Hitachi EX15

[v8druid]

Most important words

Thanks for letting us know nic9 very glad you managed a repair without huge expenditure ... the dealers employ expensive mechanics who frankly dont live up to expectations ive found... and charge the earth

aye ...... there's nothing like knowing your machines inside out ..... TBH I think it makes you a better op. too, having knowledge of how/why/what's going on, as you use something and a lot more 'mechanically sympathetic', to them.

[Muz]

Thanks for letting us know ..... never know it just may help someone else in the future

Most important words

Thanks for letting us know nic9 very glad you managed a repair without huge expenditure ... the dealers employ expensive mechanics who frankly dont live up to expectations ive found... and charge the earth

[v8druid]

Success!! Finally got my pressure gauge connected and identified that left swing is on port P2 not P1 and full pressure was getting to P2. P2, of course, is the one where the relief and make-up valves are very difficult to reach but I got the make-up valve out and found some muck when poking inside with a clean cloth on a screwdriver. Put it back together and it works. Just going to fit a new hydraulic filter before I put the floor back in.

Your long-distance diagnosis was spot on!

Thanks again to both of you for staying with me through this.

****ing marvelous mate

the schematic was the key to sussing it, together with the ol' gauges .... once you can see WTF the flow's going ... and you establish you have pressure, it's a simple elimination process and that bloody poppet was the prime candidate

Thanks for letting us know ..... never know it just may help someone else in the future

[nic9]

Success!! Finally got my pressure gauge connected and identified that left swing is on port P2 not P1 and full pressure was getting to P2. P2, of course, is the one where the relief and make-up valves are very difficult to reach but I got the make-up valve out and found some muck when poking inside with a clean cloth on a screwdriver. Put it back together and it works. Just going to fit a new hydraulic filter before I put the floor back in.

Your long-distance diagnosis was spot on!

Thanks again to both of you for staying with me through this.

[v8druid]

I magnetized a small screwdriver and used it to fish out the poppet valve. Looked nice and clean so put it back in.
BTW hoses are 1/4" BSP.

I'd have had a nice clean piece of cotton rag in there and given it a wipe out gently too Nic .... never know

BSP tee required then Boyo ... nice and handy .... BSP is a so much easier proposition

[nic9]

I magnetized a small screwdriver and used it to fish out the poppet valve. Looked nice and clean so put it back in.
BTW hoses are 1/4" BSP.

[v8druid]

Gee lets hope not

too bloody right .... needle in a hay stack, blindfolded, in the dark job

[Muz]

It didn't make a dash for freedom, unseen did it ?

Gee lets hope not

you'll need tees to suit your plumbing .. probably metric

Its surprising how many jap units are BSP especially older stuff .. although that machine looks to be at a sort of cross over period for designers when they went metric ... or worse tapered metric in some cases whereas most euro stuff was solidly metric by then.

Does that seem like normal behaviour or should the ports be completely closed when the piston is out? Unfortunately I can't get at the relief valve on the other side so I can't take it out to compare.

[ATTACH=CONFIG]3639[/ATTACH]

Hard to tell .. hydraulic pressures can be massive in relation to forces exerted by your hands for example. As long as the oil ways are clear from debris, you would accept it as looking normal. Rubber crumb, broken springs, damaged seals, and sticking spools are the most common faults in these areas

[v8druid]

Pressure gauge arrived but not operational as I didn't know you need an adapter to connect to a hose fitting. So another couple of days to wait.

http://www.hydrotechnik.co.uk/catalo...test-point-kit



I have this kit Nic .... invaluable ...... cost me 100 quid, but worth every penny for fault finding

http://www.hydrotechnik.co.uk/bsp-pressure-test-kit

you'll need tees to suit your plumbing .. probably metric

IIRC there are some decent pix of mine in my thread about last August

[v8druid]

Should have said that I removed the plug on the Make-Up valve but all I got out was a spring.

the poppet will have been on the other end of the spring Nic .... have you a small magnet, like a tool pick up pen jobbie?

It didn't make a dash for freedom, unseen did it ?

[v8druid]

Pressure gauge arrived but not operational as I didn't know you need an adapter to connect to a hose fitting. So another couple of days to wait.

However I did remove the relief valve (see pic below) and would like your opinion on whether it's ok or not. You should be able to just make out that the port(s) are half open. When I stand it on its end and apply a bit of pressure with my palm, the piston moves in and clicks. The movement is very small, a quarter of a millimetre or less. I can then pull the piston back out to the position shown. Does that seem like normal behaviour or should the ports be completely closed when the piston is out? Unfortunately I can't get at the relief valve on the other side so I can't take it out to compare.

[ATTACH=CONFIG]3639[/ATTACH]

It's a LOT more than just a plain old RV Nic .... it's a balanced pressure item and also has an anti shock shuttle in it .. quite a cartridge valve

[nic9]

Should have said that I removed the plug on the Make-Up valve but all I got out was a spring.

[nic9]

Pressure gauge arrived but not operational as I didn't know you need an adapter to connect to a hose fitting. So another couple of days to wait.

However I did remove the relief valve (see pic below) and would like your opinion on whether it's ok or not. You should be able to just make out that the port(s) are half open. When I stand it on its end and apply a bit of pressure with my palm, the piston moves in and clicks. The movement is very small, a quarter of a millimetre or less. I can then pull the piston back out to the position shown. Does that seem like normal behaviour or should the ports be completely closed when the piston is out? Unfortunately I can't get at the relief valve on the other side so I can't take it out to compare.

relief.jpg

[v8druid]

It wont .. a flow meter might tell you something but if there's no resistance to flow you will see no pressure. You need to work out what feeds each side of the slew, start with the one you know works, (your guage will help you here) look for commonality in what should be the 'other' side and try and establish back at the block how the valve works so you can start eliminating what's wrong, you wont find it until you unravel the sequence of flow .. like I said earlier.. if you can stopper it off and prove/ or not that the service its self is working from the block, you will have established something, these problems are always a conundrum .. but by a process of elimination you will get there

Where abouts in the NW are you ? .. will be up that way in two weeks for some holiday and fishing time

schematics for you Muz

Hitachi_EX15_Short_Service_Manual.COMPONENT OPERATION-Control Valvepdf.pdf

Hitachi_EX15_Short_Service_Manual Pilot Operation Circuit p69.pdf

[v8druid]

I'm in the NW Highlands so Inverness is nearest town.

I am not 100% sure that oil is getting to the swing motor. When I swing right I can clearly feel the oil flow with my finger on the hose but I feel nothing on the left. Anyway, the pressure gauge will prove it one way or the other.

My pressure guage and assorted bits haven't turned up yet, and the weather is crap so I can't go fishing - all in all, not a happy time.

Loooooong way up country then mate

you will feel oil flow in the functional circuit because it has resistance ..... if as I surmise there is no resistance in the left circuit and it's free flowing to tank, I doubt you'd feel anything.

Muz's suggestions of stop ending P1/P2 ...whichever is the left circuit, but with a gauge tee-ed into the line before the stop end, at the end of the P1/P2 line will categorically confirm whether you have service pressure or not.

if you're not sure which is which/struggling to determine them, just tee the gauge into P1 & P2 in turn .... I'm pretty sure the left circuit will not show any pressure and the right will be obvious as the gauge will rise to working pressure ........ and she'll slew right.

Swap P1/P2 lines over again with the gauge still in circuit on the right port and pretty certain the left service will give you pressure and operate the right slew port on the motor (which I understand you've already done, but without the gauge in circuit???)

My money's still on that 'make up' poppet valve, being held open with summat extraneous