AM »

I completely replaced all of the suspension components on my 66 GT Fastback, which had become "tired", and upgraded the sway bar, used poly bushings, KYB shocks, used 5 leaf springs. With those simple upgrades I noticed a huge difference in cornering & handling, albet the ride is quite firm - which is how I like it.

Good luck!

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« Reply #2 on: October 25, 2011, 10:58:23 AM »

You may have a lower control arm bushing that's gone bad.  I had similar symptoms last month and replaced my upper and lower control arms, spring perches, and strut rods with parts from http://www.opentrackerracingproducts.com/products/.  They might be overkill for what you want, but they made a big difference in handling.  Plus John at OpenTracker gives a 10% discount to SAAC members.

Ken

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« Reply #3 on: October 25, 2011, 01:37:23 PM »

It is a little tricky to diagnose an issue like this without driving the car, but it does sound a lot like bump steer that you are describing.

All stock Mustangs bump steer. Power steering cars tend to insulate you from the feel but if you change tires, or go to wider wheels the car still reacts with bump steer more pronounced.

Going from biased ply tires to radial tires right there will start to make the bump steer more apparent.

If you lower the upper a-arms be advised that it increases the bump steer and even with the Shelby 1" drop, you are close to putting the ball joints in bind.

Going to manual steering is going to accentuate the entire situation.

Recommendation is 1) NEVER install a rear antip-sway bar in a Mustang. Even with a small one, you will tend to increase over steer, sometimes to the point of what is now called snap steer. That is a sudden violent oversteer on the car.

Cars with leaf rear springs do not benefit from rear anti sway bars regardless of what anyone tells you. You will not find them on any of the Shelby factory built race cars. PERIOD.

2) You should install a bump steer corrector kit on the car. You can do without them if you use the modified tie rod ends made by Cobra Automotive. It is difficult to completely eliminate the bump steer. Everything effects it. No two cars are exactly alike. On some it is terrible, on others barely noticible.

3)Install ball joint wedges if you lower the car and if you go that route, the 1" Shelby is not the ultimate relocation.
Actually 1-1/2" is but back in the day that would have required special ball joints or the above mentioned wedges.
A safe compromise is actually 1-1/4", but again you need to use the wedges.

The actual number that your car will be lowered in relation to ground clearance will vary but it is closer to 1-1/2" in the front. You can use spring spacers on top of the front coils to bring it back up. A lot of people find the car a little weird driving after lowering because of the rake. That is all personal taste. Your mileage may vary.  Grin

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TLea
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« Reply #4 on: October 25, 2011, 02:43:01 PM »

It is a little tricky to diagnose an issue like this without driving the car, but it does sound a lot like bump steer that you are describing.

All stock Mustangs bump steer. Power steering cars tend to insulate you from the feel but if you change tires, or go to wider wheels the car still reacts with bump steer more pronounced.

Going from biased ply tires to radial tires right there will start to make the bump steer more apparent.

If you lower the upper a-arms be advised that it increases the bump steer and even with the Shelby 1" drop, you are close to putting the ball joints in bind.

Going to manual steering is going to accentuate the entire situation.

Recommendation is 1) NEVER install a rear antip-sway bar in a Mustang. Even with a small one, you will tend to increase over steer, sometimes to the point of what is now called snap steer. That is a sudden violent oversteer on the car.

Cars with leaf rear springs do not benefit from rear anti sway bars regardless of what anyone tells you. You will not find them on any of the Shelby factory built race cars. PERIOD.

2) You should install a bump steer corrector kit on the car. You can do without them if you use the modified tie rod ends made by Cobra Automotive. It is difficult to completely eliminate the bump steer. Everything effects it. No two cars are exactly alike. On some it is terrible, on others barely noticible.

3)Install ball joint wedges if you lower the car and if you go that route, the 1" Shelby is not the ultimate relocation.
Actually 1-1/2" is but back in the day that would have required special ball joints or the above mentioned wedges.
A safe compromise is actually 1-1/4", but again you need to use the wedges.

The actual number that your car will be lowered in relation to ground clearance will vary but it is closer to 1-1/2" in the front. You can use spring spacers on top of the front coils to bring it back up. A lot of people find the car a little weird driving after lowering because of the rake. That is all personal taste. Your mileage may vary.  Grin
This is all good advice but of course only after a complete check for worn components  Grin

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zray
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« Reply #5 on: October 25, 2011, 08:43:50 PM »

there isn't any binding from a 1 inch UCA drop. zero. You will start to get binding at 1.75" unless you have the ball joint angle changed.

I had nearly the same exact symptoms as the OP on a previous '66 fastbasck I once owned. The lower control arm bushing was shot. That's all.

Z.

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« Reply #6 on: October 25, 2011, 09:14:56 PM »

 
 If the suspension control arms check out ok, you may want to also check the idler arm.
  Jack up the passenger side front wheel.
Grab the front wheel and shake it from side to side and check how much play is in the idler arm.
If the idler arm moves up and down, a worn idler to mounting bracket bushing is more than likely the cause of your steering instability issue.
 Worn strut rod bushings will also affect stability,especially when braking. They can make noises that you've described.

 

« Last Edit: October 25, 2011, 09:28:11 PM by Shasmu » Logged

NC TRACKRAT
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« Reply #7 on: October 26, 2011, 06:59:43 AM »

Good advice already posted.  From the symptoms, I tend to concur with the worn LCA bushings.  Jim Cowles recently recommended that, in place of the 1" UCA drop, you can just cut your front springs down. You may need to do it incrementally to get just the amount of lowering vs. firmness you desire.  Remember, it's EZ to cut 'em but impossible to put what you cut back on!  Cheesy

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ITHERTZ
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« Reply #8 on: October 30, 2011, 07:39:33 PM »

i haven't taken it in yet (no time), but I did drive it yesterday.  Damn thing was squealing on the off ramp turns - nice and easy and still making noise.  I checked the front tires when I got home and the inside half of each tire in the front were worn severely!  less than 1000 miles on the tires and now they are toast.  Tires were replaced not too long ago because a similar thing happened before - took it into the Ford dealership where they diagnosed a broken Idler arm and replaced it - had to get all new tires and alignment.  I guess they must have missed something.  I had just gotten the car at this time, so I guess I never new how it was supposed to handle/drive.  I never though to inspect my tires for uneven wear with such very little use.

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GT350Shelb
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« Reply #9 on: October 30, 2011, 07:47:06 PM »

I would look at printout from last alinement  see where front end was set ......


something is very wrong to burn up tires in 1000 miles .


I know the hunter alinement machine I use has some errors pertaining to factory settings for 65 -66 mustangs.   if someone blindly used the machine for the correct info  this could be your issue. 

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ITHERTZ
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« Reply #10 on: October 30, 2011, 07:50:50 PM »

I would look at printout from last alinement  see where front end was set ......


something is very wrong to burn up tires in 1000 miles .


I know the hunter alinement machine I use has some errors pertaining to factory settings for 65 -66 mustangs.   if someone blindly used the machine for the correct info  this could be your issue. 

I didn't get a print out.  This was done at the Ford dealership.  Funny thing is the car always went straight down the road easily enough.

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ITHERTZ
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« Reply #11 on: October 30, 2011, 07:54:22 PM »

Oh well, I supposed now I can rotate the backs to the front and get some beefier meat back there.   I'm currently running 205/60/15 - I found 215/60/15 in the same tire, but I think I want bigger yet.


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ITHERTZ
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« Reply #12 on: December 02, 2011, 10:16:13 AM »

I decided to go ahead and replace much of the front suspension (that which wasn't already recently replaced) and aquired a set of original '65 spindles as well.  Replaced all the tires, tie rods, UCAs, LCAs Strut Rod Bushings, new larger sway bar, springs, new front disc brake setup (KH style) and am very happy with the improvements to this car.  I only got to drive it a little before the snow, but I sure liked the improvements in handling for sure!  Now I have peace of mind knowing that every piece of my suspension and brake system (front and rear) has been replaced within the past 3K miles.  I should be good for a while now! 

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