MC Blade sinking

JDMC50 · Post by **JDMC50** » Fri Jul 08, 2011 5:57 pm

Hi
Bruce in Maine here. I have a 1950 JD MC crawler that has been in the family since 1968. I inherited it and it is in excellent running condition. I have been using it on a regular intermittent basis. My problem started a couple of years ago when the blade started sinking and would not stay in a raised position. I rebuilt the control valve assembly and it continued to sink. Thinking the control valve was bad I just found a used replacement and installed it. It does the exact same thing. I have the parts and service manual and it says to check the check valve and pushrod assembly. Since I have purchased this used I do not want to start taking it apart to check things internally. Any thoughts or does anyone know where I can purchase a good used or rebuilt control valve ?
Thanks, Bruce

Post by **Lavoy** » Fri Jul 08, 2011 7:54 pm

Are you sure it is not the cylinder, that would be my bet.
Lavoy

Willyr · Post by **Willyr** » Fri Jul 08, 2011 9:49 pm

Yeah I would suspect the cylinder too. There is a hydraulic service shop in Pittsfield? Dont remember their name, I can find it if you want me to look. Otherwise I bought tie rod cylinders from NH Northern rather reasonable. There is also a Tractor Supply on outer Hammond Street past the WKIT radio station in Bangor.

Johndozer · Post by **Johndozer** » Fri Jul 08, 2011 10:20 pm

I have similar problems with the bucket slowly sinking from a full verticle lift to about 90 degrees from the ground where it finally stops and holds in place. Bucket tilt cylinders work fine.

How would the raise\lower cylinders (original) contribute to that? I have been told it was probably a cylinder problem rather than the control valve but how?

thanks,
Scott

Willyr · Post by **Willyr** » Sat Jul 09, 2011 1:10 am

The cylinder is either scored or the rings are broken from too much wear or even some ice trapped in the cylinder and was moved while still frozen.

Basically the fluid is passing from one side of the cylinder to the other at a slow rate. My 8n 3 pont hitch would do that. Its a easy fix if the cylinder is not of the welded variety.

JDMC50 · Post by **JDMC50** » Sat Jul 09, 2011 6:00 am

Thank You. javascript:emoticon(':)') I will look into revamping the cylinder. I have a friend with a machine shop nearby and I'll keep you posted n results
Bruce

JDMC50 · Post by **JDMC50** » Fri Jul 15, 2011 4:03 am

Thanks for the help on my MC hyd. cyl.
Seems all the packing's along with the rod are shot. I am upgrading to a 1&1/2" rod cylinder and it will be cheaper to buy new than to rebuild old. Should be back in action shortly
Bruce

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MC Blade sinking

MC Blade sinking

1959 440IC with 831 Loader

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