[JackandJill]

Hi everyone 

Feel a bit daft, but looking to buy my first tractor, we have about 20 acres a bit of slope and rather rough as not been cared for a while.  So thinking might need a fair sized machine and looking at an old David Brown 990, seem to be a few about and thinking it'll be about right.

However, I'm a bit confused on machinery to use, is there a standard size of the linkage, or does each manufacturer have a set standard to follow and how do I check or know if the machinery is right?

thank for your help

[oor wullie]

There are 3 standard sizes of linkage cat 1, cat 2, cat3.
Category 3 is massive and for tractors and equipment smallholders would never consider.
Cat 1 tends to be for tractors up to 40hp, cat 2 for over 40hp.

Basically it is the diameter of the pins on the implement that fit into the ball on the link arms of the tractor.

Some implements have both cat 1 and cat 2 pins on them, if not then on most implements you can change the pins so the linkage on a DB990 should be good for anything you are likely to use it for.

The pto shaft is a standard size (except for on grey fergies) so don't worry about that.

I would consider a DB990 a good choice (but I like tractors of that vintage).  But bear in mind that you are looking at a machine that could be 50 years old, good ones should still have another 50 years life in them but you should expect to have to replace the odd oil seal etc. here and there.

If you are doing much work with the pto then try to find one with a live pto (or double clutch - basically you can work the pto independently of the drive) which was an option on the 990.
I know nothing about hydraulics (as my tractor has very primitive hydraulics) but someone who knows about these things may advise you on what to look for and what the difference between the selectamatic and instamatic versions of the 990 are.

I have often fancied a David Brown if only so that I can tell car lovers that I have a DB9... (90)........  David Brown owned Aston Martin for a while and that is why Aston Martins are all named DB...

[JackandJill]

thank you so much for the details, I guessed it would be a bit of a learning curve but your answer has helped a lot. 

didn't realise that I could own a real DB 

[Cosmore]

I can recommend a DB 990 Implematic, excellent machine if you get one in good working order, just make sure the dual clutch is working ok.  I would avoid DB 990 Selectamatic, they had problems. I had a (Hunting Pink - pre. the Case white version) 990 Implematic for years with hydraulic foreloader that had been converted to positive hydraulic bucket up/down, much more useful than the gravity release. It did everything I wanted with ease. Spares are available so no real problems there, as are the spares and workshop manuals (useful for identifying parts), there is also the David Brown Tractor Club. The only problem you may encounter is the price - This tractor is a favourite with the preservation/showing fraternity who push the price up, mine was sold on by the owner after me for well over a £1000, ten years ago!
I currently have a MF 575, at 66HP it's got a bit more 'grunt'.
Good Luck.