David Brown 996 timing marks

[Scu6499]

I’m in the process of taking the crank out as the big end shells are gone on No. 1 cylinder. When I took timing gear cover off I checked for timing marks on gears and with No1 at tdc the marks on crank cam and injection pump gear were about where I expected them to be but none of them lined up with the marks on the intermediate gear. Do any of you have a workshop manual to check or am I missing something. Thanks

 

[Boohoo]

This is from the workshop manual

It says to turn the engine until the marks line up, it doesn't say anything about having No.1 at tdc.
You don't need the crank out to replace the big ends, or is the crank damaged and needs ground?

 

[Mur Huwcun]

You could be turning it all day to get the marks all back in line as all the gears have different number of tooths. When setting up you remove the intermediate, line marks up and slide idler or intermediate gear back in

 

[Scu6499]

Thank you both for that I did wonder if that was the reason as the intermediate only has 39 teeth not a even number. And yes the crank is well chewed on No1 journal hopefully it can be ground. Thanks again.

 

[Mitchell1390]

Hi all, I've got a few issues with my David Brown 1390 4wd there's a few things need attention an all help would be very much appreciated as the tractor was my father's an he sadly passed away I'm taking on the farm an need some help repairing my 1390.

1. Oil dripping down onto back wheel rim

2. Brakes are banjaxed completely tried bleeding an replaced 2 cylinders under dash but you have a reasonable pedal but no brake ( if you put hand brake on it holds fine) there is literally no brakes!

3. Oil leaking at front axle out threw knuckle on the end of the half shaft.

4. Last but not least there's an oil leak at back left hand side just below cab above where the lift arm pins on you would see it dripping down then when she is warm it runs down onto lift arm.

Many thanks sorry for so much writing but my father was one of the last David brown mechanics in are part of the country an now he's gone everyone thinks I should know an no one offers to help unless it's a massey Ford etc.. Help very much appreciated many thanks Mitchell!

 

[MF-ANDY]

You could be turning it all day to get the marks all back in line as all the gears have different number of tooths. When setting up you remove the intermediate, line marks up and slide idler or intermediate gear back in

This. A "hunting tooth" i believe, to stop the same teeth meshing every revolution and lessen wear.

 

[Bald n Grumpy]

Hi all, I've got a few issues with my David Brown 1390 4wd there's a few things need attention an all help would be very much appreciated as the tractor was my father's an he sadly passed away I'm taking on the farm an need some help repairing my 1390.

1. Oil dripping down onto back wheel rim

2. Brakes are banjaxed completely tried bleeding an replaced 2 cylinders under dash but you have a reasonable pedal but no brake ( if you put hand brake on it holds fine) there is literally no brakes!

3. Oil leaking at front axle out threw knuckle on the end of the half shaft.

4. Last but not least there's an oil leak at back left hand side just below cab above where the lift arm pins on you would see it dripping down then when she is warm it runs down onto lift arm.

Many thanks sorry for so much writing but my father was one of the last David brown mechanics in are part of the country an now he's gone everyone thinks I should know an no one offers to help unless it's a massey Ford etc.. Help very much appreciated many thanks Mitchell!

1 and 2 could be connected ,if the pinion shaft seal is leaking oil can get onto brake linings and drip out of the bottom of the hub and onto wheel rim
When you need parts go to barcley Williams, good source for parts and advice they will have forgotten more about a db than most of us ever knew

 

[Alchad]

Hi Mitchell, I've got the same tractor. Regarding the brakes, there are also individual slave cylinders on each back wheel so you probably need to fits new seals or cylinders there as well. Depending on how good a mechanic you are it can be a tricky job, I did it a month ago from underneath, not fun!, I've since seen someone post that it a lot easier taking the back wheels off first. Also remember you have to use LMH brake fluid.

Can't really help re the leaks I'm afraid, but there are 2 or 3 excellent FB groups with some very clued up people, if you don‘t find the answer on here, try them.

Regards

Alchad

 

[Mitchell1390]

Hi Mitchell, I've got the same tractor. Regarding the brakes, there are also individual slave cylinders on each back wheel so you probably need to fits new seals or cylinders there as well. Depending on how good a mechanic you are it can be a tricky job, I did it a month ago from underneath, not fun!, I've since seen someone post that it a lot easier taking the back wheels off first. Also remember you have to use LMH brake fluid.

Can't really help re the leaks I'm afraid, but there are 2 or 3 excellent FB groups with some very clued up people, if you don‘t find the answer on here, try them.

Regards

Alchad

Very grateful for help it's much appreciated!

 

[Bald n Grumpy]

I use hydraulic oil as a substitute for LHM fluid, goes fine in clutch and brakes on our 3 dB's