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Product Information

ARB, Manual locking diff

Where an application requires that the diff must be able to act as an "open" diff and a fully locked effect, the only solution is to fit a manual locking diff under the control of the driver.

These diffs need additional external parts, compressor/pipes/ solenoids, etc. and need to be plumbed in carefully if damage to these ancillary parts is to be avoided. We supply the ARB air locker, which has been proved, over a number of years, to be a reliable option.

The older 24 spline version was the RD56, this was OK but had occasional problems with the plastic cage inside failing. This has now been superseeded by the RD128 which internally is a much better as this plastic cage is no longer used making it a stronger unit.

Spare Parts

We stock spares for the ARB, to find the part number of the parts you need click here and go to "ARB Lockers" then "Parts and Service" and click on the model you have to find exploded diagrams.

Please note that the 10 spline ARB's are £770 each + VAT

The ARB"s do not come with bearings, we supply these at £20/pair.

The ARB can be supplied alone or assembled in to a diff centre. Please see here for a price on a complete assembly,



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Product Code: ARB

Installation Information » (Click to Expand Collapse)

Install tips

When installing into the rover diff please note there are 2 types of journal end cap, the earlier diffs have a "hook" attached to the end cap that stops the side adjuster nut from unwinding under load, this works fine on the stock side adjuster nut and the new ARB side adjuster nut.

The later type diffs don't have this "hook" but instead have a roll pin that goes through the end cap and locates in one of the cut outs on the stock side adjuster nut to stop it turning, the problem is that the ARB side adjuster nut sits further in board than the stock nut and this roll pin will not stop it coming undone, so on the seal housing ring side there is no mechanical locking mechanism to stop this side adjuster nut coming undone. What we have found it that under heavy load the ARB nut comes undone, particularly on the rear diff, the seal housing is eventually forced round against the roll pin forcing the seal housing off centre which results in a big air leak. I have spoken at length to ARB about this and they recommend using thread lock on the adjuster nut, we have found this approach is not adequate as the constant shock loading on the cap bolts breaks the thread lock free. We have now adopted our own method, the bearing cap is drilled and tapped 8mm and a grub screw inserted to lock the adjuster ring in place, if you do not have facilities to drill and tap the bearing cap the only option is to threadlock the side adjuster nut as proposed by ARB, if you take this approach check regularly.

Technical Information / FAQ's » (Click to Expand Collapse)





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