Expat-Magyar · Apr 18, 2020

Hi all,

Again no search result found. I have anoteher annoying oil leak from the mid section bottom of my Disco 2. Bear in mind its LHD. if it makes a difference/ This leak becomes active if the Disco is jacked up, or is level. Hopefully the pictures speak louder than words.

sierrafery · Apr 18, 2020

Hi, do you have ACE?... if yes check the oil level in the reservoir and if it's low follow the pipes to the valve block

Badger688 · Apr 18, 2020

Looking at that location where it is leaking! That's your ACE leaking

Henry_b · Apr 18, 2020

Looks like 'yer chassis is leaking!!

Expat-Magyar · Apr 19, 2020

Thanks all,

It’s the ACE. Interestingly the reservoir shows full. I gave the unit a good clean. Now it’s ok.

sierrafery · Apr 19, 2020

If it's not from the HP side it will leak only while the ACE is in action not stationary when the oil is only recirculated between the block and pump... that oil didnt come from nowhere which means there is a HP leak which occurs when the ACE kicks in and that's up to 140 bar pressure so find and fix that leak, dont drive it so cos it can push out the oil in no time then the pump gest sized and ruins the drive belt and so on.

Stanleysteamer · Apr 21, 2020

....or don't drive it, until you have pulled the ACE fuse, which should lock the AR bar but stop the Ace pump working. Whatever you do, pull the fuse, clean it off, go for a short spin and see if it is still leaking. I THINK I am right about the effect of pulling the fuse but others notably @sierrafery will know.
Out of interest. I have driven mine with the ACE locked and it drove OK. Not as good as with working ACE but like a Disco 1 normally drives!

sierrafery · Apr 21, 2020

Stanleysteamer said:
or don't drive it, until you have pulled the ACE fuse, which should lock the AR bar but stop the Ace pump working. Whatever you do, pull the fuse, clean it off, go for a short spin and see if it is still leaking. I THINK I am right about the effect of pulling the fuse but others notably @sierrafery will know.

I usually recommend to pull the relay not he fuse and that would not stop the pump working cos it's belt driven. This trick is valid ONLY if the leak is from one of the pipes which are going to the actuators cos the DCVs are closed so the fluid is recirculated between the pump and block but if the one of the pipes between pump and block is leaking pulling the relay won't help.

jamesmartin · Apr 21, 2020

Stanleysteamer said:
....or don't drive it, until you have pulled the ACE fuse, which should lock the AR bar but stop the Ace pump working. Whatever you do, pull the fuse, clean it off, go for a short spin and see if it is still leaking. I THINK I am right about the effect of pulling the fuse but others notably @sierrafery will know.
Out of interest. I have driven mine with the ACE locked and it drove OK. Not as good as with working ACE but like a Disco 1 normally drives!

pump will circulate oil all the time ,pulling a fuse will only a leak on any of the 4 ram pipes, the flow and return would still leak

Stanleysteamer · Apr 21, 2020

jamesmartin said:
pump will circulate oil all the time ,pulling a fuse will only a leak on any of the 4 ram pipes, the flow and return would still leak

James, stupid me, as long as the belt is still on of course the pump will still turn!
Where the leak is, i.e. under the chassis, not under the bonnet, doesn't that imply it occurs when the rams are actuated? i.e. from the valve block?
I think OP might want to see the missing word between "only" and "a leak", and if he doesn't I'd like to know what it was!

jamesmartin · Apr 21, 2020

Stanleysteamer said:
James, stupid me, as long as the belt is still on of course the pump will still turn!
Where the leak is, i.e. under the chassis, not under the bonnet, doesn't that imply it occurs when the rams are actuated? i.e. from the valve block?
I think OP might want to see the missing word between "only" and "a leak", and if he doesn't I'd like to know what it was!

no as oil is circulated through block and pump at all times

Stanleysteamer · Apr 21, 2020

jamesmartin said:
no as oil is circulated through block and pump at all times

Right, so as @sierrafery says, the trick would only work if the leak was the other side of the block, i.e. towards a ram, as you said. Still worth a try though isn't it? If for no other reason than to find the position of the leak?

jamesmartin · Apr 21, 2020

Stanleysteamer said:
Right, so as @sierrafery says, the trick would only work if the leak was the other side of the block, i.e. towards a ram, as you said. Still worth a try though isn't it? If for no other reason than to find the position of the leak?

yes and yes

sierrafery · Apr 21, 2020

Stanleysteamer said:
Right, so as @sierrafery says, the trick would only work if the leak was the other side of the block, i.e. towards a ram, as you said. Still worth a try though isn't it? If for no other reason than to find the position of the leak?

Rams are both sides of the block cos there are two(front and rear) but you are right that if the leak is in one of the ram's pipework it should stop with relay removed though i observed that in some cases it'll still leak a bit but not so bad as very old DCVs dont close 100% anymore

Stanleysteamer · Apr 21, 2020

sierrafery said:
Rams are both sides of the block cos there are two(front and rear) but you are right that if the leak is in one of the ram's pipework it should stop with relay removed though in some cases it'll still leak but not so bad as very old DCVs dont close 100% anymore

This all sounds very sensible.
I tend, wrongly, to think of hydraulics as I used to think of pneumatics, which is actually closer to thinking about AC systems. Which is why I forgot the pump has to be turning all the time to create the necessary pressure.
If the OP gets the block clean, then turns the engine on and climbs under, he should see which pipe is leaking. If it is one leading to a ram he can then do as you say and remove the relay to be sure it won't try to actuate so he can drive around OK. There may be still as you say be small leaks due to worn DCV and of course there will be drain down of fluid left in the pipe, which will probably drain down slowly. But if it is in a pipe from the pump, it'll leak quite obviously.
whichever it is, there have been numerous threads on LZ and elsewhere to help him find a way of replacing the dodgy connection, which is most likely where the leak is. Just wish the connections were standard pipe connections and not the fany ones LR went with. And i am sure they were used to prevent Johnny Amateur mechanic from "fiddling" with them!

sierrafery · Apr 21, 2020

Stanleysteamer said:
If it is one leading to a ram he can then do as you say and remove the relay to be sure it won't try to actuate so he can drive around OK.

If one of the ram's pipe is leaking it might not leak at all stationary cos then the ACE is inactive with DCVs closed

jamesmartin · Apr 21, 2020

Stanleysteamer said:
This all sounds very sensible.
I tend, wrongly, to think of hydraulics as I used to think of pneumatics, which is actually closer to thinking about AC systems. Which is why I forgot the pump has to be turning all the time to create the necessary pressure.
If the OP gets the block clean, then turns the engine on and climbs under, he should see which pipe is leaking. If it is one leading to a ram he can then do as you say and remove the relay to be sure it won't try to actuate so he can drive around OK. There may be still as you say be small leaks due to worn DCV and of course there will be drain down of fluid left in the pipe, which will probably drain down slowly. But if it is in a pipe from the pump, it'll leak quite obviously.
whichever it is, there have been numerous threads on LZ and elsewhere to help him find a way of replacing the dodgy connection, which is most likely where the leak is. Just wish the connections were standard pipe connections and not the fany ones LR went with. And i am sure they were used to prevent Johnny Amateur mechanic from "fiddling" with them!

with open center hydraulic systems you have pump circulating to a distribution block and returning at all times,when you select an operation its opened and return cut off
closed center hydraulics are also used in which the oil doesnt circulate,a set pressure is built then pump goes into neutral,return only comes into effect to allow a selected operations pressure to be released

Stanleysteamer · Apr 21, 2020

sierrafery said:
If one of the ram's pipe is leaking it might not leak at all stationary cos then the ACE is inactive with DCVs closed

Which was the point of my first post and the one saying you might be able to safely drive around with it like that. I think we are both actually singing from the same hymn sheet.
Leave the fuse/relay in, drive around a very short distance, if it isn't leaking when stationary and running. Then he'll find the leaking pipe to ram, but, as you have said, do not drive far and lose all fluid.
Also if preferred, could he jack up wheels in turn and then the ram would work wouldn't it? Or do the wheels have to be turning for the ACE's control unit to activate the ACE? I don't know enough about it as far as that is concerned.
Being a blessed D2 I would expect the control unit to take inputs from the speed sensor, the mercury angle sensors, etc etc. So the obvious simple testing method might not work at all.

Stanleysteamer · Apr 21, 2020

jamesmartin said:
with open center hydraulic systems you have pump circulating to a distribution block and returning at all times,when you select an operation its opened and return cut off
closed center hydraulics are also used in which the oil doesnt circulate,a set pressure is built then pump goes into neutral,return only comes into effect to allow a selected operations pressure to be released

Both of which makes sense and you are teaching me stuff I don't know. So Thanks!
With pneumatics there is never any need to return air, so it is just exhausted to atmosphere through a silencer. So no need for return pipes.
Also as it is compressible, it can be stored in tanks and only needs repressurising when the pressure in the tank drops to a set pressure, hence no need for a continuously running pump.
You know all this, so I just put this up for any others who may be interested. Fluidics and impulse generation are completely other topics but they have little place on LZ! Though I sometimes wish they could be used instead of electronics. Far less prone to interference from rust, poor connections, etc etc. Which is why they are popular in dairies, breweries, bottling and canning plants etc etc.

sierrafery · Apr 21, 2020

Stanleysteamer said:
Also if preferred, could he jack up wheels in turn and then the ram would work wouldn't it? Or do the wheels have to be turning for the ACE's control unit to activate the ACE? I don't know enough about it as far as that is concerned.

ACE works based on a vehicle speed input from the SLABS beside accelerometer's inputs though we better not transform this thread in a workshop manual... it's all explained there for those who want to study.

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