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Thread: one for the db members, why have a db 990 got an A after it?

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    Senior Member ford 7840's Avatar
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    one for the db members, why have a db 990 got an A after it?

    hi any body know why a david brown 990 i looked at today has db 990A on the vin plate, i have seen odd ones that have an A after the model number but what do the A stand for ? or why has any david brown got an A after the model number

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    Senior Member T P's Avatar
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    Re: one for the db members, why have a db 990 got an A after it?

    I know the 990 had two sizes of engine,the one with the conventional dipstick is I think the large engine, the one with the dipstick you put oil in was the small engine.Perhaps it has something to do with that? There as only a few hp of difference in the engines,we have one of the small engine ones but I've seen the other ones around.

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    Re: one for the db members, why have a db 990 got an A after it?

    The ''A'' denotes livedrive-2 stage clutch. ''B'' designation denotes single clutch models.

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    Re: one for the db members, why have a db 990 got an A after it?

    Apologies to the OP if he knows all about 2 stage clutches and livedrive but to explain if he doesn't then it means that the clutch pedal has 2 stages of movement. Depress it half way down (-ish) and it disengages the transmission, i.e. the tractor stops going forward or backwards but if there is a P.T.O. implement attached then power to that machine is maintained. If you depress the clutch pedal to the 2nd stage then the P.T.O. stops as well. And indeed you have to depress the clutch pedal through the 2nd stage to be able to engage the P.T.O.

    Prior to livedrive, tractors just had a single stage clutch but problems were encountered when say baling and you wanted to momentarily stop forward motion of the tractor to get through say a lump of hay in the swath. But if you depressed the clutch then the baler stopped as well as the tractor. The alternative was an engine on the baler but then the tractor driver didn't have complete control of the baler.

    The worst possible scenario was when using an Aliic Chalmers roto-baler with a non-livedrive tractor, say an old Fordson Major. You had to stop forward motion every time the baler tripped and completed a bale. But when you dipped the clutch the baler stopped as well !!! So you had to take the tractor out of gear, finish the bale, and engage gear again !!!! Been there, done that, got the T shirt.

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    Re: one for the db members, why have a db 990 got an A after it?

    Quote Originally Posted by zaza View Post
    Apologies to the OP if he knows all about 2 stage clutches and livedrive but to explain if he doesn't then it means that the clutch pedal has 2 stages of movement. Depress it half way down (-ish) and it disengages the transmission, i.e. the tractor stops going forward or backwards but if there is a P.T.O. implement attached then power to that machine is maintained. If you depress the clutch pedal to the 2nd stage then the P.T.O. stops as well. And indeed you have to depress the clutch pedal through the 2nd stage to be able to engage the P.T.O.

    Prior to livedrive, tractors just had a single stage clutch but problems were encountered when say baling and you wanted to momentarily stop forward motion of the tractor to get through say a lump of hay in the swath. But if you depressed the clutch then the baler stopped as well as the tractor. The alternative was an engine on the baler but then the tractor driver didn't have complete control of the baler.

    The worst possible scenario was when using an Aliic Chalmers roto-baler with a non-livedrive tractor, say an old Fordson Major. You had to stop forward motion every time the baler tripped and completed a bale. But when you dipped the clutch the baler stopped as well !!! So you had to take the tractor out of gear, finish the bale, and engage gear again !!!! Been there, done that, got the T shirt.
    Preaching to the Choir . Our old B250d has a single stage. When trying to bush hog the old field and you hit a section of heavy clover you got to clutch in, shift out of gear, clutch out to allow the bush hog to catch up, throttle down, clutch in, wait for bush hog to stop turning so you can shift into 1st without a lot of grinding, throttle up then let out the clutch.

    "Some fun, huh Bambi"

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    Senior Member ford 7840's Avatar
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    Re: one for the db members, why have a db 990 got an A after it?

    Quote Originally Posted by agrimax View Post
    The ''A'' denotes livedrive-2 stage clutch. ''B'' designation denotes single clutch models.
    Thanks agrimax for your help once again, and thanks to ever one for the help, yes it is a live drive model so that makes sense,

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