Shaking at freeway speeds

SirenSong · 02-27-2001, 12:43 PM

I have a '66 Mustang, automatic, and for the past 4 or 5 months, it starts shaking whenever I drive above 45 or 50 MPH, and gets unbearable around 65.

It used to have a cracked power steering bracket, and seemed to be a little better, but only for a few days after fixing that. I've rotated tires, had the wheels aligned -- not sure what the problem might be. Any suggestions?

------------------
Emily Walker
emily@siren-song.com
1966 Mustang

Dark Knight · 02-27-2001, 02:27 PM

did you get the tires balanced? one of the balance weights might have come off.. u-joints could be going bad too

------------------
84 convt,'95 302,AFR's, performer
3.55's, underdrives stock shorties
stock cam, 1.7's
14.16@100.08, 255RWHP on a hot day
265 on the mph/weight chart

[This message has been edited by Dark Knight (edited 02-27-2001).]

Fostang · 02-27-2001, 03:07 PM

Have you checked the balancing on the drive line?? Bent rims??

SirenSong · 02-27-2001, 03:20 PM

Well, I had the tires balanced and the rims all looked to be fine, but I also keep losing my front hubcaps -- Firestone balanced the tires, and they were the ones who said the rims all checked out, suggesting that the shaking itself might be loosening the hubcaps. My front hubcaps kept coming off even after switching the front & back, though, which stumps me. I'm not sure if these problems are connected or not.

------------------
Emily Walker
emily@siren-song.com
1966 Mustang

Fostang · 02-27-2001, 07:16 PM

Bearings? I doubt it but worth a check or the rotor is too lose. Try jacking the car and spinning the tires see what they do.

mustangII460 · 02-27-2001, 10:44 PM

As stated before,U-joints are a good start.

If your joints seem good, unbolt your shaft and rotate it a turn.

Get it up to speed and slide it into neutral,see if this changes any of the vibrations.

If nothing changes you probibly have a bad joint in the front.

Do the rims get extremely hot?

[This message has been edited by mustangII460 (edited 02-27-2001).]

PNYXPS66 · 03-02-2001, 07:29 AM

Does the steering wheel shake at cruising speed? A simple way to check your front end alignment and parts is to cruise at the vibrating speed and hold the steering wheel at the 12:00 position. Point your index finger towards the roof while holding the steering wheel. If it shakes with the vibration, check your alignment, idler arm, inner and outer tie rods, upper and lower ball joints, pitman arm, and your control arm mounts. Take it back to Firestone to check your front end if you don't want to tackle it yourself. I had a similar problem with my 66 and I found out the hard way it was the upper control arm mount on the right side. The upper control arm came off the mount bar and pierced the shock tower while I was driving on the highway. Darn near lost control at 70mph. Be careful and good luck! Hope this helps.

------------------
Pony Express 66
God Speed and keep it between the lines!

fastang · 03-02-2001, 08:04 PM

Definitely check your u joints and make sure that your driveshaft is in balance. I was having the same problem on the freeway bc my U joints were trashed and the bearings were shot. I bought the fms driveshaft and havent had a problem since.

------------------
95GT B303 cam, 1.7 rockers, 65mm TB, 73mm MAF, milled heads, 355's K&N, off road pipes, pulleys, msd coil, 9mm wires, Tremec 3550, Pro5.0 shifter,10.5 Motorsport clutch, FMS aluminum driveshaft, weld in subframe connectors

02-27-2001, 12:43 PM	#1
SirenSong Registered Member Join Date: Feb 2001 Location: Seattle, WA, USA Posts: 4	Shaking at freeway speeds I have a '66 Mustang, automatic, and for the past 4 or 5 months, it starts shaking whenever I drive above 45 or 50 MPH, and gets unbearable around 65. It used to have a cracked power steering bracket, and seemed to be a little better, but only for a few days after fixing that. I've rotated tires, had the wheels aligned -- not sure what the problem might be. Any suggestions? ------------------ Emily Walker emily@siren-song.com 1966 Mustang

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02-27-2001, 02:27 PM	#2
Dark Knight Registered Member Join Date: Oct 1998 Location: Az Posts: 854	did you get the tires balanced? one of the balance weights might have come off.. u-joints could be going bad too ------------------ 84 convt,'95 302,AFR's, performer 3.55's, underdrives stock shorties stock cam, 1.7's 14.16@100.08, 255RWHP on a hot day 265 on the mph/weight chart [This message has been edited by Dark Knight (edited 02-27-2001).]

02-27-2001, 03:07 PM	#3
Fostang Registered Member Join Date: Feb 2001 Location: Stockton, Ca Posts: 599	Have you checked the balancing on the drive line?? Bent rims??

02-27-2001, 03:20 PM	#4
SirenSong Registered Member Join Date: Feb 2001 Location: Seattle, WA, USA Posts: 4	Well, I had the tires balanced and the rims all looked to be fine, but I also keep losing my front hubcaps -- Firestone balanced the tires, and they were the ones who said the rims all checked out, suggesting that the shaking itself might be loosening the hubcaps. My front hubcaps kept coming off even after switching the front & back, though, which stumps me. I'm not sure if these problems are connected or not. ------------------ Emily Walker emily@siren-song.com 1966 Mustang

02-27-2001, 07:16 PM	#5
Fostang Registered Member Join Date: Feb 2001 Location: Stockton, Ca Posts: 599	Bearings? I doubt it but worth a check or the rotor is too lose. Try jacking the car and spinning the tires see what they do.

02-27-2001, 10:44 PM	#6
mustangII460 Factoy Five Roadster Join Date: May 2000 Location: Sevier Co,Tennessee Posts: 1,681	As stated before,U-joints are a good start. If your joints seem good, unbolt your shaft and rotate it a turn. Get it up to speed and slide it into neutral,see if this changes any of the vibrations. If nothing changes you probibly have a bad joint in the front. Do the rims get extremely hot? [This message has been edited by mustangII460 (edited 02-27-2001).]

03-02-2001, 07:29 AM	#7
PNYXPS66 Registered Member Join Date: Feb 2001 Location: Beaufort,SC,USA Posts: 72	Does the steering wheel shake at cruising speed? A simple way to check your front end alignment and parts is to cruise at the vibrating speed and hold the steering wheel at the 12:00 position. Point your index finger towards the roof while holding the steering wheel. If it shakes with the vibration, check your alignment, idler arm, inner and outer tie rods, upper and lower ball joints, pitman arm, and your control arm mounts. Take it back to Firestone to check your front end if you don't want to tackle it yourself. I had a similar problem with my 66 and I found out the hard way it was the upper control arm mount on the right side. The upper control arm came off the mount bar and pierced the shock tower while I was driving on the highway. Darn near lost control at 70mph. Be careful and good luck! Hope this helps. ------------------ Pony Express 66 God Speed and keep it between the lines!

03-02-2001, 08:04 PM	#8
fastang Registered Member Join Date: Aug 2000 Location: santa ana ca Posts: 1,349	Definitely check your u joints and make sure that your driveshaft is in balance. I was having the same problem on the freeway bc my U joints were trashed and the bearings were shot. I bought the fms driveshaft and havent had a problem since. ------------------ 95GT B303 cam, 1.7 rockers, 65mm TB, 73mm MAF, milled heads, 355's K&N, off road pipes, pulleys, msd coil, 9mm wires, Tremec 3550, Pro5.0 shifter,10.5 Motorsport clutch, FMS aluminum driveshaft, weld in subframe connectors