scag stuck open dump valve

Discussion in 'Mechanic and Repair' started by duster, Jun 1, 2011.

  1. duster

    duster LawnSite Member
    from MO
    Posts: 3

    I opened the dump valve too far on one of the pumps (it was raining, got in a hurry - don't ask) and now I can't turn it back in. The valve turns a little each way before it feels "stuck" and I don't want to force it since I obviously don't know why it's stuck. Could it be stuck on an o-ring? Its a bdp-10a pump on a scag tiger cub. Any advice would be appriciated for this novice.
     
  2. weapons of grass destruction

    weapons of grass destruction LawnSite Member
    Posts: 228

    Yes check the o ring that sounds it could be the problem.
     
  3. duster

    duster LawnSite Member
    from MO
    Posts: 3

    Thanks for the response. I suppose that means I'll need to take the pump end cap off in order to work on freeing it without further damage. From the pump assembly diagram it looks straight forward but I've never worked on a pump before. Any advice on that before I make the issue worse?
     
  4. weapons of grass destruction

    weapons of grass destruction LawnSite Member
    Posts: 228

    Yes you want to have a clean woking place.
    You should take the pump off the mower first.
    Yes its pretty straight forward.
    You are going to have to replace the seal in between the end cap.
    Jthomas is a good place to buy parts here is the part no. 51232 for the seal.
    Also when you take the hoses off cover them with tape.
     
  5. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    You dont have to pull the pump...
    BDP-10a pumps have an aluminum head. The relief valve is steel...The valve probably pulled some aluminum threads when it was loosened. Try this...you may get lucky..
    Remove the valve, clean the threads, oil it up and reinstall it.
     
  6. duster

    duster LawnSite Member
    from MO
    Posts: 3

    Well.. I removed the valve and yep...aluminum in the threads. I cleaned the threads and cleaned and flushed the hole and replaced the valve. About two rows of threads were damaged. It seemed to thread back in ok and I was able to tighten it to the proper 10lbs torque. I drove it around for about 15 minutes without issue but somehow I feel I'm on borrowed time. Is that vavle under a lot of pressure when in use? Should I fear it blowing out with force enough to damage something...like the battery that's across from it?

    Now that I understand how the valve works I know exactly what I did wrong. It's not that I turned the valve too far it's that I didn't know that it was turned out of the threads...so when I began tightening I didn't realize that I must have started to cross thread. :hammerhead: live and learn...probably going to loose a few more nights of sleep over this.
     
  7. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    The pump will be just fine....That valve is just a pointed bolt with an Oring that seats against the bypass port in the head. When its loosened it lets the fluid bypass. No other moving parts than the relief valve.

    If the mower is driving OK and you have no leaks....Forget About It.
     

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