john deere 27 c won't do zero turn

dmason320 · Oct 3, 2018

Hello I just bought a jd 27c zts and each track will move forward and back but if i try to go forward with one and back with the other it does nothing. It doesn't even make a sound like its trying too. This was a rental machine and I'm wondering if this action was disabled somehow?
Any help would be appreciated!

uffex · Oct 3, 2018

Good day
The machine should counter rotate unless it has wide track pads on a sticky surface, maybe get the pressures checked.
Kind regards
Uffex

dmason320 · Oct 18, 2018

pressures seem good. I did however find a pressure sensor broken off on the bottom of the propel linkage control box.
there are two of them, one on each side, When I look up the number it is linked to the travel alarm electrical harness.
would this be the reason it does not counter rotate?

Dave Neubert · Oct 18, 2018

Check pressures then rotatory swivel

mg2361 · Oct 19, 2018

Pressure switches in the travel pilot circuit only affect the travel alarm and "two speed" operation, not power.

dmason320 · Oct 21, 2018

can I test the pressure right at the auxillary ports on the dipper?

bmckenzie · Oct 21, 2018

dmason320 said:
can I test the pressure right at the auxillary ports on the dipper?

I think you need to test at pumps as I believe each travel motor runs off a seperate section of the pumps

mg2361 · Oct 21, 2018

Check at the pumps like bmckenzie said. Checking at the couplers creates to much opportunity for errors (control valve, circuit relief valves, etc). There should be a plug on the fittings for the high pressure hoses that can be used for testing pressures. Picture is of a 35C. 27C is the same.

dmason320 · Oct 21, 2018

Thanks this is great info! I am going to order a pressure meter off the internet and going to get a hose and fitting made up to fit on my machine and I'll get back to this post. by the way I can't find the main relief valve does anyone have an idea where it is?

mg2361 · Oct 22, 2018

Here are the locations.

bmckenzie · Oct 22, 2018

dmason320 said:
Thanks this is great info! I am going to order a pressure meter off the internet and going to get a hose and fitting made up to fit on my machine and I'll get back to this post. by the way I can't find the main relief valve does anyone have an idea where it is?

When at the hose making place get the test tee's in the 2-3 sizes that fit your machine and the gauge on a 8 foot long hose so you can see pressures as you run and work the machine, helps with the diagnosis of problems.

dmason320 · Oct 28, 2018

I just received the gauge and am going to get a hose made up this week! I was just going to take the plugs out of the tees on the 3 pumps one at a time and run the propel forward and back and then counter rotate. Does that sound like a good plan and can anyone tell me what pressure I should be looking for and if each drive is run by a different pump?
Thanks!!

mg2361 · Oct 29, 2018

Make sure to relief hydraulic tank pressure before removing test port plugs.
Hydraulic Pumps 1, 2, and 3 System Relief Valve—27C ZTS
1. Install pins or round bar stock between the sprockets and track frame to stall propel motors.
2. Engine at fast idle and oil at operating temperature.
3. Slowly actuate the left propel to load hydraulic pump 1, right propel to load hydraulic pump 2 or blade to load hydraulic pump 4. Record the pressure readings.
Hydraulic Oil Temperature 45—55 °C (110—130 °F)
Engine Speed Fast Idle
Hydraulic Pump 1, 2, and 3 System Relief Valve Pressure 20 600—22 600 kPa (206—226 bar) (2990—3280 psi)

mg2361 · Oct 29, 2018

Correction. End of step 3 above should read blade to load hydraulic pump 3.

dmason320 · Oct 29, 2018

mg2361 said:
Correction. End of step 3 above should read blade to load hydraulic pump 3.

Thank You mg2361 for all your help!

dmason320 · Oct 30, 2018

Update: I tested the blade pump pressure. I raised it till it stopped and it was 3400 psi.
i should also say that he machine is up on blocks with the tracks off because I am doing the rollers. Then switched to the right propel pump.
Well I do not want to put a metal bar into those sprockets so i put 2 x 4s and it snaps them like tooth picks. I have not figured how to "stall" the sprocket drives yet. tomorrow I'm going to cut an old tire and see if that will jam the drive.

Dave Neubert · Oct 30, 2018

That wont stop it you need to put tracks on ans put a big pin in sprocket

mg2361 · Oct 31, 2018

Dave is correct, a tire won't work. A big pin between the sprocket and the frame will work to save on installing the tracks.

dmason320 · Oct 31, 2018

I took the ball off one of my reese hitches and that fit in and worked perfectly
the left pressure was 3250 psi and the right was 3400 psi.
what does that tell you? could it be a relief valve not working?

John C. · Oct 31, 2018

You need the manufacturers specification to know. If the machine has piston pumps that sounds low. But you need the spec to be sure.

john deere 27 c won't do zero turn

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