Author Topic: TJ Pitman Arm  (Read 277 times)

Offline JeepinMaxx

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TJ Pitman Arm
« on: September 22, 2017, 09:11:57 PM »
I have to replace my PSC steering box and I figured I'll change out the Curry drag link end while I'm at it.  Why not change out the pitman arm while it's apart...  For the TJ folks with a 4.5" lift out there - do you run a stock pitman arm or a dropped pitman arm?  I'm pretty new to TJ's so I appreciate your input...
99TJ Tummy Tuck and SYE, Front D30 with alloy shafts, Detroit locker 4.56, Rear D44, ARB locker 4.56.  Detoursusa.com Rear bumper, Superwinch EP9000 Front Cage



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Offline Right Wing Curmudgeon!!!

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Re: TJ Pitman Arm
« Reply #1 on: September 22, 2017, 10:13:29 PM »
Stock.  Tried all three on mine.  Stock worked the best.
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Offline joe98tj

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Re: TJ Pitman Arm
« Reply #2 on: September 22, 2017, 11:06:53 PM »
Wouldn't you have to drop the trac bar if you drop the pitman arm?
98 wrangler • 4 cylinder • 4 in lift • clayton 4 link • front locker • Open Ford 8.8 • SYE and tom woods shaft

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Offline NickMaida

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TJ Pitman Arm
« Reply #3 on: September 23, 2017, 12:09:03 AM »
I had considerable bump steer with a dropped pitman arm on my 4.5" lift. Went back to stock and the steering was much more predictable.
This is a picture of the old geometry with the dropped arm. (for those who were like me a couple years ago, the yellow line is the angle of the track bar, the red line is the angle of the drag link) I don't have a pic handy of what it looks like now. But the stock arm obviously raises the top TRE on the drag link which brings the angle almost perfectly in line with the track bar (we're looking for the 2 lines to be parallel with each other, not necessarily overlapping). That way the suspension can cycle in sync with the steering linkages.
I'd recommend taking a picture like this and just draw the 2 lines from bolt to bolt. Otherwise it can be hard to see because of the bends in the track bar.

'97 TJ 4.0 - 35s

Offline bigdaddymack51

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Re: TJ Pitman Arm
« Reply #4 on: September 23, 2017, 06:29:59 AM »
If TJs came with cross over steering , we wouldnt be having this conversation . The engineer that designed this should be shot ! Then shot again !   FjR68

Offline JeepinMaxx

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Re: TJ Pitman Arm
« Reply #5 on: September 23, 2017, 04:29:35 PM »
Nick - that is an awesome reference picture!  I just checked mine and the drag link is pretty much parallel to the track bar...
99TJ Tummy Tuck and SYE, Front D30 with alloy shafts, Detroit locker 4.56, Rear D44, ARB locker 4.56.  Detoursusa.com Rear bumper, Superwinch EP9000 Front Cage



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Offline harryhood

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Re: TJ Pitman Arm
« Reply #6 on: September 23, 2017, 04:45:56 PM »
Wouldn't you have to drop the trac bar if you drop the pitman arm?

This. you have to use both together to get the correct geometry.
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Offline joe98tj

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Re: TJ Pitman Arm
« Reply #7 on: September 23, 2017, 04:55:46 PM »
Yup, that's always what ive been told

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98 wrangler • 4 cylinder • 4 in lift • clayton 4 link • front locker • Open Ford 8.8 • SYE and tom woods shaft

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Offline Johny Pornstash

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Re: TJ Pitman Arm
« Reply #8 on: September 23, 2017, 07:06:22 PM »
stock
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Offline Angrytj

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Re: TJ Pitman Arm
« Reply #9 on: September 23, 2017, 08:12:32 PM »
I also run a stock pitman arm
2005 Jeep Wrangler Rubicon, 35s, 5in rear stretch, Poison Spyder hiline defender front fenders and rear armor, Rokmen Sliders, custom hiline hood, Synergy front half and custom rear half roll cage, Mastercraft seats, 4pt harness, TJ rubi 44 axles, ARBs, 488 gears, chromo shafts, truss front and rear, front axle is sleeved, tie rod flip, PSC hydro assist steering box and ram, Vanco big brake kit, Raceline beadlocks and other little things.

Offline Mr. Softy

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Re: TJ Pitman Arm
« Reply #10 on: September 23, 2017, 10:29:17 PM »
4.5 inch lift on mine, stock still working just fine.
I have no idea what I'm doing... but I did stay at a Holiday Inn Express last night.

Offline joe98tj

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Re: TJ Pitman Arm
« Reply #11 on: September 24, 2017, 09:11:50 AM »
I guess the question is, is there an advantage to running a dropped pitman arm and dropped Trac bar. I know when I was on 2 inch lift the Trac bar always rubbed on my solid diff cover when flexing. But I would also assume dropping both would be one less limiting factor to more down travel

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98 wrangler • 4 cylinder • 4 in lift • clayton 4 link • front locker • Open Ford 8.8 • SYE and tom woods shaft

2014 Ram Power Wagon Tow Rig

Offline JeepinMaxx

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Re: TJ Pitman Arm
« Reply #12 on: September 24, 2017, 09:15:44 AM »
Solid diff cover is pretty large.  I run a Riddler which is much more low profile but just as strong
99TJ Tummy Tuck and SYE, Front D30 with alloy shafts, Detroit locker 4.56, Rear D44, ARB locker 4.56.  Detoursusa.com Rear bumper, Superwinch EP9000 Front Cage



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Offline NickMaida

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Re: TJ Pitman Arm
« Reply #13 on: September 24, 2017, 01:27:12 PM »
I guess the question is, is there an advantage to running a dropped pitman arm and dropped Trac bar. I know when I was on 2 inch lift the Trac bar always rubbed on my solid diff cover when flexing. But I would also assume dropping both would be one less limiting factor to more down travel

Tom just told me this over in a different thread about the rear trackbar.
you may want to get the track bar as flat as possible at ride height. this will lessen the amount the axle drags left to right when the jeep is flexed.

I would think having a flatter trackbar would have some impact on down travel by limiting the misalignment of the control arm joints. I don't think your trackbar should be the limiting factor in and of itself.
'97 TJ 4.0 - 35s

Offline Space Shuttle Commander

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Re: TJ Pitman Arm
« Reply #14 on: September 25, 2017, 07:58:56 AM »
how would a flat track bar limit control arm misalignment ?
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Offline NickMaida

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Re: TJ Pitman Arm
« Reply #15 on: September 25, 2017, 08:58:32 AM »
how would a flat track bar limit control arm misalignment ?
I was thinking it would do a better job at keeping the axle centered throughout the cycle. When the axle is dragged away from center it uses up some of the control arm's misalignment? The joint would be dealing with misalignment both vertically and laterally. I assume that would be one reason for removing the 4th upper CA on a 3 link.
But now I'm wondering why a flatter track bar would lessen the amount the axle drags left to right when the jeep is flexed. I could see it if you're making the track bar longer and therefore increasing the radius of the arc.  :confused:
'97 TJ 4.0 - 35s

Offline RedJeepster1

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Re: TJ Pitman Arm
« Reply #16 on: September 25, 2017, 09:20:13 AM »
how would a flat track bar limit control arm misalignment ?
I was thinking it would do a better job at keeping the axle centered throughout the cycle. When the axle is dragged away from center it uses up some of the control arm's misalignment? The joint would be dealing with misalignment both vertically and laterally. I assume that would be one reason for removing the 4th upper CA on a 3 link.
But now I'm wondering why a flatter track bar would lessen the amount the axle drags left to right when the jeep is flexed. I could see it if you're making the track bar longer and therefore increasing the radius of the arc.  :confused:

If the track bar is flat at ride height, then it will still be angled when the Jeep is flexed out. But if the track bar is angled at ride height, it will be that much more angled when flexed out, pushing the axle farther side to side. The flatter the track bar, the closer to straight up and down the travel will be.

You are also correct that a longer track bar will result in less lateral movement, but you are pretty limited in length due to space within the coil springs. Ideally your drag link and track bar are flat at ride height and the same length. Then they will travel along the same arc and you will have minimal lateral movement.
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Offline Space Shuttle Commander

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Re: TJ Pitman Arm
« Reply #17 on: September 25, 2017, 09:51:55 AM »
So this was a quick sketch in solidworks, I guessed on dimensions but the thought is there

The top drawing is a 36'' track bar with the dimensions at 7 inches of droop.

the bottom is the same 36'' track bar with the typical diff bends in it. Also drawn with the 7 inch of droop dimension

the flat track bar drags .86''

the bent one moves 2''
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Offline Space Shuttle Commander

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Re: TJ Pitman Arm
« Reply #18 on: September 25, 2017, 09:52:59 AM »
also a strait track bar is much stronger than a bent one
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Offline NickMaida

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Re: TJ Pitman Arm
« Reply #19 on: September 25, 2017, 11:09:04 AM »
the flat track bar drags .86''
the bent one moves 2''
I'm genuinely surprised. I guess I wasn't visualizing it right. That explains a lot though.

So a drop pitman arm and dropped trackbar bracket really should be the best option (if you could get everything to fit).
'97 TJ 4.0 - 35s

Offline Space Shuttle Commander

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Re: TJ Pitman Arm
« Reply #20 on: September 25, 2017, 11:15:14 AM »
Correct, kind of

A drop pitman arm poses other issues. Its moving the load on the box quite a bit, usually wearing the box out much quicker. the flatter the pitman arm the better, as long as it follows the same arc as the steering is cycling.

The better solution in the ideal world would be to raise the axle track bar bracket and run a stock pitman arm
Sometimes I get to drive Becca's Jeep

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