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steam_mill
06-23-2014, 12:07 PM
High Speed vibration

So, my '85 mustang has always had high speed vibration issues. I used to have vibration issues at about 70 mph. After a rebalance didn't correct the issue, I replaced the front wheel bearings and it reduced the vibration alot. I continued to have a vibration above 85 mph.

Fast forward to the recent modifications:

New Ball joints
New Tie rod ends
Aero Spindles
New brakes
New rebuilt 3.55 rear end (upgraded from 7.5)
Aluminum FMS driveshaft
Steeda caster camber plates
Various bushings replaced
new rear discs
new tires on all four corners
Fresh alignment (with 1/8 toe in)
Offset steering rack busings
New rag joint

Also have a strut tower brace, sub-frame connectors, k-member brace.

After all of these parts, car has the same type of vibration, although to a lesser degree.

Car has always been lowered 2".

Here's my view:

1. Essentially, most of my front end and drivetrain components have been replaced.
2. Car displays same type of vibrations post replacement of parts.

Vibration is the steering wheel, not so much side to side but more up and down. It's not an out of balance type of vibration. I feel no difference in the seat of my pants.

I've tightened down all the bolts in the column including the ones behind the signal lever.

Lastly, vibration also varies by road surface. Change in road surface influences vibration, sometimes less, sometimes more vibration.

I used to have a four runner that behaved in exact same way. I figured car was not made to drive at 80 or 90 mph.

Is that how a fox should feel? It's totally driveable but just would like to figure out if there is anything that can be done.

I'm running 245/50/16's at all corners also.

My last thing is the rack itself. All original - almost 30 years old. Could it be the inner tie-rods?

I'm looking for any suggestions.

RedSN
06-23-2014, 12:53 PM
I continued to have a vibration above 85 mph.
that's the flux capacitor warming up.


sorry.
only thing i can think of that you haven't replaced is the rear axles. Maybe one has a slightly bent flange?

mazzon
06-23-2014, 04:52 PM
drive shaft or your tires arent balanced properly. Maybe lost a weight?

Intmdtr
06-23-2014, 04:54 PM
My bet is on slightly bent axles....