[msy6280]

Thank you. I had fun and learned a lot while restoring it. All the information I needed to do the job was found here at CCI. Everything from how to put it all back together, to where to get the decal kit. :thumbsup:

ING6018-I'll check the rpm this week.

 

[msy6280]

RPM at full throttle is 3260. I did the deadhead test again. With the oil cold, I engaged the PTO. The pressure held at 2300 psi for about 60 seconds and within 5 minutes at full throttle it dropped to 0 psi. I then installed the gauge in-line to the tiller. While traveling forward, with the tiller engaged the pressure fluctuated between 0 and 500 psi. with an occasional spike to just over 1000 psi. If I stopped travel the psi would drop to 0. It didn't make any difference if the tiller was working in the dirt or not, or if the tiller was running in forward or reverse.

 

[msy6280]

I just read the instructions from "bhildret" again and realized I put the gauge on the wrong side. I don't have the fittings to put it on the inlet side so I will have to do that another day.

 

[msy6280]

O.K. now the gauge is on the inlet side. :thumbsup: While tilling and traveling forward in low range, at full throttle (3260 rpm) it stays at 1000 psi. When I take my foot off the pedal, it drops to 200 psi. I don't have very heavy soil but when I hit a spot that would make it work harder, it would jump to between 1500 and 2000 psi. After about 30 minutes when it hit the spot that made it work harder the pressure would go back to between 1500 and 2000 psi and the tiller would stop rotating. After that, the tiller would rotate very slowly while traveling forward and would speed up when I took my foot off the pedal. With the bucket against a tree, in low range, it stays at 1500 psi but there is no squeal.

 

[gator_rider2]

You need drive motor good one off 400 series tractor this fix tractor if in forward pulling spool all way out Travel control Valve being you get 1500 every time it probably linkage good.
There only one other way test system thats buy plugs are cap cap off both travel lines going to drive motor.Then test pressure against caps that should give you noise from reliefs.

The tiller slowing as travel faster is common. I got old 1974 446 runs good stall tiller and try drive at same time it kill engine choke down hydraulic fluid warm up good.

You do know that tiling is done at slowest speed you travel forward creep along.

 

[msy6280]

Thank you Gator. Yes I was creeping slowly in low range. At first it seemed to work OK, but when the oil got hot, it acted like it didn't have enough power to run both the tiller and drive the tractor at the same time. I already changed the drive motor a week ago. I had one here that was from a 224, so I figured it wouldn't cost me more than a little time and oil to try it. It increased the top speed and lost a little of it's push(which I figured it would) but when the oil got hot it acted the same as it did with the old drive motor in it. When I test with the drive lines capped, do I leave the gauge where it is, on the tiller inlet?

 

[gator_rider2]

Yes guage is in good place.
What you testing is new pump and TLC main relief if that good then drive motor is bad.
The 224 drive always going to be weak it design to give power on low height tire the loader never work satisfactory with low profile drive motor, but should show good pressure when stalled.
Some things to test in future we get there you have best loader out there.We set main relief on PTO then one on travel control valve, the problem low pressure not found yet getting plugs are caps is best place to start.

 

[doublet]

I agree with bowl builder. Best looking 646 that I have seen.

doublet

 

[begonesnow]

Is this problem coming from the TCV, the relief in it, or something messed up inside it, just wondering. If PSI for relief not set high enough, putting load on tractor would make it start to open, not sure if this has anything to do with it, but make sure reliefs are set correct on the TCV & PTO, something telling me to make sure those are set right.

 

[msy6280]

Capped both lines from TCV to drive motor. :mechanic:
-Full throttle. Oil, cold.
-Neutral-0 psi.
-Forward, pedal depressed,pressure holds at 1600 psi.
-Reverse, pedal depressed, pressure holds at 1600 psi.
-No squeal.

 

[bhildret]

Overall these readings don't look too far off to me.

I've often noticed that the tiller motors will bypass oil when hot and loaded heavily, hence the loss of pressure over time. These are not overpowered mechanical drives ... you will need to feed the tiller at appropriate rate in hot loaded conditions. It is, after all, tearing down 41" at a time.

As for the 1600PSI cold w/travel control, that seems to me to indicate a little more spool adjustment could be in order. Not sure ... but possible. You seem to have good pump output and not hitting relief. If the spool is slightly open still (not 100% passing to the motor) then it might just not be at peak torque/pressure. That would just get a bit worse (lazier performance ...) as the oil heats up.

If you are going to run the tractor good and hot, switch up to 20W50 if you aren't already there. That will help some. (I don't recommend using 20W50 in cold weather ... or if you use it only occasionally, give it good warm up time).

My 2c

Brian

 

[vfrman91]

I am following this thread with a lot of interest as my 648 loader is more or less behaving in a similar way with a good drive motor, full spool travel and existing good pump.

Since msy6280 has isolated the pump with the capped travel valve and still has low pressures with his new pump, is it possible the spools and bore are worn on the valve? I don't have much hydraulic experience, but I understand the spool valves isolate the oil path through the clearance between the spool and bore, and the O-rings only seal the outside. Not sure if that could be a possibility or not.

 

[gator_rider2]

msy6280
Great work on you part now time turn up pressure on main relief start with TCL if go up by half turn on relief instead 1600 may go up to 2,000 are may just set right there on 1600, but does move adjust to 2250 psi and stop with that relief.
As we see your gauge gain 100 psi by capping off drive motor so losing 100 psi not bad at all because gerotor motor and drive motor is good.

Step 2 move to PTO lever and work that check pressure first you need to get ready so take off tiller lines make both female disconnects on ports of pto valve this give you deadhead out ports that what want be like same as TLC check.
Whatever gauge reads set to 2350 psi you want 100 psi difference in to main reliefs.
Its possible we want get to pressure golds if reliefs are bad are pump I now new but some egg are cracked.
I'm looking forward to your next post on what find TLC relief and PTO relief.

I no I'm off from what manual says for relief setting we going to give pump easier life time.

The squeal not sounding is one indicator pump bad if want set up to 2250 that confirm bad pump.

 

[gator_rider2]

vfrman91

Its not worn spool valve only lubrication oil go by spools there are what called A, B, C Spools A standard size bore line bore honed if have known problem with spool best just get used part.

 

[msy6280]

I adjusted the high speed to 3600 rpm. I left the tractor set up with the gauge the way it was for the last test.
-Turned relief screw in one full turn.
-Full throttle, pedal depressed the pressure held at 2200 psi for about one minute and slowly dropped to 1000 psi.
-Turned relief screw out two full turns. The pressure spiked at around 1500 psi and dropped quickly to below 1000 psi.
-Turned relief screw in three full turns(this felt like it bottomed out the screw). The pressure spiked at about 2200 psi. and dropped quickly to 1000 psi.
-No squeal yet.
-I started the test with cold oil, so the quick drops may be because the oil was warming up?

 

[gator_rider2]

Okay time to go to PTO relief un connect tiller lines no lope hose hook up we want those ports blocks. Work with that relief as did TCV relief set at 2300 if get there. leave travel ports block until problem fixed we need blocked later. The fall in pressure at tcv to 1,000 psi is a indicator of bad pump If PTO main relief does same we got pump cornered.
As hold pressure on high it falling slippage in pump it okay hold it for few seconds but oil get hot not being moving.
The relief screw all way down that another indication bad pump all relief need to be back off to zero on next new pump install and pressure walk up for break in new pump in other words we not going force new pump to maximum pressure.
You doing great job on your testing reporting back thanks.

 

[msy6280]

Plugged both work ports. At full throttle the pressure held at 2200 to 2400 psi. When I depressed the pedal it dropped fast to around 500 psi.
I removed the TCV relief screw and pulled out the spring.
It looks broke to me. Did I find the problem?

 

[gator_rider2]

Yes that broke spring is problem there small pieces some place in system but down spend time looking for it.
That great PTO pressure was working right that tell story something wrong with relief spring in TCV.

Call on michianfan Dan White for good spring these springs have to same as original a Dealer may have one in stock new on this item is good way to go.
New and pressure up system your finish I just Love 10 dollar repairs enjoy your tractor.

 

[msy6280]

Thank you to everyone one who helped with this, especially "gator" for talking me through the pressure testing. I'm sure the broken spring is the problem, but I'm more than a little concerned about where the other piece of it ended up.

 

[msy6280]

I found the other part of the spring, it was about a 1/4" long. I got a new one from Brian, along with more instructions for setting the relief. With the bucket against a tree, PTO engaged and in high range I got around 2150 psi. In low range it would spin the tires. I hooked up the tiller and headed for the garden. After about 30 to 40 minutes of tilling it lost all power again. It hardly had enough power in low range to pull itself through the soft soil. :crying: :crying: :crying: :crying: