1974 Bronco handling issues

[DJs74]

Hello Everyone,
I am new to this forum, actually I've never been a part of any forum and looking forward to getting and offering help.
My problem right now is handling on my 1974 Bronco. I completed my restore in November 2013 and had not driven it too much during the winter but now am taking it out often. It is wandering / darting on rural roads & uneven pavement but behaves nicely on smooth dual lane highway. it's like the contour of the road will throw it left to right. Pretty much everything on this Bronco is new, Front: front coils, shocks, new radius arm 7° bushings & donuts bushings, adjustable track arm, ball joints, adjustable Moog insert bushings (+1° to -1°), inner and outer tie rods, steering link, front disc brake conversion, power brake booster, new Delphi steering box and new stabilizer. Also new rear leafs and shocks. My steering link rod and track arm are probably within 5° of being parallel to each other and I just had a front end alignment done today and all the number are perfect. The Bronco has a 3" suspension lift and I'm running 33x12.50 BFGs all terrain radials. Anyone have advice on why it still wants to dart around on the rural roads? These roads are not bad, just narrow and not perfectly flat like the interstate. It kinda feels like bumpsteer but not really either??? Just wondering if I should put a track arm drop bracket on it to lower it by a couple of inches or maybe a second steering stabilizer? Help and advice is greatly appreciated. Oh, by the way - air pressures are around 32-34 in all 4 tires

thanks,

DJs74

 

[70_Steve]

...and I just had a front end alignment done today and all the number are perfect. ...

Oh, by the way - air pressures are around 32-34 in all 4 tires

Welcome to CB.com and congrats on getting your Bronco back on the road.

Saying the number are perfect means nothing... Sorry... What would really help is if you posted the "after" numbers.

Also try playing with the air pressure in your tires. I run 35's and keep around 28 psi in them. For me that seems like a happy medium between being a harsh ride and the steering getting sloppy. I think I know the feeling you're describing. Like the tires want to follow the ruts in the road. Remember, the tread on those tire is 10 - 10 1/2" wide. With that much air pressure in the tires keeping the tread ridgid, if the road isn't flat, you'll only have part of the tread contacting the road, and the tire will want to follow.

 

[m_m70]

I have the same tires and found that running them at 26 to 28lbs made a huge difference. Also, I had to re-torque the u-bolts after a few hundred (also had new springs) and that helped quite a bit. What were your "perfect" numbers? Adding the power steering makes the bronco want a little more caster than stock. Also went a little heavy on my toe-in, 5/16". Drives great now.

 

[broncojo]

Maybe a few pics of the front end would help some of the gurus access the situation. The track bar being out of parallel seems to cause a lot of problems. And by the way welcome to CB.

 

[DJs74]

Hey Guys,
Wow, thanks so much for the quick response and the warm welcome. What I meant by "perfect" numbers was the numbers on the monitor at the shop were green and within the range of acceptance (per 66-77 Bronco input). I cannot remember all the numbers and didn't get a print out but I do remember the camber was around +1.24° and the toe was within 1/16". Cannot recall the caster numbers. With the Moog ball joint bushings, I think the caster will be a result of the camber adjustment. Other than adding radius arm drop brackets, I don't think I can do much with caster. By the way, my coil spring appears to be perfectly vertical with no bowing or anything so I think the caster should be pretty good.
My only reservation with the alignment numbers was that I don't think the software takes the 33" tires and lift kit into account - probably the acceptance is based on stock suspension and tire size??. I will definitely play around with the tire pressures. We have about a tenth of a mile gravel road stretch in front of our house so I have been able to somewhat pattern the "rubber to the road" so to speak and I actually do notice that the tire tread (width) is not 100% covered in road dust -maybe 1/2" on the edges are not making great road contact so the PSI could be significant. Any thoughts on the track arm being dropped even though it is fairly parallel with the drag link? I was thinking that even though they are parallel, I might still be getting some bumpsteer affect due to the lift and new angle??

Again -thanks so much for your input and quick responses and nice welcome to CB.com

I will try some pressure changes tomorrow.

DJs74

 

[DJs74]

Hello broncojo!

thanks for your reply - yes, no problem I can post some pics of the front end components and will snap some shots tomorrow so everyone can get a perspective on my setup. Thanks for your nice welcome!

P.S. when I installed the new 7° radius arm bushings, I had to loosen and tighten the caps about 5 times (each side) to get the radius arms level to each other. I let both ends (threaded ends) of the radius arms down on the garage floor to level them. that was kind of tough but well worth the effort to ensure a level stance.

DJs74

 

[DJs74]

Good morning everyone,
Seems I am not able to post any pics. I've tried a couple of times and cannot figure out how to post the pics in the post. On a previous post, I referenced that the track arm bar and steering link were approx. 5° different - actually they are probably less than 1° different - so basically they are parallel already. I'm still wondering if lowering the track bar might help the darting around problem.

70_Steve: You replied to me yesterday and stated "the tires follow the road" - you are exactly right but things get more complicated after that. When it tries to follow the road and I correct, it correct hard and fast - as if I've jerked the wheel and over-corrected. But actually I corrected easy and slow

Hope this helps in lieu of being able to show any pics.

Do I have to become a "Contributor" to post pics?

thanks,

DJs74

 

[surfer-b]

I would say its caster more than anything, you need to get the #'s and go from there. The camber you have is a little high for my likes, here are the #'s I shoot for.

Caster in the + 6~8*

Camber
Driver: ~+.5
Pass: ~ +.25

Toe +1/16"

Don't get too caught up in the factory specs on these things, they were ok for non pwr steering but not good for pwr.

To get that caster needed you will prob need to rotate the yokes, or do a drop radius arm bracket which I don't like but some do. If you decide to rotate the yokes, replace the 7* C's with 4* and go get the numbers, by doing this it will align the front pinion the way it should be.

 

[Casey835]

I wish I could help you! I can offer this....you are describing my issue to a T! You have put it in words better than I could. It seems like my prob increased when I went to power steer. The only thing I can narrow it down to is a caster issue. I've been told and found info in the search on here to indicate it as well. I'm gonna rotate my Cs in very near future and see if that helps. I've already made other minor adjustments with no success.

 

[70_Steve]

On a previous post, I referenced that the track arm bar and steering link were approx. 5° different - actually they are probably less than 1° different - so basically they are parallel already. I'm still wondering if lowering the track bar might help the darting around problem.

No, it won't help.

You need to know the caster numbers. I would guess the numbers the alignment shop was using were the stock numbers. That stock caster isn't enough when lifting a Bronco and going to bigger tires. With power steering, shoot for numbers above 5°.

Hope this helps in lieu of being able to show any pics.

Do I have to become a "Contributor" to post pics?

Either become a Contributor ($12/Year) or upload pics to a picture hosting site, then imbed the link to the picture in your post.

http://classicbroncos.com/forums/showthread.php?t=34373

 

[jlylec]

You might want to try pulling your toe in in a little more. Your issue is the same as many (including me!). There is a lot of info out there on this, but apparently no magic bullet. Like others have said caster is the most important. ~1* isn't enough. I have a 3.5" SL running 35s and the best I've been able to do with all the upgrades is just over 4*. Like Steve said if you could get about 5* you would be happier. I've read many places that toe in should be 1/4" or so for best results. A whole lot more than that can chew up tires, but it certainly helps with the wander. I would think with only 3" SL (although it's probably 3.5"?) you can dial it in. A lot of guys on here have the same set up and claim they can steer with one finger. Good luck man!

 

[DJs74]

Thanks a million guys - to say I'm appreciative for such early and helpful support would be an understatement so all I can do is say thanks!

Casey835: we'll figure this out together - just stick with me and I'll stick with you!

surfer-b: thanks for the info and numbers to shoot for, I will call the shop I was at yesterday and see if they by any chance still have my numbers stored but its doubtful. I'll probably just go back and take your target numbers with me. I did radius arm drop brackets on a '78 F150 with good success but it had very pronounced bows in the coils. The Bronco coils sit fairly vertical and the radius arms are running pretty much in line with the frame (slightly angled but nothing crazy). I apologize but I'm not following when you say "rotate the yokes". Do you mean replace the 7° radius arm bushings with 4° bushings which will result in rotating the Dana 44 yoke?

thanks all

DJs74

 

[DJs74]

Hey guys,

my caster number from the alignment yesterday was 2.47°

so, if I'm suppose to shoot for 5 - 6°, I'm just about half way there it seems


thanks,

DJs74

 

[BroncoDawg]

Adjust the toe in to 1/4" in and tires will slightly pull to center and will dart around less. Shop should have known to do that, but i would measure myself.
Jack up whole front end, put chalk mark on center of tires and then measure distance between with chalk marks facing forward at 9 o'clock while looking at wheel. Then rotate tires so chalk marks face rear at 3 o'clock and measurement there should be 1/4" more than front measurement to create a little toe in.

Unless checking caster, no need to ever pay to align, just do the above and call it good. No caster adjustment on axle anyway. For minor caster adjustments, there are offset ball joints that clock to adjust camber.

Good luck and welcome to the bronco community.

 

[Casey835]

Rotating the Yokes require grinding the weld between your C knuckle and axle tube to aquire better pinion and caster degrees

 

[70_Steve]

my caster number from the alignment yesterday was 2.47°

so, if I'm suppose to shoot for 5 - 6°, I'm just about half way there it seems

There was another thread, just a couple months ago, by a guy in your situation. 3 1/2" lift with 7° bushings, and couldn't come close to the caster numbers he needed. I don't remember ever seeing a final resolution to his problem...

I believe what surfer-b was referring to, when mentioning "rotate the yokes" was rotating, or turning the inner C's. And that is referring to the c-shaped piece of forged steel, welded onto the end of the axle housing, and is what the knuckle ball joints are fastened to.

One of the things a lot of us have come to realize is that there is nothing standard or uniform or repeatable from one Bronco to another. So where you would expect 4° C bushings to provide sufficient caster for a 2 1/2" lift, there have been some that have installed 7° bushings with a 2 1/2" lift and still not achieved sufficient caster.

Turning the inner C's refers to grinding away the weld that holds the C to the axle tube, turning the C, then rewelding. I first read about this as a way to achieve acceptable front pinion angle while still retaining good caster. As you might be able to picture, the farther you rotate the front housing using degree C-bushings, in an attempt to get good caster, the more you are lifting the front driveshaft yoke (rotating it forward). Lift the front yoke far enough and you can cause the u-joints and CV Joints to bind.

 

[blubuckaroo]

Around here, studded tires are allowed part of the year. This causes a wallow or track in the freeway lanes. It can cause some instability when you drive in the bottom of the track. I've found that a shorter wheelbase just makes things worse. A little lower tire pressure definitely helps.

 

[DJs74]

Thanks Everyone!

BroncoDawg: thanks a bunch. yes, I did do the toe measurement first (I actually used white out) found center of tread width, marked, measured front distance and then rolled Bronco forward to get white out marks on rear side of tire and was within an 1/8". *Then* later, I installed Moog camber bushings in the top ball joint because I felt I had too much positive camber. it all went well but as I began to make adjustments, everything got complicated on me because the Moog bushings have camber & caster built into them (eccentric bushing). I kinda panicked, threw my hands in the air and went over to the alignment shop because I didn't feel that I could keep track of the camber / caster and toe all at the same time.

BUT, now that the alignment has been done and bushings have been adjusted, I will adjust the toe to 1/4" like you suggest

I assume I am wanting the front measurement less than the rear by 1/4" - yes?

 

[74BroncoX]

I also have a 74. I have had three different sets of tires on it and it has driven three different ways. I have to stay on top of mine at all times, if I let it get away for me things could get out of hand real fast.

You mentioned you didnt drive it much. I recently hauled my bronco from Minnesota to Cali. I've driven a few hundred miles since and I can tell you Im 100% more comfortable and confident in the way my Bronco runs and handles simply because I got the feel back from driving it. It was in storage for WAY TOO LONG. A lot of stuff on my Bronco is original still, so I couldnt tell you about how the resto effects things. But I think it should be running good, sounds like a neat truck.

Hope you figure it out. Long live the 74's!

John

 

[74BroncoX]

PS POST BRONCO PICTURES! We love em.