My vibration issue.......

ecyrbh

Registered User
I have read some posts on a particular driveline vibration that a lot of people have had experience with.The vibration I have starts around 70 and progressively gets worse as speed increases or even worse yet on decell from these higher speeds.It is a cycling/harmonic type vibration that this car had even way back when my Father-in-law bought it from the previous owner......I started out on a quest last weekend to solve my vibration once and for all.
It all started by ordering the differential(pinion mount) bushings that are still available from Ford;( if I could have purchased the diff. cover mount new,I would have replaced it also).I installed these bushings and relocated the driveshaft 180 degrees.The test drive afterwards was considerably better than before,but still there.
Today,I replaced every bushing,(upper control arm-inner and outer,lower control arm-inners and outers,toe compensators links,lower shock mounts,and new wheel bearings).The only thing I didn't replace was the coil spring insulators(they weren't bad).
In the process I found alot of dry rotted,worn-out,even missing rubber in these bushings.I didn't think my suspension was that bad,but...Holy-Cow....
Took it out for another drive and MAN what a difference.The ride quality is 100 percent better right off the bat.So I got it up to 70 on the highway..No Vibration...75,No Vibration...80,No Vibration.I held it at 85 for a while and took my foot off the gas....Absolutely,NO VIBRATION what-so-ever.It's like driving a different car now.I'm very pleased with the results,I'm gonna give her a wash and a wax tommorow,Fill up the tank,and just go Cruisin'......
P.S....Oh-Yeah....Then take it to the alignment shop for a check on Monday......:D:D:D
 
Driveline Vibration

A few years back (well almost 7 years now) I had our local Ford dealer service department replace all the wearable suspension components along with the driveshaft u-joints (and crankshaft seal that was leaking tons of oil) and when I got the car back, it now had the type of vibration you describe. I've don't drive this car that often, but I've always thought that it was caused by a defective u-joint that the Ford mechanic installed. Your post seems to imply that it may be some other suspension component. Can you detail all the mods you made that finally caused the vibration to disappear? I'll compare them with what I had Ford do and hopefully by a process of elimination, I can figure out what wasn't done on my car and that may be the culprit. Thanks for your help!

Steve
1990 White stock SC
 
Here is my list of Mods or replacements:
Pull up a chair;Here We Go.......
I totally Rebulit the engine using BHJ balancer and having rotating assembly balanced at time of rebuild.Installed new solid motor mounts and trans mount as things went back together.At the same time I put new U-joints in the driveshaft,but didn't have the balance checked.I would probably advise everyone to do that,if anything,for piece of mind.I put new tires on it as the car became streetable after sitting on old rubber for 7+ years.While the engine was out,I totally rebuilt the front suspension and brakes in preparation for that first drive.Had the car aligned.The car now has 11,000 (+,-)miles on it since rebulid and I finally got around to checking this vibration issue.I had read some posts and spoken to various people about this and I decided to tackle the problem.The first thing I did was install the differential pinion mount bushings(new from Ford)and re-clocked the driveshaft 180 degrees.This proceedure helped a little,but was not the cure.I then removed all of the rear suspension from a 90 parts car that I have and installed every bushing there is available as I stated in my initial post.The upper control arm inner and outer bushing were toast on my Daily Driver as well as the parts car.They were literally making metal to metal contact within each one.The toe compensators rattled when the cars weight was on the ground.The only bushings that may have been reused were the lower control arm inners and outers,but I replaced them any way.I did reuse the sway bar end links and mount bushings,they were still OK.I also put in new wheel bearings as preventative measure while everything was apart.The bearings might have also been reused,but I was tired of chasing my tail.I feel that the metel to metal contact within the upper controll arm was the MAJOR cause of my vibration,sending that rotating-cycling-harmonic type vibration through the entire body of the car.It would vibrate so hard,at 70 mph,if you looked in the inside rear view mirror,you could not make out what was behind you.The steering wheel would bounce and shake,the passenger side seat would wiggle and shake,...I could go on and on...But now its fixed.I would advise everyone to check these components out,even on the low mileage cars that are still out there,due to the fact that time will take its toll on the rubber and the way the construction on the original bushings on the upper arm looked to be kind of inferior...........Sorry for the long post,and the length of time it took to reply(Just got home from the Hospital after giving birth to a nice Kidney Stone...I wouldn't wish that pain on anyone!!!... OWWW )
 
I can figure out what wasn't done on my car and that may be the culprit. Thanks for your help!

Steve
1990 White stock SC
Try indexing the driveshaft to the differential. That is, unbolt it, shift it 90 degrees and test it out. Take note of which setting produces the least vibration in the rear wheels. You can do this with the rear wheels off the ground and the car fully supported; front wheels chocked. :cool:
 
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