bump steer? pictures added comment 14

[Jdgephar]

Based on the photos, the drag link and trac bar are definitely not parallel. You have many options to fix it. The simplest would be to replace the drop pitman arm with a stock one. That should help quite a bit.

 

[chuck]

Start by removing the drop pitman arm.

 

[Scoop]

I run both the WH track bar riser and the stock pitman arm. (I went back to stock pitman when I went to the TB riser.) I have no bump steer with 3 1/2" coils in front.

Was putting air in all the family cars and checked the Bronco--was at 35PSI and it said 65PSI on tire so pumped them up---that said it was still scary to drive at the lower inflation

LOL! You need to recheck all your cars' tires then! What's on the tire is just the maximum safe inflation - not what you should run on every vehicle. Check the recommended inflation specific to each car - usually on a tag on the door or door frame.

 

[SP66]

gonna start with lowering air pressure in tires down to like 30PSI see if that helps

 

[Bronco Biff]

I see a trac bar of a much shorter length and greater angle off horizontal than the longer closer to horizontal drag link. Compression would definitiely make it turn left and extension turn right, throw in a little effort to "steer" it (or fight it!) with the steering wheel......I agree stock pitman OR add to existing axle riser Or frame drop bracket.

 

[Skiddy]

gonna start with lowering air pressure in tires down to like 30PSI see if that helps

my brothers full size had real bad bump steer after doing a D60 conversion. at the round up this year he aired down some to go on the trails and all bump steer went away

 

[okie4570]

Was putting air in all the family cars and checked the Bronco--was at 35PSI and it said 65PSI on tire so pumped them up---that said it was still scary to drive at the lower inflation

65psi are the max psi on D rated 16" tires like on my diesel excursion and f250. Does it say 65psi max on the tire? Are they 15's?

Edit: sorry, just saw your other thread.

 

[xcntrk]

gonna start with lowering air pressure in tires down to like 30PSI see if that helps

The good news is that you live in an area where the air density doesn't change much (since the temp is similar year round).

Try living in the mid-atlantic where it goes from teens in the winter to 100 in the summer. The change in air density plays havoc on your air pressure. If you're not careful that 35psi you have set in the winter will blow up to 65psi in the blazing hot summer...

 

[Justafordguy]

gonna start with lowering air pressure in tires down to like 30PSI see if that helps

I bet that will help but you need to get the trac bar and drag link a little closer to parallel. The next thing you need to check it the caster of your front end. You need the caster about +6 to +8 degrees and it will track true even on bad roads. I have + 8 degrees on mine and I can drive 1 finger on the wheel at 70mph on the interstate no problem.

 

[73stallion]

rather than removing the drop pitman arm, try putting the drag link ON TOP of the pitman arm first. it'll make that heim about 3/8" higher than it'd be under a stock arm.

 

[muskrat]

It wont fix it. I agree with Scoop. Start w switching to a stock pima arm. Easy fix and it will really help. If you need more, go w the track bar riser off of the front differential. I'd avoid thentrack bar drop bracket.

Youll find a ton of advise on how to do it right on this site.

 

[admin]

jlylec, I'm going to separate your posts out into a different thread. I know your issue is the same as Bronconumber2's, but it's getting confusing as to who is responding to who.

I'd ask those that are replying help out by checking both threads. Thanks!

New thread for jlylec's bump steer issue is here: http://classicbroncos.com/forums/showthread.php?t=213658

 

[jlylec]

jlylec, I'm going to separate your posts out into a different thread. I know your issue is the same as Bronconumber2's, but it's getting confusing as to who is responding to who.

I'd ask those that are replying help out by checking both threads. Thanks!

New thread for jlylec's bump steer issue is here:

I'm real sorry about that bronconumber2! I didn't mean to hijack.

 

[admin]

I'm real sorry about that bronconumber2! I didn't mean to hijack.

I'm sure he's fine with it. I just want to get you both the help you need and I was afraid advice would get mixed up between the two of you.

 

[SP66]

First picture is mine.
Second picture is the goal? Is that what I'm trying to achieve related to this thread? Thanks

 

[Jeff10]

Hi,

I may have missed it; but, were you able to get an alignment report? Knowing the caster and toe-in would be a big help in providing accurate recommendations.

I only have experience with two Broncos (and a Jeep Rubicon), so you can take if for what it's worth.

Your last statement is pretty accurate, although even in the second picture the track bar and drag link aren't really parallel. Ideally you'd like those two to be as close to parallel as possible. (You'd also like them to be the same length. In the real world it's pretty tough to achieve both angle and length. I have been told that length isn't as critical as angle.)

It may be easier to tell in other pictures; but, is there a riser bracket for the track bar on the axle? If not, that would probably be the place that I would start, if it was my Bronco.

With the tires deflated, how is it driving?

Good Luck

Jeff

 

[ericbee]

Replace the dropped pitman arm with a stock one and you will have a significant improvement. $50 for a stock pitman arm plus labor, cheap fix.

 

[blwngsket]

I agree with an earlier post. Put the drag link on top of the pitman arm and see what changes you get. It's free and only takes a moment.
I run 40's, 5.5 springs, a WH riser on the axle and a stock pitman arm. My drag link is mounted to the top of the pitman arm. My tie rod and drag link are Bullet Proof with hiem joints. I welded a saddle on the tie rod, paralell with the lower trac bar mount (axle) and I have zero bump steer.
I can hit speed bumps at 40+ mph. Both tires or just one, with no hands and she is rock solid straight.

 

[chuck]

I don't think putting the drag link on top of the pitman arm is a good idea. First the drag link will bind much sooner on droop and you will have to ream the tapered hole from the top which means you will need a TRO bushing. Just my .02 but keep in mind I do sell TRO bushings

 

[u10072]

Why would you even recommend to this guy fixing parts on his bronco when the geometry is wrong? After a quick mechanical check.This is so easy to fix-- first you need tires at 35psi. Second you MUST get a drop trac bar bracket in order to get your geometry parallel to each other. The Duff one is probably the nicest one as it has more surface area to weld to--and should absolutely be welded on. This is simple EB steering 001-- if the steering links are not parallel you are going to have bumpsteer. Flatter steering is better no matter what. Raising the trac brac at the axle and lowering it at the frame with a 5.5" lift is a must. To fine tune the steering you then put the draglink either on top or bottom of the pitman arm. Heres the best pearl I ever learned from someone else... take a picture of the steering, look at it on your computer screen and do go from mounting point A to B --forget the shape of the bar as it has no effect on the geometry. There will not be one shread of bind in those heims.