Hymac 580 C Cross-Line Relief Valve Adjustment

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Hymac 580 C Cross-Line Relief Valve Adjustment

Post #1 by strontium90 » Sun Jan 20, 2019 11:05 am

I'm looking a bit of advice.
My Hymac has had a problem since I got her..

When the machine is sitting with the boom and bucket lifted or you are tracking without the slew lock engaged, it tends to creep slightly to the right (clockwise)….Also if you are working on a slope and loading a trailer the bucket tends to creep to the right and this can be inconvenient...I have worked round this by trying to load to the left (anticlockwise) but this is not always possible....It is not too bad but my understanding of hydraulics is limited. I always presumed it was the staffa slew motor needing internal seals.


However, could adjustment of the CLRV remedy this and could I adjust it without a pressure gauge?...How would I turn the adjustments to make it stronger to resist moving on it's own to the right?...I know you guys are a lot more knowledgeable than myself and I would be grateful for any advice..


Is there just one crossline body containing both CLRV's with the adjustment underneath? (See Image)
IMAG1447.jpg


Or could it have something to do with the check valves, which I presume are the circled objects in the cross line feed (see image)
crossline.jpg


The workshop manual isn't very clear.

Thanks in advance..
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Re: Hymac 580 C Cross-Line Relief Valve Adjustment

Post #2 by Jeremy Rowland » Sun Jan 20, 2019 6:10 pm

I have pm'd you about this. :thumbup:

Jeremy


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Re: Hymac 580 C Cross-Line Relief Valve Adjustment

Post #3 by strontium90 » Sun Jan 20, 2019 6:30 pm

Thanks...


Alex


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Re: Hymac 580 C Cross-Line Relief Valve Adjustment

Post #4 by Andy80 » Mon Jan 21, 2019 1:21 pm

Please keep us updated of how you get along with this. My Hymac tend to creep to the side to when digging in a slope


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Re: Hymac 580 C Cross-Line Relief Valve Adjustment

Post #5 by strontium90 » Mon Jan 21, 2019 3:46 pm

I will...
I have been in contact with Tony Flint of http://www.hymac-spares.co.uk/hymac-service.html on the advice of Jeremy Rowland of this site..
He suggested swapping the check valves over to start with...I assume it will be removing and turning the cross line feed over which contains the check valves...I need to be careful as you can see in the photo on my first post, that one of the junctions has been repaired by brazing it..

If this doesn't work I will have to buy a hydraulic pressure testing kit with th appropriate adapter and test the cross-line relief valve...
It could be the seals in the staffa motor which will be more awkward...
Everyone I have spoken to locally who has owned a Hymac has had similar problems with many replacing the slew motor...we will see..

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Re: Hymac 580 C Cross-Line Relief Valve Adjustment

Post #6 by FOWLER MAN » Mon Jan 21, 2019 3:55 pm

Hi, I'm sure Jeremy will have sorted you out, but in answer to your question the cross line release valve only has one pressure setting so there is no way to vary the pressure to left or right.

You problem is probably with one of the two check valves which you will find in the tubes feeding the Staffa, (slew motor). This could be
just something stuck in the valve, a weak or broken spring or a damaged / worn seat. A swap will tell.

There are also four check valves in the CLRV. These are behind two plugs on the sides of the CLRV and two plugs on the underside. You will also find the releif valve setting on the underside of the valve.

You will need a pressure gauge if you disturb this setting, but if the slew is working properly one way it's probably OK so perhaps leave well alone is the best advice here.
The CLRV setting will be higher than the main releif valve which is in the slew control valve so if resetting it you will have to increase the main releif valve pressure to above the required CLRV pressure first, then set the CLRV.
This done return the main releif pressure to its original setting. It's so long since I worked on these that I can't remember the actual settings I think the main releif was 2,200 lbs. thats just under 152 bar. I'll search out the pressure settings if you need them.

Good luck.
Fred


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Re: Hymac 580 C Cross-Line Relief Valve Adjustment

Post #7 by strontium90 » Mon Jan 21, 2019 5:11 pm

Thanks so much Fred...This is exactly the information I was hoping for... :bow:
I will remove the flexible pipe with the check valves and swap them over...Will I need to plug the main slew pipes to stop Hydraulic fluid?
Hopefully it will be a quick fix...fingers crossed
I have the pressure settings in the workshop manual, the only thing I was wondering was what size is the adaptor to fit into the slew motor?
Many thanks
Alex


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Re: Hymac 580 C Cross-Line Relief Valve Adjustment

Post #8 by strontium90 » Mon Jan 21, 2019 8:29 pm

Sorry to bother you Fred..
Are these the two Check Valves (circled in red) located coming off the two main feeds to the slew motor from the CLRV, joined with a flexible pipe and a feed on back to VB3?...According to the workshop manual there are supposed to be arrows on them but I can't seem to see any directional arrows. Maybe if I cleaned them first...
Image
Also, which check valves in the CLRV should I check/change?...The two on opposite sides of the Cross-line Relief Valve?

I will wait until a dry, windless day when I can park the machine on a dry concrete surface as I don't want springs or valves disappearing into the muck or a pool of oil..
Sorry for being such a dope but I want to be sure as I've little knowledge of hydraulics...

Thanks in advance

Alex

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Re: Hymac 580 C Cross-Line Relief Valve Adjustment

Post #9 by FOWLER MAN » Wed Jan 23, 2019 4:59 pm

Hi Alex,
No bother at all. The Valves you circled look like the ones.
They are each teed into one of the two feeds to the Staffa motor. The one feed for clockwise and the other for anticlockwise rotation. They close under pressure when the slew is operated,(or under load), and open when off load to release the discharge from the motor back to tank.
I think you will find the outlets from the valves are teed together somewhere and run back to dump the fluid via the control valve.
If swapping these makes no difference and you wish to check the valves in the CLRV you should be able to make a visual inspection.
Probably easier to remove the CLRV from the machine if this proves necessary. You will not need to disturb the pressure setting.
Please let us know what you find.
Fred


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Re: Hymac 580 C Cross-Line Relief Valve Adjustment

Post #10 by strontium90 » Wed Jan 23, 2019 5:12 pm

Thanks Fred for clarifying that....I will be working with the machine towards the weekend doing some digging and will swap these afterwards...
Yes...there is a Tee on the flexible pipe which feeds into VB3...
I will try to do it on a concrete surface so as if I drop something (which always happens) it won't be lost...I will try to swap the check valves on the CLRV too...will let you know.


Alex


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