I have changed the hydraulic fluid in my M4700 tractor before with no problems but this time I let it sit draining for three hours. The reason I drained was that this past winter my hydraulics would not work when the ambient temps were below zero. After filling with oil I have no steering or hydraulics. I have run the tractor three or four times for approx 30 minutes total run time with no luck. In fact at the start the steering wheel was basically locked because of no pressure now it turns freely but won't try to move the wheels. I have loosened a pressure line on the hydraulics pump and have no fluid there. I am sure that the pumps have just bled down but how do I prime them? Was there a sump screen that I should have cleaned before I dumped 40 some qts of oil in?
M4700 hydraulic bleed
- Thread starter Brad Schwarting
- Start date
North Idaho Wolfman
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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Check the large suction line for seeping leaks, there is 5 O-rings that can leak or even a cracked line.
Did you change both filters?
It's either not sucking (bad pump) or Suction lines or fittings are letting air in.
That model came with 2 different pump styles.
You might need to pull the pump and have it tested/rebuilt, or worst case scenario replaced.
One trick to get it going (temp fix) is to burp the filters, and burp the suction line, and worst case, prime the pump by removing the high pressure line and fill pump full of fluid allowing it to drain back a few times, reinstall line and fire it up.
Did you change both filters?
It's either not sucking (bad pump) or Suction lines or fittings are letting air in.
That model came with 2 different pump styles.
You might need to pull the pump and have it tested/rebuilt, or worst case scenario replaced.
One trick to get it going (temp fix) is to burp the filters, and burp the suction line, and worst case, prime the pump by removing the high pressure line and fill pump full of fluid allowing it to drain back a few times, reinstall line and fire it up.
There is no seepage or leaking on any of the lines to or from the pump.
I had run the tractor prior to draining for a couple of hours to get the oil warmed up.
I don't have any way to get the rear higher than the pump to burp it but I will try to remove the pressure lines and filling.
This will be when it warms up out and quits snowing since I am working in the Big Sky Garage.
I had run the tractor prior to draining for a couple of hours to get the oil warmed up.
I don't have any way to get the rear higher than the pump to burp it but I will try to remove the pressure lines and filling.
This will be when it warms up out and quits snowing since I am working in the Big Sky Garage.
North Idaho Wolfman
Moderator
Staff member
Lifetime Member
Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
lugbolt brought up a good point, you can put pressure on the sump to get it to force oil into the pump, it's a risky move because too much pressure and you could just pop a seal ring out.
I only recommend using a blower to add pressure or very well regulated compressor at only a couple pounds.
I only recommend using a blower to add pressure or very well regulated compressor at only a couple pounds.