Hydraulic Leak

Wed Jun 11, 2014 6:49 am

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This leak started a few days ago. It seems to be dripping from the bottom of the hydraulic housing area.

What could be the reason for the leak?

Thanks,
Dell

Re: Hydraulic Leak

Wed Jun 11, 2014 7:04 am

More than likely it's from the control valve. The small rod sticking out the front. Just needs oring replaced if that's the case. Can be done with unit on tractor. They are proud of that oring, however

Re: Hydraulic Leak

Thu Jun 12, 2014 6:11 am

I could not find the sevice manual for instructions on changing the control valve o-ring while on the tractor. But from reading other posts this is what I understand.

Drain the fluid.
Remove the pin.
Slide the control valve out forward.
Remove the old o-ring and install the new one.
Lube the o-ring.
Slide the control valve into place.
Install the pin.

Is that all there is to it? Will the control valve line up correctly and easily.
Is it necessary to drain fluid? What can go wrong.

Thanks,
Dell

Re: Hydraulic Leak

Thu Jun 12, 2014 6:25 am

Pretty much that easy. On draining the fluid-up to you. If you don't, some will come out when you remove valve. Not really a problem since it has been leaking already.
Lube the oring and shaft before putting oring on. Be very careful not to nick the oring

Edit: clean front of block really well before starting. I degrease and pressure wash before starting. Of course this is probably a given :-)

Re: Hydraulic Leak

Thu Jun 12, 2014 7:53 am

Thanks Thomas,

Is it important to use a IH oring or do you go to the hardware and match it up.

Dell

Re: Hydraulic Leak

Thu Jun 12, 2014 7:53 am

Thanks Thomas,

Is it important to use a IH oring or do you go to the hardware and match it up.

Dell

Re: Hydraulic Leak

Thu Jun 12, 2014 8:58 am

If you're like me(out in the country) you'll spend the price of the oring in gas and time trying to find one. If you decide to look for one, it needs to be able to withstand the hydro fluid it will be in. Maybe one of the guys on here knows of a cheaper source. I have always just bit the bullet and buy from TM. That way I KNOW I have the proper one and it'll last

Re: Hydraulic Leak

Thu Jun 12, 2014 10:08 am

The 0-ring is a real oddball size, and is made of a material that stands up to heat and oil. The 0-ring from IH which is about $7 is worth it. Here is a link from TM Tractor, one of our sponsors at the bottom of the page. O-ring and shipping will run about $10.
http://www.tmtractor.com/new/hy/674fp.htm

Re: Hydraulic Leak

Thu Jun 12, 2014 12:05 pm

The correct O ring has a "fatter" (technical term) cross section that ones that you can buy locally. When installed on the shaft rod and down in the groove, the ring should be a little proud of the rod to have a good seal. Don't ask how I know this.

Re: Hydraulic Leak

Thu Jun 12, 2014 7:39 pm

Anyone have the dimensions on this o-ring?

Re: Hydraulic Leak

Thu Jun 12, 2014 8:33 pm

IH parts store just calls it a 0.482".

Re: Hydraulic Leak

Thu Jun 12, 2014 9:44 pm

Dell wrote:IH parts store just calls it a 0.482".

John *.?-!.* cub owner wrote:The 0-ring is a real oddball size..........

Boy that's the truth, that doesn't come close to converting to anything, fractional or metric. I would think it has something to do with a "compression fit" into the bore to give it more surface area and holding power. But where did the IH designers come up with that number in 1950? Plus actually find somebody to supply it?

Re: Hydraulic Leak

Thu Jun 12, 2014 10:05 pm

It is very difficult to measure a loose o-ring, but thickness (technical term) of this one helps. Using a digital caliper I got an
ID of 0.478 (0.482 in parts catalog),
OD of 0.776, and
thickness of 0.147, which is very fat for an o-ring of that ID.

Re: Hydraulic Leak

Thu Jun 12, 2014 10:19 pm

John,
Are those dimensions from a new one? Thanks.

Re: Hydraulic Leak

Thu Jun 12, 2014 10:26 pm

Don McCombs wrote:John,
Are those dimensions from a new one? Thanks.

yes. I had to replace a leaking one a couple months ago and shipping was the same for 2 as for one, so also ordered a spare.