Drilling or Reaming for your Jeep Steering Upgrade?

Trail Forged HD Steering Ream Drill Knuckles

Depending on what Jeep model you are starting with, there is a chance you may have to modify, drill, or ream your knuckles and pitman arm to accept larger, stronger parts when upgrading your steering. There are more than a handful of different mounting types, and it can get a little confusing, so today we are breaking down all the common upgrade options and what is needed for each.

Lets break it down into steps…

  1. Determine what you are starting with
  2. Determine what you are upgrading to
  3. Get appropriate tool
  4. Drill/ream to size
  5. Check fitment
  6. If you fucked up, FIX IT, don’t just run it!

I’ll go into more detail below, but first, we put together a few handy reference charts to help you.

Steering upgrade options by Jeep model

Trail forged steering upgrades for your XJ

Trail Forged Steering Upgrades for your XJ/MJ

Trail forged steering upgrades for your zj

Trail Forged Steering Upgrades for your ZJ

Trail forged steering upgrades for your wj

Trail Forged Steering Upgrades for your WJ

Trail forged steering upgrades for your tj or lj

Trail Forged Steering Upgrades for your TJ or LJ

Trail forged steering upgrades for your jk

Trail Forged Steering Upgrades for your JK or JKU


Next is a chart detailing all the different steering mount types, sizes, and tools needed to drill or ream to that size

ApplicationTypeMinor DiameterMajor DiameterAngleTool Needed
XJ/MJ, ZJ, TJ/LJ, & WJ StockTaper0.52"0.63"7.125° or 1.5" per footN/A
3/4" Heim Steering, common on XJ/MJ, ZJ, TJ/LJ, & WJStraight0.625" (5/8")N/A5/8″ Reamer for HD Steering Kits (except JK)
JK/JKU StockTaper0.63"0.74"7.125° or 1.5" per footN/A
7/8" Heim Steering, Common on JK/JKU, 1 ton trucks, truggies, etcStraight0.75" (3/4")N/A3/4″ Reamer for JK HD Steering Kits
GM 1 Ton Tie Rod Ends (excluding high angle)Taper0.664"0.773"7.125° or 1.5" per footOne Ton Tapered Reamer
GM 1 Ton High Angle EndTaper0.70"0.83"7.125° or 1.5" per footOne Ton Tapered Reamer
Trail Forged JK Full Flip Drag Link StudStraight, press fit0.796875" (51/64")N/A51/64″ Reamer for JK HD Steering Kits
TRE Flip Sleeve (JK and 1 Ton kits)Straight0.875" (7/8")N/A7/8″ Reamer for TRE Flip Kits
JL/JT Pitman ArmTaper0.701"7.125° or 1.5" per footOne Ton Tapered Reamer
JL/JT KnucklesTaper0.572"9.462° or 2" per foot

We posted that chart first as it will come in handy for steps 1-3.

1. Starting Point

   Which Jeep model are you starting with? And even more important, has the steering been modified or is it still stock? Stock, refer to the chart above. If it’s been modified, you will need to determine what your knuckles and pitman arm are reamed out to first.

2 & 3. Upgrade path and the correct tools

   What sort of kit are you switching to? Heims, 1 ton TRE, etc? Refer to chart for applicable mounting hole and tool needed.

Tools and Inserts

Now for the fun part…. 4. Ream it

   Some starting notes:

  • Use the right tool for the job! 
  • Make absolutely sure you have your hole straight through the knuckle, and not canted off to one side.
  • Low to medium speed, medium pressure, and LOTS of good cutting lube! If you send er full speed with little to no lube, don’t come complain you smoked your reamer or drill bit. We use a heavy cutting oil, but any cutting fluid works, even motor oil if you need to.


The two different hole types:

Straight through/non tapered

   If you have a straight through hole, you CAN use a standard drill but, but in our experience they are a major PITA to use. You will likely end up with a wallowed out hole that will cause death wobble or other problems, they are nearly impossible to align straight through, you will likely break the cutting edges off required the use of two or even three drill bits, and they aren’t really any more economical because you may need several of them.

   Having said that, and assuming you’re using a bridge reamer, drop it down into the hole and flop it back and forth a few times. You can easily find the center left-right and forward-back and keep the hole nice and straight. Lube excessively, and start in with a nice medium speed and pressure. Keep the bit lubed, clear away chips, and send this bit fully through the knuckle until it stops cutting and drops through.

Tapered Seat

   First, you have to ream this using the correct angle reamer, and from the correct direction! If you are mounting UTK (under the knuckle) ream from below, mounting OTK (over the knuckle) ream from the top.

   Second…. DO NOT, I repeat, DO NOT full send all the way to the bottom of the reamer. These holes are very size dependent (yes, that is what she said).

   You will want to start reaming ONLY until you have a nice, clean, even taper all the way through and none of the old taper is still showing. Once you do, seat your new tie rod end into the hole, hand tighten down the castle nut, and check to make sure it’s seated flat against the knuckle, and see how much deeper you need to go to align the cotter hole through the castle nut slot. Continue reaming in small steps, checking depth along the way, ONLY until the cotter key hole aligns with the castle nut slot. Going too deep can cause bind in your steering system and damage joints or dust boots prematurely.


5. Check it!

   Straight through holes: just make sure the bolt sits flat against the surface of the knuckle and isn’t canted off the one side. Also make sure it doesn’t have room to wobble about a lot. If you were sloppy or used a drill bit you may have a loose hole.

   Tapered holes, both depth and straightness are important. Make sure your castle nut sits flat, and that you haven’t reamed too deep.


6. You fucked it up, didn’t you?

If you have a massively wallowed out hole, you reamed your taper way too deep, or it’s not straight and the bolt or TRE stud sit in there crooked…. don’t just send it. You will have issues with it later.

   If it’s a straight through hole, sleeves are a sloppy fix, unless you weld them in place. A new knuckle is honestly the best course of action. Or sleeve it, weld the sleeve in, and flatten the weld out. Again, needs to be flat, and the sleeve needs to be precise in it’s hole size.

   If it’s a tapered hole, there are flip kit taper sleeves that you can use to fix your knuckle. You will need to buy the right sleeve, buy the right size bridge reamer, ream out the hole to the larger straight through size, and insert the sleeve.


Leave a Reply

Your email address will not be published. Required fields are marked *