Massive front end vibration

[5buckaroos]

Could use some ideas on caring for my '71

Out of the blue-not speed dependant but usually 30-40mph range, a touch on the brakes and I'm out of control. Doesn't happen alot-could be 15 miles without incident. Travel now reduced to "is someone dead".

I have no determined cause other than it seems to be related to braking. Turning or rolling over a few bumps while initiating braking also seems to facilitate it. The only way to stop it once started is to stop the vehicle.

-Lugs tight
-wheel bearings adjusted
-brake pads new
-rotors new but port side seems slightly warped
-slight play in both upper ball joints
-all other joints feel tight-did not disassemble
-nothing visibly broken
-wheel balance not checked but assumed this would
cause a more consistant problem and would relate to
speed.

Running short on things to check and not wanting to throw $ at it until it obeys. rocked my world the first time. Wife followed as I gimped home. She viewed once and said front left tire was going to let loose - very obvious from her perspective but nothing obvious to me. Any advice welcome.

 

[bert]

How are the track bar bushings and radius rod bushings? Something has to be loose. Worn out shock will allow wheel hop but I wouldn't think it would show up while braking. Slight warp in rotor will start it going, loose parts will allow it to continue. HTH Let us know what you find.

 

[blackjack]

I am having the same exact issue. I just posted this. I know everything on the rig is good mine that is. It's your trac bar bushings just replace them and the problem will go away.

I know it's like you whole front end feels like it's going to fall off doesn't it. The trac bar bushings are cheap and easy to replace just a little muscling.

Hope this helps

Blackjack

 

[Hnrys69]

check your trac arm bracket and make sure where the bolt goes through the track arm arnt ovaled out... Mine did the same thing until I replaced the bracket..

 

[griff]

I was thinking what everbody else said, but I was also thinking it could be a blown shock in the front. A couple weeks ago we blew a shock on my friends truck at pismo. At 1:30 a.m. we started going home (not knowing we had a bad shock) and would get a voilent shake in the front end that would get worse until he stopped.

 

[5buckaroos]

all in favor of track bar say aye. Seems unanimous

I have the poly bushings and they look good enough but will pull anyway. I've been deceived before. Shocks were next on the list.

 

[SeanNollan]

Not quite just the track bar. I had the same problem, replaced the trackbar bushing and 85% of the shake was gone. Then had to replace the radius arm bushings and now all is smooth (well as far as broncos go)

 

[Broncmeister]

I had the same problem. replacing trac bar bushings helped me.

 

[bobtailbronco]

aye track bar

 

[BRONKEN]

I just replaced the trac bar with a adjustable one and new bushings but I still have the shake.

 

[red76]

Try checking the bolt and the hole and see if the bolt is to small or hole is too big etc. I'm sure you would have noticed but just ideas. Also severly un-balanced and un even tires have a chance to cause this so thats what i have. Good luck!

Will

 

[BRONKEN]

The one thing that I have not checked yet was the tire balance. I'm also going to check the front shocks but they only have about 100 miles on them.