Knocking hydraulic pump. Why does this happen.

It is quiet enough that if nobody ever told me I
probably would have never noticed any knock at all.
But at the top with a load, that is noticable.

Just curious as to why it happens that way.

Thanks.

Pooh Bear

It sounds like your touch control mechanism is a bit out of adjustment causing the system to relief via the relief valve when the cylinder dead heads at the end of travel. This causes the pressure to rise to the relief valve setting. You can verify this by chaining the lift arms down and raising the quadrant lever. I suspect the knock will inicrease just as it now does at the top of travel.

You could go completely through the lift adjustments to repair this but it is much easier to set the lift control lever top stop below the point where this occurs.

Dean

Thanks.

Pooh Bear

It is a pretty straight forward job if you have a fixture like Zane sells to set the adjustments. It is a frustrating, time consuming, two man job without one.

Dean

Pooh Bear

I have had one for over a year but have not yet found the time to go through my 51 8N again. Maybe this winter?

Dean