Range Rover Classic (RRC) Self Leveling Suspension

[Root Moose]

I've been looking at auxiliary air bags for my Jeep while at the same time researching Land Rover vehicles for interest's sake.

The thought occurred that I might be able to combine the ideas and fangle a self leveling setup on the Jeep using the RRC parts. I'm not terribly keen on the standard Jeep helper air bag setup. Seems in-elegant.

I've been reading old magazine articles that talk about the self leveling suspensions in RRC's (1970s-1990s vintage magazines). It appears to be some kind of a shock/strut widget that pushes down the axle from a frame crossmember.

Is this unit tunable?

In real world usage are they useful? Reliable?

How will it react with a trailer hooked up to the vehicle? For the sake of discussion lets say 350 lbs of tongue weight is being added to the rear bumper.

Does it affect axle articulation much? I think between lift height and driveline clearance I may have enough room directly over the center of the axle to fit one.

Any insights or comments appreciated.

Thanks.

 

[R_Lefebvre]

Just sell the Heep and buy a Rover!

 

[Root Moose]

I won't rule out adding a Land Rover (or two) to the collection eventually. But for now it's not in the cards.

 

[SeaRubi]

I've been looking at auxiliary air bags for my Jeep while at the same time researching Land Rover vehicles for interest's sake.

The thought occurred that I might be able to combine the ideas and fangle a self leveling setup on the Jeep using the RRC parts. I'm not terribly keen on the standard Jeep helper air bag setup. Seems in-elegant.

it is an elegant solution. when it works

I've been reading old magazine articles that talk about the self leveling suspensions in RRC's (1970s-1990s vintage magazines). It appears to be some kind of a shock/strut widget that pushes down the axle from a frame crossmember.

the purpose of the BOGE self-leveling strut is to allow the use of very soft, low-rate springs on the corners while keeping the ability to carry heavy loads directly over the axle. the geometry of the setup doesn't really lend itself to working as well for heavy tongue loads on the bumper; it was really more designed to even out loads in the cargo space.

the rear suspension on a D1/Defender/RRC is basically a 3-link. the top link on the axle is connected to the pointy side of a huge A-arm with a ball joint that is then attached to a giant cross-member in the frame. The strut pushes between the cross-member and the mounting point at the axle to support heavy weights. when new the system works magnificently. the strut wears down relatively fast, though, and the soft springs really take a beating off-road with much weight on them, and start to sag real bad. mine were nearly on the bumpstops when I finally moved to some lift.

Is this unit tunable?

no - it's sealed.

In real world usage are they useful? Reliable?

useful, yes - reliable? sure - but they're effectiveness wears like a regular strut. with heavy springs or air-bag helpers it's not really getting worked.
a new one runs around $600 in the US.

How will it react with a trailer hooked up to the vehicle? For the sake of discussion lets say 350 lbs of tongue weight is being added to the rear bumper.

don't expect much. see above comment.

Does it affect axle articulation much? I think between lift height and driveline clearance I may have enough room directly over the center of the axle to fit one.

not at all - it's purpose is to support load without affecting articulation. The RRC has some of the best RTI #'s ever posted for a stock vehicle, due to the soft spring rates. The BOGE strut and the springs are all worn out by these days, though, so everbody just tosses them and puts on an OME kit which will still perform better under load, off-road and on than the stock setup.


hope that helps a little ...

cheers
-ike

 

[Root Moose]

Very helpful - thank you!

Looking at the tip in cost I wonder if it might be more practical to do something with a Fox coil-over or similar. At least then I'd be able to tune to my spec. I really only need a little bit of a boost when loaded.

I forgot about the upper A-arm. Was thinking the rear suspension on a RRC used a Panhard for some reason. I don't have either with the leaf rear suspension in the Jeep.

I wonder how dependent this helper strut system is on lateral constraint. Leaves will let the axle walk from side to side a touch and if there is a strut caused force at the center of the axle this will be increased somewhat (I think). I really don't have room to add a Panhard (fuel tank in the way) and an A-Arm is starting to sound like work.

Hmm...

 

[muskyman]

Very helpful - thank you!

Looking at the tip in cost I wonder if it might be more practical to do something with a Fox coil-over or similar. At least then I'd be able to tune to my spec. I really only need a little bit of a boost when loaded.

I forgot about the upper A-arm. Was thinking the rear suspension on a RRC used a Panhard for some reason. I don't have either with the leaf rear suspension in the Jeep.

I wonder how dependent this helper strut system is on lateral constraint. Leaves will let the axle walk from side to side a touch and if there is a strut caused force at the center of the axle this will be increased somewhat (I think). I really don't have room to add a Panhard (fuel tank in the way) and an A-Arm is starting to sound like work.


Hmm...

You could use a coil over located in the center of the housing going to crossmember and as long as the eye of the coilover runs perpendicular to the housing it would not inhibit articulation of either side and the leafs will still carry on their roll of locating the suspension. This has worked on a number or really functional rock crawlers over the years as alot of the spring rate can be moved inboard to the coil over allowing the the leafs less resistant to stuffing and drooping.

 

[R_Lefebvre]

You could use a coil over located in the center of the housing going to crossmember and as long as the eye of the coilover runs perpendicular to the housing it would not inhibit articulation of either side and the leafs will still carry on their roll of locating the suspension. This has worked on a number or really functional rock crawlers over the years as alot of the spring rate can be moved inboard to the coil over allowing the the leafs less resistant to stuffing and drooping.

Interesting concept... couldn't the same thing be achieved just by moving the outer shocks/springs inboard on the housing? You loose roll stiffness but retain the load carrying ability.

 

[Root Moose]

You could use a coil over located in the center of the housing going to crossmember and as long as the eye of the coilover runs perpendicular to the housing it would not inhibit articulation of either side and the leafs will still carry on their roll of locating the suspension. This has worked on a number or really functional rock crawlers over the years as alot of the spring rate can be moved inboard to the coil over allowing the the leafs less resistant to stuffing and drooping.

Yeah, that's where I'm heading I think. The issue becomes coming up with something that is adjustable (in cab or easily externally). Maybe a centrally mounted air bag versus a coil over makes sense... Not a fan of futzing with N2 anyway.

I don't want to go too soft with my leaves. Hell, they are brand new and I don't want to swap parts at this point. I don't want to end up having having to add an anti-roll bar to help the roll stiffness. This is a daily driver sorta exped' style vehicle and I will sacrifice articulation for good road manners. That said, I'm not adverse to tuning down the road.

What to do, what to do. Need to do some more thinking on this.

Feel free to throw ideas at me.

 

[SeaRubi]

is this for your YJ or one of the cherokee's? I ask because it seems like the solution chosen could vary greatly given the load-space size of the two rigs.

 

[Root Moose]

This would be on the Cherk. It's got a decent amount of cargo space plus towing. There's a fair amount of steel on the rig too between the rear bumper/carrier, unibody stiffeners and rock rails. But that is static. The vehicle's going to be loaded most of the time it is really used. And unloaded for driving back and forth to work.

So I take it that there hasn't been a lot of messing around done with these units on LRs? What is the normal procedure? Pull it once an aftermarket suspension goes on? Surprising that there isn't a bunch of links that talk about making this system work. At least I haven't been able to find much with Google.

I did find this:

http://www.landyonline.co.za/techtalk/bodge_to_coil_conversion.htm

Same images?

http://www.landroverclub.net/Club/HTML/Range_Boge_conversion.htm

Otherwise I can only find normal replacement procedures and parts sourcing... and some P38 general complaining.

 

[SeaRubi]

most people just leave them in there and forget about them ... kind of like your appendix. A small percentage of folks who are installing a lift will uninstall the old one.

lifting the vehicle changes rate on the strut, for the worse, as I've been told. Some of the crazy SA guys have tried wedging a coil spring in it's place, as I recall from LRO threads years ago. Given that the expense for just the Boge unit is about the same as a nicely complete OME suspension, it's not popular to replace it and also have to shell out for new springs.

For your Cherokee, it seems like you could rig up some kind of air-spring in the middle and run a schraeder valve out to the bumper. one thing about the way the LR's are mounted is the angle. It might not work so well to mount it vertically, depending on the arc of travel during compression and extension of the rear axle. something to consider as you try to visually mock it up. i wish i had a new rig here to snap some pics for you. it looks pretty slick when you get under there and see how they did it.

 

[revor]

D110 county.. It had one standard, Nice thought but ineffective due to the roll axis created by the position of the strut (with a life and no sway bar). I tried some other things with the mount.. A big air spring and a coilover but the truck felt tippy with a a load. It's now off the truck.
In the end I will finish my cabin controlled air springs inside the coils. The prototype version worked great.

 

[Root Moose]

For your Cherokee, it seems like you could rig up some kind of air-spring in the middle and run a schraeder valve out to the bumper.

Oh, I like that idea! I have OBA for the ARBs. Integrate the two...

one thing about the way the LR's are mounted is the angle. It might not work so well to mount it vertically, depending on the arc of travel during compression and extension of the rear axle. something to consider as you try to visually mock it up. i wish i had a new rig here to snap some pics for you. it looks pretty slick when you get under there and see how they did it.

Good points. A leaf spring in a rear application effectively has the axle tube rotating around the front leaf pivot and the radius of the arc elongates slightly as the spring flattens. It's pretty minimal in my case though, not a huge arch to my springs. I'm thinking that if I slant the air spring at say 45 degrees or so that should fit and effectively halve the rate of the air spring at that position. Adjust with pressure.

Hmm...

 

[Root Moose]

D110 county.. It had one standard, Nice thought but ineffective due to the roll axis created by the position of the strut (with a life and no sway bar). I tried some other things with the mount.. A big air spring and a coilover but the truck felt tippy with a a load. It's now off the truck.
In the end I will finish my cabin controlled air springs inside the coils. The prototype version worked great.

Interesting about it feeling tippy. I think I can visualize that.

Do you have a web URL for the air springs you are considering?

 

[James86004]

Looks like your question is already answered, so I will add an anecdote. Years ago, I met an Englishman who told me they would get a "field lift" on Range Rovers when they needed it by lowering the tailgate and bouncing up and down on it to pump up the self-leveling unit.

Also, our 93 Range Rover with air suspension was an order of magnitude better at self-leveling than our 89 Range Rover with coil springs and the Boge self-leveling unit.