175 Response Dashpot

21hunter · Apr 4, 2017

I have an early 175 tractor and was cleaning up the response dashpot and noticed that the plunger and needle are of a different design as the ones in the parts and repair manual. Mine did not have a spring under the needle or a steel ball between the needle and plunger. The plunger and top of the needle are bull nosed so a steel steel ball would not fit there anyhow. The question is: will this design work with just the needle and plunger? Does there need to be a spring under the needle in order for it to function properly?
Thanks

DavidP, South Wales · Apr 4, 2017

Hi,
The parts book for the 175 shows only one possible arrangement. Starting from the top is the long plunger with the side screw to enable the upper spring loaded plunger to make contact with the shaft from the response lever when it is set. Underneath this plunger is a ball then you have the pin with the mushroom head which sits on the lower spring.
Yours may have been lost at some time. When you lift the cover off or hinge it back it is always a good idea to fit an elastic band around the plunger adjustment screw and around the dashpot body to keep it all in place.

DavidP, South Wales

21hunter · Apr 4, 2017

Yes, I took a closer look. I added a 1/4" ball between the needle and the plunger. With the needle seated in the hole and the ball between the plunger and needle; the side screw is practically disengaged from the side slot on the body. It really does look like a slightly different design than the one in the parts diagram. This is an early model 175, guessing 1965 or 1966. Thanks for your response David.

DavidP, South Wales · Apr 5, 2017

Hi, I think that you will find that a 1/4" ball will be too big. With the plunger compressed and the side cover refitted the plug in the cover should be removed and a small socket spanner inserted to engage on the adjuster screw. Move the RESPONSE lever to approximately 3/8" from the SLOW end and slacken the adjuster screw. You should hear a small 'click'. Nip the screw up and replace the plug.

DavidP

21hunter · Apr 5, 2017

Hi, The AGCO parts book listed it as a .250" ball. I assembled the dashpot an immersed it in oil. Once it was purged of air it did seem to offer fair resistance when actuated. When pushed harder it would unseat the needle valve and release the pressure. Massey made a fair amount of engineering changes on their equipment through the years. I beleive this may be an instance of that.
Thanks

175 Response Dashpot

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DavidP, South Wales

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DavidP, South Wales

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