is it a white or red tractor? And has it got a big plastic control pannel on rhs of cab or look older/basic?
There is a switch over valve between depth / height and external control which may be the problem with the lift IMPORTANT:to change it from depth to lift etc the lift lever needs to be all the way to lift so you can hear the pump working against the releif valve or you can break the selector! , if not it could be a stuck hold valve which is under the cab to the right hand side, once he cap is off a piece of dowl and a mallet usually frees them.
if it’s a red only with the plastic dash there may be a combining lever for the hyd pumps ( some tractors but not all had twin pumps) if it has twin pumps you can combine the flow to power higher flow machines or separate them to have good lift and good external so you can lift machine and work hyd services to machine at same time on the field headland. If it’s in combined mode it cause strange things with the lift. story if I’m a bit vague is 15+ years since I worked with a 94 series!
if you change the back end oil there is a pressure filter on the rear axle but the suction side also has a (washable) screen in the bottom of the gear box that often gets forgotten and can cause probs.
this diagram/instructions may be slightly different to the controls you have depending on tractor year but the valve chest and setting should be the same:
Selectamatic Hydraulic System
DBTC.CO.UK
A schematic diagram of the David Brown Selectamatic Hydraulic System. Also a guide to repairs and some other useful tips. The DBTC are indebted to Mr....
the David Brown tractor club forum (all 94 series tractors are David brown just some are painted in case colours as case took over) is very good for info but don’t expect any off topic talk or banter, stiff upper lip old boy!
DBTC Forum - David Brown Tractor Forum
DBTC.CO.UK
I can’t remember the bonnet apart from if the springs/linkage go they are a bitch to change and as a 13 year old shutting yourself fingers in it breaks them ?
he best places for parts are:
Home | David Brown Parts Ltd
WWW.DAVIDBROWNPARTS.COM
Home page - Worldwide Parts for David Brown Tractors
Untitled Page
WWW.BARCLEYWILLIAMS.CO.UK
Hope that’s some help, I may be able to help more with a pic of the controls to the rhs of the Seat.
as to oil, engine is super universal tractor oil (15w30 or 40), for the back end some will tell you hi-tran (cases own oil) others will say same as the engine poss depends on year and gear box option fitted