Topic: Front Suspension Noise 1966 Mustang

[Building 3]

After rebuilding the front suspension and brakes and driving the car around a while, (100 miles or so) everything was fine. No odd noises, vibrations or anything else.  After this “break-in” period, I wanted to do some more aggressive driving to check the components. Again, everything was perfect except during a panic brake stop to lock-up. There was quite a loud sharp metallic “bang” as the car was rebounding back up after dipping downward during the stop.  It is coming from the right front suspension area. This happened each time I tried an aggressive stop. So the noise happens as the car is rebounding and coming back up. After the drive we put the car on a lift and looked at and checked all of the components and we could find nothing wrong, out of place, mis-torqued, leaking or broken. Has anyone run across this problem?  Any suggestions as to where to start looking?  PS, PB, 289 2V, auto, no A/C.
Thanks

[J_Speegle]

Would start with all the mounting and attaching points. Might find that something is less than really tight. Top (top and bottom). Spring mount to upper arm, Upper A arm to shock tower, anything attached to the lower A arm and every mounting point. Spindle nuts & strut rod hardware, even the wheel nuts is where I would first start

[jwc66k]

Did you replace the rubber insulator on top of the front spring (NPD 5415-1 -$3.75)?
Jim

[midlife]

I had the same thing on Midlife, and even had a very experienced front end specialist look at it.  We found nothing.

A couple of weeks ago, I saw a video on a forum that had a GoPro mounted on the front valence, pointing towards the strut rod/LCA area.  You could see the flexure when the car made an aggressive stop.  It even captured the sound that I was experiencing.  The noise was coming from the strut rod bushings as the strut rod enters the cupped washer/bushing area towards the center of the car.  There's a lot of movement there, believe me!

[WT8095]

This video?



That's a really cool angle!

Follow-up with aftermarket struts:

[midlife]

That's the one!!!!

[67gtasanjose]

I noticed this car (in videos) sits much lower than stock, this may be some of the issues with noises.
Another thing to consider is whether or not the bushings (noisy set) are installed in the correct order. Usually the "assember" is the problem, not usually the design or manufacturer of the "assembly".

These cars were somewhat weak in design, designed as disposable, not Race Cars & Show Cars. I DO LIKE the upgrades in the 2nd video but "Not Concours" enough for me to use.

[WT8095]

These cars were somewhat weak in design, designed as disposable, not Race Cars & Show Cars. I DO LIKE the upgrades in the 2nd video but "Not Concours" enough for me to use.

Disclaimer: I was not endorsing the new design when I posted the video     But I  like the results too. In the first video, the bushings look suspiciously squishy - are original factory bushings that soft? Note how much the spindle turns under braking load - caster angle drops dramatically, possibly going negative, which means steering stability is affected. After seeing the videos, I'm inclined to go with the highest durometer (hardness) bushings available that maintain a reasonably original appearance.

[Building 3]

Thanks for all of the replies.  That video shows it perfectly. That is why we cant find it up on the lift.  Everything is torqued to the proper specs, so it's the movement of the rubber bushings. Does anyone know if someone makes a harder rubber bushing set that would not flex so much?

[Bob Gaines]

Thanks for all of the replies.  That video shows it perfectly. That is why we cant find it up on the lift.  Everything is torqued to the proper specs, so it's the movement of the rubber bushings. Does anyone know if someone makes a harder rubber bushing set that would not flex so much?

I would think that since Mustang strut rod bushings don't typically make that noise and you have confirmed that is the source of the noise then the  rubber that the bushings are made of may be defective. You can go to poly urethane but those have a tendency to squeak I am told (not from flexing but because there is almost no give). They don't look original ether. If that is not a concern then it doesn't matter then it may be a viable alternative . Logically since other Mustangs don't have this problem trying another set of stock type bushings should be a improvement . Millions of Mustangs are testimonials. 

[WT8095]

If I'm not mistaken, there should be a steel sleeve running through the bushings. The sleeve keeps the threaded portion of the strut rod from contacting the hole in the bracket. If the sleeve is missing and the threads are rubbing and catching on the edge of the hole, it could explain the noise. (Picture the threads "ratcheting" into place as you brake, then "popping" loose as braking pressure subsides) Likewise, if a sleeve is present, it may have a notch worn in it that is catching on the hole. Under normal circumstances there shouldn't be a problem, but this does not appear to be a normal circumstance.

Another thing to look for - in the first video the spindle turns as the brakes are applied. For this to happen, the LCA has to move backward, which means it is twisting the mounting bushing. If you have that much movement in yours, perhaps something is catching there and making the noise.

[jwc66k]

If I'm not mistaken, there should be a steel sleeve running through the bushings.

Not used for 64-66 strut rods. From the outside in: Nut; large special steel washer (small hole); rubber bushing, with a "step" that goes into the -> ; frame, with a large hole for the "step"; rubber bushing, no step; large special steel washer (larger hole). The entire assembly is not adjustable and per instructions, the nut 34426-S8, 9/16-18hex, cone, is torqued 40-55 foot pounds (66 Shop).

If the sleeve is missing and the threads are rubbing and catching on the edge of the hole, it could explain the noise. (Picture the threads "ratcheting" into place as you brake, then "popping" loose as braking pressure subsides)

The only metal parts are the two large washers. They may be hitting the frame's channel top or sides.
Jim

[midlife]

Not used for 64-66 strut rods. From the outside in: Nut; large special steel washer (small hole); rubber bushing, with a "step" that goes into the -> ; frame, with a large hole for the "step"; rubber bushing, no step; large special steel washer (larger hole). The entire assembly is not adjustable and per instructions, the nut 34426-S8, 9/16-18hex, cone, is torqued 40-55 foot pounds (66 Shop).The only metal parts are the two large washers. They may be hitting the frame's channel top or sides.
Jim

I think what is happening in the video is that the strut rod bushings were not tightened down enough at rest.  The bushings are popping out of the frame, allowing the strut rod to hit the frame hole.  The popping sound is either that or the whole assembly coming back to its nominal position.  There is no specification for the tightness of the strut rod nut in the frame area, but the rubber bushing should be reasonably "smushed", IMHO.

[jwc66k]

There is no specification for the tightness of the strut rod nut in the frame area, but the rubber bushing should be reasonably "smushed",

- - the nut 34426-S8, 9/16-18hex, cone, is torqued 40-55 foot pounds (66 Shop).

Not true. The outer washer is up against a ridge on the strut rod, the nut is torqued down to that. The outer and inner rubber bushings "float".
Jim

[Building 3]

Thanks for all of the input and suggestions. I think I will try a new part. That seems to make sense since the left side does not make the noise.  I must have gotten a defective one. If that does not work, I will look at the lower control arm.  Clearly, something is different from the right side to the "good" left side, and the majority of the cars without this problem.