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1970-1995 Range Rover Classic
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Discussion Starter #1
Hello--after doing a search over several websites including this one, I've so far found only one place that rebuilds these units (http://www.wwshockabsorbers.com/), located in Oz. I have a message in to them asking if they still do this. I want to retain the soft springing and originality of my 98% original 1991 RRC 2-door, so won't go with stiffer springs if at all possible.

Does anyone know a place that has experience rebuilding these units in the US?

Thanks,
Wil
 

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1970-1995 Range Rover Classic
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Discussion Starter #2
WWShockAbsorbers replied, they will rebuild it for AUS$400.00. An extra hook though--due to being pressurized, the strut can't be sent by AirMail. SeaMail takes 3-4 weeks each way. Great. Sounds like a good way for it to get lost too. I guess I could run the RR without heavy loads while the strut is being rebuilt. I don't think this strut is anything really unique, seems there must be some firm that can competently rebuild it here in the US. I'll keep looking, any help or comments would be appreciated.
 

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1970-1995 Range Rover Classic
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How does this thing work? It's one of the things I always forget is on the earlier ones. Is it all self contained? Or is it powered with the powersteering pump like on a Mercedes?

I shall also go dig into my RAVE for more answers
 

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It is, for all purposes and over simplified, a short fat shock absorber with progressive dampening. The more weight in the back the more pressure it applies to separate axle from framing. It actually does a very good job of keeping the back end up!
 

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1970-1995 Range Rover Classic
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hmm, makes sense. seems a little over kill and heavy for what it does.

Mercedes just used some special shocks with a sensor and power steering pressure to level their cars. They were prone to leaking if you didn't change the fluid often enough. But the system probably didn't weigh nearly what the Boge system does.
 

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The Boge unit probably only weighs 15 or 20 pounds complete, including the ball joints top and bottom. It's entirely self-contained so there's no extra plumbing or connections to the P/S hydraulic system.

I would suggest locating a decent used one to swap in while you're having yours rebuilt so you can keep the truck on the road. I removed the Boge unit entirely from my '91 when I went to the lift and stiffer springs, mostly because both ball joints were shot. But i miss having it and plan to replace the ball joints and reinstall it. I have medium-duty OMEs on the rear and don't want to go any stiffer, but am tired of it sagging when loaded up for a trip.
 

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1970-1995 Range Rover Classic
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Discussion Starter #8
To date no further luck finding a US rebuilder. New ones are available, but generally run US$1,000 landed here. Now that my 'new' truck came, the Boge doesn't appear to have any leaks. So it's working, or it's out of fluid. Now I'm looking for a used one to send by SeaMail to Oz. If anyone has a used one they will sell, please let me know. If I find one, and after it's finished, I'll update this thread with Oz rebuild/shipping costs and time needed.

From what I've found, the Boge strut entirely self-contained function is: the sensing/contol valve inside the strut 'sees' the truck being heavily loaded and sagging. When the truck gets underway, the strut uses the bouncing motion of the truck to pump itself up until the sensing/control valve sees that the truck is back to the original 'neutral' point. It then ceases pumping and holds that position. When the truck is unloaded, the valve senses that the truck is too high now and self-deflates back to neutral, again using the pumping movement of the suspension. I don't believe the strut has any damping function at all, that is handled by the separate shockers. Pretty elegant solution imo. From this analysis, I'm betting that the truck wouldn't care at all whether the strut is attached, as long as rear loads are kept light.
 

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As above the unit pumps up a chamber to raise it's spring rate internally when the vehicle is loaded via the action of extension and compression of the vehicle as it moves along, so no external input required.

The self levelling sensing ability is solely related to the shock internal geometry with no ability to know vehicle height. It does this (in a simplified description) by having if you imagine the main shock rod of a tube sliding inside another tube. If you have holes at a fixed height in the outer tube then as you compress the vehicle with load then the inner tube passes the holes and seals off the spring chamber by doing so, then the pumping action pressurises the spring chamber with oil as those holes are the exhaust route for the pressure chamber. Pressure builds up until the holes are exposed again which regulates the pressure built up and the vehicle ceases to rise any more.
The installed geometry of the unit sets the vehicle height when in use, therefore there are no sensors.
If you run the vehicle with a suspension lift you'd also have to fit a lift method to the boge unit to get it to self level at the new vehicle height else the valving would still be at the original relationship to the chassis.
As I understand it they do damp their own spring rate so the main shocks only have to control their own spring dynamic.
Boge units were used on quite a few European estate cars a while back with no other damper units fitted to the vehicle, they are of a much thinner longer type more in keeping with conventional shock sizes though identical mechanical design inside.
Search for "Boge Nivomat" and you'll get some more useful schematic \ diagrams of the internals and explanation of operation.
 

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And BEWARE, there can be 30bar pressure inside the unit, even it is non functional!

It is totally rebuild-able co's German MM treads, but rubber seals are not available.

Boge is owned by Sachs.
 

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Apparently they can still be overhauled directly at Boge for a price that is lower than an iffy new old stock unit. At least that's what I have read on a German forum.
 

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1995-2002 Range Rover P38A
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If you google "monroe nivomat self leveling dampner" it seems like that Monroe might have a replacement unit? I don't have a classic Range Rover but it might be worthwhile for one of you guys to look in to if the originals are hard to repair and/or expensive to replace with new units.
 

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1970-1995 Range Rover Classic
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Hello all,

I figured I'd save some of you trouble and enlighten you with my experience having my '92 RRC's BOGE self-leveling unit 'reconditioned' at W.W. Shock Absorbers (Brisbane, Australia).

Quick backstory:
A few weeks ago, I decided to have my repair shop perform the arduous task of replacing all—28-year-old—suspension bushings/ball joints with OEM parts. When they pulled the self-leveling unit out to replace the fulcrum bracket bushings/ball joints, I figured it'd be the perfect time to send it off and get rebuilt so I needn't worry about it for another ~28 years...

So, I recently took a leap of faith and sent my RRC's BOGE self-leveling unit to W.W. Shock Absorbers to get rebuilt... I figured with so many people recommending them on various forums (and charging less than 'ZF Tradition' in Germany), I'd go for it... I sent it out via USPS, and a week later it had arrived at W.W. Shock Absorbers. I received an email 2 days later stating it had been "reconditioned' and ready to be paid for and picked up...". I wasn't provided with any details on how weak the unit was, which parts were worn, any fluid leaks—nada... So I paid them and arranged for DHL to pick the package up from their facility. Upon receipt, I unboxed and inspected the unit, then proceeded to take it to my repair shop for the reinstallation. Upon completion of everything, I picked the vehicle up and found that the ride height was higher in the rear and a ton stiffer. The bushings made a world of difference in ride quality everywhere else, but the rear end was bucking like a bronco over bumps and very firm—something that made me really upset, given how gracefully our vehicles glide over bumps.

I reached out to W.W. Shock Absorbers and asked whether or not the unit needed time to 'settle', to which they replied: "...the unit is gas-filled and needs zero time to settle and will sit higher and be stiffer than before...". I frantically replied and asked if they'd removed the internal components within the unit and simply charged it with gas (as it's filled with fluid, seals, valves, chambers, etc.) to which I didn't receive a response... I repeatedly specified that I'd need to know if it was gutted of its internal components as I had intended to send it to 'ZF Tradition' to get rebuilt to its original specifications, and no response was received. Finally, I had politely noted that I hadn't expected to be reimbursed as it was my mistake for not asking enough questions and to please provide details of the work done to my unit, to which they replied: "The unit is completely disassembled and all wearing components are replaced".

Unless you intend to have your complex, wonderfully-supple BOGE self-leveling unit turned into a simple gas-filled shock absorber, PLEASE DO NOT send it to W.W. Shock Absorbers... Now, I have to decide whether to take a risk and send my 'reconditioned' unit to 'ZF Tradition' (unknowing if they can rebuild it, with internal parts potentially missing) or plunge ~$2500 for a Kingsley Cars unit...





Until I decide what to do, 320lbs worth of salt in the cargo area helps level the suspension and soften the ride quality:



Sadly, after W.W. Shock Absorbers' 'reconditioning', the self-leveling unit no longer self-levels...

 

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1970-1995 Range Rover Classic
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let the rage flow through you

then just get new springs and some helper bags and pocket the change
 

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let the rage flow through you

then just get new springs and some helper bags and pocket the change
The rage is real, and it feels good to let out. Moreover, I just hope no one endures the same ordeal!

I will certainly consider that among my other options....once my nerves have settled a bit longer. ?
 

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The rage is real, and it feels good to let out. Moreover, I just hope no one endures the same ordeal!

I will certainly consider that among my other options....once my nerves have settled a bit longer. ?
Really sorry to hear that you got kinda shafted there, my boge unit doesn't leak, but I'm not sure how much its actually functioning anymore. I added some airlift bags to my rear springs and they're doing a pretty good, job, load support when needed (although not nice and automatic, gotta air 'em up and down) but they don't ruin the ride when it's empty (unless you forget to air them back down!).
 

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Really sorry to hear that you got kinda shafted there, my boge unit doesn't leak, but I'm not sure how much its actually functioning anymore. I added some airlift bags to my rear springs and they're doing a pretty good, job, load support when needed (although not nice and automatic, gotta air 'em up and down) but they don't ruin the ride when it's empty (unless you forget to air them back down!).
Appreciate the sympathy, and thanks for the insight—sounds like a good setup!

If I were you, I wouldn't touch the self-leveling unit unless the ball joints/bushings up there are causing a racket. ?
 

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1995-2002 Range Rover P38A
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Land rover used them so they could run absurdly soft springs in the back..

Never seen the point of the BOGE units I fitted Police spec springs to my Vogue manual, it had a saggy arse..
 
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