Steering Geometry and Squeak Question

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Groover
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Steering Geometry and Squeak Question

Post by Groover »

So I finally got my adjustable strut rods installed and had the Caliente re-aligned.

Was able to get 4 degrees of caster and maintain close to 0 camber and about .3 total toe.

Results as expected. Drives great, holds the road better, feels a little stiffer in responding, but still smooth steering.

But... now I have an annoying squeek in the front end on very little bump, rock, etc (chirp, chirp, chirp). Nothing (I can hear) when I'm cruising highway speeds on pavement, and nothing when I push the front up and down standing still. Nothing when I jack it up and try to push/pull on the tire. Only when in motion and hitting bumps, dips, rocks, etc. Embarrassing nonetheless.

I originally redid all my entire front suspension with the PST original performance front end kit. Rubber not Poly bushings (as per Roy and everybody else's advice). I have swapped in roller bearing spring perches a while back, so no rubber there. I just re-greased all the fittings. Still chirp chirp.

I was thinking that it may be the upper or lower control arm bushings, now under new stress/alignment as the adjustable strut rods have pulled the LCA/spindle forward. But the ball joints should allow for some subtle change in geometry, right?

Would 4 degrees of caster (up from 0) be enough to bind the control arm bushings and cause this squeak? If so, can anything be done short of releasing some/all of the caster?

Is there any way to confirm? Alignment rack time costs, so I'd rather not take multiple bites of this apple.

And I don't want to go through the pain of the swapping the UCA/LCA bushings on a hunch.

Thoughts?
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1964 Comet Caliente Convertible
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Santa's Comet
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Re: Steering Geometry and Squeak Question

Post by Santa's Comet »

I think the lower control will bind with more castor.
I used a adjustable LCA that gives camber and castor adjustment.
Pacific Thunder? Has a Heim threaded joint.
NP Dave
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Groover
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Re: Steering Geometry and Squeak Question

Post by Groover »

Thanks Santa

Take it you mean these?

https://www.pacificthunderperformance.c ... 7590262789

That looks super cool (but sold out - for now).

So do you think the lower control arm busing is the squeak point? and if so, do you think if I dropped back to say 2 degrees of caster it would resolve? I'm not really sure how much length of the strut-rod equates to 4 degrees. Doesn't seem like it would be much.
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1964 Comet Caliente Convertible
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poboyjo65
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Re: Steering Geometry and Squeak Question

Post by poboyjo65 »

I'm with santa. Sounds like your strutrods have the lca pulled forward too far & binding the bushing. I did my own alignment & could feel the pressure building as I tightened up the s.rods. so I went back & got as much caster as possible on the uca shims. then only used the s rods to fine tune & get both sides equal. I have a vario centric camber kit . having camber & caster adjustments separate makes it lots easier to align up. If you took the trouble to take off the LCA & grease those bushings really good would probably quiet it down but will most likely wear out quicker in a bind like they are.
those pac thunder arms have the heim like santa mentioned that replaces the rubber bushing. I noticed a few months back that p thunder was sold out of most of his stuff & asked Joe about it. Joe helped that guy develop a under engine brace for comets/falcons. there is also a kit to make your lca's like his, but it is sold out too. :roll: Seems like all his stuff is sold out :? :?
https://www.pacificthunderperformance.c ... 7155379781

btw that toe in sounds a little big, I'd want it around 1/8''-1/4'' I have mine at 1/16''
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Comechero65
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Re: Steering Geometry and Squeak Question

Post by Comechero65 »

All that you have done to the front end sounds good. Having the ability to easily adjust camber and caster is great. Settings sound good but .3 on toe-in sounds too much. I set mine at 1/16" and no more which steers and handles just fine but tires don't wear as fast.

As far as squeeks mine had some some squeeks for awhile when I started driving it but but eventually those shut up. I had completely rebuilt the front end with everything being new so there was no reason for it. Don't know what was the cause but it all went away and it's all quite now.
Ron
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Groover
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Re: Steering Geometry and Squeak Question

Post by Groover »

John,

I might have that toe number wrong. I can't recall exactly, I know it was less than book value.

I have about all the shims I want (which only got me about =.5 caster while still keeping close to 0 camber). That's why I went to the adjustable strut rods.

Here comes the geometry again...

If I take a turn or two of each strut rod nut to reduce the caster (and the tension on the LCA bushing), will it increase or decrease the toe?

Any idea how many revolutions of the strut rod nut equals each degree of caster?
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poboyjo65
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Re: Steering Geometry and Squeak Question

Post by poboyjo65 »

Not a clue as to how much a turn would make. but if you change anything it will change everything to some degree & you'll have it all out of whack. So either do it all yourself or let them do it. maybe you could get some aerosol grease & coat those rubber bushings, drive it till something wears out then either hail mary or punt! :lol:
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Johno

Santa's Comet
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Re: Steering Geometry and Squeak Question

Post by Santa's Comet »

Just went to the P Thunder site. Bummer, I was looking at his strut rods to kill the rubber binding.
The owner was great to work with! I'll check again this winter.
NP Dave
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Lou's Comet
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Re: Steering Geometry and Squeak Question

Post by Lou's Comet »

Groover wrote:?...................

Here comes the geometry again...

If I take a turn or two of each strut rod nut to reduce the caster (and the tension on the LCA bushing), will it increase or decrease the toe?

Any idea how many revolutions of the strut rod nut equals each degree of caster?
Taking a turn or two on each strut rod isn't going to change your toe in much.

Increase or decrease in toe in would depend on the geometry/relationship between where your outer tie rods are and where the pitman arm and idler arm joints are.

Imagine a straight line thru the center of the pitman arm/center link joint and the idler arm/center link joint. Now extend that line out past the outer tie rods/spindle joint. If the outer tie rod joint is in front of that line then taking away caster would increase toe in.

If the outer tie rod/spindle joint is on that line or behind it then taking away caster would decrease toe in.

Either way I really don't think it would be much? Not enough to worry about right now or to stop me from taking away a turn or two to see if it get's rid of the squeak, or even makes the squeak less kwim?

Lou

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Re: Steering Geometry and Squeak Question

Post by comethead »

Santa's Comet wrote:Just went to the P Thunder site. Bummer, I was looking at his strut rods to kill the rubber binding.
The owner was great to work with! I'll check again this winter.
NP Dave
I believe the sold out status is temporary. He got over whelmed with orders and has to catch up. He's a one man show.
Pretty sure his inventory will come back in the next few months. The problem is the Mustang dudes- there's millions of them!!!! :lol:
1965 Caliente HT- 289/4 speed
1964 Falcon HT- track car- 302/4 speed
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poboyjo65
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Re: Steering Geometry and Squeak Question

Post by poboyjo65 »

Joe you should call & check on him, he is sold out of everything! :shock:

Groover how close does your tires get to the fender? when my first go around my tires rubbed the front fender when turning so I had to back off the strut rods from my first setting, I could only get about 3.5* + caster without rubbing. Of course my frontend is a lot lower than yours. it wasn't a squeak it was a different sound but I am just curious how close yours is.
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Jims65cyclone
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Re: Steering Geometry and Squeak Question

Post by Jims65cyclone »

Here are the alignment specs from DazeCars :
**********************************************************************************************************************************************
Please align to these specs “1960-1966 Mustang and Falcon Performance Alignment with or without UCA drop”.

These specifications are in order of importance.

1. NO more than .25 degrees difference between driver’s side and passenger’s side.

2. +2.0 to +3.5 degrees caster.
NOTE: for cars with Adjustable strut rods. Please attain as much caster as possible using the shims (at least 1.5 to 2.0 degrees), and then use the adjustable strut rods to increase the caster and make the sides the same. Also, please note that the caster difference between the driver’s side and passenger’s side needs to have no more .25 degrees difference prior to the adjustment of the strut rods.

3. -.5 to 0 degrees camber. No positive camber, please. There is no problem having a slight variation from driver’s side to passenger’s side to account for the crown in the road.

4. 1/16" to 1/8” toe in
*************************************************************************************************************************************************

I recommend that you do as John had to do, and these specs state, and get as much positive caster as you can with UCA shims first, then adjust the struts. That will lessen the severity of the angle of the LCA relative to its bushing, which I think is causing binding and squeaking. I would experiment by backing off on the struts a turn at a time to decrease the caster, and see if you get to a point where the squeak goes away. Back off both sides equally or it will pull to the more positive side. That's why the specs call for no more that .25* difference side to side. That should also change your camber slightly toward negative, but since the spec calls for -.5 to 0, and you're at 0, you've got some room to play with. It should also change your toe-in toward more toe-out (I think), but you've got way too much toe-in now at .3". Since all your parts are new and tight, you shouldn't need more than 1/16" (.0625!) toe-in. Assuming you can adjust the squeak out by backing off the struts, then it's decision time. If you've got pretty close to a full stack of shims on the front bolt on both sides of the UCA shaft, you could take it back to the alignment shop and just get him to put the gauges on and give you an actual reading on caster and camber to make sure you're within spec. If there aren't many shims on the UCA shafts, you should probably get him to realign it from scratch to maximize the caster with shims first, then finish it with the struts. Either way, you need to get the toe-in reset to 1/16" toe-in.
Jim
Last edited by Jims65cyclone on Sun Sep 03, 2017 2:17 pm, edited 1 time in total.
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Re: Steering Geometry and Squeak Question

Post by comethead »

Just noticed on Pacific Thunders website it say "internet sales suspended". Not all sales.
Seems like if something needed to be ordered a phone call would do it.
Probably his way of slowing orders down a little.

Joe
1965 Caliente HT- 289/4 speed
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Groover
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Re: Steering Geometry and Squeak Question

Post by Groover »

For the record, the squeak is resolved and it wasn't the lower control arm bushing.

When I bought the adjustable strut rods, the guy at Falcon parts said I'd need the 63 bushings (suggesting to me that there must be some difference in size of the bushing ID)? So I bought them and put them on.

Turns out there is a size difference but not ID, rather OD and overall depth, etc. The 64 bushings are much larger. I swapped them back on and the squeak went away.

I'll go back and re-align again to set the toe (I may not be remembering that setting correctly, but I need to get it re-aligned since the bushing thickness will make some difference in the caster).
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1964 Comet Caliente Convertible
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Comechero65
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Re: Steering Geometry and Squeak Question

Post by Comechero65 »

If you ever had the uca shafts out or have replaced them a good thing to do is cut a grease slot through the threads on each end of the threads. Helps grease get through all the way when you grease the uca's. The threads can be so close that the grease can't get all the way through. The failure of grease to get all the way through the threads can cause sqeeks and accelerated wear. This particular one has a hole in the middle of the threads where grease should come out from the grease fitting and channel throught the center of the shaft but still can have a hard time getting both ways through all the threads. Not all shafts have that hole in the middle.

Most that know this trick do it when installing new shafts and bushings.

Should look like this after cutting the threads.
DCP_0959.jpg
DCP_0959.jpg (32.69 KiB) Viewed 3234 times
Ron
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