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Bronco swerves HARD side to side over 10 MPH

John_parkeriv

Jr. Member
Joined
Feb 24, 2020
Messages
192
Loc.
Arcadia, FL
Almost got my project bronco at a point where I can drive it on the road. Engines in, trans is in, lift is installed, it's all coming together. Take it for a quick rip down my local road, and can barely keep it between the ditches. Fastest I think I've had it is 15 miles an hour, and it was a struggle to keep it on the road at that speed. Alignment toe on the front end is withing 1/16th of an inch, I have an adjustable track bar and drag link, and power steering.

Nothing seems overtly loose that would be a serious cause for concern. I have 2.5" of lift, so I don't have a track bar drop bracket. Somebody who's lifted one of these in the past, what would cause this? Only thing I can possibly think of is my steering box. It's from a 78 f250 doing a 4x4x2 conversion and it's held in with 2 bolts.

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fluffybunny

Contributor
Newbie
Joined
Oct 28, 2015
Messages
180
I agree with c0astie31, Pop a hole through the frame and put a good bolt, washers, and nut on that. That's where I would start. The top of your steering box is probably flexing.
 

m_m70

Contributor
Sr. Member
Joined
Jun 14, 2001
Messages
1,459
Loc.
Pacifica, CA
check your rear suspension and the torque on the u-bolts and shackles.
Did you add degreed c-bushings with your lift?
What size tires? My truck likes a little over 1/4" toe in with 33"x12.5"
 

EPB72

Contributor
Sr. Member
Joined
Jul 13, 2019
Messages
801
Loc.
Pleasant Hill, CA
As noted check rear supension bushings ,u bolts;;

that steering box really needs to be properly secured ,,don't just run a bolt through the frame you will have the add a sleeve in side the frame as well as check the existing ones for any rust..

Front end inspect with wheels on and on the ground and have someone wiggle /turn steering wheel back and forth .look at king pins for any slop;tie rods for any slop,even the new components for any slop...look at the radius arm frame bushings for condition...and if your done installing your track bar make sure you install a cotter pin in the lower mount nut appears missing..and others that my be missing..

Then at some point you may/probably will need to address Caster {lack there of} issues especially if you are running 35 inch tires and still running the what appears original rubber C bushings.

If everthing checks out tight you could add a little more toe in ..and tire pressures what are running
 

rocknhorse76

Contributor
Bronco owner since 1993 💪🏻
Joined
Jun 7, 2014
Messages
339
Loc.
Central WA
I’d be willing to bet that the steering box is flexing from side to side without that top bolt. I have the same box on mine, and I ended up utilizing the top rear hole for the stock box and new holes for the other two. I welded plates to both sides of the frame, knocked the factory sleeves out of the frame and put DOM sleeves in there. I had to trim the body mount to make it fit, but it’s not a big deal.
 

Timmy390

Bronco Guru
Joined
Jan 1, 2011
Messages
5,609
Loc.
Conway, AR
I’d be willing to bet that the steering box is flexing from side to side without that top bolt. I have the same box on mine, and I ended up utilizing the top rear hole for the stock box and new holes for the other two. I welded plates to both sides of the frame, knocked the factory sleeves out of the frame and put DOM sleeves in there. I had to trim the body mount to make it fit, but it’s not a big deal.
This ^^^^^^^^

Tim
 

OX1

Bronco Guru
Joined
Aug 26, 2003
Messages
3,458
This ^^^^^^^^

Tim

I second "This" ................. :)


Both those bolts in the same plain, and level, barely keeping that box from rocking back and forth about those two pivot points.
 
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John_parkeriv

John_parkeriv

Jr. Member
Joined
Feb 24, 2020
Messages
192
Loc.
Arcadia, FL
check your rear suspension and the torque on the u-bolts and shackles.
Did you add degreed c-bushings with your lift?
What size tires? My truck likes a little over 1/4" toe in with 33"x12.5"
Yep, she has C bushings. Running 35x12.5's
 

bax

Contributor
Old Member
Joined
Aug 22, 2005
Messages
14,491
Looks like you have a great pinion angle. That makes me wonder how far forward your king pin is?
 

tutone

New Member
Joined
Oct 21, 2014
Messages
7
I had this happen once, and I was convinced it was the steering box. It wasn't. One of the half-shaft u-joints was seized, and the power steering could force the joint to go left, or right, but not straight.
 
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John_parkeriv

John_parkeriv

Jr. Member
Joined
Feb 24, 2020
Messages
192
Loc.
Arcadia, FL
Feel kinda stupid for this one, one of the bolts on the drag link was barely finger tight! I was gonna test if that was the problem, but my distributor cap broke because bronco. 😂 I'll get it running again and let y'all know if that solves it. That's for the suggestions so far!
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,834
I wouldn't drive it until that 3rd bolt is in the steering box. If that box is flexing, it could snap off the lower ears. Everyone who has looked at your pictures is commenting how bad that is. Because it is that bad. Fix it before taking it for another drive.

Also, what degree of C-bushings are installed? Not if there are any installed, but the amount of offset.
A little harder to answer, are they installed correctly? If they go in wrong they will provide no correction, or worse negative correction.
 

nvrstuk

Contributor
Just a Bronco driver for over 50 yrs!
Joined
Jul 31, 2001
Messages
8,605
What everybody else said FIX THE STRG BOX before you drive it. You seem to obviously not understand the importance of doing that as you have addressed it in your response.

Not trying to &*(#% you off, you NEED to fix it before you drive it.
 
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John_parkeriv

John_parkeriv

Jr. Member
Joined
Feb 24, 2020
Messages
192
Loc.
Arcadia, FL
What everybody else said FIX THE STRG BOX before you drive it. You seem to obviously not understand the importance of doing that as you have addressed it in your response.

Not trying to &*(#% you off, you NEED to fix it before you drive it.
What's the best way to add that hole in the frame for it? Drill barely got the bottom rear hole. Is there some kind of bracket for it that I can make?
 
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John_parkeriv

John_parkeriv

Jr. Member
Joined
Feb 24, 2020
Messages
192
Loc.
Arcadia, FL
I wouldn't drive it until that 3rd bolt is in the steering box. If that box is flexing, it could snap off the lower ears. Everyone who has looked at your pictures is commenting how bad that is. Because it is that bad. Fix it before taking it for another drive.

Also, what degree of C-bushings are installed? Not if there are any installed, but the amount of offset.
A little harder to answer, are they installed correctly? If they go in wrong they will provide no correction, or worse negative correction.
OH Y'ALL MEAN IN THE FRONT! No, I have the bushings but haven't got them in just yet. I think they're 4°
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
34,834
OH Y'ALL MEAN IN THE FRONT! No, I have the bushings but haven't got them in just yet. I think they're 4°
After you get the steering box attached correctly, put the bushings in. With a lift and stock bushings you will have negative caster, that will not track well.
Since they sound like they are new and never installed, return the bushings and get 7° bushings. The 4° with the 2½" would be a good match if you still had manual steering. But with power steering the extra 3° of caster will make things better.

Get the steering box bolted on correctly and 7° bushings and it will drive just fine.
 

stout22

Contributor
Bronco Guru
Joined
Dec 13, 2006
Messages
2,692
Loc.
Athens, AL
Definitely need the correct C bushings and a third bolt in the steering box.
I rolled my first Bronco because of wore out C bushings. Things got squirrely real fast.
Your frame will eventually crack with just the two bolts.
 

Timmy390

Bronco Guru
Joined
Jan 1, 2011
Messages
5,609
Loc.
Conway, AR
With the location of the bolt holes I don't see you being able to add DOM inserts inside the frame. My suggestion is to weld 1/8th plate top, bottom, and sides. The frame will flex. My frame was cracked from flexing....

Tim
 
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