What would happen IF?????

Discussion in 'Lawn Mowing' started by rjtlawncare, Mar 2, 2011.

  1. rjtlawncare

    rjtlawncare LawnSite Member
    Messages: 88

    Just wanted to make a thread of WHAT IF's???????

    1. IF you over tighten the relief valve on your hydro pumps? IS there torqu values on these. Don't understand the saying on the motor. Are these supposed to be hand tightened or torqued?
  2. Jason Rose

    Jason Rose LawnSite Fanatic
    Messages: 5,858

    I think just tightened with a wrench. Wouldn't put a lot of torque on them though.
  3. CLS LLC

    CLS LLC LawnSite Senior Member
    Messages: 487

    Just hand tighten. It's not crucial. You're just closing a bypass port. As long as it is fully closed there isn't a problem. You really just need to make it tight enough that it won't loosen up. Which isn't very tight at all.
  4. rjtlawncare

    rjtlawncare LawnSite Member
    Messages: 88

    1 Has anybody ever over tightend their hydro pumps? What Happens when you over tighten these valves

    2. Will the wheels move if the relief valves are TOO TIGHT?
  5. JB1

    JB1 LawnSite Fanatic
    Messages: 5,904

    is that what you did, they don't need much.
  6. rjtlawncare

    rjtlawncare LawnSite Member
    Messages: 88

    No, I just don't understand the concept of these valves, or why they state that you shouldn't over tighten. What is tight to me might not be tight to someone else. I just wanted to know if you where to tight these what happens to the movement of the machine/preformance of the hydro pumps.
    Thanks for your help, if anyone can answer the question.
  7. LCPullman

    LCPullman LawnSite Senior Member
    Messages: 589

    If the valves are not closed properly, they could allow fluid to bypass, reducing efficiency, and probably not good for the pump.
    If the valves are over tightened, you could have thread damage, I believe the pumps are aluminum which is softer than steel. Also the valve has a well machined, tapered end, if you put it too tight, it might damage the mating surface it seals against which could at some point result in failure to seal properly.
    That is my understanding of why you shouldn't make it too tight.
    BTW I've seen the spec of 7-10 lb-ft for how much you should tighten it, that gives you a little more objective sense of what you should be aiming for.
  8. LCPullman

    LCPullman LawnSite Senior Member
    Messages: 589

    I'm pretty sure the bypass valve seals against something that isn't metal, whether its rubber or some other soft material, it would be damaged by applying higher amounts of torque to it. Once its damaged fluid will be dumped through the bypass valve and you incrementally lose drive power depending on how bad it is.
  9. JB1

    JB1 LawnSite Fanatic
    Messages: 5,904

    I've seen some where they were pretty well hand tight.
  10. ALC-GregH

    ALC-GregH LawnSite Fanatic
    from PA
    Messages: 7,051

    You were right the first time. They don't use any material to seal. It's a taper fit. Similar to a brake line fitting. All the valve does is allow fluid to transfer to the wheel motor. Loosen it up and it dumps the fluid to the return reservoir allowing the wheel motors to turn without fluid pressure on them.

Share This Page