Newby - Looking for help on hydraulic issues 880A 1968

The place to discuss all matters relating to David Brown Tractors. You will need to register your user name before you can post. If you have already registered could you please make sure that your location details have been completed. Go to My Account in the Main Menu on the left, and then go into "Edit Your Information" and complete your location details. Give the Country (and State/Province if you wish) if outside the U.K. County if within the U.K. Location details helps other members if you need spares, technical advice, or the nearest practical help.

DISCLAIMER - Please be aware that any views expressed or advice given on the Forum are purely the opinion of the relevant poster. The David Brown Tractor Club Ltd does not endorse any of the views expressed, or advice thus given. Forum Visitors should be aware that any action they may take as a result of such information is taken at their own risk.

Any user inactive for more than 3 months will automatically be deactivated, please contact admin@dbtc.co.uk if you would like to be reactivated.

Please be aware that your user name and entered location can be seen by all members. We only store information you have entered which is your email address and username, your IP is also stored, we have no access to private passwords.

If you do not agree with your information being stored, please do not register an account, If you wish to unsubscribe at any time please email admin@dbtc.co.uk giving your username.

Amended 19/09/18

Moderators: Segrie61, admin

Post Reply
43fraseraemurray
Posts: 8
Joined: Wed Jun 20, 2018 8:32 pm
Location: Herts

Newby - Looking for help on hydraulic issues 880A 1968

Post by 43fraseraemurray » Tue Aug 07, 2018 6:36 pm

So I took the plunge and bought a vintage tractor for light work - rolling, harrowing and pushing up the muck heap - found a local guy selling a 1968 880A s/n 547085 with an L8 loader with an additional HUSCO single lever spool valve. This might be a stupid question, but is there any reason why I can't spray the underside of the tractor with engine cleaner and jet wash all the crap off?

I've got loads of manuals (including the Case Agricultural Service Education Department Selectamatic Hydraulic System) and have read a huge amount about the hydraulics. The linkage goes up and down (goes down slowly, even with the adjuster fully open), the mechanical lift latch works , the dump valve works. That's as far as I can tell.

The first issue I want to deal with is the late type lever operated 3 way valve. In position L1 (nearest to the seat), and with the selector dial pointer in the External/TCU position the following happens. Moving the hand lever forward, the linkage rises, but when it gets to the top the loader starts to rise and continues until it reaches the highest point. Moving the lever back towards the "select' position, the loader drops and, once the loader is on the floor, the linkage slowly lowers. My understanding is that with the 3 way valve lever in this position, the loader shouldn't move. The loader is the simple type single ram each side, power up, gravity down, mechanical release bucket. The 'feed' for the rams is connected to Output Connection 1 and both oil return lines are connected to the top of the gearbox housing

If it would help, I can post pics/videos. Really appreciate any suggestions - very keen to get it all working, as original.

User avatar
Lofty
Posts: 190
Joined: Fri Dec 23, 2016 5:04 pm
Location: South Australia

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by Lofty » Wed Aug 08, 2018 1:11 am

L is for rear lift, 1 for loader. L/1 is a red herring.

philedge
Posts: 133
Joined: Sun Dec 03, 2006 11:27 am
Location: Chester UK

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by philedge » Wed Aug 08, 2018 5:19 am

In position L/1 oil is routed to both the rear links AND port 1, the top port. As the links are lighter than the loader they will lift first and when they are fully up pressure will start to build until there is enough to lift the loader. The reverse happens when releasing the pressure ie loader drops first followed by the links.

Without changing the plumbing just use position 1 for the loader and position L for the links. Ive got my loader on port 2 so I only have to move 1 position when flicking between links and loader.
'66 880 Selectamatic rat.

43fraseraemurray
Posts: 8
Joined: Wed Jun 20, 2018 8:32 pm
Location: Herts

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by 43fraseraemurray » Wed Aug 08, 2018 10:54 am

Thanks both - so this morning I tried it in position L and position 1 - in 1 the loader doesn't move, although you can hear the motor working. In position L the linkage goes up and slowly goes down without the loader moving. With the control lever forward to linkage goes to the top, but the pump continues to 'scream'. Is there a by-pass valve that should stop the motor working? Secondly, would the loader not moving in position 1 mean that the valve is blocked to out put 1. I guess I could swap it to output 2 to see if that makes a difference.

More thoughts anybody.

User avatar
ollek
Posts: 3479
Joined: Tue Apr 10, 2012 1:20 pm
Location: South West Finland

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by ollek » Wed Aug 08, 2018 12:18 pm

You said "with an additional HUSCO single lever spool valve". What is this for and how is it plumbed into the tractor hydraulics? Philege told you all about the 3-way valve and its functions. If the flow to the loader cylinder is taken from the 3-way valve, and you have selected TCU/External, then the loader (or the 3-point hitch) will lift when the hitch lever is fully back in the quadrant, this is the select position (lever kept back against the spring). The loader or the 3-point hitch should hold when the control lever is pushed forward by the spring without moving the lever by hand. There is a leak in the system if the linkage or the loader will not stay up. The loader will lover when you push the lever forward about half way of its total movement. Pushing the lever more to the front will start to increase the pressure. This pressure is the TCU pressure and can be adjusted between 0 an 50 bar, depending on how far forward you push the lever. You said "both oil return lines are connected to the top of the gearbox housing". What are this return oil connections for and how are they plumbed into the hydraulic system? You also said "that should stop the motor working?". The motor (I think you mean engine) is working if it is running. If the hydraulic pump is working against dead end, then the main relief valve will open, also called "pump screaming". This is wrong as the pump is not screaming but the noise is produced by the open relief valve. Are you sure that you know the correct positions on the 3-way valve lever for selecting 1, 2, L/1 or L? A slow lowering speed with little or no load on the lower links is normal for the Selectamatic system. If the hydraulic system is OK, then the linkage will stay up even if you shut off the engine. This is not the case with all tractors. A Massey Fergusson from the same era will not hold the linkage up with engine shut off, the linkage will drop down (fast) when you stop the engine and there is no system whereby you can adjust the lowering speed in these tractors.

43fraseraemurray
Posts: 8
Joined: Wed Jun 20, 2018 8:32 pm
Location: Herts

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by 43fraseraemurray » Wed Aug 08, 2018 3:33 pm

Many, many thanks for your time oliek

The husco valve is attached to the RH hinge of the loader frame. It was there when I bought it, so I can only guess that it was put there to raise/lower the loader. See attached images for plumbing arrangements.
rsz_img_8993.jpg
rsz_img_8993.jpg (50.78 KiB) Viewed 505 times
rsz_img_8981.jpg
rsz_img_8981.jpg (67.2 KiB) Viewed 505 times
rsz_1img_8992.jpg
rsz_1img_8992.jpg (48.37 KiB) Viewed 505 times
"that should stop the motor working?" should read "that should stop the pump working?" - OK thanks for the info on the screaming pump - if it is the open relief valve, I wont worry about it.

Are you sure that you know the correct positions on the 3-way valve lever for selecting 1, 2, L/1 or L? took that info from this image
rsz_screen_shot_2018-08-08_at_152743.png
rsz_screen_shot_2018-08-08_at_152743.png (93.27 KiB) Viewed 505 times
If the hydraulic system is OK, then the linkage will stay up even if you shut off the engine - the linkage stays up, but the loader doesn't.

Hope the pictures help.....

User avatar
ollek
Posts: 3479
Joined: Tue Apr 10, 2012 1:20 pm
Location: South West Finland

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by ollek » Wed Aug 08, 2018 4:20 pm

The relief valve opens when the pump pressure is at maximum. Using the tractor with the relief valve constantly blowing off will ruin the pump in a very short time (just a couple of hours). Looking at the picture, where is the steel pipe going to and where is the rubber hose going to. If the steel pipe is feeding the loader then you have to select position 2 on the 3-way valve when you use the loader. .

43fraseraemurray
Posts: 8
Joined: Wed Jun 20, 2018 8:32 pm
Location: Herts

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by 43fraseraemurray » Wed Aug 08, 2018 4:41 pm

OK - so back the control lever off once the linkage is at the top?

The steel hose goes to a spare outlet at the rear of the tractor under the LH side of the drivers seat. The rubber hose goes to the Husco valve - ypou can see it as it crosses the gear box lever area.

Many thanks for all this.

User avatar
ollek
Posts: 3479
Joined: Tue Apr 10, 2012 1:20 pm
Location: South West Finland

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by ollek » Wed Aug 08, 2018 5:48 pm

You said that the loader have single acting lift cylinders and mechanical bucket control. If this is the case, then the husco valve have to be removed and the feed from the 3-way valve connected via a T-connector to the piston end of the loader lift cylinder. You can not connect a hydraulic feed to a valve designed for double acting cylinders and then feed the cylinders with hoses from this valve, it will not work. The hose connections on the piston rod side of the single acting cylinders has to be fitted with small breathers, or there will be an air lock in the cylinders that can even split the cylinders. It looks that a double acting loader with hydraulic bucket control have been fitted to the tractor, and now this loader have been removed and a single actin one has been fitted. The best you can do is to get someone that understands how different hydraulic connections have to be made to help you out and do the connections. It will take ages for me to explain how all this has to be made correctly.

43fraseraemurray
Posts: 8
Joined: Wed Jun 20, 2018 8:32 pm
Location: Herts

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by 43fraseraemurray » Wed Aug 08, 2018 6:43 pm

Thanks Oliek, that makes good sense. The rear linkage did drop after I turned the engine off - any suggestions where I might start to look for a leak?

User avatar
ollek
Posts: 3479
Joined: Tue Apr 10, 2012 1:20 pm
Location: South West Finland

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by ollek » Thu Aug 09, 2018 11:23 am

Lets take one step at the time. Remove the Husco valve with all the extra hoses. Then re plumb the loader as I have said earlier. Do not start to do any fault finding before the loader plumbing is correct.

philedge
Posts: 133
Joined: Sun Dec 03, 2006 11:27 am
Location: Chester UK

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by philedge » Fri Aug 10, 2018 9:04 am

Not sure how your Husco valve is configured but I have a Gresen spool valve for my loader and it works for both single and double acting rams. My lift rams are single acting with a single hydraulic connection to extend them and gravity brings them back. Theres no vent or other pipe connection on these rams.

The bucket is double acting so a piped connection at both ends.

On the spool valve theres 2 pipes for the bucket and a single pipe for the lift rams. Theres a steel pipe that runs through the engine bell housing that connects the 2 lift rams together so theres only a single pipe from the spool block serving both rams. The spool that the single acting lift rams connect to has a second port that is blanked off so I assume the lift rams can be configured as double acting??

If youve got a mechanical bucket tip then a Ollek says you could dispense with the Husco spool block altogether and just use the quadrant lever to raise and lower the loader. Reconfiguring all the pipework may cost you a few bob so it may be cheaper and possibly easier to get the Husco spool working if its just a case of swapping pipes/ports?

One of the pictures you posted shows 4 pipes coming off the spool block. Have you got separate pipes going to each lift ram? If so these would both need to conndcted to the same port unless there is an internal connection inside the spool valve??
'66 880 Selectamatic rat.

User avatar
ollek
Posts: 3479
Joined: Tue Apr 10, 2012 1:20 pm
Location: South West Finland

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by ollek » Fri Aug 10, 2018 9:40 am

Philedge, the OP wrote "The loader is the simple type single ram each side, power up, gravity down, mechanical release bucket. He has also said that the loader will raise using the hydraulic main lever, not the lever on the Husco valve. The feed from the 3-way valve is connected to the Husco valve and the feed to the single acting loader cylinders looks to be connected from the Husco valve, and this is all wrong, you should not feed single acting cylinders using a double acting valve as it does not make any sense to divert oil to a separate return line when you lower the loader. It also looks that a return line is connected to the transmission oil filler plug and this will eave the gear box without lubrication from the by pass valve. Because of this I have said that the Husco valve has to be removed and the feed hose from the 3-way valve has to beconnected via a T-connector to the single acting loader cylinders. I have said all tis in my previous posts, but I have now repeated it because it looks like these facts has not been understood. One more time, the loader has single acting lift cylinders and no bucket control. A loader like this shall be operated with the tractor hydraulic lever. NO extra valve is needed and must not be connected into the loader cylinder circuit. The Husco valve must be a left over from the tractor a time when the tractor was equipped with a double acting lift cylinders and bucket control. And, there must be a vent of some kind on the piston rod side so that the air can get in and out, if the piston diameter is bigger than the piston rod diameter. This type of cylinder can also be used as double acting. A single acting cylinder with the piston rod and piston of the same diameter will not need a vent. Both types are used on front loaders.

philedge
Posts: 133
Joined: Sun Dec 03, 2006 11:27 am
Location: Chester UK

Re: Newby - Looking for help on hydraulic issues 880A 1968

Post by philedge » Sun Aug 12, 2018 10:53 pm

Ollek, philedge wrote " if you've got a mechanical bucket tip then a Ollek says you could dispense with the Husco spool block altogether and just use the quadrant lever to raise and lower the loader."

Ive read everything you and the OP have written and commented positively on what you have said, as above, but alternative solutions MAY work and MAY be more suited to the OPs needs- thats for the OP to decide.
'66 880 Selectamatic rat.

Post Reply

Who is online

Users browsing this forum: No registered users and 22 guests