Thread: Boge Load Leveller On Early Classics

I'm going to get to it too ................... As soon as I have a little spare time .......

Here's some piccies and details of a nivomat someone pulled down

if i link it the forum tries to load the pdf ...... and sucks at it. So here is the message it is attached too:

http://www.aulro.com/afvb/2457583-post28.html

seeya,
Shane L.

I had some pics where the boge unit was replaced with a coil spring to provide a similar effect.

Sent from my GT-I9300 using AULRO mobile app

Originally Posted by loanrangie

I had some pics where the boge unit was replaced with a coil spring to provide a similar effect.

Sent from my GT-I9300 using AULRO mobile app

My preference (and a one day job) is to fit an airbag (maybe rear off Disco 2) in there. Then it is adjustable. With an on board compressor you could make it either self levelling or adjustable on the move via switches.

This should be fun ...

I crawled under the old Rangie tonight. 1/2" (bloody non metric crap ) bolts x 4 at the top.... Do not ... I repeat NOT reach over the top of the leveller to unscrew the last two. Bloody thing ... as I removed the 3rd bolt it rotated up and trapped my finger .... bloody lucky the thing is buggered. I'm amazed there was pressure there to push in out. If it was a working one I'm sure it would have trapped and crushed by finger.

Anyway, you have to lift the back high ... bloody high ... way higher than any jack I own ( I'll post a piccie later of how I got it high enough if you guys want a laugh. Then you pop the lower boot. Using a ground down opened ended 19mm spanner and a 2nd 19mm spanner unscrew the leveller from the lower ball joint.



Er, "apperently" if you throw one of these things in the laundry trough and wash the with burning hot water and cloths washing powder .. they come up really clean ... So I've heard anyway ... I'd never be game enough to try it myself





24mm and your ground down 19mm will unscrew the top ball joint ( the 19mm is to big, but it's not tight, and it's already ground down, so it saves your grinding down another spanner).



I used some vice grips on these two screws, as I expected they have an 'O'ring under them (how else would they have gassed the thing at the factory). There was pressure there .... probably a few bar. It'll leak away slowly, just crack them and let the pressure bleed away slowly

The next problem was, I was going to have to make up a special tool to hold the top enough. I tried my super strong strap wrench that I used to remove Citroen suspension spheres ... but no go, not even close (damn it !). I was wandering around the shed trying to find something I could modify to work ... and was thinking along the lines of cutting the right sized hole out of some plate steel (somehow ) and using grub screws to lock it on...... When I spotted this
























Thinking I was wasting my time ... but what the hell. I reversed the jaws on the 4 jaw chuck... I be damned if the shocker rod didn't fit through the middle of the chuck. I woudn the jaws outwards to grab the inside of the low boot ridge....



And it moved But I have a problem... I big problem I'm not sure how to overcome. You see there is pressure behind it. I've unscrewed enough suspension spheres to know to the touch, when I'm unscrewing against hydraulic pressure ( yep, I've had the odd hydraulic fluid shower in my time ). Jokes aside, hydraulics are really dangerous, the fluid can be forced out under enough pressure to inject intself into your blood stream.



Not being really keen on wearing a heavy 4 jaw chuck, I pull it out and placed the chuck against the workbench leg, and pointed the other end out of the shed .... worse case (hopefully) it takes a joyride across the paddock. So keeping it covered with a heavy rag (so I don't get sprayed with high pressure hydraulic oil) I slowly unwound it. Not a huge amount of pressure was there... enough to blow it apart by about 30cm.



I'm going to have to understand how it works to fix it. It's not obvious by looking at it.

'Here's some photos of the thing.






See the slots cut into that housing. Much like the slide valve in a Citroen height corrector. I bet they allow pressure to either get added to the leveller or removed, dependent on the postion of the cut-outs in the bore (ie: if they match the pressure or exhaust ports in the bore, they'll allow fluid flow).



This is from inside the piston, that is actually the bore for the piston inside the housing. The white'ish ring I reckon is a seal that worn down, so the pump no longer generates enough pressure for the leveller to work.





The black thing is the diaphram/bladder the nitrogen sits behind.

I still haven't got my head around how this works, and what will need to be repaired. I'll need to have a think about this, and hit up google for explanations of how the boge works.

seeya,
Shane L

Oh for those waiting for an update... I started a thread down in the technical section:

Attempt to rebuild Boge leveller.

I reckon the failure mode of these things is:

--over time, say 10years, the nitrogen permeates through the rubber bladders. So you end up with for example.... 10bar inside the hydraulic unit and 10 bar in the accumulators/bladders. The net effect would have to be the unit will no longer work as the accumulators are effectively at 0bar.

So a rebuild consists of, whipping the end cap off to remove the nitrogen pressure from the central hydraulic portion. Then regassing the bladders to about 25bar.... it'll then work for maybe 5->10years until the gas once again permeates through the rubber and pressurises the hydraulic area.

So the good news, is it appears they probably don't wear out and it's probably only 50cents of nitrogen to get them working again ... the bad new is you'll need to build a jig or some sort to regass them.

seeya,
Shane L.

Shane,
Great work. You want to have a go at rebuilding the active heave comp accumulator on our 400 ton Heave Comp crane? Similar to Boge but Nitrogen pressure is 200bar. Unit weighs 10 tons so maybe a tight fit in your garage? If you think possible, I'll have a word to vessel managers!