John deere 70 gas PTO

Hey Everyone,

My pto snaps in and out (which I think is what it should do?), but it does not brake when disengaged. If i put light down pressure on the
lever, it stops. If i brake it and hold the shaft with my hand and release the pressure, I cannot hold the shaft still, and it spins. I'd
like some advice on what to do. Hard to hook PTOs up with the shaft spinning.

"[b:654c4848f0][i:654c4848f0]<font color="#6699ff">it does not brake when disengaged.[/i:654c4848f0][/b:654c4848f0]</font>"

Take a look at the diagram below.

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Note the adjusting cam (Key 40), locking screw (Key 37), clutch brake facing (Key 17), cam disk (Key 15), power shaft (Key 1), and clutch brake plate facing (Key 32).

Reviewed the [b:654c4848f0]SERVICE MANUAL FOR JOHN DEERE DEALERS MODEL 70 DIESEL TRACTOR (GENERAL PURPOSE AND STANDARD[/b:654c4848f0] in the [b:654c4848f0][i:654c4848f0]Engine Driven Power Shaft[/i:654c4848f0][/b:654c4848f0] section under the [b:654c4848f0]CLUTCH ADJUSTMENT[/b:654c4848f0] topic on pages 135-10-7 and 135-10-8.

"Before attempting to adjust the clutch be sure the power shaft shift lever is in the disengaged position.



Now remove large plug ?A? and small plug ?B? from the right side of the clutch housing.



The large opening will expose the adjusting cam and locking screw provided for making clutch adjustment. The small opening will permit you to check clearance between the clutch brake facing and cam disk.

With power shaft clutch engaged, peer into the large opening and see if you can locate the locking screw in one of the notches of the clutch adjusting cam.



If the screw cannot be seen, engage the clutch, then, using vise grip pliers or a suitable wrench on the power shaft, turn the shaft (and cam)a few degrees. The adjusting cam will turn only with the power shaft clutch engaged.



Disengage clutch and again see if the locking screw is visible. It may be necessary to engage the clutch, turn the power shaft, and disengage the clutch several times before the locking screw is correctly positioned. The screw must be visible before proceeding with the adjustment.



Engage the clutch. Working through the small opening, use a piece of wire .090-incb in diameter to measure clearance between clutch brake plate facing and flange of cam disk.
On a properly adjusted clutch this clearance is .090-inch minimum. [i:654c4848f0]NOTE: 3/32-inch welding rod gauge is satisfactory for minimum clearance.[/i:654c4848f0]

Working through the large opening, turn the adjusting screw cam locking screw in until its head clears the slot in the adjusting cam. Now turn the adjusting cam in a counter-clockwise direction (viewed from the rear) to tighten the clutch moving the adjusting cam only one notch at a time while checking clearance through the small hole. Turning the cam counter-clockwise, which [b:654c4848f0]tightens[/b:654c4848f0] the clutch, will [b:654c4848f0]increase[/b:654c4848f0] the clearance. Turning the cam clockwise, which [b:654c4848f0]loosens[/b:654c4848f0] the clutch, will [b:654c4848f0]decrease[/b:654c4848f0] the clearance.

After the .090-inch clearance has been obtained, rotate the clutch and check clearance in two or three different positions to make sure that adjustments satisfactory in all positions.

When the adjustment is completed, turn the locking screw outward, into one of the notches of the adjusting cam. Replace the plugs.

If tractor is equipped with a clutch fork adjustment screw (tractors with Serial No. below 7031300), remove cap nut, engage clutch and turn adjusting screw in until it touches fork. Back adjusting screw off ? turn; then secure it in place with lock nut and replace cap nut."



Hope this helps.

Don't try to hold that PTO shaft with your hands. Or with your foot.

Pipe wrench on the power shaft splines !?! Do you clean the splines with a file afterward? The pto shaft is hard steel but I think a pipe wrench will still leave "tooth" marks.

A better way to turn the shaft would be to use a punch through the hole where the implement's universal joint "locking" bolt goes.

"[b:654c4848f0][i:654c4848f0]<font color="#6699ff">A better way to turn the shaft would be to use a punch through the hole where the implement's universal joint "locking" bolt goes.[/i:654c4848f0][/b:654c4848f0]</font>"

Agree.

Thanks for the helpful tip.

"[b:654c4848f0][i:654c4848f0]<font color="#6699ff">The pto shaft is hard steel but I think a pipe wrench will still leave "tooth" marks.[/i:654c4848f0][/b:654c4848f0]</font>"

No marks were made by the pipe wrench because there was not much resistance in turning the shaft.

"[b:654c4848f0][i:654c4848f0]<font color="#6699ff">Do you clean the splines with a file afterward?[/i:654c4848f0][/b:654c4848f0]</font>"

No.

Although a file has been used before to clean axle splines.