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Pitman arm differences

bronccar

Sr. Member
Joined
Feb 21, 2005
Messages
811
How much drop is there in the 76-77 pitman arm?

I had a stock arm from a 6 turn (basically flat) and it was hitting the bolt on my shock hoop (even after I flipped it)

I had another aftermarket pitman arm with a stupid amount of drop and now my drag link and trac bar aren't near parallel.

I am running Duff's stone crusher, tie rod over.

Hoping I can get good geometry with a different pitman arm and not have to use a riser bracket.

TIA
 

KyddsPly

Sr. Member
Joined
Nov 30, 2012
Messages
941
Not sure about what Pitman arm to use, but a riser would definitely bring that into alignment


Sent from my iPhone using Tapatalk Pro
 

broncodriver99

Bronco Guru
Joined
Jan 27, 2008
Messages
4,780
Loc.
Glen Allen, VA
It looks like your drop arm is for a truck instead of a Bronco. An arm for a Bronco would have the area where the drag link attaches rotated the opposite direction. Getting a drop arm specifically for a Bronco may help your geometry.

How much lift are you running?
 

thegreatjustino

Contributor
Red Head Grease Monkey
Joined
Jan 23, 2002
Messages
15,624
Loc.
Stockton, CA
There were two different EB arms in terms of drop/flatness - the manual steering arm and the power steering arm. Manual arm was flatter, power arm had maybe a 1" drop. Picture comparing the two below.
 

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broncodriver99

Bronco Guru
Joined
Jan 27, 2008
Messages
4,780
Loc.
Glen Allen, VA
Is that really how the drag link attaches to the pitman arm? Seems to me the cone shaped spacer should be below the arm. That would bring the bolt head down considerably. You could also trim a couple of threads off of the shock hoop bolt and pick up a little more clearance.
 
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OP
bronccar

bronccar

Sr. Member
Joined
Feb 21, 2005
Messages
811
It looks like your drop arm is for a truck instead of a Bronco. An arm for a Bronco would have the area where the drag link attaches rotated the opposite direction. Getting a drop arm specifically for a Bronco may help your geometry.

How much lift are you running?

3.5"

Interesting, it came with the lift from JBGY

Thanks
 
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OP
bronccar

bronccar

Sr. Member
Joined
Feb 21, 2005
Messages
811
http://www.dufftuff.com/SearchResults.asp?Search=Steering+linkage&x=12&y=17


The actual photo connected to the Duff steering linkage on an eb looks like the drag link above the pitman arm.

The diagram shows the drag link mounted beneath the pitman arm.

Should be able to go either way.
You may want to reconsider the the axle riser.

I thought about that (over the PA) - but I figured I'd explore a different arm first as I assume the more drop = more stress

BTW, great idea putting your handle on your Bronco window :)

Thanks
 
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OP
bronccar

bronccar

Sr. Member
Joined
Feb 21, 2005
Messages
811
Is that really how the drag link attaches to the pitman arm? Seems to me the cone shaped spacer should be below the arm. That would bring the bolt head down considerably. You could also trim a couple of threads off of the shock hoop bolt and pick up a little more clearance.

No, you're correct - I just threw it back together like that to move it on the casters the other day

I had it correct before and still hit
 
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OP
bronccar

bronccar

Sr. Member
Joined
Feb 21, 2005
Messages
811
There were two different EB arms in terms of drop/flatness - the manual steering arm and the power steering arm. Manual arm was flatter, power arm had maybe a 1" drop. Picture comparing the two below.

Thanks, I def have the flatter one. I am 99% sure the proper arm would do it.


Why not run the drag link on top the pitman arm?

Def an option but I'd prefer less drop if possible
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
You're basically running a 100% custom setup now, so you need to make more custom modifications to make the angles match.

You have a '76/'77 frame, with the larger trackbar bracket.
You have an "Inverted-T" steering linkage, which was appropriate for the earlier frame with the smaller trackbar bracket.
You have a 3.5" suspension lift.
You have a dropped pitman arm, which (aside from having the wrong angle on the end) would have been too much drop anyway with TRO.
You have the tie-rod on top of the knuckle (TRO) so your angles wouldn't match even with a stock pitman arm.

The arm itself is not a big issue. Lots of members here have used the full-size truck arm on their '76/'77 EB's to correct an angle issue with the T-steering. But yours has other mods that work against it. I sell them for exactly the shorter drop they provide. But when using a FS arm with the wrong offset tip, you need to make sure your draglink has a head start by working to keep the angle to a minimum.

So your current options to at least minimize the issues are:
1. Raise the draglink to the top of the arm as was suggested. But this partially defeats the purpose of a dropped arm.
2. Put the tie rod back under the knuckle. This is normally how many '76/'77 owners get good steering after a lift and having changed to the T-linkage. Again, going away from the advantage of better angles, but at least making the two bars more parallel.
3. Lower the upper trackbar mount. Not as desirable as a riser with your TRO and probably needs to be custom.
4. Add a riser and use whichever hole works the best. You won't necessarily be able to go by instructions, as nothing is stock with yours anymore anyway.

Personally I like the idea of the riser the best. If absolutely needed after the riser, an EB specific arm will lower the draglink another inch approximately to where you can match the trackbar angle if needed. And at the same time it would get you an even shallower angle on the draglink. Shallow is better up to a point, but it's all about keeping the angles reasonable AND keeping the two links parallel.

Good luck. But more than luck you're going to have to do mock-ups both in your head (but with tape measure handy!) and physically (more parts, more money, but fewer headaches) until you find just the right combination of parts and design to get the best of both worlds. Low as possible angles, and parallel angles between the links.

Paul
 
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OP
bronccar

bronccar

Sr. Member
Joined
Feb 21, 2005
Messages
811
You're basically running a 100% custom setup now, so you need to make more custom modifications to make the angles match.

You have a '76/'77 frame, with the larger trackbar bracket.
You have an "Inverted-T" steering linkage, which was appropriate for the earlier frame with the smaller trackbar bracket.
You have a 3.5" suspension lift.
You have a dropped pitman arm, which (aside from having the wrong angle on the end) would have been too much drop anyway with TRO.
You have the tie-rod on top of the knuckle (TRO) so your angles wouldn't match even with a stock pitman arm.

The arm itself is not a big issue. Lots of members here have used the full-size truck arm on their '76/'77 EB's to correct an angle issue with the T-steering. But yours has other mods that work against it. I sell them for exactly the shorter drop they provide. But when using a FS arm with the wrong offset tip, you need to make sure your draglink has a head start by working to keep the angle to a minimum.

So your current options to at least minimize the issues are:
1. Raise the draglink to the top of the arm as was suggested. But this partially defeats the purpose of a dropped arm.
2. Put the tie rod back under the knuckle. This is normally how many '76/'77 owners get good steering after a lift and having changed to the T-linkage. Again, going away from the advantage of better angles, but at least making the two bars more parallel.
3. Lower the upper trackbar mount. Not as desirable as a riser with your TRO and probably needs to be custom.
4. Add a riser and use whichever hole works the best. You won't necessarily be able to go by instructions, as nothing is stock with yours anymore anyway.

Personally I like the idea of the riser the best. If absolutely needed after the riser, an EB specific arm will lower the draglink another inch approximately to where you can match the trackbar angle if needed. And at the same time it would get you an even shallower angle on the draglink. Shallow is better up to a point, but it's all about keeping the angles reasonable AND keeping the two links parallel.

Good luck. But more than luck you're going to have to do mock-ups both in your head (but with tape measure handy!) and physically (more parts, more money, but fewer headaches) until you find just the right combination of parts and design to get the best of both worlds. Low as possible angles, and parallel angles between the links.

Paul

Thanks Paul.

I agree. I was hoping the stock pitman arm would get me close to parallel but I don't think it'll be enough.

Also, I still have more weight to add which will flatten the Trac bar and change the whole discussion a bit.

I was mostly curious how much actual drop was built in to the factory pitman arm since I have this one with the big drop and the other which is flat.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
What about reversing the bolt on the shock mount so that just the head is sticking out under the frame? That, along with just the head of the bolt on top of the stock pitman arm (obviously without the offset angle spacer) would give you some extra clearance.
Would it be enough? How much were the two hitting each other the first time you tried?

It's not like you can't use a stock pitman arm with your TRO setup. Other than the interference, the angles are not ideal maybe, but acceptable to many. I just think that dropping things a bit can be even more help when you can get it.

But maybe by letting the two bolt heads pass by each other you won't have them hitting?

Paul
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
Oh, and how much more weight are you going to add? You missing an engine right now?;D
That would definitely lower the angles!

Paul
 
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bronccar

bronccar

Sr. Member
Joined
Feb 21, 2005
Messages
811
What about reversing the bolt on the shock mount so that just the head is sticking out under the frame? That, along with just the head of the bolt on top of the stock pitman arm (obviously without the offset angle spacer) would give you some extra clearance.
Would it be enough? How much were the two hitting each other the first time you tried?

It's not like you can't use a stock pitman arm with your TRO setup. Other than the interference, the angles are not ideal maybe, but acceptable to many. I just think that dropping things a bit can be even more help when you can get it.

But maybe by letting the two bolt heads pass by each other you won't have them hitting?

Paul

The bolt flip wouldn't have done it. The issue appears to be that I had a perfectly flat factory pitman (manual maybe based on post above) and I think a stock with that little bit of drop would fix it. That being said, it may take a wee bit more.

Oh, and how much more weight are you going to add? You missing an engine right now?;D
That would definitely lower the angles!

Paul

LOL, not that much but front clip, radiator, WS frame, JD bumper
 
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