ARB locker installation in the Jimny

A slight incident with my car resulted in requiring a bit of work to the differential centre in the rear. Rather than repair the stock centre I elected to fit an air locker to the back of my Jimny. This had always been something I had considered doing but just brought it forwards a bit.

The installation is not hugely difficult and the ARB installation instructions are well written and comprehensive. There’s also a number of installation videos online, so this might not be a fully thorough installation guide, but just pointing out some of the tricks and traps you might fall into if you undertake this at home.

In general, I’d advise people to get it done professionally. The ARB installation cost is quite reasonable given the work involved and setting up the diff again properly can be a little tricky. That said if you have the axles out already for doing rear wheel bearings then you’re very close to being ready to pull the differential out and do the installation.

Sections


Things you’ll need

ARB rear locker to suit the car: RD208

1/4″ NPT tap for bulkhead fitting

Teflon sealant for pipe fittings


Mechanical install

Remove the axles

Start by stripping the car down to the point where you can remove your axles. Rather than repeating myself, just read my rear wheel bearing change article and get down to the point where you have removed the rear axles. So this means:

  • Jacking the car up, suspended by the chassis rails so you can lower the axle to make removing the diff easier.
  • Draining the rear diff oil
  • Removing wheels
  • Removing rear brake drums
  • Remove all rear brake components
  • Remove ABS sensors
  • Undo retaining nuts for rear brake backing plates
  • Use a slide hammer to pull axles out on each side.
    Note you need to be careful not to damage axle seals if you are planning on refitting without changing seals

Remove the diff carrier from the axle housing

With that done, you begin by undoing the rear propshaft. Hold the propshaft still using a screwdriver or similar wedged through the universal joint (being careful not to damage the rubber seals on the universal joint bearings), and use a breaker bar to break loose each bolt. Do this for all 4 bolts, then fully remove the bolts. Support the propshaft but off to the side so you have access to the diff.

Supporting the diff using a trolley jack (it weighs about 15 kg)

Unbolt the two diff carrier to axle housing bolts that have the rear headlight levelling sensor bracket mount on them first, and tie the arm and the bracket up out of the way. Undo all of the diff carrier bolts, and then tap the diff carrier with a soft faced hammer and you’ll unstick it from the sealant between it and the axle housing. This can take a bit of effort, just be careful if you end up levering onto the mounting point so you don’t deform the mounting faces as it’ll always leak.

Diff then can be lowered on the jack and removed from underneath the car.

Strip down the old diff centre

Bearings off each side with puller if reusing (I bought new ones)

Undo ring gear bolts

Clean ring gear bolts

Clean ring gear itself

Clean out carrier

Prepare locker for install to carrier

Heat up ring gear to 100º

Grease locker centre where it meets ring gear to stop any corrosion into the future

Drop ring gear on

Install ring gear bolts with (ideally) new bolts or (less ideally) blue loctite

Install side bearings: easiest with a press

Install bearings into carrier and loosely get affixed

Modify carrier as required

Set up diff

Need to get preload on side bearings such that a) you get the backlash in the factory specs and b) the rotational load required < 1.5 Nm to start it turning.


Electrical install