885 hydraulics pulsing

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tfmyorkshire
Posts: 5
Joined: Mon Aug 19, 2013 3:54 pm
Location: Skipton

RE: Hydraulics question

Post by tfmyorkshire » Mon Aug 19, 2013 3:57 pm

Hi my 885 arms are pulsing all the time at what ever height and when the tractor gets turned off the arms drop straight down , has any body had or heard of such a problem

Guest

RE: Hydraulics question

Post by Guest » Mon Aug 19, 2013 5:11 pm

The hold valve in the chest is sticking open.

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tfmyorkshire
Posts: 5
Joined: Mon Aug 19, 2013 3:54 pm
Location: Skipton

RE: Hydraulics question

Post by tfmyorkshire » Mon Aug 19, 2013 5:49 pm

Thanks for info power rabbit so where do I find the chest to find hold valve ?

John_Allen
Posts: 1894
Joined: Sat Dec 31, 2005 3:59 pm
Location: Cumbria UK

RE: Hydraulics question

Post by John_Allen » Mon Aug 19, 2013 6:25 pm

There is a FAQ that should help:

http://www.dbtc.co.uk/index.php?module= ... ew&pid=182

Also search for hold valve, there are several topics about servicing them. The Selectamatics are all much the same (from 770 to 990/5/6), so it won't matter if the question is about a different model.

http://www.dbtc.co.uk/index.php?name=PN ... hold+valve

As an aside, when using the search section, open the resultant topics in a new tab (right click on the topic and select "Open in new tab" or, when you have looked at the topic and gone back to the search, you'll have to start the search again!

I have split this topic from another one as it will be easier for others to see (and it will not get mixed with another subject!).

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tfmyorkshire
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Location: Skipton

RE: Hydraulics question

Post by tfmyorkshire » Mon Aug 19, 2013 6:37 pm

Thanks for that John I know where am looking now :lol: :lol: :lol: :lol:

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oily
Posts: 104
Joined: Tue May 10, 2011 10:31 am
Location: northyorkshire

RE: Hydraulics question

Post by oily » Mon Aug 19, 2013 7:14 pm

it could be the lift ram seal to

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erkki
Posts: 2032
Joined: Sun Apr 09, 2006 12:02 pm
Location: North Finland

RE: Hydraulics question

Post by erkki » Mon Aug 19, 2013 7:17 pm

it could be leaky dump valve also.

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tfmyorkshire
Posts: 5
Joined: Mon Aug 19, 2013 3:54 pm
Location: Skipton

RE: Hydraulics question

Post by tfmyorkshire » Tue Aug 20, 2013 4:39 pm

I took out hold valve and lost little ball out of it so problem there but now worse so dose any body know if the small ball can still be got ?

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ollek
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Location: South West Finland

RE: Hydraulics question

Post by ollek » Tue Aug 20, 2013 6:04 pm

Any steel ball with diameter 1/8" will do the job. The ball is acting as a non return valve for the TCU pressure. There shall be a round disc with 3 holes between the ball and the spring. This disc is there to prevent the ball flying around and not sealing when TCU is used.

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tfmyorkshire
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Location: Skipton

RE: Hydraulics question

Post by tfmyorkshire » Tue Aug 20, 2013 6:30 pm

There was a disk but only had one hole in the middle of it could this not seating properly be any thing to do with arms pulsing

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ollek
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Location: South West Finland

RE: Hydraulics question

Post by ollek » Tue Aug 20, 2013 7:01 pm

The disc and the ball in the hold valve has nothing to do with the missing hold position that is giving the "pulsing" when the tractor is running and the selector is in the center (hight) position. The 3-point lift will lift, hold and lower normaly even without these parts, but the TCU will not work. Please assemble the valve and put the dump valve in place without the cover plate. There is a small hole in the side of the dump valve (just under the plate) and there will be an oil leak from this hole if the dump valve O-rings are leaking.

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