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Trigg

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Joined
Sep 27, 2022
Messages
6
Hello, new here and new to skid steers. I purchased a older Bobcat 630 (Serial 4995-M-13088) this past saturday. It has the 4cyl Wisconsin engine. Bought it not running or driving from a fella that claimed to have bought it off a buddy that needed money. That buddies father owned it and let it set for lord only knows how long. But anycase, the guy i bought it from said it ran when it was parked. I have the repair manual and parts manual for the rig and have done alot of reading. But I still have a alot of questions.

First look, leaves and dirt everywhere. Obviously sat uncovered in the weather.
Hydraulic's is Milk
Motor oil looked New and tasted like 10-30
Chain case. Imagine Pancake Batter with the smell of Gear oil filled half way up the chain sprockets. (I hate gear oil)

The absolute first thing I did when I got it home was check the Bronze Filter. Looks Brand New. Like not even been ran on new. (Correct one for this unit?)
Got the Engine running well Minus the Starter sticking like a crazy and the Key not turning it off. (Any ideas on that would be helpful)
Ok Motor Runs. Then popped the Chain case cover. Drained and sprayed and wiped and cussed and refilled with 10-30.

Engines running, Chains Lubed, Newish looking Bronze filter, Arms lift and Tilt Tilt's. No Drive. Turned it off and looked at manual. Went back to machine found the Left Lift Cyl line busted.
Replaced both the Left Cylinder lines and looked at the Three bypass/relief Spring and plunger thingy's. Springs not broken plungers had some rings that finger nail would barely catch.
Tried and am still trying to drain the system. But put everything back together and refilled with 10-30 per the manual. ( Any input on how to actually Drain and or Bleed the System would be helpful )

Third Fire up and we got a whine. like the normal whine that I've heard around Skids. Ok so Engines running, Tilt is working, and Lift made it half way up and there goes the Right Cylinder gushing. Ohh and two hard lines in the rear are leaking.

All this and the bad decision of saying I'll buy a Skid over a Forklift.

I'm committed at this point. Things I could use some advise on.

Starter hanging up.
Key not shutting motor off
How to actually Drain and Bleed the Hydro System
No Forward or Reverse. There is No resistance, bogging, whining, or bucking to the sticks. They freely move around. I find it hard to believe both Drive motors would be bad with no sounds or resistance.

What are the chances of the Hydraulic/Motor Oil they had in the system is just that broken down that it wont drive the Motors?

Long winded for a first Post but I've gotten myself in a pickle. Thank you all in advance.
 

brdgbldr

Well-known member
Joined
Jun 1, 2012
Messages
1,157
The only way to get all of the oil out of the system is to remove all the lines. Even then you will have to cycle the cylinders and turn the pumps and motors to empty them. It sound like all of the hoses and tube need to be replaced so this would be a good way to go.

The next best option would be to put in new oil, cycle everything on the machine, several times, and then repeat over and over until you are satisfied the oil is ok.

You can use hydraulic oil instead of motor oil like the old manual says. A good AW46 or ISO46 would work depending on your climate. As old as that machine is I would just go with a cheap brand like NAPA. It's usually around $55 for 5 gallons of AW46. Hydraulic oils have additives in them that help the hydraulic system like water separators. Motor oils have completely different additives That actually keep the water suspended. Oils have changed a lot in 40 years.

You should probably just replace the ignition switch. They are cheap and, in my experience, go bad more often then they should.

Not sure about the drive. Could be to motors or the hydrostatic pump. Like you said though. You may be trying to pump old oil or, more likely, water through the hydrostatic system. Oil floats on top of water. So if this machine was sitting that long the water would work it's way to the lowest points which would be the drive motors.

Sounds like a fun project.
 
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T

Trigg

Member
Joined
Sep 27, 2022
Messages
6
Thank you. I've been able to get most of the fluid drained out. I've gotten to the point that the rig will try to move forward and back and if I rock the levers it will try to rock with it.

I've cracked the lines on the hydrostatic pump while running and I'm get pressure. Wether it's enough I'm not sure.

Should I try rebuilding the Drive Motors first or the Pumps?
 

brdgbldr

Well-known member
Joined
Jun 1, 2012
Messages
1,157
That would be a personal decision.

The drive motors would be my first choice. If you do the drive motors make sure, while you have them out, to replace any motor carrier seals. They are probably going to go out.
 
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