Introduction and questions!

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Max
Posts: 9
Joined: Tue May 11, 2021 9:19 am
Location: United Kingdom

Introduction and questions!

Post by Max » Fri May 14, 2021 10:55 am

Hi, my name is Max from Lancashire, England. I recently bought a 995 which has been painted up and looks great. Unfortunately I may of been dazzled by the shiney paint and there are a couple of issues with the tractor. The main one being with the hydraulic system. The lift goes up and down in position and draught settings but from the point it starts to move it continues to the top and then still continues to try and pump rather than holding. The position setting does the same and can't be moved incrementally as you would expect. Does anyone know if this is an issue with the adjustment of the spool valve or some other cause? Also can these adjustments be carried out with the valve block fitted to the tractor or does it have to be removed?

Sorry for the long post but am keen to do a few jobs with it!

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ollek
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Re: Introduction and questions!

Post by ollek » Fri May 14, 2021 11:53 am

The reason for this can be a sticking spool valve. A faulty adjusted spool valve is normally resulting in no lift. Have the main control lever and the linkage fully down and remove the plate on top of the rear axle just behind the control lever. In the rear part of the opening you will see two nuts. Move the control lever from fully lower to fully lift and back again with the engine stopped. The two nuts should move up and down about 2,5 mm and the washer below the nuts should be clamped against the valve chest body when the lever is in full lift position and the washer should be loose when the lever is in lower position if the spool vale is operating correctly. Do you know if the tractor has been standing without being used for a long time or have somneone had the valve chest or any other 3-point hitch part out of the tractor. You can also try to do all group 3 settings shown in the following link https://dbtc.co.uk/index.php/informatio ... lic-system You do not say if the tractor is a stradle model or a Q-cab version.

Max
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Location: United Kingdom

Re: Introduction and questions!

Post by Max » Fri May 14, 2021 12:16 pm

Thanks Ollek, yes I believe it has been stood for a while and hasn't done any work for years. I intend to put it on my pasture topper and give it a run. I was hoping that using it would free up any sticking valves etc but I'm not normally that lucky!

It doesn't have a a cab but not sure if it ever did. It is painted white and brown and is fitted with arched mud guards. Looks very similar to a 990 but has 995 decals and is stamped 995 on the chassis. Doesn't have power steering either.
Last edited by Max on Fri May 14, 2021 12:20 pm, edited 1 time in total.

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ollek
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Re: Introduction and questions!

Post by ollek » Fri May 14, 2021 12:17 pm

ollek wrote:
Fri May 14, 2021 11:53 am
The reason for this can be a sticking spool valve. A faulty adjusted spool valve is normally resulting in no lift. Have the main control lever and the linkage fully down and remove the plate on top of the rear axle just behind the control lever. In the rear part of the opening you will see two nuts. Move the control lever from fully lower to fully lift and back again with the engine stopped. The two nuts should move up and down about 2,5 mm and the washer below the nuts should be clamped against the valve chest body when the lever is in full lift position and the washer should be loose when the lever is in lower position if the spool vale is operating correctly. Do you know if the tractor has been standing without being used for a long time or have somneone had the valve chest or any other 3-point hitch part out of the tractor. You can also try to do all group 3 settings shown in the following link https://dbtc.co.uk/index.php/informatio ... lic-system Dirt and water in the (oil creamy) can make all valves in the valve chest sticking. When have the tractor had a gear box oil and filter change? You do not say if the tractor is a stradle model or a Q-cab version.

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ollek
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Re: Introduction and questions!

Post by ollek » Fri May 14, 2021 12:18 pm

I have made some additions to my writing, please check. Trying to free sicking valves by using the hydraulicks does not normally work. You will have to clean and/or work any sticking valve sepately.
Last edited by ollek on Fri May 14, 2021 12:22 pm, edited 1 time in total.

Max
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Location: United Kingdom

Re: Introduction and questions!

Post by Max » Fri May 14, 2021 12:22 pm

It has recently had oil and filter in the back end but who knows what it was like prior to that. Thanks again for your help, very much appreciated 👍

philedge
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Joined: Sun Dec 03, 2006 11:27 am
Location: Chester UK

Re: Introduction and questions!

Post by philedge » Fri May 14, 2021 1:23 pm

Max wrote:
Fri May 14, 2021 12:22 pm
It has recently had oil and filter in the back end but who knows what it was like prior to that.
If you dont know what it was like prior to the oil change, I assume you didnt do the oil change and filter replacement??

From experience I know that a flush and oil change can get things working again without further intervention. I'd double check that the oil is clean and clear and change it again if its contaminated. If youve got your 3 way valve plumbed to a loader or can rig a return route to the gearbox from ports 1 or 2 then you can have the tractor running with oil circulating through the selectamatic valve without the pressure releif valve operating. Allowing the oil to warm up flowing through the valve and operating the quadrant lever freed off my hydraulics and they have been fine for 20 years:) Obviously theres no guarantee youll be so lucky!
'66 880 Selectamatic rat.

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erkki
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Re: Introduction and questions!

Post by erkki » Fri May 14, 2021 2:31 pm

Hmmm.

The follower roll on the RHS ed of the cross shaft is one key element in giving control impulse to the spool valve. When the arms are going up, the follower is sensing the position of the cam plate on the top face of the cross shaft. When the desired height is achieved, the roller pushes down the slide bar , which pushes down the outer end of the rocker bar , which locates in the fork, which is connected to the selectamatic selector. The inner end of the rocker bar then lifts the spool valve up and the system turns to "hold" position. You can see the system behind the steel cover on the RHS end of the cross shaft. If the roller follower has damaged it may cause the described problem. Also its possible that the cam plate adjustment is made wrong, or the nuts which hold the cam plate on the correct alignment are loose. If the spool valve is opened too late, the lift piston can come as far out as the mechanism has space and the pump still keeps on pushing full pressure oil to the ram line.

Max
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Location: United Kingdom

Re: Introduction and questions!

Post by Max » Sat May 15, 2021 6:04 pm

Ok, have done some spannering and discovered that the cam follower was stuck in its lowest position. I removed the retaining block that holds the position follower and the draught lever. I found that the position cam follower was bent and was sticking in its housing. I straightened it and reassembled (bit fiddley!!) Now as soon as I started it up with it set in "position" the lift raised approximately 40%. I could then move the lift up incrementally as you would expect in the position setting but then it wouldn't lower more than approximately 20%. If I select draught it will (most of the time) lower to the bottom. Im guessing that the solution to this will be to adjust the spool valve? Another question ref the photo in the link, when in draught setting the position cam follower is still just over the lever that operates the valve, is this correct?

Thanks Max

995 Hyde valve https://imgur.com/gallery/uRUZ8tN

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ollek
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Re: Introduction and questions!

Post by ollek » Sat May 15, 2021 7:44 pm

There is only one spool valve setting and it works with all functions, draught, height and TCU/external. A wrongly adjusted spool valve will effect all functions, not just one. Have you done all groop 3 settings, as I have asked you to do? If not, do the settings in the correct order and in the correct way, as told in the link I sent you. The cam follower rod will only get in contact with the rocker lever when the hitch is almost at top, not in any other positions of the linkage and this is to stop ,the lifting when ther linkage is at top.

Max
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Location: United Kingdom

Re: Introduction and questions!

Post by Max » Sat May 15, 2021 10:14 pm

Hi Ollek, sorry haven't got round to that yet, thought I had found the issue when I discovered the cam follower was stuck fast in the max height position. Will report back when I I have tried to adjust the settings.

Thanks Max

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ollek
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Re: Introduction and questions!

Post by ollek » Sun May 16, 2021 12:34 am

I forgot something important. You need to ensure thet the spool valve and the by-pass and hold valves are moving freely, before you do the groop 3 settings. IOt can be impossible to do the settings if the valves are sticking.

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cobbadog
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Location: beautiful Coopernook NSW. near Taree. NSW. Australia

Re: Introduction and questions!

Post by cobbadog » Sun May 16, 2021 7:20 am

There are no short cuts on doing the adjustments on this system. Follow the instructions to the letter then see what happens until that is done it is never going to work for you.

Max
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Location: United Kingdom

Re: Introduction and questions!

Post by Max » Sun May 16, 2021 7:35 am

ollek wrote:
Sun May 16, 2021 12:34 am
I forgot something important. You need to ensure thet the spool valve and the by-pass and hold valves are moving freely, before you do the groop 3 settings. IOt can be impossible to do the settings if the valves are sticking.
Hi Ollek, I also forgot to mention that I undid the valve cover plate and rotated it to view the valves as you suggested earlier. When I moved the quadrant lever I could see the spool valve lifting and lowering as you described. Although I couldn't measure the amount of lift it did look approximately 2.5mm as you said above.
Are there any instructions for checking the bypass and hold valves?

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ollek
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Re: Introduction and questions!

Post by ollek » Sun May 16, 2021 8:55 am

Remove the cover and the plugs on top of the valves and take out both springs. Lift up both valves using a wooden stick that fits snugly into the valve plungers. Then remove the threaded brass plug from inside of the by-pass valve and take out the restricor and the nylon screen (it any fitted) and check that the small hole in the restrictor is open. Then check that the small hole in the tip of the hold valve is open and check that both valves moves freely in the bores. Be careful not to drop any part into the rear axle. The first drawing in the link about the settings shows the parts in the valve chest. See also page E7 in img 262 in the following link https://drive.google.com/drive/folders/ ... kFFNE5qU00 Please note that the height control rod will bend only if someone has done something wrong, not on its own. This makes me think that somebody who does not understand the system can have damaged other parts as well, who knows.

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