Hydronic pump robbing starting power

Bab4020gas · Jun 23, 2014

Hello can anybody tell me why I have to screw the valve(?) down on top of the front hydraulic pump on my 4020 gas to allow motor to turn over fast enough to start. And what to do about it thank you

buickanddeere · Jun 23, 2014

That is a destroker screw to take the pump out of stroke so it doesn't use starter motor power to build hydraulic pressure.
Your tractor has a high pressure hydraulic
The destroker screw is a much better and classier solution than going fiddly twiddly with the steering wheel.

Robert Major · Jun 24, 2014

Hi
totally get what you mean about the fiddle with
steering wheel deal. Got a 8430 here for a
customer. The motors totally shot/ tractors
heading to a wreckers as it needs more either,
than fuel to start and the blocks cracked between
the sleeves, plus 7200 hard hrs on the rest.
If it fires it better run first time as it"s so
sick it won"t turn over to start again till the
system bleeds down again. even turning the wheel
side to side don"t help much on this one.
Regards Robert

buickanddeere · Jun 24, 2014

(quoted from post at 12:48:52 06/24/14) Hi
totally get what you mean about the fiddle with
steering wheel deal. Got a 8430 here for a
customer. The motors totally shot/ tractors
heading to a wreckers as it needs more either,
than fuel to start and the blocks cracked between
the sleeves, plus 7200 hard hrs on the rest.
If it fires it better run first time as it"s so
sick it won"t turn over to start again till the
system bleeds down again. even turning the wheel
side to side don"t help much on this one.
Regards Robert

Odds are if the operators had used a block heater instead of ether. And left the injection pump at factory settings. The tractor would have lots of life and value to this day.
Assuming this is a 1975-1978 vintage 8430 ? Or the 2006-2009 8430 ?

Robert Major · Jun 24, 2014

Darn your good, the only bit you missed after the
horse power update for towing a huge air seeder,
was the fact he added a 12ft Dozer blade. while it
was only just worn out, from the seeder L.O.L, and
drove it like a D 10 Cat pushing huge trees.
I didn"t need to measure bore wear, it wasn"t far
off being able to knock a 7/16 wrench in the
cylinder, and it disappear down the piston side
into the oil pan.
Have heard that 4000 hours is the point where
these all started to crack blocks and blow heads
if used pulling hard. 7200hrs seems good to me for
the abuse it"s had with no overhaul and original
30 series motor, with about 75hp over from what he
hasn"t told me "wink".
Regards Robert

Hydronic pump robbing starting power

Bab4020gas

New User

buickanddeere

Well-known Member

Robert Major

Well-known Member

buickanddeere

Well-known Member

Robert Major

Well-known Member

Similar threads