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DB 780 or 885

Posted: Tue Nov 15, 2016 11:01 am
by pacer204
I have finally come to my senses and have decided that I want to add a David brown as company for my MF35x.

Donkeys years ago we used to own a 780 narrow but I cant trace it. I have seen several 885's and a 780. All I want is a straight tractor that I can tinker with but is essential sounds and running for moving timber about and topping in the summer.

My questions is what sort of money should be looking at for either and which is the better model? I guess there are less 780's than 885's, but there maybe more parts for 885's? Either way, I would welcome some advice.

I have seen a fairly original 780, but the front end is a bit wobbly and it needs a new pivot pin and bushes - I can't seem to find the pivot pin anywhere.

780 vs 885! (I'm not considering the narrow ones by the way).

Any advice would be appreciated.

Thanks in advance.

RE: DB 780 or 885

Posted: Tue Nov 15, 2016 11:26 am
by ollek
The gear box in a 780 can be 6-speed (2 gear levers) or 12-speed (3 gear levers), non synchronized. The gear box in a 885 is always a 12-speed with gears 2 and 3 synchronized and 2 gear levers.

RE: DB 780 or 885

Posted: Wed Nov 16, 2016 2:28 pm
by pacer204
Thanks for the info. I've gone for the 780, hopefully collecting her next week.

She going to need a full service, whats the best engine and rear end oil to go for?

Thanks

Richard

RE: DB 780 or 885

Posted: Wed Nov 16, 2016 2:41 pm
by ollek
The easiest way is to use STOU (Super Tractor oil Universal), SAE 10W-30 (or 15W-30), GL4, in both engine and Gear box/hydraulics and air filter. The wheel reductions call for SAE 80W-90 or SAE 90, GL4. Use only mineral oil. Do not use synthetic or semi synthetic oil. The oils and the classifications mentioned fulfils all requirements stated by David Brown.

RE: DB 780 or 885

Posted: Sun Nov 20, 2016 3:02 pm
by richbug
Anyone with a lathe and drill press can make a pivot pin, certainly cheaper than what it would be from Case.

RE: DB 780 or 885

Posted: Mon Nov 28, 2016 3:38 pm
by pacer204
Ok, so thanks for the advice so far.

I finally had some time to have a good look around the DB780 on Saturday. She starts well, but runs a bit rough when at higher revs. Anyway the throttle was a bit sticky and she'd only idle at 1100rpm! On inspection some clown has bent the throttle arm on the Injection Pump and it was hitting the stop mechanism. That got removed, straightened and put back and she now idles at 750rpm. The only problem is that the throttle cable has now broken and kinked at the other end. I have just ordered a replacement for those nice chaps at Barclay Williams. The Agriline one looked too cheap!

Next, after running her for a while I put an oil pressure gauge where the sender usually sits and had a constant 40 -45 psi. I guess that will do. I then drained the engine oil and removed the filter. I will be removing the sump and clean the pick up gauze before I re fill her - that's for later this week. I have also started to drain the final drive boxes of the black nasty tar stuff. It comes out so slowly, I thought I'd leave it for a few days to get itself out.

I've ordered my new Hydraulic filter and gasket, and oil from Rye Oils - very helpful.

Whilst looking around on Saturday I notice that front part of the tractor, forward of the engine is 2 inches deep in mud! Not oily stuff, but actual soil, it seems like good compost! Anyway, thats been dug out and so has the crap in the bottom of the oil filter.

My plan is to get all new fluids and filter back in before I start spending money in the wrong places.

I do have question, I drain the coolant, its wasn't that bad, but for some reason I dont seem to be able to get much back in. I think it should take 9 litres but so far only three have gone back in before the rad was full. Any thoughts?

More again at the end of the week.

RE: DB 780 or 885

Posted: Mon Nov 28, 2016 5:36 pm
by ollek
It is possible that all coolant have not drained out. Disconnect the lower radiator hose and open the tap on the right hand side of the engine block. Use a piece of string to clear both the engine and the radiator drain taps.

RE: DB 780 or 885

Posted: Wed Nov 30, 2016 8:59 pm
by bedwards1966
It's very possible that dirt/rust flakes could have blocked the taps while draining and so the system's still half full.
Sometimes cooling systems can airlock as they're filled (always pour in slowly) but I don't recall it ever happening on a DB, though I've never worked on an 885 or 780. I often give radiator hoses a good squeeze a few times to get coolant moving and help displace air if I've any doubts when refilling.