Powerfab 125 WTD Hydraulic control valve problem

[Chris Selwyn-Smith]

Hi
This is my first post to the group having recently purchased a
Powerfab 125 WTD on Ebay all seemed fine until today when I first put
it to serious use, digging a trench things. After about half an hour
of digging I suddenly found myself without any power from the
hydraulic system, closer inspection showed that on engine start up
that oil was leaking badly from the underneath of the hydraulic
control unit, this it would do for a minute or so and then reduce to a
drip. Visibility is all but impossible there but inspection leads me
to believe it is coming from under the bucket/dipper control valve .

unfortunately my digger is now immobile stuck with its bucket in a
ditch until such time as I can repair this. Does anyone have any
pointers as to the possible trouble and a cure? I think to effect any
repair I will have to detach it from all it's hoses (which fills me
with some dread ) and remove it.

Any advice would be very gratefully received as would details of any
Powerfab friendly hydraulic valve specialists in the Hampton Court/
Surrey area.

[Jim]

Hi Chris,

First thing to check is the hydraulic hoses starting with the high
pressure hose from the pump to valve block. Because the oil spurts out
it is often hard to see the true source on first inspection. I'm
afraid a certain amount of dismantling may be necessary to find the
leak.

If the leak isn't coming from a hose, and it is the valves then it
would be safest to remove the block from the digger
to repair it as this sort of job isn't recommended in a ditch!

Cheers Jim

On Sep 10, 7:50 pm, Chris Selwyn-Smith <chris.selwynsm...@gmail.com>
wrote:

[Chris H]

Hello, First question is there sufficient hydraulic oil in the
resevoir? If it is below minimum then bung a couple of litres in and
see if it works. Even if it leaks out at a rate you should be able to
retreive it. There are plenty of much more experianced folk on here
than me! Try the simple things first. Fingers crossed!

On Sep 10, 7:50 pm, Chris Selwyn-Smith <chris.selwynsm...@gmail.com>
wrote:

[Chris Selwyn-Smith]

Thanks for the prompt replies.

The oil levels are OK,they are dropping due to the leak but I have
been topping up so they haven't actually got too low. but still no
movement
I will probably remove the unit tomorrow I will have to do a fair bit
of pipe labelling first to make sure they all go back from whence they
came there being sixteen different pipe connections. but your quite
right a ditch is no place to do fiddly repairs especially when you
can't see what you are trying to repair.

Are there any bleeding or special procedures to be aware of when
connecting everything back up?

[Narrowboatseb]

Ok. Here's how it works. The spool block is made up of sections, that,
assuming they are not split or leaking, can operate independently. So.
Consider this.

The small pipe from the pump, is the main incoming flow. The larger
pipe to the tank is the return.

Now, let's consider your issue

'no movement, and oil loss'

This suggests to me, that either the spools have separated, or, the
main incomming pipe is leaking.

Some thoughts

Check all pipe unions to the spools are tight first, then check the
bolts hoding the spool sections together are tight.

Past that, stop worrying. It's hydraulics. Oil goes in, and gets
directed where it's needed, nothing could be simpler.

There are no special 'methods' or 'tricks' to worry about.

Label the pipes u remove, catch the oil so u don't pollute, and before
you start machine again, pull the engine over 10 times slowly with
engine kill set to off to prime the pump with oil.

99% certainty that 'total loss of movement' will be a pipe or union.

[Chris S-S]

OK I have removed the control unit and found underneath that one of
the capping bolts has stripped its thread pictures can be seen at:

http://flic.kr/s/aHsjvZQTup

Sorry I don't know if one can post links or pictures here. it was a
right fiddle getting at all the pipe connectors but eventually I got
it free looking at the the area that had been leaking one of the
capping bolts appeared less tight than the others I tried to tighten
the capping bolt that was there and with no effort at all it turned
and came totally free , the thread was stripped I certainly didn't use
nearly enough effort to have managed to strip it my self so I reckon
this is the source of my problem. unfortunately while not the
trickiest part to get made up I will either need to find a replacement
or get someone to machine one up for me so not an instant fix.
hopefully that is the cause of my problem I have no Idea what it
actually does they are not found on all the spool units, they are to
be found on rotate left wheel,slew,boom,dipper and right hand wheel
but not on bucket or outriggers. if anyone should have a dead unit
around that they would be willing to sell me the offending part or
knows of a source I would be very grateful.

Chris

[David Chandler]

Hi

 try www.hy-power.com search by name/make on valve block eg kontak, (possible kontakv8000)  a very quick delivery service (phoned one fri dinner parts on sat morning)

no connection apart from a very happy customer and right price

Dave C

Chesterfield

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[Chris S-S]

Thanks for pointing me to Hy-Power they look very useful the valve
block doesn't have anything useful like a name on it but does have a
logo which can be seen at
http://flic.kr/p/amhxpM
does anyone have a name for the manafacturer to go with it or with
reference to the photos of the part I am looking for does any one know
what that is called ?

Thanks

Chris


On Sep 11, 5:12 pm, David Chandler <davidchandle...@yahoo.co.uk>
wrote:
> Hi
>  trywww.hy-power.comsearch by name/make on valve block eg kontak, (possible kontakv8000)  a very quick delivery service (phoned one fri dinner parts on sat morning)

> no connection apart from a very happy customer and right price
> Dave C
> Chesterfield
>

> To unsubscribe from this group, send email to diggers-dumpers-...@googlegroups.com.

[Chris Selwyn-Smith]

       I just found a newer version of Google groups which seems to have a much nicer editor so I will add the pictures I have been linking to in previous posts here.

[Chris Selwyn-Smith]

Hi
well I managed to repair the leaky control unit, Pirtek gave me a couple of threaded bolts from there bits bin of the correct size and thread and I turned up a spacer to give me a shoulder and the correct length drilled out the centre to match the old one it should do the trick I hope.
However on start up ther is still no power and examining the pump shows it to be very hot old oil smoking off its body so looks like those that thought it was the pump were right  I have taken it off to get the numbers off it and will get in touch with Hy-Power whom I have found out are also the same people as Whitehouse products.  I have found there range of pumps for Powerfabs at  Whitehouse Powerfab pumps my pump has the numbers S8912 and IL9DE10R these numbers don't match exactly any of the pumps they have , does any one have any Idea which one I should be looking at? the guy I spoke to on the phone didn't really seem to know ,however I will phone him back with the numbers which I didn't have when I last spoke to him.

[Tom Carty]

Hi Chris

The 19LDE10R is a Roquet pump.  It outputs 6ccs per Rev.

White House can do an equivalent for around £95 plus carriage. I know because I priced one recently.  All the symptoms of excessive heat and loss of hyd. power arehighly symptomatic of pump failure.

When you are doing this, I suggest that you put in a canister filter (10 micron) on the return line to the pump,because the tank-mounted filter is at best just about adequate. Crap in the hyd. oil is the greatest likely cause of pump failure.  So if you are replacing, why not significantly improve the new pump's life for about £50-£100 extra incl fittings? If got a very good filter canister head and 2 filter cans off e-bay for £40.  Great addition.

Also, check out the pressure relief valves (PRV).  These are probably not user- adjustable, and rated at up to 2500 PSI (the rating is stamped on the casing.) In particular the main PRV should be checked, as with a new pump, you will get huge volume and resulting pressure improvements that will need to be managed.  While the PRVs are allegedly not user adjustable, in fact, they can be adjusted using shims/washers as needed.

Hope this helps.

Tom  

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[Tom Carty]

Chris

Sorry, where I said 

"When you are doing this, I suggest that you put in a canister filter (10 micron) on the return line to the pump"

this should have read

"When you are doing this, I suggest that you put in a canister filter (10 micron) on the return line to the tank"

Tom

[Mark & Jane]

Hi Tom.
I am reading the posting and have a similar problem with my machine.
Could you be more precise about the equivalent pump from White House.
Has it got a number for reference?
Any help appreciated, thanks.
Mark.

[Tom Carty]

Hi Chris

WHP have a pump referenced 5S1/39600POW. This is a Sauer Danfoss type pump,but outputs 8cc per rev. rather than the 6cc per rev that your current pump outputs.  It is an equivalent for the Roquet 1L12DE10R.

So a basic question arises:  Do you want to use a pump that outputs 33% more hydraulic fluid per engine revolution that you current pump does?  Do you understand the pros/cons of this?

I you want to replace like for like, I would suggest that you contact WHP and ask them if they have a pump that has the same form factor as their 5S1/39600POW but outputs only 6CC per rev.

If you need to consider the pros/cons of using a higher output pump but don't understand such pros/cons, I recommend that you broaden out the question and post back here, as I am sure many people will have constructive advice to provide.

So as I have found- before you make a change, research, research, research..  If you have an urgent need to replace the pump, and can't wait for consideration of pros/cons of an upgrade, then let me know what engine you have on your Powerfab, and I'll let you know if you should just get the 8cc pump from WHP. In the meantime, register with them on their website, as they require that you do this before you get access to prices and order subsequently.

Rgds

Tom

[Chris Selwyn-Smith]

Thanks Tom for your information

Do I want a pump that will put out 2cc more oil per rev? what are the pros and cons? I have the 11HP Honda engine on it and am definitely a Hydraulic newbie.presumably this doesn't equate to greater pressure but to greater flow ( I don't want to fix one thing to have something else go because it couldn't take the pump spec changing ) would this mean a faster/less controllable moving arm/bucket etc. or an engine that is underpowered? or just a need to reduce revs? or something else entirely.

I will get on to WHP today with the model numbers today and see what we can work out. I am in a bit of a hurry to get running again as it is stuck in a trench at the moment and the digger needs to move and the trench needs to be dug.
 
I will keep an eye out for a return line filter, would This One on Ebay be the type of thing, I take it by your username that yours is  on a 125 if so where did you mount it ?

Are the PRVs the pale blue units that can be seen  here?


 or are they the part that I have been trying to repair?

I am sorry to bombard the group with so many questions  but I really am appreciating and need your help

Thanks again
Chris

[Chris Selwyn-Smith]

I phoned WHD this morning and they had an alternative compatible pump available that puts out 6cc per revolution so I ordered it. hopefully this will get me out of trouble.

Chris

[Tom Carty]

Hi Chris

Hopefully this will sort you out.  When you get it, can you post the make/model of the pump for future reference.

I placed the canister filter setup between the output from the oil cooler and the tank.  I'll take a few photos when I can and post them here.

Tom

On Tue, Sep 20, 2011 at 6:50 PM, Chris Selwyn-Smith <chris.se...@gmail.com> wrote:

I phoned WHD this morning and they had an alternative compatible pump available that puts out 6cc per revolution so I ordered it. hopefully this will get me out of trouble.

Chris

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[Tom Carty]

Chris

The Canister filter on E-Bay that you linked is the exact one I installed.

The main pressure relief valve on mine was stamped with 2500 on the front nut.  My valve control unit is different from yours- You have the later 'joystick' type controls that combines some actions in a single handle while mine is 1 handle per function. The key for me was the stamped PSI rating on each of the relief valves.

Hope this helps

Tom   

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[Chris Selwyn-Smith]

Thanks for the info Tom and I will certainly post the pump details when I know them, at the moment my oil cooler is out of commission as it leaked and had been bypassed by the previous owner, however I understand it is for cooling the oil when using the hydraulic PTO and that those models without a PTO didn't have it fitted.

I will eventually get it recored but as I don't intend to use the PTO it's not high on my list.

I haven't noticed any markings showing pressure anywhere but I am a bit worried that if the bolt like cap that I machined up as a replacement for the stripped one has slightly different internal dimensions it will effect the pressure of the relief valve.

Chris

[Chris Selwyn-Smith]

Well I have to say I am not a happy bunny I cleaned out the tank where I found the probable cause for the pump failure which was the inlet oil strainer sitting in the bottom of the tank  which I cleaned and screwed onto the  tank outlet I cleaned the inside of the tank and  fitted the new pump and a filter on the return line and fitted a replacement capping bolt (see original problem) very kindly provided by Charles from Microplant.   I filled everything with oil and turned the engine over to prime the pump when all was set up I started the engine followed by a fountain of oil from the control unit the spools had separated between the first and second spool.
I really don't understand why, it wasn't a problem before. The feed and return pipes would appear to have been connected up correctly. Or how easy it will be to sort out. The pressure relief valve appears to be adjustable as can be see the hex set screw in the picture checking the filter shows that no oil at all returned to the tank and the filter is the correct way around. I am about at the end of my tether with this thing it seems to be one thing after another.

Does any one have any experience of this happening and why, is this repairable and how do I stop it doing it again.?

Thanks again guys

Chris

[Tom Carty]

Chris

 

A few points:

 

1. You have installed a new pump.  So, you are now pumping oil at the originally designed flow rate, therefore you are now in a position to attain original design pressure.

 

2.  The management of that pressure is now critical- It wasn't a problem when you weren't getting any.  Clearly, correct connections are required.  You are sure that all that was done properly.

 

3.  The PRV (pressure relief valve) is next in the chain.  That dumps oil back to the tank when the pressure exceeds the relief setting.  Let's assume that setting should be 2500PSI, and is properly set. If the pressure exceeds 2500 PSI, oil is dumped back to the tank until pressure drops to 2500, and heat is given off.  At this point, a) No part of the system downstream of the PRV can exceed 2500 PSI, and b) a full 2500 PSI is available if needed downstream of that PRV.

 

4. If the PRV is set to high, say 3500PSI, all components downstream are subjected to that pressure.  If that is higher than those components are capable of dealing with, something is going to have to give- burst pipes or other parts are much more likely. You have an adjustable PRV.  It seems to me that it is very likely that, either it is not working at all or has been adjusted too high. Originally your system could not achieve pressure because of the pump failure. All of sudden, with the new pump, huge pressures are possible.  If the PRV doesn't dump back to tank, it will find its way through the path of least resistance to the weakest part of the system. In your case, that was the spool block.  If the block is made up of individual sections or slices, these have gasketry/o-rings between them and are held together by long bolts. 

 

I think you've blown a gasket.  That will need to be sorted.  But the PRV needs to be checked out to prevent a repeat of the current problem, or other problems downstream.

 

Hope this helps and hang in there.  The newly found pressure is what you have been looking for to make the thing work. But that pressure needs to be managed to achieve proper AND SAFE working.

 

Tom

[Tom Carty]

Chris

 

I meant to say:

 

Also, you mention that

 

"the filter shows that no oil at all returned to the tank and the filter is the correct way around". I can't be sure of your situaion, but the dump from the PRV may go into the top of the tank rather than the main return line. Can you check if that is the case on your set-up.  

 

Have you better/higher quality photos so that I could zoom in and see things better?

 

Tom

[Chris Jackson]

 Hi Tom
 
You are responding to the wrong person (Wrong Chris)!
I have no idea what you are on about mate
 
Besides, I have a Benford ME130 digger not a Powerfab 125.
 
But, I'm curious now so am going to check out the posts
 
Cheers
 
Chris

---

Date: Thu, 13 Oct 2011 21:05:43 +0100

Subject: Re: Powerfab 125 WTD Hydraulic control valve problem

From: tom....@gmail.com
To: diggers-du...@googlegroups.com

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[Chris Selwyn-Smith]

Thanks for all that information Tom very much appreciated . Looking between spool 1 and 2 one can now see approximately a 1mm gap that wasn't there before  which presumably means that the connecting bolts have stretched I will have to remove the unit again (groan) to be able to really see what is going on.

According to the spec sheet the main relief valve setting should be 165 bar which would appear to be 2393 PSI while the pump is rated for 3625 PSI so that would indeed explain that.

The hex screw presumably adjust the pressure relief any idea which way turn that would decrease the pressure ?

Chris

[Chris Selwyn-Smith]

Hi Chris you are receiving these messages because you are subscribed to the Google Groups "diggers-dumpers-plant" group.

I am also Chris and own the Powerfab in question

Chris

[125WTD]

Chris

Slacking off the screw will decrease the pressure setting, while tightening it will increase it, up to the maximum pressure rating of the valve. Slackening off or tightening depends on the thread of the adjustment device. I suspect anticlockwise to slacken, but I can't be sure.

you hav a lot going on with your hydraulics. I suspect you will find more problems in the spool valve when you get back up and running. Personally I would bite a bullet and get the system pressure tested at various points, thereby getting a clear understanding of the state of each individual component and circuit once and for all.

Also remember that you felt a lot of sh@t may. Have gone through the system leading to your pump failure. You replaced the fluid, in the tank. however, the old fluid that was not drained is still in the system and, even though it will be better filtered with your new setup, it would be better to get it all out while you can. Your are going to have to do so much disconnecting again now that you may as well go the whole hog and empty the oil out of the pipes and rams as well.

Tom

[Chris Jackson]

Apologies, I have my thick head on this week instead of my thinking one.
 
Chris
 

---

Date: Thu, 13 Oct 2011 15:48:02 -0700
From: chris.se...@gmail.com
To: diggers-du...@googlegroups.com

Subject: Re: Powerfab 125 WTD Hydraulic control valve problem

Hi Chris you are receiving these messages because you are subscribed to the Google Groups "diggers-dumpers-plant" group.

I am also Chris and own the Powerfab in question

Chris

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[Chris Selwyn-Smith]

Hi Guys

Sorry to have dropped off the map for a while, real life has been getting in the way, however things have been happening with the digger after the control unit blew up I removed the unit and took it down to my local hydraulics service place who for £50.00 an hour + Vat sealed it all up again, pressure tested it and set the pressure relief valve to the required 165 bar I had to leave it at that as to have them entirely strip and service it would have cost a fortune.

All connected back up and start up the engine runs for about 10 seconds and stops further attempts to start it fail and turning the engine over becomes really difficult my thinking at this point is that there is substantial back pressure in the system.surely this isn't right?

I then backed off the pressure relief valve which didn't help, leaving it backed off I disconnected the return pipe where it attached to the counter balance valve  ( see the diagram below, ) and after removing the spark plug turned the engine and therefore pump over a few times giving me a flow of oil and no back pressure I then reconnected the CBV back up and moved on down the return line( where it says X to cooler base on the diagram this is the return to the tank via my in-line filter) where it displayed back pressure leaving the CBV as the pressure culprit and presumably what was responsible for blowing the control spools apart and propably the reason (if you can remember that far back.) that the capping bolt stripped its thread. presumably a counter balance valve has to supply back pressure to do it's job does't it?  below are pictures of the valve and a diagram of the return circuit. the entire circuit diagram can be downloaded from oily hands at :
Powerfab 125 WTD parts pdf

Fortunately the valve is a purchasable part being made by Sun Hydraulics
 http://www.sunhydraulics.co.uk/cmsnet/Cartridge.aspx?ModelCode=CBCHLJN&CatModelID=27&Lang_ID=1 
assuming that it is actually faulty. it is adjustable but given that it did work I don't think its set wrong, It might be that the engine doesn't have enough compression but I don't think so either it did run fine before but I will check this.

As usual any information or thoughts would be gratefully received.

Tom you asked for some larger images I have uploaded some to My Powerfab Picassa Album

All the best
Chris

[Chris H]

Your experience prompted me to wonder 'well what is a CBV?' when it's
at home! There is certainly alot more to 'simple' little digger
hydraulics than I thought! this googled link, (hopefully) has a good
explanation - http://www.wisc-online.com/objects/ViewObject.aspx?ID=HYP3106
I had, sort of, wondered what those big 'blocks' underneath could be
for! Turns out they are pretty vital. I do hope you are up and running
soon and that you share your knowledge gained is great.
Regards, another Chris...

[Chris Selwyn-Smith]

Hi Chris

I hadn't thought about them until troubleshooting this problem, yes they do seem a bit crucial  when you think about it don't they?

I had a thought of to a possible reason for my problem and that is that during fitting the pump I disconnected the pipe leading to the pilot inlet on the counterbalance valve, if it  is pressure operated  (i.e.there is no flow on the pilot inlet) and there was air trapped in the pipe which could be possible, that air would compress and not allow the CBV to function.

I could be clutching at straws here and haven't had the chance to check it out but it sounds plausible to me.

Another good place to have a look at counterbalance valves and see how they work is E4 Trainings counterbalance valve widget

All the best Chris

[Christopher Harper]

Hi again, Sorry, can't really be constructive here with this! Just the sort of thing we hope never happens. you will get there. But, as you found, it takes alot of time/effort and cost. Gawd! It's interesting but really just want to get that digging done!
What I will have to do sometime is try and work out the precise function (or at least an 'inkling') of ALL the components used in the sytem before it goes bust. Your worry might be - has it gone wrong before, previous owner, and been fixed, sort of.
You would have thought that if it was pumping into a 'dead stop' the relief valve (where ever it is) would have protected it from severe damage! Or that the weakest link to burst would be a flexi pipe. The E4... webpage looks complicated, but loads of info. Ah...steam engines...

========================================
Message Received: Nov 14 2011, 05:57 PM
From: "Chris Selwyn-Smith"
To: diggers-du...@googlegroups.com
Cc:

Subject: Re: Powerfab 125 WTD Hydraulic control valve problem

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[Tom Carty]

Hi Chris

 

Can I dare ask:  Is it at all possible that the return fluid is prevented from returning to tank at the new filter head?

 

Tom  

 

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From: diggers-du...@googlegroups.com [mailto:diggers-du...@googlegroups.com] On Behalf Of Chris Selwyn-Smith
Sent: 13 November 2011 18:59
To: diggers-du...@googlegroups.com
Subject: Re: Powerfab 125 WTD Hydraulic control valve problem

 

Hi Guys

 

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[Tom Carty]

By the way, I am getting a page not found error on the Picasa Album…

 

Tom

 

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From: diggers-du...@googlegroups.com [mailto:diggers-du...@googlegroups.com] On Behalf Of Chris Selwyn-Smith
Sent: 13 November 2011 18:59
To: diggers-du...@googlegroups.com
Subject: Re: Powerfab 125 WTD Hydraulic control valve problem

 

Hi Guys

 

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[Chris Selwyn-Smith]

Hi Tom
it is possible and I haven't ruled it out, that what was what I was trying to find out by tracing flow through, there was no flow past the counterbalance valve when manually turning the pump it was also where the back pressure  I would suspect that pressure that can stop the engine would have done something nasty to low pressure piping jubilee clipped on or indeed the filter itself. I had hoped to get out and refit the CBV this afternoon but didn't have the time.

Incidentally you mentioned the pipe to the top of the tank the other day which I think is the return from the wheels also of course there  is the one that is the return from the control unit. 

Here is another go at the link Powerfab Picassa Album which worked when I tried it.

Chris

[Tom Carty]

Hi Chris

 

That Picasa Album works ok now.

 

Thanks & good luck with next steps

 

Tom

 

---

From: Chris Selwyn-Smith [mailto:chris.se...@gmail.com]
Sent: 16 November 2011 22:20
To: diggers-du...@googlegroups.com
Cc: tom....@gmail.com
Subject: Re: Powerfab 125 WTD Hydraulic control valve problem

 

Hi Tom

[rspb...@aol.com]

Chris, just wonder if you found the problem in the end?

page 52 is your unit and page 50 show adjustment to the cbv and shows the CBCH LJN, says set at 210 bar standard unless asked to be different value, clockwise to release load.

www.ingenieriaydistribucion.com/pdf/sun/Assemblies%201.pdf 

[Chris Selwyn-Smith]

HI

My bad.

I did write a long message some time ago detailing my progress with pictures and everything and lost it as I was about to post and didn't get around to writing it all again.

The source of the probem was indeed the counterbalance  valve and replacing it solved my problem so the pump overheating and oroginal leak was  due to the return being blocked  replacing the pump increased the pressure which was still blocked and blew the spool valve apart, the valve works a bit like a relay in that its flow is controlled by pressure from another point in this case just after the pumps output  and with that part of the valve blocked it was not allowing any return flow and a build up of pressure to the point where something had to give .unfortunately I started troubleshooting from the wrong end.

It is an external counterbalance valve and its explained rather well in this YouTube Video go to 12minutes 15 seconds in where he starts describing the Valve.

I had another expensive incident when the nut holding the piston in one of the rams came undone while in use and the rod pulled out making everything longer than it should have been and resulting in a bent rod and the need for getting a new one made.

I am now trying to find a new bush and pin for the bottom horizontal pivot on the arm which is quite badly worn.

I did however manage to dig my electricity cable trenches and get my electricity connected,

sorry for not having reported back more promptly.

Chris

[rspb...@aol.com]

Interesting video Chris.

 

Main reason I came back to this post was that I think I have the same fault.

 

When all levers central I have back pressure in the system, enough to stall the engine (set tickover to help stop blowing system)

 

I can run the engine up if I use any of the wheel drive lever section fwd or rev (fully open) and the shut off lever set to toe position, so the return oil flow is via the small pipe on tank not the cbv.

 

When I move the wheel drive control back to center, you can hear the system come up on pressure but not release to a point the pump stalls the engine.

 

When I carried out a tank and control valve clean, I found a few bits of fine pea gravel.

 

My thoughts were that they got into the system via the drive wheel quick release picking up crap or maybe a pipe replacement made the cbv fault.

 

Now thinking about it the pump feeds the cbv directly and yours and my pump was worn, perhaps as its not filtered thats the answer.

 

So...

 

Did you replace just the valve or the whole cbv unit, if not the same whos?

 

Also as its adjustable did you, if not what preset pressure did you go for.

 

Mine is the single lever version but the general presure/flow is the same level and the result should be the same at the cbv.

 

Regards Rob

 

Ps.. Im based Banstead Surrey, if you get stuck on replacement pin and bush.

 

 I'm replacing mine next week some point, if I need to make a pin, its just as easy to make two...if no luck

[Chris Selwyn-Smith]

It does sound like it may well be that,if so you dont need to get the whole unit just the valve will be needed the block is just a manifold to mount everything to so is unlikely to be faulty I got mine from Sun Hydraulics  Sun Hydraulics CBCH-LJN

As I recall I backed of the adjuster of the old unit fully counting turns as I went and set the new one to the same setting  which seemed to work holding the bucket up and allowing the arm to push into the ground

I didn't try starting  with the wheel controls open because mine died with them on the ground and left me with no way to use them  but there was so much back pressure I couldn't start the engine it would  run for a second or two and stop and any attemts to turn the engine over after that was impossible due to a fearsome kick back due to the pressurized system.

I am not that far from you I am in Hampton Court and would be interested if you find yourself making pins I have found 32*40 bushes i think at http://www.bearingboys.co.uk/   I did approach http://www.powerfab.co.uk/ but it seems impossible to pin the guy down to actually sell you parts, he never gets back to you.

The pin seems to be 32 by 230mm and if you find yourself making one I would be very interested  in one for my machine.

Hope you get your machine sorted but at least you seem to be starting at the right/cheap end

[rspb...@aol.com]

Chris, email / pm me a contact no.. if you need a pin.

 

I have already replaced the pump... lol, So starting to add up, but saying that, the old pump was so worn it needed it..

 

I got the bushes from Croydon, Orbic bearing.. not the cheapest place but local although there not lots in the 1st place anyway.

 

Just order a bag full to carry out a quick replacement of slew to bucket of all the bushes.

 

By the way ''starting with the wheel controls open" comment, I found as the control was held open on the drive lever and side direction control block (on tow) so it just returns hydraulic oil straight to tank didn't matter if

 

wheels on the ground or in the air.

 

Cheers for the link

 

Rob

 

 

 

 

[Rspblake]

Hi chris, little update...

Not all the bushes are the "du type"! The main cylinders have a "spring steel bush" which is larger in OD, than a standard DU

the wall thickness is around 3mm not 2mm, The bushes in the bucket and arms are Du, I'll check the slew during the week..but can't see it being any different than the ones in the 125w which was DU....

 
Got a working digger now...   Removed the CBV and cleaned,air line /brake cleaner, it was set at 2.5 turns out, I refitted then as a starting point released the pressure off by turning it in, then started motor and while running back it out till you could here it loading up system around 1 turn
 
I was informed that the CBV unit can be stripped but never did...Was hoping that on min release pressure the flow of oil would do the final cleaning job. it now works so maybe it did..