My wandering 76 Bronco. Help Please!!!!!!!!!!!!!!

[LHardin]

Recently Bought this Bronco for my daughter, thinking I could figure out what the problem was but I can't find it. Maybe you can tell me what I missed.

Rides great until I hit about 40 MPH then it becomes an abrupt and random drifter/white knuckle ride (drifts left and right).

I have installed a new steering box, steering linkage, C bushings, progressive springs, new KO2 tires, new wheels, re-torqued the ball joints and wheel bearings but I still can't keep it in a lane. I Hoping to make this safe for my 16 year old daughter to drive to school, but right now I don't want her to be a passenger in it.

Any educated and helpful thoughts would be greatly appreciated.

 

[chuckji]

People more experienced than me will chime in, but there is some basic information that can be provided to start out.
1. Tire size and air pressure
2. Alignment numbers
3. A photo from head on of the front end - we’ll want to see the drag link and track bar geometry.

 

[1969]

What degree C bushings did you install?

 

[LHardin]

Hi chuckji,

Thanks for responding.

I have a new set of BF Goodrich KO2's in the size of LT265/70R17 with 35 pounds of air. There wasn't much difference between the new set of 31"s and the old set that were 33"s.

Driver's side alignment was Camber 0.9, Caster 2.88, Toe 0.06. Right Alignment was Camber 1.0, Caster 3.1, and Toe 0.06. All numbers were in the green from the alignment shop.

I'll need to get you a photo since I'm not near it at the moment, but the track bar is parallel to the drag link.

Thanks for the help.

 

[LHardin]

Hi 1969,

I like your name 1969.

I had 7 degree C bushings installed before I had the front end aligned.

Thanks

 

[SteveL]

First thing I check when steering gets funky is the trak bar bushings. I've gone through enough I keep spares on the shelf. Maybe some 76-77 guys will chime in but I wonder about the inverted y tie-rod set up handling 35s. Might be worth upgrading to a beefy version of the early style tie-rods. Look up che*y 1-ton swap or they sell beefy heim joint kits. The heims may not be street legal in your area depending on dot approval and safety checks.

 

[bronco italiano]

Did the alignment shop "inspect" the steering/suspension components?

 

[Rbuddy98]

Ok this is a long shot but I had similar issues. After I exhausted all the normal steering adjustments/settings.

First thing if you installed a new rebuilt steering box and are using a dropped pitman arm make sure you time the steering box. Make sure you have equal turns from left to center and right to center. Duffs has a video how to do it. I had a pitman arm that wasn’t Index and was one of the issues I had.

Second this was my main issue I had a bad 3rd member which was causing rear steer it drove fine at low speeds but was all over the place as I increased speed. I had my 3rd member rebuilt with a tru-trac and it made a huge difference. Very happy with it Note. If you have your 3rd member rebuilt make sure you ask whats the correct oil to use. That is very important.

Good luck.

 

[Mikes Early Bronco]

Did you try rotating the tires by chance? Reason I’m asking is because the last time we went to Super Celebration we drove down our FJ Cruiser (Broncos still isn’t finished). I was always good about rotating the tires every 3000-5000 miles and I have the same exact tires as yours. So before our trip, I rotated the tires. Afterwords, I took it out on the highway and the result was the same as you are explaining with yours. I rotated them back and everything was fine. Mine might’ve been more of a wear issue. but I figured I’d throw it out there. Good luck buddy.

 

[LHardin]

SteveL,

One of my first thoughts was the track bar so I replaced it along with the steering dampener. I like your thought process.

Thanks.

 

[LHardin]

BroncoItaliano,

Cool screen name. Makes me want to start talking with my hands. LOL

Yes, the shop has done most of the work on this trying to stop the wandering.

Thanks and have a cannoli for me.

 

[LHardin]

Ok this is a long shot but I had similar issues. After I exhausted all the normal steering adjustments/settings.

First thing if you installed a new rebuilt steering box and are using a dropped pitman arm make sure you time the steering box. Make sure you have equal turns from left to center and right to center. Duffs has a video how to do it. I had a pitman arm that wasn’t Index and was one of the issues I had.

Second this was my main issue I had a bad 3rd member which was causing rear steer it drove fine at low speeds but was all over the place as I increased speed. I had my 3rd member rebuilt with a tru-trac and it made a huge difference. Very happy with it Note. If you have your 3rd member rebuilt make sure you ask whats the correct oil to use. That is very important.

Good luck.

I installed a brand new Borgeson Steering box with a slightly dropped pitman arm (not flat). I'll check out the Duff video and thanks for that.

I hadn't thought about the third member but that makes sense. Now I think your on to something. Many thanks.

 

[LHardin]

Did you try rotating the tires by chance? Reason I’m asking is because the last time we went to Super Celebration we drove down our FJ Cruiser (Broncos still isn’t finished). I was always good about rotating the tires every 3000-5000 miles and I have the same exact tires as yours. So before our trip, I rotated the tires. Afterwords, I took it out on the highway and the result was the same as you are explaining with yours. I rotated them back and everything was fine. Mine might’ve been more of a wear issue. but I figured I’d throw it out there. Good luck buddy.

I had the drifting issue when I had my 33's on it but after spending about $3K with very little to no improvement, I put on a new set of 31" KO2's and I still experience drifting. The Ko2's have less than five miles on them at the moment.

Were you ever able to determine what caused your issue when you rotated the tires? Was it a bent wheel? Just curious.

Thanks.

 

[.94 OR]

Rear leaf spring bushings and U-bolts tight?

 

[Mikes Early Bronco]

I had the drifting issue when I had my 33's on it but after spending about $3K with very little to no improvement, I put on a new set of 31" KO2's and I still experience drifting. The Ko2's have less than five miles on them at the moment.

Were you ever able to determine what caused your issue when you rotated the tires? Was it a bent wheel? Just curious.

Thanks.

Our FJ model is the Trail Teams Edition so it came equipped with larger BFGs, rather than the base tires. The air pressure recommendation from Toyota is set higher for the BFGs.

Part of the deal when I bought the vehicle was free oil changes for a lifetime. Every time it went in for an oil change, the shop would fill the tires to the base tire setting and not for the BFGs. I would always go behind and fill them to the proper setting. I forgot to check once and there was uneven wear between the front and rear. When the tires were rotated the front tires were worn on the outsides of the tire and it drifted from side to side and the steering wheel would wobble. Quite a strange result. As soon as I rotated the tires back, it stopped.

 

[LHardin]

Our FJ model is the Trail Teams Edition so it came equipped with larger BFGs, rather than the base tires. The air pressure recommendation from Toyota is set higher for the BFGs.

Part of the deal when I bought the vehicle was free oil changes for a lifetime. Every time it went in for an oil change, the shop would fill the tires to the base tire setting and not for the BFGs. I would always go behind and fill them to the proper setting. I forgot to check once and there was uneven wear between the front and rear. When the tires were rotated the front tires were worn on the outsides of the tire and it drifted from side to side and the steering wheel would wobble. Quite a strange result. As soon as I rotated the tires back, it stopped.

That's some good to know information. Unfortunately, I have not been able to find a hard number to stick with since my 31" tires are not the stock size causing me to try experimenting with lower and higher pressures. Thanks.

 

[jamesroney]

Rear leaf spring bushings and U-bolts tight?

@LHardin This guy asked you a question. I didn't see a reply. I'm not saying that @.94 OR is always correct, but if he told me to shake a wooden stick over my Bronco and say a rhyming chant...I'd try it.

(...mostly because I think he's right. Loose rear axle will behave exactly as you've described.) Tire pressure doesn't mean squat. I've run from 5 psi to 50 psi, and it doesn't drift. You've got something loose, or your running a Detroit and you have something loose.)

 

[Shimmy]

every bronco is different. 2.88 caster may not be enough for some broncos... it wasn't for me. i needed +5 caster to track 65mph straight.

that being said, you could have something loose. perhaps an ovaled out hole even? i may have missed it, but you are lifted?

 

[LHardin]

@LHardin This guy asked you a question. I didn't see a reply. I'm not saying that @.94 OR is always correct, but if he told me to shake a wooden stick over my Bronco and say a rhyming chant...I'd try it.

(...mostly because I think he's right. Loose rear axle will behave exactly as you've described.) Tire pressure doesn't mean squat. I've run from 5 psi to 50 psi, and it doesn't drift. You've got something loose, or your running a Detroit and you have something loose.)

I have looked at all of the Bronco Supply shops and they don't carry the wooden stick. Lol

I had a similar thought earlier today since nearly everything in the front is new and the only thing left is the rear suspension.

How did that chant go again? I can only remember the part that goes "I got a Bronco and now I owe"

Many thanks

 

[lars]

@LHardin This guy asked you a question. I didn't see a reply. I'm not saying that @.94 OR is always correct, but if he told me to shake a wooden stick over my Bronco and say a rhyming chant...I'd try it.

(...mostly because I think he's right. Loose rear axle will behave exactly as you've described.) Tire pressure doesn't mean squat. I've run from 5 psi to 50 psi, and it doesn't drift. You've got something loose, or your running a Detroit and you have something loose.)

This, plus my canned rant: you want it to steer straight? Make the caster be 6°. You can fix everything else, practice avoidance on tackling that (arguably relatively expensive and complicated) problem, but until you do, you'll be rationalizing "it handles great." Except once you try an early Bronco where that's been done, you'll realize that it doesn't.