Pastycrimper Posted September 19, 2011 Share Posted September 19, 2011 Hi Folks, OK firstly this is more of a hydraulics/tipper question however its on a series 3 so I thought I'd post here as I'm unsure where else best to ask.....please advise if a more suitable forum exists. We have on the farm a SIII 1982 90 which had a tipper conversion done on by a tree surgeon who used it for wood chippings. Its a good beast but the tipper wont go down and as we only know about the Landrover side of things I thought i'd check here to see if anyone can help. We *think* the tipper, hydraulic ram and electric pump assembly came from an LDV or DAF truck but aren't sure. A picture of the SIII below..... Apologies for my hydraulic terminology, I hope this will make sense. The hydraulic ram is powered one way - as in a 3 way switch is either up (and on) which activates the motor and extends the ram. In the middle position the motor is off and also a return valve is also off so the tipper stays where it is. Finally and probably obviously with the switch down a valve thing is electrically opened which should allow the fluid back into the tank under the weight of gravity ...ie a return valve. However when the tipper is fully up, if we push the switch down the tipper wont naturally lower so we have to use force after which it slowly returns down. When it is about 3/4s of the way down it will continue naturally back to its resting position without any assistance. I at first thought that the chap who did the conversion may have got the ram badly placed such that at full extension "the balance point" was incorrect such that there is not enough weight to take it down, but I now think it maybe the return valve. As a test, with the tipper fully up I unscrewed and removed the return valve and (while I got sprayed with hydraulic fluid ) the tipper came down without any assistance whatsoever suggesting the conversion is good but the fluid return system is faulty. Below is a picture of the hydraulic unit and the funny valve. I have labelled the valve which has a black elctromagnetic collar surrounding it. (I have also labelled what is a black easily removed plastic plug which I dont know what it is but wonder if it is a level plug - if so then the whole tank is way overfilled!!! - should the fluid level be at this height and if so, why the massive fluid tank???) When 12V is applied to the black electromagnet that actuates the valve something definitely clicks - it must work to some extent because the tipper does come down with our help wheras without the valve on it simply wont budge (as we would expect). The return valve is clearly a pressure regulating valve which makes sense else the tipper would drop rapidly if allowed to free flow unhindered back to the tank (as it did during my test ). Maybe then the unit came from originally a much much heavier tipper and this is a valve specific for lowering a certain weight (i.e the amount of pressure regulation) OR the valve is faulty and just not opening "enough". Does anyone recognise this system and valve. I cant help thinking this is a simple fix such as a replacement valve but at the minute we know nothing about this type of equipment or who makes it and we are learning just by taking things apart. Sorry for my longwinded explanation (again!!!).....anyone with any ideas welcomed... Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted September 19, 2011 Author Share Posted September 19, 2011 ps I can take more pics of any bits if that will help... Quote Link to comment Share on other sites More sharing options...
steve b Posted September 19, 2011 Share Posted September 19, 2011 The return valve is clearly a pressure regulating valve which makes sense else the tipper would drop rapidly if allowed to free flow unhindered back to the tank (as it did during my test ). Maybe then the unit came from originally a much much heavier tipper and this is a valve specific for lowering a certain weight (i.e the amount of pressure regulation) OR the valve is faulty and just not opening "enough". I think you have it there , the original tipper body would have longer and heavier , the return port in the valve needs to be a bit bigger to compensate for the reduced wieght I'd say Do you have a local friendly hyd shop to talk to about the estimated wieght on the ram when empty? cheers Steveb Quote Link to comment Share on other sites More sharing options...
discomikey Posted September 19, 2011 Share Posted September 19, 2011 being a farmer (im assuming), you should know about basic hydraulics the system has a reservoir, pump, spool valves, and a ram. if the ram has 2 pipes going to it it is double acting, if theres just a single pipe its single acting, im guessing it is single acting and it comes down again by gravity, if so there will either be a problem with the spool block (wont open again to let pressure out, or the pump is stuck on, constantly keeping the ram under pressure even if the spool block is working, try isolating the pump power and seeing if it will then come down, otherwise try replacing the spool block, (make sure to prop the tipper up with something safe whilst working on the hydraulic symptom else you will be sandwiched as a Land rover/human hybrid tipper. Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted September 20, 2011 Author Share Posted September 20, 2011 Thanks Steve and Discomikey, We're going to show it to the local tractor/digger man. We're hoping it is just the wrong return valve. being a farmer (im assuming), you should know about basic hydraulics Having re-read my post, I have underselled myself, although Dad is the farmer not me, but as I'm an offshore engineer then I've no excuses either. We do indeed have a basic knowledge of hydrauluic systems and more. I seem to have written like a child which is silly given my audience on these forums are generally very technically minded people. Dad and I are most used to double acting rams. This is definitely a single acting ram. It is definitely not the pump jamming on as we've eliminated that possibility. There are only two electrically trigerred "modes" if you like. 1) Pump on and ram extending. When the pump is off the return valve is naturally in the closed position. 2) To get the thing down the return valve opens via an electric solenoid. I've just cleaned the valve up and find it is manufactured by hydraforce in Birmingham so we are onto them. They make loads of valves and the pressure regulation is one of the main factors as they all define a flow rate when open. I am hoping that as Steve B mentioned we are using a system that came from a much heavier tipper and the chap who did the conversion jsut assumed ram and pump would swap out onto any system. Unfortunately the model number has alluded us so we aren't quite sure what flow rate valve we have. Hopefully a hydrualic chap will take one look and suggest the type we need. The problem is defintely associated with letting the pressure out and this valve is the only part we can see that has anyuthing to do with this. Thanks again Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted September 20, 2011 Author Share Posted September 20, 2011 Discomikey......my hydraulic knowledge disappears when I am asked whether it is a "spool-type" valve or a "poppet-type" valve. As mentioned from the part number I now know we've got a poppet-type but what does this mean? This is the valve we have http://www.hydraforce.com/Solenoid/Sol_html/1-010-1_SV08-20/1-010-1_SV08-20.htm . I'm working in getting the same type but with a larger flow rate. The trouble is without knowing the true pivotted weight of the tipper and perhaps more importantly what the wiight of the original tipper is I'm not quite sure what flow rate valve to get? Quote Link to comment Share on other sites More sharing options...
steve b Posted September 20, 2011 Share Posted September 20, 2011 secure a known weight to the empty body and check for rate of descent , when you have the speed you want your hyd supplier should be able to work it out from your existing valve . Put the load above the ram pivot when testing. One other point to raise , what weight / viscosity of oil are you using ? 30 or less should be adequate for this app hth Steveb Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted September 20, 2011 Author Share Posted September 20, 2011 Steveb, I was playing around with weights just to get the damn thing down without releasing the valve manually and I guess that its at the very least about 50kg required to just get it to come down. Re Fluid....GOOD POINT!!!! Of course we just chucked in our standard tractor hydraulic fluid which is ISO-46. I'm assuming that 46 is the viscosity here and not just an arbitrary ISO code (am I right in thinking tractors must use biodegradable hence ISO status??). So indeed a thinner oil may well solve this. Essentially a new valve with a larger hole/flow rate is £60. We thought before buying one we may try two ramshackle experiments first. A little crazy but we have masses of brakefluid (30 Viscosity) which we will try instead - NOT permananetly but just to see if a thinner fluid will work The old man spoke with the valve manufacturer who said (unofficially of course) that we could just drill the holes out in the valve in 0.5mm steps and try that way Thanks again for your thoughts - cant believe I didn't question the viscosity issue! Quote Link to comment Share on other sites More sharing options...
discomikey Posted September 20, 2011 Share Posted September 20, 2011 Thanks Steve and Discomikey, We're going to show it to the local tractor/digger man. We're hoping it is just the wrong return valve. Having re-read my post, I have underselled myself, although Dad is the farmer not me, but as I'm an offshore engineer then I've no excuses either. We do indeed have a basic knowledge of hydrauluic systems and more. I seem to have written like a child which is silly given my audience on these forums are generally very technically minded people. Dad and I are most used to double acting rams. This is definitely a single acting ram. It is definitely not the pump jamming on as we've eliminated that possibility. There are only two electrically trigerred "modes" if you like. 1) Pump on and ram extending. When the pump is off the return valve is naturally in the closed position. 2) To get the thing down the return valve opens via an electric solenoid. I've just cleaned the valve up and find it is manufactured by hydraforce in Birmingham so we are onto them. They make loads of valves and the pressure regulation is one of the main factors as they all define a flow rate when open. I am hoping that as Steve B mentioned we are using a system that came from a much heavier tipper and the chap who did the conversion jsut assumed ram and pump would swap out onto any system. Unfortunately the model number has alluded us so we aren't quite sure what flow rate valve we have. Hopefully a hydrualic chap will take one look and suggest the type we need. The problem is defintely associated with letting the pressure out and this valve is the only part we can see that has anyuthing to do with this. Thanks again im not saying you are thick and that you know nothing, sorry if i came across that way, i also only really have a basic and a bit more knowlwdge, (farmers son and engineer) Discomikey......my hydraulic knowledge disappears when I am asked whether it is a "spool-type" valve or a "poppet-type" valve. As mentioned from the part number I now know we've got a poppet-type but what does this mean? This is the valve we have http://www.hydraforc...0-1_SV08-20.htm . I'm working in getting the same type but with a larger flow rate. The trouble is without knowing the true pivotted weight of the tipper and perhaps more importantly what the wiight of the original tipper is I'm not quite sure what flow rate valve to get? my understanding, again not a 100% expert, is that spool is more of a variable speed valve, (ie you can control the flow better) than a poppet valve which i understand is a bit like a plug in a hole.. wereas a spool valve is a hole or series of holes in the housing and the vavle cylinder, which when the valve is opened these valve holes start to line up letting oil through. agian i could be wrong Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted September 21, 2011 Author Share Posted September 21, 2011 im not saying you are thick and that you know nothing, sorry if i came across that way, i also only really have a basic and a bit more knowlwdge, (farmers son and engineer) my understanding, again not a 100% expert, is that spool is more of a variable speed valve, (ie you can control the flow better) than a poppet valve which i understand is a bit like a plug in a hole.. wereas a spool valve is a hole or series of holes in the housing and the vavle cylinder, which when the valve is opened these valve holes start to line up letting oil through. agian i could be wrong Hi, Double sorry - I didn't mean to imply that I thought you were implying I was thick - the opposite in fact! Your original response actually made me smile lots but also struck me how for some unbeknowst reason I seem to write differently to how I normally would when writing a starter thread - weird! What you mention on spool valves now makes real sense. I've been on the Hydraforce website a lot now as there tech specs on different types of valve are interesting and indeed the next "level up" of valves from the poppet type seem to be doing exactly what you say....almost semi-intelligent valves that alter the flow as the pressure changes. Thanks again! Quote Link to comment Share on other sites More sharing options...
tacr2man Posted September 22, 2011 Share Posted September 22, 2011 I would not go putting brake fluid in as it may not suit seals ! Quote Link to comment Share on other sites More sharing options...
tacr2man Posted September 22, 2011 Share Posted September 22, 2011 I had a ldv with a electro hydraulic tail lift that was much slower to go down , when not loaded ! It is most probably lack of load on return that is making it slow/immobile . reposition of ram might solve problem , HTSH Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted September 29, 2011 Author Share Posted September 29, 2011 OK well after some more research I now know that the ram and pump unit came of a Transit tipper and having just looked at one there is lots lots more weight acting on the ram when lowering. We've used a much thinner oil (10 viscosity I think) which has improved things. Having studied the valve in more detail, the return hole is tiny - less than 0.5mm. New valves are £70 though. I'm considering drilling the exit hole wider but I'm thinking with this poppett type that the valve is needle operated so my concern is if I drill the hole wider I may end up ruining the valve all together. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 29, 2011 Share Posted September 29, 2011 Worth a trawl on eBay, always loads of hydraulic gear on there for cheaper than new. Quote Link to comment Share on other sites More sharing options...
Pastycrimper Posted September 29, 2011 Author Share Posted September 29, 2011 Worth a trawl on eBay, always loads of hydraulic gear on there for cheaper than new. I've had a look but cant seem to find anything close. Even if I search for hydaforce I only get some coils and not valves. It seems odd seeing as cetainly every ford transit tipper will use them and I daresay many other tippers use the same pump and valve assembly..... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 29, 2011 Share Posted September 29, 2011 I meant just finding a generic valve - the good thing about hydraulics is most of it is well documented, part numbers can be cross-referenced and specs found via google to ease replacement. It's not like they've used some rare and exotic gizmo to make "thing go up, thing go down". Quote Link to comment Share on other sites More sharing options...
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