Hydravlic control valve 743

[nester]

Hello. At me Hydravlic control valve

6592483 has sprung a leak.

I have bought the repair complete set 6816251.

In the complete set it has appeared on 8 O-RING

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but the different form and color for spool. As at me old were black color as those that in the center, I and have put them. But through some business hours Hydravlic control valve has sprung a leak. Can to me it is necessary to put others o-ring? Or it is necessary to change spool? Can rearrange spool from additional hydraulics? But on the scheme they at different numbers, 52 and 7 can't replace 53?

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Advise, to me to change on new spools or new Hydravlic control valve?
And from the complete set I haven't found applications of a plastic ring in the form of a spiral and to it

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I will be grateful for any help as to remove the distributor the big work.​

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[OldMachinist]

There were several design changes thru the production years of the 743 and the kit contains some parts that may not be used on your valve. When you dis-assemble keep track of what type of seal was used. The plastic plug is used on the lift spool.

 

[nester]

There were several design changes thru the production years of the 743 and the kit contains some parts that may not be used on your valve. When you dis-assemble keep track of what type of seal was used. The plastic plug is used on the lift spool.

Well and how to me to be with a leak? Only to change the control valve? If yes, where such to get or it is possible is more modern?

 

[Tazza]

Well and how to me to be with a leak? Only to change the control valve? If yes, where such to get or it is possible is more modern?

If you don't remove the spring, the plastic plug is not required. The only ones you will need in that control block are the black quad rings.
Its a shame they don't sell kits for the older machines, saves the extra seals that you will never need. My S150 needed new seals, it took the green ones.

 

[OldMachinist]

If you don't remove the spring, the plastic plug is not required. The only ones you will need in that control block are the black quad rings.
Its a shame they don't sell kits for the older machines, saves the extra seals that you will never need. My S150 needed new seals, it took the green ones.

Here's a few pages from the control valve manual that shows how to identify which seals to use.
http://www.mediafire.com/?2ehk2894picojbg

 

[mrdeere1959]

Here's a few pages from the control valve manual that shows how to identify which seals to use.
http://www.mediafire.com/?2ehk2894picojbg

you can buy the seals separate. I never buy the whole kit.

 

[Tazza]

you can buy the seals separate. I never buy the whole kit.

I get mine from the local hydraulic seal shop too. The quad rings were about $1 each, O rings were a fraction of that.

 

[nester]

I get mine from the local hydraulic seal shop too. The quad rings were about $1 each, O rings were a fraction of that.

In the very first post I have written that have replaced Seal:

In the complete set it has appeared on 8 O-RING,

but the different form and color for spool. As at me old were black color as those that in the center, I and have put them. But through some business hours Hydravlic control valve has sprung a leak.​

My error was in that that I have written

O-RING, and it was necessary simply seal and you haven't understood me.​

I install what stood at me - qard-ring. But the leak through small time has renewed!
From here also there were other questions.
Thanking OldMachinist in control valve manual, I have read that is important protect the qard-ring seal by putting plastic material. I didn't do it, and have simply greased spool and install the qard-ring. The leak reason in it can. And I asked, what the reason in deterioration control valve and spool can?

 

[Tazza]

In the very first post I have written that have replaced Seal:

In the complete set it has appeared on 8 O-RING, but the different form and color for spool. As at me old were black color as those that in the center, I and have put them. But through some business hours Hydravlic control valve has sprung a leak.
My error was in that that I have written O-RING, and it was necessary simply seal and you haven't understood me.

I install what stood at me - qard-ring. But the leak through small time has renewed!
From here also there were other questions.
Thanking OldMachinist in control valve manual, I have read that is important protect the qard-ring seal by putting plastic material. I didn't do it, and have simply greased spool and install the qard-ring. The leak reason in it can. And I asked, what the reason in deterioration control valve and spool can?

It depends on where it is leaking, it could be a crack in the casting letting oil out.
Are the surfaces where the quad rings run nice and smooth? or do they have rust marks or scratches.
Its possible a quad ring was cut when installing the spool. I try and push and twist the spools when i install them to try and not damage the sealing lips.

 

[nester]

It depends on where it is leaking, it could be a crack in the casting letting oil out.
Are the surfaces where the quad rings run nice and smooth? or do they have rust marks or scratches.
Its possible a quad ring was cut when installing the spool. I try and push and twist the spools when i install them to try and not damage the sealing lips.

Thanks all who has responded. Unfortunately, new qard-rings will come only the next weeks. I will try to install more accurately them, but I want to try without removing control valve.
Really it is impossible to overturn spools on 180 ^?

 

[Tazza]

Thanks all who has responded. Unfortunately, new qard-rings will come only the next weeks. I will try to install more accurately them, but I want to try without removing control valve.
Really it is impossible to overturn spools on 180 ^?

They can be changed in the machine, its just a little harder, i have done it before. Just make sure when you pull the spool out the back, do not bend it if a tube line is in the way, you will damage the spool.
You can rotate the spools 180 degrees, no problem.

 

[nester]

They can be changed in the machine, its just a little harder, i have done it before. Just make sure when you pull the spool out the back, do not bend it if a tube line is in the way, you will damage the spool.
You can rotate the spools 180 degrees, no problem.

Has changed quad rings, now all ok.
Somebody can give the reference on service manual 743 S/N 501962734?
I for older models also is many distinctions, especially in valve control.

 

[nester]

Has changed quad rings, now all ok.
Somebody can give the reference on service manual 743 S/N 501962734?
I for older models also is many distinctions, especially in valve control.

Hello Back to the topic. After replacing the square rings after some time visible oil leak. Two lower Valve spool not involved. Can I replace them on top? If you look at the picture, the upper spool to replace the lower and replace the second to the third.
http://www.skidsteerforum.com/Portals/57ad7180-c5e7-49f5-b282-c6475cdb7ee7/TTTGallery/Nester1/%D0%A0%D1%99%D0%A0%D1%95%D0%A0%D0%85%D0%A1%E2%80%9A%D0%A0%C2%B0%D0%A0%D1%94%D0%A1%E2%80%9A%D0%A1%E2%80%B90525[1].jpg

 

[nester]

Hello Back to the topic. After replacing the square rings after some time visible oil leak. Two lower Valve spool not involved. Can I replace them on top? If you look at the picture, the upper spool to replace the lower and replace the second to the third.
.jpg']http://www.skidsteerforum.com/Portals/57ad7180-c5e7-49f5-b282-c6475cdb7ee7/TTTGallery/Nester1/%D0%A0%D1%99%D0%A0%D1%95%D0%A0%D0%85%D0%A1%E2%80%9A%D0%A0%C2%B0%D0%A0%D1%94%D0%A1%E2%80%9A%D0%A1%E2%80%B90525[1].jpg

 

[antfarmer2]

Take a good look at the two bottom steal lines where they cross mine failed there.......was not good to cut up the shroud

 

[nester]

Take a good look at the two bottom steal lines where they cross mine failed there.......was not good to cut up the shroud

On the bottom two lines of the hydraulic valve to connect additional hydraulics. I am interested in are the same there as spool and control the boom and bucket?
Shroud cut the previous owner. Cut off part of the plates screwed into place. It is easier to access to the valve. 743 I have seven years and everything is OK.

 

[antfarmer2]

On the bottom two lines of the hydraulic valve to connect additional hydraulics. I am interested in are the same there as spool and control the boom and bucket?
Shroud cut the previous owner. Cut off part of the plates screwed into place. It is easier to access to the valve. 743 I have seven years and everything is OK.

The lines I am talking about cross just to the right of the center of the shroud you might be able to peek in there and see they rust and fail often

 

[nester]

The lines I am talking about cross just to the right of the center of the shroud you might be able to peek in there and see they rust and fail often

That they were worn once and soldered copper.
Spools different, lower no small holes near the edges. Change rubber rings again and clearing the snow.

 

[antfarmer2]

That they were worn once and soldered copper.
Spools different, lower no small holes near the edges. Change rubber rings again and clearing the snow.

good job