As previous posts - do not remove panard rod, it stops the axle moving sideways. Any live axle wether on coild or leaves needs a panard rod (or equivalnet, watts linkage etc) to properly locate it. Vehicles on leafs rely on the leaves but they do allow the axle to move sideways.
There will be a degree of rear steer from the rear axle when it fles's - its just inherent in the design especially with the short top links that a T2 has, with no ARB you're getting more flex so could be that, removing the front ARB will help even out the handling a bit I found with just the rear removed it started to understeer, taking off the front re-established the balance. Off road removing the front ARB will reduce the amount the rear flexes by allowing the front to do some of the flexing, this may help reduce the effect you ae getting.
I suspect though, that as has been stated above, you have some worn bushes in the trailing links which will exagerate the rear steering effect.
I do agree, to a point, that NIssan spent a lot of money getting the T2 right, though of course the suspension set up is actually from a much older vehicle and they just stuck a shorter chassis under the T2 (especially in SWB guise). However Nissan set the vehicle up as a compromise, biased towards on road use.
If your leaning (no pun intended) is more towards off road use then you can definitely make improvements. I spent many years building rally cars (for some of that time it was my full time job) and you most certainly can improve on standard set ups in respective enviroments.
ARBs are fitted to vehicles for in order to allow softer road springs (for passenger comfort) to be fitted whilst still maintaining acceptable levels of body roll (again for passenger comfort).
On macpherson strut and similar set ups it is necessary to control body roll to maintain suspension geometry too as any roll tends induce a similar amount of dynamic positive camber in the outside loaded tyres. ie you run on the outside edge of the tyre and the inside lifts - not good, the tyre needs to remain in full contact for good grip. This is why touring car and similar sallons run on almost solid suspension as with the wide racing rubber they cannot tolerate mch variance in tyre angle. It is also why most racing saloons and many fast road cars, to a lesser degree, have static negative camber so that under roll the tyre comes upright.
With a beam axle this is not necessary, as the axle itself hold the wheels/tyres perpendicular to the road.
Likewise twin wishbone set ups (as on the front of a T2) do not suffer fron the inherent problems of the macpherson strut and are usually designed so as to negate body roll and maintain at least the outer wheel in an upright position.
ARBs do not increase grip in fact they reduce it, by trying to lift the unloaded wheel further off the floor - anyone remember 3 wheeling lotus cortinas and Mk1/2 escorts.
Further on Mk1 and Mk2 escorts as a bit of a case study.
Early base model Mk1s had no anti roll bars front or rear, higher spec models got front anti roll bars combined with softer front springs, sports models got and stiffer springs. On the base model it was down to cost the did what was cheapest. On the sports models they traded comfort for handling and the more luxury models were biased for comfort - relative terms this was the late 60s/early 70s.
This pattern was also echoed at the rear in a more pronounced way with the mk2 escort (based on an almost identical floorpan and suspension setup). The more basic models, L, GL etc had no rear antiroll bar. The Ghia models got a rear ARB, this was purely to control roll and to allow the fitting of softer rear springs for comfort as of course they had a beam axle which doesn't need the geometry controlling. The sports models, RS2000, RS1800 Mexico RS etc had no rear antiroll bar as with the Mk1 these were fitted with anti-tramp bars to locate the rear axle more properly where with the more basic models you could most definitely feel the axle moving around if you drove them hard.
