Lift Cylinder piston

Pakhoss

New User
When rebuilding the hydraulics on my 9n I put in a new lift cylinder piston that uses an o-ring. Just discovered I forgot to put in the back up washer, what's worse is everything is back in and the top cover is bolted down and sealed. Is the back up washer a must, what happens if I don't put it in?
 
It will roll a little bit more than normal. So will wear quicker but will last quite a while unless used every day a lot .
 
(quoted from post at 10:03:02 07/09/20) When rebuilding the hydraulics on my 9n I put in a new lift cylinder piston that uses an o-ring. Just discovered I forgot to put in the back up washer, what's worse is everything is back in and the top cover is bolted down and sealed. Is the back up washer a must, what happens if I don't put it in?

The backup washer is used to support the oring against hydraulic pressure that pushes the edges of the oring into the gap between the piston and housing bore. This extrusion causes premature wear of the ring. The width of the oring groove is also increased to accommodate the backup washer and without it the oring will not get sufficient "squeeze" for the seal and the potential for damage from extrusion is increased even more than normal. Just a matter of time until it starts to tear and leak. How long is anyone's guess but it will not last as long as it should. If it were me I'd bite the bullet and fix my mistake - not a huge job or expense to make it right.

TOH
 

Yep the engineered "squeeze" can be a nightmare at times. I Just fixed an engineered squeeze nightmare yesterday one I have chased for over 20 years...

Go after that backer...
 
Good morning.....
I'm an owner, not an authority on "N" Ford Lift pistons, and "anti extrusion rings".
My past carrier and responsibilities included a wide variety of machinery including PISTON RINGS and anti extrusion rings. Some made of LEATHER, others made from Teflon..
I had an individual who had forgotten to install the anti extrusion back up ring . Eventually the O-ring was forced between the Piston and bore....seized the machine!
The anti extrusion ring must be installed on the proper side of the O-ring...
You now have a situation that shall come back to cause you a migraine..

Bob..Owner Ferguson TEA-20...MF 35 X...2-N Ford...and other Tractors..
 
(quoted from post at 10:03:02 07/09/20) When rebuilding the hydraulics on my 9n I put in a new lift cylinder piston that uses an o-ring. Just discovered I forgot to put in the back up washer, what's worse is everything is back in and the top cover is bolted down and sealed. Is the back up washer a must, what happens if I don't put it in?
ell, looks like you do have choices......."not to worry it will all work out", all the way up to "a disaster waiting to happen". Freedom is wunnerful! :)
 
(quoted from post at 09:53:28 07/10/20)
(quoted from post at 10:03:02 07/09/20) When rebuilding the hydraulics on my 9n I put in a new lift cylinder piston that uses an o-ring. Just discovered I forgot to put in the back up washer, what's worse is everything is back in and the top cover is bolted down and sealed. Is the back up washer a must, what happens if I don't put it in?
ell, looks like you do have choices......."not to worry it will all work out", all the way up to "a disaster waiting to happen". Freedom is wunnerful! :)

Just repaired one of the steering cylinders from a "7400" John Deere.

The piston O-ring was torn up.

The last guy in there put the backup ring on the wrong side of the O-ring.

Of course, LOTS more pressure and movement there than a typical "N" 3-point cylinder.

Surprisingly, for a modern tractor, the old and replacement backup rings are leather.
 
I would bet that deep down you know the right answer on this one. I was happy to read the responses to see everyone on the same page.

Our company has a simple repair philosophy in that we find the cause of breakdown, determine what it will take to repair it and then look at the design and determine if we can improve it to last longer or make it easier to repair next time. It gets in the way of cheap and fast fixes but our uptime is so far better than before we can't go back. And we also have banned duct-tape being used for any repair other than a short term emergency fix.
 
(quoted from post at 14:26:29 07/10/20) I would bet that deep down you know the right answer on this one. I was happy to read the responses to see everyone on the same page.

Our company has a simple repair philosophy in that we find the cause of breakdown, determine what it will take to repair it and then look at the design and determine if we can improve it to last longer or make it easier to repair next time. It gets in the way of cheap and fast fixes but our uptime is so far better than before we can't go back. And we also have banned duct-tape being used for any repair other than a short term emergency fix.
hat will sure make some happy! :(
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