I just got my 742 project running. I purchased it with a dismantled hydro pump. I rebuilt the pump with new seals, swath plates and bearings. I also re sealed the entire engine, new u joints, replaced various hoses, change the chain case oil and changed the hydraulic fluid and filter. The engine runs fine, and the hydro pump works as I have Tilt and lift functions. I have some movement on the left side forward and backwards, but not a ton of power. The right side won't move at all and sometimes will kick back the handle a bit when pushed forward. I area he'd a bleeder line to the top of the pump to help bleed it out. The right side motors appears to be leaking. I want to start by removing that motor, but will the oil leak out? Where else do I go for the low power on the left side. Thanks for the help.
742 movement problem
- Thread starter Dmc10140
- Start date
Quick follow up after reading a previous post from Tazza, I decided to remove the right motor. It looks like water had gutter into it when the hydro pump was out. It was leaking oil past the seals around the chain case seal. Does anyone have a rebuild manual fir this pump?
Do you need a manual for the pump or the drive motors?
Look up my profile, flick me an email, i'll have a look at what i have.
Tazza, I opened the motor and it is shot, water got into the gerotor and seized it. I ordered a good used one from ag and installed it. I still have no movement from The right wheel. The left spins, usually after a brief hesitation. Do u think I blew out the newly rebuilt hydro pump on the right side with the motor being seized?
I would doubt the pump was damaged from itbeing seized. The pump has relief valves, so if it was locked up, the oil would just go over the relief, preventing damage.
Not loving the hesitation you are talking about on the other side, can you swap motors from side to side to see if the one you got from ag hesitates too?
So, the pump was fully rebuilt before you got it?
![Pampers Sensitive Baby Wipes, Clinically Proven, Fragrance Free, Unscented, Water Based, Hypoallergenic, Multi-Use, Hand Wipes 336 Wipes Total (6X Flip-Top Packs) [Packaging May Vary]](https://m.media-amazon.com/images/I/41KLBHu9CAL._SL500_.jpg)
I can try swapping motors tomorrow. I did a service o. The pump, it was apart when I bought it. I replaced the main bearings, both stash plates and seals. I sent you pictures of the rotating assemblies to help verify they were good. I believed I re assembled the pump and followed the manual.
Ok, I switched the motors this morning (that was a bit of fun). No real change, left side barely moves (maybe less than before). Little to no movement on the right side. Is there some sort of relief or bypass valve? Also I noticed the right side wheels, I can spin them by hand with some effort. I do not believe this is correct.
When the motors are full of fluid, they should not turn by hand.
The relief valves are in the middle section of the drive pump, you un-screw what look like 1” plugs from memory. They are inside here.
The only thing that really comes to mind is that something may have been installed backwards? The wear plates need to have the groove facing the leading edge of the direction that the rotating groups run on it.
I was thinking the hydro pump may not be working to give the pump fluid, but you said that part works.
Another thing you could try is installing a pressure gauge on the lines to the motors, then operate the steering levers and see what pressure you are getting. You should hit 5,000 PSI, or there abouts.
All i can think of is that something was installed in the pump incrrectly or it was already worn.
The motors are now locked when i go to push them (except a little chain slack). So i believe that is the way it should be. Am I able to pull the reliefs out without first draining the hydraulic fluid? I tried pull the charge pressure relief and that caused quite a mess, and I had to put the plug back in to stop it. I did think about the swash plates, i matched the plates up the the drawing in the manual and also confirmed the part numbers on them (since they were new) to the drawing of the pump. So it is possible but unlikely. The rotating groups looks good, one looked like ti was recently replaced. I ordered a hydraulic gauge to check the charge pressure before i decide to pull the pump. I just want to make sure there is no blockage. The one side worked fine before, and it is odd that both sides do not work now. Let me check the charge pressure and go from there. Thanks for the help
The motors sound like they are ok, when they have oil in them, they will not move, you do feel chain slack as you have mentioned.
As soon as you remove a relief, oil will come out.... What makes it worse, is that i believe that you can only get two relief valves from the top, the other two are at the bottom.
Start with the charge pressure, then we can move on.
Tazza, I do not have any charge pressure. I started another thread (you replied to) to cover the issue. Thanks for the help.
when we remove parts on the hydraulic system we have a small shop vac, remove the hydraulic cap and slide the hose in a bit, turn on vac and work away, you can get just enough vacuum to prevent oil leakage
I have heard of people doing this too, works well.
