Hydraulics issue MF 135

Red Rex · Mar 30, 2020

I changed the o rings and plastic sealing rings on my standpipe to remedy a leak out of the cap on the lift cover over said standpipe.

Now the hydraulics do not work at all. What may be my issue?

DavidP, South Wales · Mar 30, 2020

Hello, it's quite likely that you have
refitted the stack pipe but it has not
engaged in the front pump plate. All you
will have is a fountain of oil coming
from the pump. If you remove the cap it
will probably lift out freely. Check that
the pipe is engaged fully in the cap and
that the O ring is in place. Replace the
cap and pipe and 'fish' around gently
until you feel the bottom end of the pipe
engage in the chamferred hole in the pump
plate. Check the gap between the cap and
cover and make sure that the cap is level
in both directions. If it is, give it a
firm push downwards. It should go down
with a reassuring 'clonk'. Tighten the
bolts to 55 lb.ft.
DavidP, South Wales

Red Rex · Mar 30, 2020

Thanks for the reply David!

I did work with it for a couple hours today and it certainly felt like it seated.

Tomorrow I will drain some hydraulic fluid and run an inspection camera in there to get a better understanding.

Red Rex · Apr 1, 2020

David as always you are correct, however, with a twist.
I measured both ends of the standpipe and found that the end I was trying to insert into the pump was .005 larger than the end in the cap. I switched and it went right in. Hydraulics now work but I am back to my original issue, a leak at the cap but now with new o rings.

DavidP, South Wales · Apr 1, 2020

Hello, glad to hear that you are making progress. At each end of the stack pipe you have the O ring. Inside each O ring should be a white PTFE spiral back-up washer. This wraps the pipe under the O ring and acts as a cushion for the O ring as the pipe is inserted. Do you have these in place? In addition there is another O ring of the same size that fits in a recess in the cap. Do you have this one in place? It is important that both faces are clean and free of any rust or debris. A very thin paper gasket can be fitted in addition but generally I find that this is not necessary.
DavidP

Red Rex · Apr 1, 2020

Thanks for the reply!

I did replace the o ring and white plastic spiral on both ends of the standpipe but did not replace anything in the cap or under it around any holes.

Hydraulics issue MF 135

Red Rex

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DavidP, South Wales

Well-known Member

Red Rex

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Red Rex

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DavidP, South Wales

Well-known Member

Red Rex

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