bought the truck thinking it needed steering gear box. replaced with red head and rebuilt PS pump but its still all over the road. the truck has 4" blocks and body lift with 39.5 " super swampers. the tires are old and cracking even with decent tread left.
i went to junkyard and bought 4 stock tires and rims. when i put 2 on front it drove ok but still felt a little loose. it was a vast improvement over big tires that made it undrivable. I'm going to put other 2 small tires on back tommoro and see what happens. my buddy that did the steer box says front end is fine and no reason to drive bad. could old, big tires really cause it to drive crazy (not play in steering but fight it to keep it in the road at 30 mph)
want to confirm my problem is tires before i break the bank on a set of 37" tires.
thanks

 

Yes old worn out Swampers will definitely make a truck drive like you are drunk. Even new aggressive tread tires will do the same if they are not balanced correct, and you definitely dont want any that are way out of round.

 

especially the old belted tires, more than likely when they get up to road temp (which takes a really long time) it would drive a bit better. But odds are if the truck has sat for a long time with them on they have bad belts.

I would also make sure that you don't have a stiff ball joint or stuck front axle u joint. That could also lead to it.

When you say blocks are you referring to the rear? I hope they didn't put that big of spacer in the front, that can also lead to it.

 

Check your alignment. It should be towed-in just a hair. Any toe-out and it will dart all over the place. The wider the tire and more aggressive the tread, the worse it will drive on the street. Has the trac bar been relocated to keep all your geometry correct, or did someone just throw longer springs in?

 

Thanks fellows. I haven't been able to do anything at all today. Will try to post some pics

 

Someone else please chime in, I'm use to 80-96 setups. But that looks like an extreme angle on your drag link. I think a drop pitman arm would make a world of difference.

 

I agree it looks like a lot. We talked about a drop pitman arm but my guy said he thought it was ok as it is. Jury is still out on that

 

If it was mine it would have a drop pitman arm. I tried to post a pic but I'm having issues with my internet. Just google 78-79 bronco steering images. Your drag link angle should be less than your trac bar.

 

Alignment and check the trac bar mounts and bushings. Have someone turn wheel left and right while watching the connections. I am assuming the steering shaft to red head box is solid since you just changed it.

 

X2 on the track arm bushings, and ALL of the bushings, C-bushings, shocks and stabilizer. The track arm bushings look worn, and will make a marked improvement.

 

What they said ^^ is all true. Having said that those IROC tires will most likely never give you any kind of feeling of a good "safe" ride. It appears the passenger side has quite a bit more wear on the inside. The "scalloping" of the lugs will make it want to dart everywhere. They are great tires for what they are designed for. They are not designed for riding down the highway at 55.

 

Thanks fellows. It looks like my whole problem was tires. With 4 junkyard tires/wheels it drives good.

 

Larger tires = larger stresses. Big tires will always make weak points in steering show up. I run 33x12.50-15s on my '78 and have changed the trac arm bushings, steering stabilizer and had to retighten the mounting bolts at the frame end of the trac arm. It actually started to do the dreaded "death wobble", not fun at 65MPH.

 

I still believe you would see a big improvement with a drop pitman arm. If I'm wrong here someone explain to me why. The steering geometry is wrong, and it's never going to drive the way it was intended. I've lifted a couple Broncos(80-96) 4" and always with a drop Pitman arm on 15x10's with 33x12.50's. Both drove and handled better than they did before the lift.

 

I'm open to suggestions if anybody has an opinion. it still has a slight bit of what id call "slop" in it but not bad. if i can get 37" all terrain tires to ride like it does now, id be fine