50 8N lift arms will not go back down.

Braxmaier

Member
I know I know, IM sure its been covered before, im working on a friends lift at first it would not do anything so we changed the hydraulic oil/ replaced the piston and pressure relief valve, when we put the top cover back on it had looked like someone had bent the control arm, it was very hard to get it back into the pump, so im thinking that we should have replaced the rod at that time but we did not, should we replace the rod and cam follower pin? the lift. Now it will lift but not come back down plus it will only work whet the draft control lever is in the forward position.. thanks
 
" should we replace the rod and cam follower pin? "

Yes. The control rod needs to be straight & you need to replace the cam follower pin. And, you also need to get a jig from Zane Sherman to adjust the linkage.

That MIGHT fix the lift problem if the control arm & cam follower were not allowing the exhaust valve to fully open, but chances are that Tom is correct. You'll need to drop the pump and clean it out.

With all of the fluid drained out, block the front wheels & get the rear wheels up at least a foot. (you'll see why soon enough) Remove the 4 bolts holding the PTO shaft in & pull it to the rear & out of the tractor. Loosen all of the bolts. Remove all but 2 corner bolts. Then, carefully remove them. If you are lucky, the pump will drop free (and dump a pint or so of hydraulic fluid down your sleeves). If not, wrestle it free. The pump has 'ears' that fit into the housing; wiggle it a bit & it will drop free. If you have the rear tires a foot or more off of the ground, you will have enough arm room to hold the pump & lower it at the same time. Put it on your work bench & remove the safety valve (p/n 638) and the control arm lever (p/n 643) which will allow you to remove the intake & exhaust valves (p/n?s 640 & 698) Drop all of it in a bucket of diesel (or mineral spirits) or your parts washer & let it soak overnight. Once it has a good soaking, get it on the bench & start blowing it out w/ compressed air. Run cleaning fluid into the hydraulic discharge near the test port & make sure you get a good flow out the small hole in the side of the pump were the control valve fits. I don't see much need to pull it down any further just to clean it. But, I always replace the safety valve (p/n 638, about $25)

Reinstalling the pump is harder than pulling it out because you have a gasket to worry about. (no sealer on the gasket) And, you will probably need a helper to guide the control rod into the pump rocker shaft unless you?ve done this 6 or 7 times before!

While you have the PTO shaft out, it would be a good time to replace the seal on it. It's got two spring clamps around it. Take your needle nose pliers & remove the one in the front. Then, hang the shaft & bearing housing in your vice & tap the butt end of the shaft; the bearing cap will come off (and the shaft will land on your foot). Then, remove the other spring clip from the other side of the bearing. At this point, remember that you never bought a seal driver & go get a BF socket & drive the seal out. If you have the new style seal, the white side goes out. (open side to the oil) Put some grease on it.

Contrary to conventional wisdom, not a lot of water gets in the oil from the shifter boot. Of course, if it's bad, replace it, but you get water from the draft control spring & the dipstick. But, most water is just a byproduct of the heating/cooling cycle of the oil.

You?ll need a pump gasket, safety valve, inspection plate gasket(s), PTO seal, PTO gasket, gasket sealer & 5 gallons of fluid to do all of the above.
75 Tips
 
(quoted from post at 22:52:33 11/23/15) I will probably buy a new control rod do to me not having a jig the rod was twisted pretty good.
Chris, the jig is well worth the money if you're working on them!
I don't want to undercut Zane but if you need it just for one, you
can borrow mine. I bought it from Zane. Great tool.
 

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