BC 743 Control Valve

[nelso1]

I have looked at the threads back to the Fall of 2010 and did not find anything related to control valves specifically. I browsed a bit on the net looking for manuals or pictures and have not seen any yet that freely advise; everyone wants money.

So let's take another route. Can anyone here tell me if control valves can be fixed? Here is what the invoice says:

"Resealed both lift cylinders and the tilt cylinder. The boom is still drifting down. Removed the lift spool and resealed. The lift check valves all checked ok. Serviced the machine, greased, and washed. The lift is still drifting down. There is a problem internally in the control valve."

They claim I need to spend around two grand on a new control valve. Maybe I'm old school, but I believe in fixing problems rather than replacing old parts with new ones. Besides, many of the old parts were made of good quality materials - not so true these days.

I am picturing something in my mind but am not sure if it is accurate. It would be nice to see a control valve. Is it the whole assembly under the seat or just part of that?

I noticed Cat has a shop near here where they claim to fix control valves. They are very pricy on everything so I don't plan to take it there - just noting that someone has the know-how to fix control valves.

Any help?

Thanks.

 

[J_J]

You can fix some things on a control valve, like o-rings, springs, steel balls, replace parts, etc,

If the spool is worn, there is not much one can do, as most spools are a precision fit.

Is there any reason that you can't change style , manufacturer, shape, etc.

If the valve does several functions, like 4 spools operation will another valve fit and do the same thing?

Here is a Prince loader valve, and you can see all the o-rings and small parts that can be replaced.

http://www.princehyd.com/Portals/0/products/valves/LVManual.pdf

There is a leak test that determines if the valve is replaceable when under warranty. After that, it is up to you to determine the time to change out the valve.

I don't think anybody will sell you a new spool to go in an old valve. Off course they will sell you one hoping you never come back, because it probably ain't going to fix it.

If you can get the re-builder to guarantee the valve that would be a good thing.

 

[J_J]

If all you need is a basic loader valve, you can probably adapt a loader valve to fit, maybe something like this.

Surplus Center - 2 SPOOL 25 GPM JOYSTICK LOADER CONTROL VALVE

If you stick with factory new parts, it will cost big bucks.

 

[nelso1]

Wow, JJ, you came across some great information. That manual is especially helpful. And you're right, I don't need to buy one from Bobcat if I end up replacing the whole valve.

So far, I have one offer from a friend to take apart the valve, but I know of a business southwest of here that rebuilds valves - I may check with them before I go too crazy. At least now I have some really good information. Thanks!

 

[Ed L]

I'm thinking you are stuck buying the correct replacment valve. I've changed seals on mine several times, it isn't fun. The valve is squeezed between the machine body and pump, there isn't much room to do modifications, the valve has the aux. hydraulics running through it, can't recall if the travel lines are in it or not.

Not sure how one would convert a joystick type valve to work with the Bobcat footpedal linkage.

Ed