Violent Shake at 60 mph

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BillsFan76

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Here is the second issue with my recently purchased 69 Bronco Sport  I'll tackle this after the electrical issues are corrected but wanted to ask and get some ideas.

The truck has a really scary shake at around 55-60mph.  The owner who has had the truck since 1995, said the front end has never had any work done to it and is in need of a rebuild.  There is no shaking or pulling at all till it's at highway speed.  The alignment is solid (no pull or wander at lower speed or even highway speed for that matter), steering is tight on it, and the tires have good pressure..  It has the factory Dana 30 in it by the way.  What in the front end would cause such a violent shake at that speed?  Would worn out ball joints do that?  I didn't  drive it past 60mph but he said at higher speed the shake actually goes away.  I wasn't willing to find out so took his word on it.  I've never done front end work on anything so any suggestions on a solid starting point are appreciated.  Thank you again everyone.

Alex

 

Bully Bob

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Again.., this is a pretty easy/cheap fix. (but very important)

It would be a big help & save a lot of -back questions- if you fill-in your profile.  Everything & anything

you know or don't know about your rig.  (Eng. ,suspension, mods, your mech. experience, etc.)

(see mine at left & below)  Can be up-dated at any time.

Is this rig lifted..? check the track bar drop bracket.

Put left & right axle tubes on jack-stands & "wiggle, shake, push-pull things" under there.

The track bar bushings are a common issue.

You have King-pins not ball joints. wiggle tire up & down. If it moves.., they may be worn.

Also the axle u-joints, wheel bearings, & alignment (toe-in) come into play @ front  end shimmy.

More later...

 

Rons beast

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Do everything Bully said above...and check the tires for broken or slipped belts. ( spin the tires by hand and look straight on at the tread for a wave or bulge.) I have had broken belts on tire that only gave me a feel at very low speed and highway speeds.  In between I couldn't feel it.

Good Luck

 
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BillsFan76

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Updated what I know about it so far, thank you.  Funny thing,  the seller has owned the Bronco since 95 and is an avid Ford fan and early Mustang restorer; you would think he would know it had king pins and not ball joints.  He kept saying the ball joints may have a flat spot on them and may need to be replaced.  Then again, he said in 20 years of owning it, he never did any front end work to it whatsoever so maybe he really didn't know.  He also mentioned that the pitman arm broke on the trail one time and that he had to re-weld it after limping home by tying steering pieces together with rope till he could make it to a friends shop.  only mentioning the weld job in case that may have any bearing on the shaking issue.  I'll lift the front end up this weekend and shake everything around and see what moves. 

From what I'm reading, it sounds like the track bar bushings are probably shot.  At $54 for the replacements on Wild Horses, I'm much happier then I was when I bought this Bronco thinking I needed to have the entire front end rebuilt.  Thanks again both of you

Alex

 

Bully Bob

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Hmmmmm..,

Either he was a bit dense.., or, it has a Dana 44 transplanted into it.  (common mod)

Dana 30  has 4 small bolts on top of the knuckle. D-44 has a large nut.

The bad news.., one should never weld a pitman arm except for temporary use.

Good news is they're cheap.

Don't buy one however.., 'til you decide on doing a lift, or not.

'69 came with a 302.., do you suppose the eng. was swapped..?

Get the #'s off the block & intake manifold.(& post)  That will tell the year of mfg.

Sounds like a nice rig.., just a few details we will walk you thru... :-B

If you want, take some pics of the front axel (center & ends when you get it up). 

 We may be able to spot some things.

P.S. I forgot to mention the radius arm "c" bushings & the round donut bushings

at the back of the arm.  If they're real bad, the front end will be floating around.

 
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BillsFan76

BillsFan76

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He actually had a Dana 44 setup for disc brakes he was offering to sell with the Bronco to put in the front end but I didn't have a place to store it before the swap happened and also didn't want to pay the 1200-1400 he said it was worth :) /emoticons/[email protected] 2x" width="20" height="20" />

I think he said the engine was out of a late 60's mustang and the heads were off of a late 60's 302. He mentioned something about better compression with those heads because they were pre 1972 I think. There's an emblem on the side of the front fenders that says 289 Shelby, what that really means I don't know. I'll get the numbers and post them. Interested now in finding out myself.

Do Dana 44s have ball joints versus the dana 30s kingpins? I'll get it up on a jack this weekend and shake the front and see what moves.

 
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BillsFan76

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So I may have mixed up what he said now that I think about it. It may have been a factory 302 with 289 heads from a late 60's mustang. That would make a little more sense with the 289 Shelby emblems at least. Just saw some pics of a dana 44 vs a 30 as well, gonna verify tomorrow and see what's actually under it.

 

Bully Bob

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"Do Dana 44s have ball joints versus the dana 30s kingpins?"

Yes.., & either is fine.  There's not a whole lot of difference.

"I'll get it up on a jack this weekend and shake the front and see what moves."

A "jack" works but safety-wise.., better to use jack-stands or HD wood blocks.

Something sturdy as you'll be crawling 'round under there.., yanking-n-wiggling things.

NOTE:  Don't buy anything yet.., may sound crazy/expensive but depending on what you

find going on under there..., it may be best to remove the axle & freshen up everything at once.

i.e. not doing it over-n-over again.

It looks confusing but it's quite easy & cheap when doing it yourself.

Guessing you don't have pwr steering..?

 
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BillsFan76

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It does have power steering, I sent a text to the original owner this morning asking what it's out of as well as about the engine and heads so I know form future reference. The power steering box is wet so that's a project for another time.

 
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BillsFan76

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I'm sure multiple things on the front end can use some freshening up. After I get it up on jack stands I'll get back on here and cry about what I find :) /emoticons/[email protected] 2x" width="20" height="20" />

 
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BillsFan76

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Bob,

I googled replacing the power steering box on an early bronco and came across a post you were helping someone with replacing the seals on theirs from 2005, you're doing good work here man.  Thanks.

 

Bully Bob

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I know.., I hate it when that happens.... ^_^ /emoticons/[email protected] 2x" width="20" height="20" />

Usually it's the pump/hoses that leak a bit & it runs down the hoses & wets the box.

De-grease it.....,  blow-dry it,  & watch/feel around for the leak. (when time permits)

P.S. Ya.., stay friendly with PO..., you will likely need additional info. hear-n-there.

        Hopefully WH sent along a catalog with your order. It's very helpful.

 
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Elmo

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20 years with PO not haveing to do any work to the front-end i would bet nearly everything rubber is begging for some love.

 

Bully Bob

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YEP..!!

Doing the front axle & steering bushings/joints, (while doing the 2.5" lift) was one of the most fun & rewarding

projects I've done on my rig. Same for the axle u-joints, hubs, wheel bearings, etc.

Cheap insurance & nice to know everything is new & clean.

 
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BillsFan76

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Finally had a chance to look at the front of the Bronco.  The C arm bushing seem to have been replaced at sometime as they were dark red and not the old black plastic rubber as well as the donut bushing behind it.  That's all I could see as far as what looked new.  The scary part is what someone did to the drag link  and pitman arm.  Look at these pictures and see  what this weld looks like.  I'm hoping that the shake at highway speed might be due to that.  I had someone at discount tire look at my tires and told me that even though they look brand new, they are actually 13 years old lol  He said those may need to be replaced soon as well.  So now, im on the forums looking for a stock pitman arm and drag link and if that doesn't fix it, will be back for more assistance.  Thank you everyone that offered advice, I appreciate it.

Alex

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Bully Bob

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I wouldn't worry 'bout the tires just yet.

The tierod looks in good shape.., assuming the joints aren't sloppy.

The pitman arm looks to be OK. (assuming it has no welds)

What they put on there is an early '66 EB draglink. It was soon discontinued.

(mine had one)

There's a plug on the end with two springs, some cupped washers, that press onto a ball.

The springs act as a cushion but often fail causing slop.

       ---- YA...!!  That's gotta go. (B/4 it goes on it's own)  <_<   -----

All you need for now is an "adjustable" drag link. (adjustable in case you ever want a small lift.)

I would call www.tomsbroncoparts  they may have some "good-used" parts that will fit your pitman arm.

Or.., a new adjustable draglink for sure. 

(you may have to measure the pitman arm hole &/or make sure it's not egg-shaped or drilled out)

As I recall.., stock, it's a tapered hole...?

You could pull that steering stabilizer off & see if it has resistance both ways.

Did you check for slop in the PS box..? There shouldn't be any.

 
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miesk5

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yo,

Wobble Diagnosis

Source: by Carl J at http://web.archive.org/web/20090402131611/http://www.jantz4x4.com/deathwobbles.php

Here is Carl's article in full for posterity.

..."...Death wobbles are caused by two main factors; loose or incorrect front-end alignment parts and large out of round or imbalanced tires. Assuming your tires are still in balance, not full of dirt clods and you don't have a bent rim, here is what I look for when experiencing "death wobbles" on the following rigs.

*Note: Always have your rig on level ground with motor off prior to doing any vehicle inspection!

One thing to remember - a steering stabilizer or two may get rid of the death wobbles, but will not fix the problem that is causing the wobbles. I have personally run 44" tires on all my rigs for the past 21 years and have been able to run without a steering stabilizer once the root cause was corrected.

Of course if you need any of the following suggested parts we will be glad to provide them for you. Read on to see how to diagnose: coil sprung, leaf sprung, and independent front suspensions.

Bronco's & Ford ½ tons

I'm going to assume that the rig by this time has already had someone install the 14 piece urethane bushing kit in the front end trying to remedy some of the death wobbles. If not install a kit and look for the following as you do it.

1st thing on early broncos is to get a friend to rock the wheel (with the motor off) back and forth about a 1/3rd of a turn. Look at the track rod from the frame to the axle (mounted just behind the steering box) Are the bolts holding the track-rod mounting bracket loose? Is the bushing in either end of the track rod worn? Are the holes for the track rod bolts in good shape, or are they egg shaped so that even when the bolts are tight they can be forced back and forth?

FIX --> To correct this quick and easy, weld a washer that fits tight on the bolt to the front side of the bracket and weld the nut to the back side. Is the large bolt in the front end housing wobbling with the steering wheel? FIX --> by welding the bolt head back to bracket, or buy a tapered bolt kit, (for cast mountings) and install.

2nd Check the steering box bolts, are they loose? Look for chipped paint or rust rings around the bolts, better yet just go ahead and retorque them now, you will probably get a full turn out of them. If they do not tighten to a firm stop... FIX by installing new solid sleeves between frame rails. The early Bronco's had sleeves in the frame but they were a split design and crush open after awhile.

3rd Tighten the pitman arm nut; you can usually get ½ a turn out of it.

MIESK5 NOTE; BE VERY CAREFUL HERE; see Steve83's Pre-load Adjustment, All Bronco & Ford, mid-70s to 00 (http://www.supermotors.net/vehicles/registry/media/513527)..

and his Steering Troubleshooting

Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net (http://www.supermotors.net/vehicles/registry/media/513527)

*Note some aftermarket drop down arms will slip up the splines far enough that the lock washer will bottom out on the shoulder of the pitman shaft and you will think it tight but it is not, so you have to lathe a special spacer to push the arm father up the splines with out bottoming out the nut.

4th Check all the tie rod ends for endplay. With the wheel-rocking trick, start at the pitman arm, there should be no motion between the arm and the drag link, or the drag link to the tie rod, or the tire rod to the steering arms. Replace and align as required.

5th Place the front end on jack stands, then grasp the tire at top and bottom and alternately pull and push the tires with opposite hands. If the tire moves more than 1/16" either the upper and lower ball joints need to be replaced or the wheel bearings need adjustment, or in a worse case scenario the spindle is cracking or the spindle bolts are lose.

Leaf spring vehicles

My 1st death wobbles occurred when I was about 16 years old and decided to lift my Scout with 12” long shackles. I bought 2 kits used for raising the back of a Mustang and in a couple of hours I had the tallest Scout in town. My 1st drive was quite interesting; any speed over 30 miles per hour and it was all over the road. After talking with several experts it was decided that my caster had changed. At the time I did not have the $14 bucks for a couple of degree shims and so with 16 year old logic decided that since the rig had leaf springs under the axles all the weight of the vehicle was carried through the U bolts and that a set of wooden shims would not carry any weight but would tilt the front end in the correct direction. After several practice splits with a sharp hatchet and some carving with a knife I had a set that looked about what I needed. I loosened the U-bolts placed in the shims and sure enough it drove fairly good again. Unfortunately about 100 miles from home a week later the wood splintered and came out. I did not have a wrench with me to tighten up the bolts so I had to drive at 15 miles per hour all the way home because anything more produced death wobble. So……

1ST thing to check for is loose U bolts and then have a friend rock the wheel back and forth about 1/3 of turn while you observe the following steering components.

2nd I check for loose spring bushings

3rd look for loose tie rod ends & drag link ends.

4th Check that the steering box mount to the frame is solid. Jeeps are notorious for cracking these mounts and an after market steering brace should be added to any vehicle you plan on taking off road. Have a friend rock the wheel back and forth about 1/3 of turn while you observe the box and related steering components.

5th Place the front end on jack stands, then grasp the tire at top and bottom and alternately pull and push the tires with opposite hands. If the tire moves more than 1/16" either the upper and lower ball joints need to be replaced or the wheel bearings need adjustment, or in a worse case scenario the spindle is cracking or the spindle bolts are lose.

.

Note: Although it takes a little longer, I have seen the cast aluminum shims eventually break apart just like my wooden shims did. I now make steel shims to fit all applications.

Independent Front Suspensions

Look for all the loose stuff mentioned above and look for loose bolts holding the A-arms onto the frame and or loose center pivot bushings.

Finding loose parts is best accomplished by having a friend (MOTOR OFF!) Rock the steering wheel back and forth about a 1/3 of a turn at 1 second intervals with the vehicle sitting on the ground, in park or 1st gear with Emergency brake set, while you crawl underneath and check for relative motion on every suspension connection and steering component..."

 

Bully Bob

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There is no real  "alignment" per-se for an EB.  Lifts req. "C" bushing changes to put caster back to spec.

That's it. I wouldn't recommend trying to bend rad. arms however, huge lifts may req. this. Or, there's modified

rad. arms on the market for this purpose.

Camber is "set" at the factory (1deg. 30min.) on D30's & D44's. & can't be changed.

You can, however, square up everything "on-center"  Meaning the steering wheel straight across, the

pitman arm runn'n north-n-south,  & the tires runn'n straight ahead.

I think there's a kit for the egged-out hole on the axle tubes trac-bar bracket. I think it was drill the hole round

& use a shoulder bolt & a spacer on the other side. (I'd have to look it up.)

I've not had any rigs that wore into this egg-shape.

Other than that.., a great write-up on the coiled front end there M5..!!

B

 

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