western Posted November 13, 2019 Author Share Posted November 13, 2019 Thought about that on the way home, I just can't get my head around the fact it slips when disengaged, at least I can get the OD off fairly quickly & swap my original springs in to it in a dry place. looks like that's a Saturday morning job now. Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 13, 2019 Share Posted November 13, 2019 After that, I am out of ideas. That unit has had two new sets of springs but I guess they may be faulty. Its a shame noone knows anyone at gkn who could locate the specs of the originals. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 13, 2019 Share Posted November 13, 2019 You could measure the ones you have (spec and dimensions) , then go on a hunt for stiffer, similarly proportioned springs. The only other option is that the solenoid is not sealing properly and allowing some pressure through to disengage slightly. Perhaps even an over-pressure situation - though why that would happen at idle waiting at lights is another question. Quote Link to comment Share on other sites More sharing options...
western Posted November 13, 2019 Author Share Posted November 13, 2019 Got my original OD's springs out of the box of bits & ready to swap over. the solenoid is from my original unit too & has new seals fitted internally & externally on its shaft/valve,so I'm sure the solly is causing the fault. if changing the 4 springs for my originals doesn't cure the fault, this OD is coming off as I mentioned above. Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 14, 2019 Share Posted November 14, 2019 Can you measure the springs against the two sets from the od you bought for comparison? Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 14, 2019 Share Posted November 14, 2019 What about replacing the broken parts from your original OD (and only those parts) with the intact ones from the one you are currently using? Surely that should produce a working unit? Quote Link to comment Share on other sites More sharing options...
western Posted November 14, 2019 Author Share Posted November 14, 2019 The planet gear set on my original unit was busted, siiezed, using the original fully resealed rear case now with planet gear set & front case from current unit, not much else to swap over, I will measure my original springs against the new set that's currently fitted & see what we get. Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted November 14, 2019 Share Posted November 14, 2019 I agree wit Rich, the springs have the be the solution... At rest the unit is not producing any oil pressure as it relies on the running gear spinning. It's feed is after the gearbox, therefore at rest, no oil pressure. When pulling away there is some oil pressure potentially developed but not much because the clutch engagement is the start point and the pump speed is only based on the gearbox output, i.e. really slow. Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 14, 2019 Share Posted November 14, 2019 (edited) slipping when disengaged does not need any oil pressure. The springs provide the force needed. Spring Length of spring D-outer D-inner Wire thicknes windings used (Buckeye Triumph) 52,6 – 53,2 14,9 8,9 2,97 12,5 used (my old OD) 54,1 – 54,2 14,9 8,9 3 12,5 new (Devon4x4) 53,7 14,9 8,9 3 12,5 since I found out the above, I think it is better to put one or two shims (washer) under the springs in order to pressurize them. Sigi Edited November 14, 2019 by Sigi_H 1 Quote Link to comment Share on other sites More sharing options...
western Posted November 14, 2019 Author Share Posted November 14, 2019 Thanks for the above info, the springs in mine right now were brand new from Devon4x4, I still have the original springs from my original unit, any thoughts on what thickness the washers should be, I can get suitable alloy washers in 0.5mm, 1.0mm, 1.6mm, 2.0mm. Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 14, 2019 Share Posted November 14, 2019 Noone can recommend the right thicknes I believe. I think 2 mm will work. Since there is 3 mm wire thicknes and 12 windings, the spring will not go on block at a given length of about 53 mm Quote Link to comment Share on other sites More sharing options...
reb78 Posted November 14, 2019 Share Posted November 14, 2019 That is interesting. Looking at the numbers old springs vs new springs are around 0.5mm difference. I suspect the old springs will be slightly shorter due to being used? 0.5mm might be all you need though. Its a shame you cant get a 0.75mm thick washer! Too much and it might not be able to run in the engaged position properly! Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 14, 2019 Share Posted November 14, 2019 Normally used springs will be shorter. But surprisingly the new ones from Devon where. I believe it is not a fault, to compress them a little harder as stock. But it will be possible, that the OD becomes slipping when engaged, because the hydraulic pressure is to low. But this will point to another problem Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 14, 2019 Share Posted November 14, 2019 At least with it not running in engaged, you can turn it off and get home, at least for this experiment. Looking at the spring length, coils and thickness, you can compress it 16mm before coil bind. Do you know how much they do compress when engaged? That would be the safe check. Either way, I don't reckon a 2mm shim would hurt it. M8 washer is 1.6mm x 16mm , I think, could work! Quote Link to comment Share on other sites More sharing options...
western Posted November 14, 2019 Author Share Posted November 14, 2019 Hmmm, 🤔 I'll see what thickness springs we have at work. Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 14, 2019 Share Posted November 14, 2019 10 minutes ago, Bowie69 said: At least with it not running in engaged, you can turn it off and get home, at least for this experiment. Looking at the spring length, coils and thickness, you can compress it 16mm before coil bind. Do you know how much they do compress when engaged? That would be the safe check. Either way, I don't reckon a 2mm shim would hurt it. M8 washer is 1.6mm x 16mm , I think, could work! In my eyes the movement of the conical clutch restricts this compression of the springs. The clutch will only have to move between the body of the annulus and the brakering in the body of the device. I think this will not be more than a few millimeter. 2 or 3 ... thats it. 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 14, 2019 Share Posted November 14, 2019 1 minute ago, Sigi_H said: In my eyes the movement of the conical clutch restricts this compression of the springs. The clutch will only have to move between the body of the annulus and the brakering in the body of the device. I think this will not be more than a few millimeter. 2 or 3 ... thats it. Cool! So 10mm shim it is then Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 14, 2019 Share Posted November 14, 2019 10 mm will be quite a lot (to much). Try to press it 10 mm between your fingers and you will get a feeling of force increase. Don't forget, you have 4 springs Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 14, 2019 Share Posted November 14, 2019 Sorry, my sarcasm failed to translate there Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 14, 2019 Share Posted November 14, 2019 I'm german speaking ... what means "sarcasm" ? 😇 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 14, 2019 Share Posted November 14, 2019 Mit eine Prise Sarkasmus! Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 14, 2019 Share Posted November 14, 2019 ahhhh ... I understand ... but never heard about sarcasm ... I had to consult wikipedia 😂 Quote Link to comment Share on other sites More sharing options...
western Posted November 14, 2019 Author Share Posted November 14, 2019 No suitable washers easily available at work, so will see what I have in my M8 fastener stock in my garage, OD let me down again 4 times morning, it's not doing itself any favours with me, but once it grips drive is OK, would be good to see what's going inside when it's working. 1 Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 14, 2019 Share Posted November 14, 2019 When it is striped, have a look at the brake ring. I saw pictures with hotspots on it and it is available separately at Devon4x4 ... possibly not without reason Quote Link to comment Share on other sites More sharing options...
western Posted November 14, 2019 Author Share Posted November 14, 2019 The fixed brake ring is fine, the cone with the friction material on is new, Quote Link to comment Share on other sites More sharing options...
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