I remember when dad had his replaced on his 77 model. It did make a fair bit of difference when towing our caravan, (however it was almost 30 foot long). Plenty of rangies, (and all discos I believe) do fine without it.
In the quest to keep RR's as god (or at least LR) intended them I would always replace a faulty part. Even if I wasnt intending on using it. Reason being one day you might find you need to sling 20 bags of sand in the boot. It's nice to keep level.
Also, I've notcied when the self leveling boge is actually working, when bouncing about off road the back end is generally an inch or so higher than it would be normally, which is a help for obvious reasons.
BOGE units are a seriously great bit of engineering. There are places that rebuild them if yours has failed. I have to agree with the above, fix it. You never know when the inlaws will visit and you might snap. All those bodies in the boot would be a serious drag if you can't level things out. :thumb:
I broke a spring mount once crossing some ruts - the spring and shock fell off leaving one rear side completely suspensionless. If it wasnt for a functioning Boge that compensated (not part of the design breif i'm sure!) I wouldnt have been able to drive the 15 miles cross country home.
Not really servicing, it's a pressurised unit - you can prevent failure by inspecting the rubber boot and making sure the seals are clean from mud and road grime etc. If you have access to ramps its easier to clean and check.
Be carefull if your going to disconnect the boge unit to replace the boot. There's a huge amount of pressure in them! I can't rememberexactly, but taking off a rear shocker with the car high up on chassis stands, and let the axle hang untill the boge unit is fully extended - somehing like that.
This is a nice unit when working , and very expensive to replace . If memory serves ( which is less and less lately ) its an $800 part. Mine has failed recently, was working sometimes now not at all , bumper drags on steep inclines . Im going to remove it and replace rear springs with discovery rears this weekend .