pre-implematic hydraulics on 950

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testbed
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Location: Perthshire

pre-implematic hydraulics on 950

Post by testbed » Mon Nov 30, 2015 9:29 pm

Can anyone explain the changes on the hydraulic levers on the pre implematic 950 that I have when compared to the 900 model? On the 900 there are (according to the instruction book I have) two hyd working levers, one for up,down and hold and another to activate the TCU which is then operated as I understand it by adjusting the knurled pressure adjuster wheel on the front of the casing.

On my 950 however there is only one lever and one connecting rod, operated from the wing like the 900. There is no obvious indication that there was ever a second lever but it is possible I suppose.

On the front of the axle the knurled adjuster wheel is in place with alongside it what appears to be some sort of pivot with a missing or broken off part that seems to enter the casing next to the pressure wheel, and related by a short rod external to the casing and in line with it to a lever about an inchand a half long. the lever has nothing attached but has a hole to allow connection of a rod perhaps.This is leading me to thinking that a connecting rod or similar is missing?

My questions are,
1/ What does the second TCU lever on the 900 and presumably the broken parts on my 950 actually do inside the axle casing that presumably activates the TCU?

2/ what parts am I likely to have missing from my linkage controls if any? How does the 950 not require that second lever?

3/Can someone explain the mechanics of the TCU, not the operation as I understand that it is varying lift pressure transfering wheight onto the driving wheels, but what is actually happening inside the casing to cause this to happen?

If you are all as helpful with this as you were with my last question then I am about to learn a lot!

Guest

RE: pre-implematic hydraulics on 950

Post by Guest » Mon Nov 30, 2015 10:44 pm

The 950 hydraulic system is better explained by means of the chart and text in the I&T manual, this will be more useful to you than anyone trying to explain it here. I have a PDF file of the section that I can send to you if you PM me your email address, you can then download it, print it off, read and digest it at your leisure.

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db950man
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Post by db950man » Tue Dec 01, 2015 8:41 am

Powerabbit is right, it is best to look at a chart to interpret the controls. However, I will attempt to explain.

The 950 has only one quadrant lever to operate the hydraulics. The slot in which it moves is divided towards the front. The right hand part is the lift position and the left is the TCU position. The rearward is to lower your linkage. You should have two rods coming from the quadrant. One goes to the control valve, which, by what you say is present on your tractor. The other goes down to where you say it appears there is a missing lever beside the TCU knob.

You need to obtain or make up a rod and relay lever to attach to the tractor in order for the TCU to function. I hope this helps and good luck with your tractor!

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db950man
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Post by db950man » Tue Dec 01, 2015 8:51 am

I should also have explained the TCU operation; When one lowers a soil engaging implement such as a plough, the lever is brought backwards to allow the implement to drop, the rate of drop being adjustable by means of an adjustable stop. To operate TCU one then moves the lever forward keeping it in the left hand part of the slot. TCU then applies a slight lifting force to the implement, which isn't enough to raise it but enough to improve traction. To start with the knob is screwed completely anticlockwise and adjusted as required.

If the going gets tough and wheel slip starts, one can screw the knob clockwise a 'click' at time until traction is restored. this operation increases the lift force on the implement. There are adjustments to both the top link and levelling lever, which are explained in the handbook to improve the performance whilst operating with TCU, but these are 'trial and error' depending upon the implement being used.

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mistermcgregor
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Re: RE: pre-implematic hydraulics on 950

Post by mistermcgregor » Tue Dec 01, 2015 8:59 am

[quote="Powerrabbit"]The 950 hydraulic system is better explained by means of the chart and text in the I&T manual, this will be more useful to you than anyone trying to explain it here. I have a PDF file of the section that I can send to you if you PM me your email address, you can then download it, print it off, read and digest it at your leisure.[/quote

There are people who can address the original posters queries. Some of the questions asked will not be answered from a PDF file scan of a DB I&T manual.
There are people who fully understand the intricacies of the DB 900 and 950 hydraulic systems and to suggest otherwise is an insult.

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testbed
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RE: Re: RE: pre-implematic hydraulics on 950

Post by testbed » Tue Dec 01, 2015 8:06 pm

Thanks for that everyone, I will post you Powerrabbit that will be very helpful I'm sure.
It will probably not be long before I am back for more!

Although I seem pretty clueless about my DB 950, I do have a fair understanding of mechanical subjects generally but we had MF tractors from about eleven years old and later a DB 1412 (Nov 1978) and a DB 1210 (Feb1982), before moving on to Renault tractors in 1982.The DB 1210 we kept until we stopped farming in 2003 and was used regularly for general transport duties, wish I'd kept it now! Twenty three years completely reliable apart from one clutch replacement and tyres and 5900 hours. Oh and lots of oil grease and filters!

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mburns
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Post by mburns » Tue Dec 01, 2015 10:00 pm

Mistermcgregor please could you show me where Powerrabbit says no one on here can explain the workings of the 900 or 950 hydraulic system
I am sure he just said it maybe easier for the chap to understand how it works by reading the manual
your post was again no use to anyone
DB 900 1958
DB 1394 4wd 1988 com
Email. Db900@me.com

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mistermcgregor
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Post by mistermcgregor » Tue Dec 01, 2015 11:14 pm

mburns if you read the posters questions you will realise that the PDF file from the DB I&T manual does not contain all the answers or describe the mechanical differences between the 900 and the 950 hydraulic system.

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mburns
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Post by mburns » Tue Dec 01, 2015 11:34 pm

I understand that but he only refers to the workings on the 950 and despite not fully answering all his questions , he is trying to help !!
I fail to see where he states no one on here is capable of explaining the intricacies of the hydraulic system , testbed seems happy to receive the pdf

You are the only one insulting , I fail to see where you have attempted to help at all , I thought this club and forum was to help DB owners , I will read through your posts maybe I have missed something
Regards Mburns
DB 900 1958
DB 1394 4wd 1988 com
Email. Db900@me.com

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mistermcgregor
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Post by mistermcgregor » Wed Dec 02, 2015 4:52 pm

Mburns. When you have scrutinised my contributions to this forum would you please substantiate any technical or other information that is incorrect.

Scooby
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Post by Scooby » Wed Dec 02, 2015 5:17 pm

Play nicely please !
ImageImage


Three is twee, four does snore, but 6 just clicks........Scooby

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case-ih1594
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Post by case-ih1594 » Wed Dec 02, 2015 5:48 pm

Hi, I think the danger here is there are increasingly fewer people (each year) who are able to accurately answer technical questions on older machines. The best thing is to get an instruction book (which are fairly common) and read up the PDF file that Powerrabbit kindly offered to send.

An original workshop manual would be good if one could be located and a spare parts book would also be useful to see which parts are missing.

To be fair to the people who answer questions it would be difficult and time consuming (as PR said) to try to answer such a question as "Can someone explain the mechanics of the TCU" in an internet forum. It would take ages and most likely be subject to criticism or opinion. The DBTC forum and its contributors must have their limitations

8) 8)

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mburns
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Post by mburns » Wed Dec 02, 2015 6:26 pm

Case-ih1594
Spot on that's saved me lots of one fingered typing time
The rabbit and others may not get it right all the time but they do try ,even when occasionally they may be a little bit well you know
Hello David hope you are well , I will play nicely as always Merry Xmas :-)
DB 900 1958
DB 1394 4wd 1988 com
Email. Db900@me.com

Scooby
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Joined: Tue Jan 03, 2006 8:16 pm
Location: Warwickshire

Post by Scooby » Thu Dec 03, 2015 5:40 pm

mburns wrote:Hello David hope you are well , I will play nicely as always Merry Xmas :-)
Yes thank you Martin, quite well here thank you. And hope you are as well.
ImageImage


Three is twee, four does snore, but 6 just clicks........Scooby

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testbed
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Post by testbed » Thu Dec 03, 2015 6:46 pm

Well what an interesting introduction to DB club forum, I have enjoyed the responses from all of you even if some had little to do with my question!

I accept entirely the comment about instruction book and workshop manual, which I am and have tried to obtain, those of you who know early 950s will realise, as I am beginning to do, that they are a bit of a mixture of a 900 and a 950 implematic, combined with a few unique parts of its own. That mixture seems to vary between tractors and the books for the early 950 model,which were produced for anly about a year I think, are almost non existent. I have a 950 implematic workshop manual now and will probably need to buy a late 900 one two, and then make up the rest with all your help. Thanks I'm having fun.

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