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Rack and pinion in my ‘48 Plymouth


Scott Knecht

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Thanks for the tips guys! I am going to attempt making my own steering arms.  I ordered an eBay reamer which hopefully will last long enough for two holes.  Lol. 
I had the bump steer nearly dialed out with the stock arms by altering the pivot point height of the inner tie rod ends so I’m going in the direction there. The new arms will be about 1.2” shorter which should give me a good turning radius with the rack.  I’m going to bend them the same angle as the originals to keep the Ackerman the same but I will run lines to the rear center to be sure they’re within reason.  I’m so glad to have stumbled on this sight.  It’s great to be able to share info and gain encouragement! 

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My friend, you seem to have front suspension theory down pat.  Good to see.  Too bad the aftermarket suppliers don't seem to out that kind of attention to detail into their "kits".

 

Now, about those arms, might be someone might want a set too (hint).

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Well not sure I’d go that far Sniper.  I just read a lot.  Lol

Yeah maybe I’m on to something here! I could mass produce these if they work! Ha

Here’s a pic of what I’m starting with.  I did get the angles bent in them this evening.  I’ll post some more when I start drilling. 
 

4A0D4FF2-AF4A-47E8-9F85-37CC4B22FD15.jpeg

Edited by Scott Knecht
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  • 2 weeks later...

Holy cow guys it’s been awhile but I had a few hours this week to dedicate to the rod.  
Soooo I finally got the steering arms fabbed up.  Being they were 1x1 cold rolled steel I wasn’t afraid of welding on them so long as I left them cool without quenching. Looking back I should have started with 1-1/4” bar stock and just removed what I didn’t need.  A 9/16” hole takes a lot of material away.  None the less I believe they will work fine. I could not bend them in my 20 ton press without heat so I’m pretty sure they ain’t bending.  Also the eBay reamer I purchased for $68 worked like a charm. The tie rod ends fit perfectly.  

05ADC5CB-9F2E-4793-884D-FB15AF8F6DEA.jpeg

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I also got to fab up the inner tie rod mount today I was eluding to.  It raised the tie rods right in line with the lower control arm pivots ultimately giving me ZERO bump steer!  Keep in mind I had to move the rack slightly to the driver’s side for header clearance and also keep it and the hydraulic lines (slightly repositioned from stock) south of the LS swap oil pan. This may not be the case on your ride.  I stuck the motor as low and far back as possible.  I made a crude, but effective enough, wooden buck to hold the spindles straight and take measurements.  I ended up moving the inner tie rod pivots up 1-7/8” and to the passenger side 1/2”.  This put things right in the middle. I previously purchased an inner tie rod bolt and bushing kit.  I cut the spacers from the kit in half and used a half on each side of my 1/4” plate. I used half of the urethane bushing on the rack side to seal up the rubber bellow on the rack. I welded two more 12mm x 1.25 bolts to the plate as well as the other half of the spacers I cut. This along with the spacers on the rack side put the tie rods squarely on the rack and right in line to my shorter fabbed steering arms. So here’s some pics to enjoy.  

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B164CFC1-A61C-4A35-A739-308876821C33.jpeg

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Scott.....some nice work there......is there enough clearance between the frame and tie rods on full rebound as it looks a little close.......and those steering arms look a quality job........andyd   

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9 hours ago, Andydodge said:

Scott.....some nice work there......is there enough clearance between the frame and tie rods on full rebound as it looks a little close.......and those steering arms look a quality job........andyd   

Thanks Andy.  No the tie rods have about an inch clearance on full compression and that’s with out the rubber bumpers in the control arms.   Once they’re in place it should be safe.  The factory steering arms actually incline upwards a few degrees from the attaching bolts in the spindles. The new arms are straight in line with the bolts which brings the tie rod down a bit, further putting it in parallel with the control arm.  Almost brought a tear to my eye when I saw no bump steer.   Lol

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11 hours ago, Scott Knecht said:

I also got to fab up the inner tie rod mount today I was eluding to.  It raised the tie rods right in line with the lower control arm pivots ultimately giving me ZERO bump steer!  Keep in mind I had to move the rack slightly to the driver’s side for header clearance and also keep it and the hydraulic lines (slightly repositioned from stock) south of the LS swap oil pan. This may not be the case on your ride.  I stuck the motor as low and far back as possible.  I made a crude, but effective enough, wooden buck to hold the spindles straight and take measurements.  I ended up moving the inner tie rod pivots up 1-7/8” and to the passenger side 1/2”.  This put things right in the middle. I previously purchased an inner tie rod bolt and bushing kit.  I cut the spacers from the kit in half and used a half on each side of my 1/4” plate. I used half of the urethane bushing on the rack side to seal up the rubber bellow on the rack. I welded two more 12mm x 1.25 bolts to the plate as well as the other half of the spacers I cut. This along with the spacers on the rack side put the tie rods squarely on the rack and right in line to my shorter fabbed steering arms. So here’s some pics to enjoy.  

D8C99F12-71EB-4F04-8450-E8A4FEE291E3.jpeg

0AA07247-1897-4476-8EC0-B37515AE9678.jpeg

6757D61C-3568-4805-8E1D-827293DCFA14.jpeg

6236388C-0745-4299-9FB7-9DE7751AF862.jpeg

F5538B7D-5FAA-4E4B-9AC4-F2F2E7AD06E1.jpeg

72075D3B-B560-4A32-9C65-11080777C74A.jpeg

60FD303A-47E0-4BDB-AB20-14FD3E015B8A.jpeg

B164CFC1-A61C-4A35-A739-308876821C33.jpeg

I also had to cut about 3/8” off each mounting bolt attaching the new fabbed up bracket so they wouldn’t bottom inside the rack.  

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1 hour ago, Bob Riding said:

Excellent work! Did you plan to do the front shock relocation ala Rusty Hope's kit?

Thanks Bob.  You know I’m intrigued by the factory design but it does seem a stiffer shock is needed for the limited travel it sees.  I might just keep these to see how bad they really are and if I decide to go with a traditional set up I’ll probably just make my own.  But we’ll see.  

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  • 2 weeks later...

I reinstalled my springs and then pulled the motor for some upgrades this past Saturday.  
  So I snapped a few pics with the motor out.  You can see how the tie rods follow the angles of the lower control arms.  The next project is getting the steering shaft connected to the column via some double “d” shaft and another u-joint. Gonna try to keep the original shaft and steering wheel up top along with the “3 on the tree” shifter to work the turbo 350.  So that’s going to be a whole other project.  

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Edited by Scott Knecht
Listed steering arm instead of control arm
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Scott........nice work.....am curious about the tie rod clamps....are they OEM/aftermarket or custom made?.....they look like "billet" pieces..............very tidy and neat work..........andyd

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Well thats an interesting way to do it.........the Camira(oz version of the GM Cavalier) rack that I have doesn't have the tie rods so they maybe on the Oz version also.............andyd

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  • 2 weeks later...

 

 

What I have learned from you guys so far is:

  1. The J car racks and their various derivatives are used because they are a "center" pivot style and offer the best chance of not having any steering tie rod induced bump steer.
  2. Fatman has kits that allow the mounting of R&P to 48-52 Plymouths.You need to purchase outer tie rod ends from a ‘04-‘05 Explorer- they use the same taper. NAPA # 269-3274
  3. The tie rod pivots need to be centered exactly with the lower A-arm pivots which should completely eliminate the bump steer
  4. Steering arms can be swapped or modified to tighten the turning radius using various methods.
  5.  The tie should rods follow the angles of the lower control arms. 

Got some shop time yesterday and started looking at the Fatman instructions. Not sure if I messed up or not... it says

 

"Before disassembling anything, measure the height of the inner tie rod ends and record that number. Remember the new rack & pinion inner tie rod ends MUST maintain the same ride height as the stock system."

 

I didn't measure the height and the only photo that I have shows the tie rod, but I can't tell height. I wasn't planning on installing the R&P so I didn't take many pictures of that area.? 

Also I'm not sure I understand #5 above. How can the tie rod assembly be parallel with the lower control arm angle?  Wouldn't straight and level be the ideal?

 

IMG_6399.jpeg

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