Instructions - Front Upper Control Arm (UCA) (ISUZU D-MAX & MAZDA BT-50 2020 Onwards, ISUZU MUX 2021 Onwards - 4JJ3 Engine) Posted on 15 Jan 15:45

Installation Guide:

The installation of these Upper Control Arms requires good mechanical knowledge and tools. It is important to follow these instructions, including reviewing engineering information at the bottom of this post.

N.B: Be very careful when working underneath your vehicle, ensure you are correctly using jack stands or the hoist locks if working on a hoist. Ensure the Ignition is switched off for at least 30 seconds before disconnecting any wiring connections.

Munji Recommended Wheel Alignment Specs:

  1. Caster: +3 Degrees LH & RH
  2. Camber: 0 Degrees LH & RH
  3. Toe: +0.5mm LH & RH - Total +1mm


  • 22mm, 12mm, 13mm Spanner
  • Socket Set
  • Ratchet
  • Flat Screwdriver
  • Pliers/Adjustable Pliers


  1. Lift the front of vehicle up to partially take the weight off the front end. Do not lift it too high, as you don't want the droop stops to contact the UCA. 
  2. Remove the 10mm bolt and nut holding the 2x ABS Line brackets to the control arm. Carefully loosen off the 4x 12mm bolts and nuts holding the balljoint to the control arm and slowly separate the UCA and the balljoint. The spindle will move around and settle in a different spot once the UCA has been removed. You can now loosen off the 2x 22mm Bolts and nuts which hold the UCA to the strut tower. Slide the bolts out and remove the control arm.
  3. Remove both ABS brackets from the ABS line. One bracket will need to be spread open carefully with pliers, while the other will simply unclip, and the clip cut off. Prepare your new Stainless Steel ABS line bracket by fitting a wiring holder clip to it as shown below. 
  4. You can now fit your new MUNJI UCA to the vehicle. Follow the photo below when fitting the arms to ensure you fit the correct arm to each side. Slot the UCA into the strut tower and loosely thread the 22mm bolts onto the nuts. Lift the arm up and down and check where the factory droop stops contact. Due to their weak design, they will may have bent from their original position. The factory stops may need to be bent in or out till they correctly hit the droop stop contacts on the MUNJI UCA.
  5. Using the provided bolts, align the balljoint with the upper control arm and fit 4x 13mm Hex Bolts with washers into the control arm. The 2x bolts furthest from the balljoint will also have washers fitted underneath, and then nuts tightened down. The 2x bolts closest to the balljoint will be fitted with the stainless ABS line bracket in place of washers, then the nuts tightened up. Refer to the photos below for arrangement of bolts and washers.
  6. The second wiring holder clip can be fitted to the UCA in the threaded hole closest to the balljoint. The ABS line can be fitted to the arm by using fitting a silicone tube to the ABS line, then clipping the line into the wiring holder. The wiring holder clip will snap closed and hold the ABS line in place, as shown below. Adjust the ABS line until it sits in the factory position. Make sure it will not be pinched during turning or articulation. 
  7. Repeat Steps 2-6 on the opposite side.
  8. The car can be lowered down and the 2x 22mm bolts that hold the UCA to the strut tower tightened, once the car is sitting on the ground. The nuts will need to be held with a spanner to tighten the bolts fully. Repeat on the other side as well. A wheel alignment can now be carried out. That's it, your done!

If you have any issues please contact me and I am more than happy to assist.
All the best with your 4wheeling. Stay safe.


Once the upper control arms are fitted, the arms need to be Mod-plated/Engineered by a Relevant Signatory/Engineer in their State/Territory to be compliant for on-road use. We have had the testing done and the arms have passed in QLD. This is up to you as the customer to complete. 

You can view the vehicle control arm load test report here.

Munji Final Front Upper Control Arm Drawings for S4 4JJ3 Engine