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Author
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Topic: Hydraulic oil pressure relief
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63super
True Blue Posts: 9
From: Mackay, QLD, Australia
Registered: May 2007
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posted March 24, 2008 07:03
  
Hi all. I have been reading an IT manual and it states that there are two types of pressure relief vales. The early valve when opened will return to approx 300psi and the control handle must be returned to the netral position to reset.This is fitted to my tractor. The newer valve will maintain system pressure. I am wondering which models were fitted with this new valve and are they still availble. Thanks AndyIP: Logged |
Brian
Rules All Things Blue Posts: 2853
From: United Kingdom
Registered: Feb 2002
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posted March 24, 2008 10:03
Sorry but I am going to be very harsh. That is total rubbish and is the reason that I do not rate those manuals.The Fordson Major E1ADDN had the first type of relief valve you describe not a Super Major.The valve blows off then the lever has to be placed in neutral and the valve will reset. The valve was part of the lift design and officially called the "unloading valve". It went out in 1960 with the introduction of the Super Major. The Super did have two types of valve but did not have to have the lift go into lower for the valve to reset. The early Super relief valve blows off and the lift retains that pressure, it does not shut down, it will blow off and be usable all day. If you leave it blowing off the oil will overheat. This valve fits into the front of the lift housing and has a flat head. The second PRV used in a New Performance Super and from 1963 used as a service replacement in all earlier Supers, is a "progressive" one. This means that it does not blow off at (say) 2500psi as the earlier valve but starts to open at (say) 2300psi and fully opens at 2500psi. This is to eliminate hydraulic shock loadings on the pump and internals on the lift. This valve is identified by having a longer head sticking out of the front of the lift. ------------------
Kind regards
Brian IP: Logged |
63super
True Blue Posts: 9
From: Mackay, QLD, Australia
Registered: May 2007
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posted March 24, 2008 10:25
Thanks for your response brian,
My tractor is fitted with the flat head relief valve. I use a three point linkage bucket with the tractor and when i load the bucket it sometimes lifts and then falls to the ground and i have to move the lever down to pick the load up again. I tried testing the prv pressure i installed a guage into the aux port and operated the lever the pressure spiked to 1800psi and then returned to 300psi.Do u think that adjusting the pressure to 2200psi will make a difference?
When i am using the rear bucket do you think the lift cylinder safety valve could to opening?IP: Logged |
Brian
Rules All Things Blue Posts: 2853
From: United Kingdom
Registered: Feb 2002
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posted March 24, 2008 19:26
Think you possibly have two seperate problems. If you get a pressure of 1800 psi that drops to 300 psi it could be a faulty relief valve that is not reseating. If you take it out, take the rubber "O" ring off and unscrew the bit with the holes in, you can check the spring and valve seat. Also, if possible try another valve from another tractor.You do not say if you are in draft control or position control when your load on the arms drops. This is nothing to do with the pressure problem IMHO, it sounds like a linkage problem in the lift. A worn position control roller would cause something like that, or bent linkage. I have come across something similar when the weight of the load is pulling back on the top link. Try putting a second pin in the second hole on the top link piviot and see what happens. Hope this helps, if not, get back to us. ------------------
Kind regards
Brian IP: Logged |
63super
True Blue Posts: 9
From: Mackay, QLD, Australia
Registered: May 2007
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posted April 02, 2008 13:29
I haven't been able to get hold of another relief valve yet but have been playing around with the bucket. I fill the bucket with the tractor in position control.I followed Brian's advise and installed two pins into the top link pivot and the loader worked a lot better. When the bucket is full of dirt and is lifting sometimes it falls and starts to lift again, once this happens once it repeats over and over. When i had the top cover off some time ago i did notice that a roller was worn away this must have been the roller that brian was talking about. Part number E190-gf-9.
IF this roller is replaced will it stop the hic up action of the bucket or should i just install two pins into the top link.
Will i have to make any adjustments to the linkages if i replace the roller. Thanks Andy
IP: Logged |
Brian
Rules All Things Blue Posts: 2853
From: United Kingdom
Registered: Feb 2002
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posted April 02, 2008 18:18
Andy,Do not operate the loader in Position control!!! You must use Draft control for ANY service where you are using an implement not connected to the arms. Not because you will damage the tractor but because you can damage yourself. If the tractor is in Position control, it does what it says, it sets the position of the arms. If the arms were to sink down, the lift will automatically try and bring them back to the set height. If you are diverting the oil to a trailer or loader instead of the ram cylinder there is no cutout of pressure as the arms are not being moved. The loader or trailer will continue to lift EVEN IF YOU PUT THE CONTROL LEVER TO THE BOTTOM OF THE QUADRANT. You will have no control. I have seen people demolish sheds and smash equipment doing this. I even tipped a load of scenery from our local dramatic society in the local market place when it happened to me. The corrections you note are because you are using the wrong service not due to wear on the roller as this is not in use when you are using the loader. The problem is due to a load on the top link if it goes away or decreased when you put two pins in the top link rocker. ------------------
Kind regards
Brian IP: Logged |
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