Need help with control valve rebuild on my Bobcat

[willie59]

I'm replacing the seals on the tilt spool of a 763 this weekend.
From the posts I'm guessing if I'm careful, I can take out the 2 allen's holding the detent cap on the lift spool, and pushing the spool from the link end - push it out of the valve body and just leave the end cap/detents in place?
I left the valve attached, and thus far pulled out the tilt spool (it was leaking a stream out the little hole in the end cap)

That's the way I do it. I can't remember for sure on the 763, but you may have the control valve locks like on the 773 and other models. If you do, they hold the spools in the locked position when machine isn't running and you can't pull the spool out. What I do is take the linkages loose connecting to the spools, remove the rubber dust boots, have the seat bar down, turn on iginiton, then press the drive enable button on the control panel. This will release the spool locks and you can slide them off the spools at the front of the control valve. The float detent mechanism is only on the boom lift spool, the end cap is longer and has a snap ring on the end of it. You don't have to remove the snap ring uness you need to make a repair of the float detent. Otherwise, once you've removed the spool locks from the front of the valves, you just remove the two allen head screws that secure the end cap to the valve body and slide the entire spool out of the rear of the valve body. It will usually bring the seal along with it. Remove old seal and slide matching new seal onto spool, then insert spool back into valve. Just be careful sliding new seal on spool, the machining is sharp and can damage the seal if you get rough with it.

 

[wmshooke]

Thanks so much, finished the machine this weekend and it's been running no leaks so far... Did the boom and tilt spool with the control valve in the machine. Replaced the old brown/black seals with the new green ones from the same seal kit shown in an earlier post pic. Wrapped cling/saran wrap around the sharp spool shaft, wet with hyd oil and slid the seals over with no problem and no cuts/nicks!

That's the way I do it. I can't remember for sure on the 763, but you may have the control valve locks like on the 773 and other models. If you do, they hold the spools in the locked position when machine isn't running and you can't pull the spool out. What I do is take the linkages loose connecting to the spools, remove the rubber dust boots, have the seat bar down, turn on iginiton, then press the drive enable button on the control panel. This will release the spool locks and you can slide them off the spools at the front of the control valve. The float detent mechanism is only on the boom lift spool, the end cap is longer and has a snap ring on the end of it. You don't have to remove the snap ring uness you need to make a repair of the float detent. Otherwise, once you've removed the spool locks from the front of the valves, you just remove the two allen head screws that secure the end cap to the valve body and slide the entire spool out of the rear of the valve body. It will usually bring the seal along with it. Remove old seal and slide matching new seal onto spool, then insert spool back into valve. Just be careful sliding new seal on spool, the machining is sharp and can damage the seal if you get rough with it.

 

[willie59]

Thanks so much, finished the machine this weekend and it's been running no leaks so far... Did the boom and tilt spool with the control valve in the machine. Replaced the old brown/black seals with the new green ones from the same seal kit shown in an earlier post pic. Wrapped cling/saran wrap around the sharp spool shaft, wet with hyd oil and slid the seals over with no problem and no cuts/nicks!

Ah yes...it's always good to hear someone get their machine fixed, did it themselves, and it didn't cost them a loader bucket full of money. :notworthy

 

[beno]

gday . i am on this post to find out about the placement of the seals on the spool shafts. there are three types of seals . and i dont have a manual to show me which one goes on what end and what order the the combination off seals go. i abtained the valve body stripped and so i didnt have the seals in place to ever know the correct order.
any help on this would be appreciated

 

[wmshooke]

spool seals

I've got the manuals for a 763 at the shop, can check to see if it details seal placement. From what I remember, the replacement seals are a different color from the original as well.
William

 

[SuperDirty77]

WMSHOOKE I have the same machine and did your just leak fluid? Mine likes to do right hand circles on its own. But if i hold the left stick back slightly it will stop. but when i pull it backwards it wants to do circles backwards. As its looking taking apart the valve body looks like to much fun for me! Not to hijack your thread ( I can't post any thing yet and need to get my machine runnig soon) If any one has any idea whats wrong any help would be great. Thanks

 

[mrfixitpaul]

Probably an adjustment on the steering, check and make sure both 'triangle' arms are tight on their shafts and the rollers/cams are tight on the arms, then get all 4 wheels off the ground to adjust steering, loosen both adjusting blocks and adjust neutral, starting with the left side (farthest from the centering spring).


To fix the fuel pickup, lift the cab, follow the hose back from the primer bulb to the other side of engine where it goes into tank and pop the hose and grommett out with a screwdriver. when reassembling it is easier to use a new grommet and they're cheap enough at the dealer, if there's one close.

 

[Hardline]

Thanks so much, finished the machine this weekend and it's been running no leaks so far... Did the boom and tilt spool with the control valve in the machine. Replaced the old brown/black seals with the new green ones from the same seal kit shown in an earlier post pic. Wrapped cling/saran wrap around the sharp spool shaft, wet with hyd oil and slid the seals over with no problem and no cuts/nicks!

Congrats on getting your machine fixed. Its not a bad job. all the seals start out the same color. As they get older and go through heat cycles I believe they start to look brown. JJ

gday . i am on this post to find out about the placement of the seals on the spool shafts. there are three types of seals . and i dont have a manual to show me which one goes on what end and what order the the combination off seals go. i abtained the valve body stripped and so i didnt have the seals in place to ever know the correct order.
any help on this would be appreciated

Looking at the spool from the front side of the block. Remove the two allen screws that hold the front cap. This will remove the cap and the boot. Next will be a washer with a step in it. Then the seal. The seal will have a slightly larger side on the OD. That side will face inward. As you push out the valve most likely the washer with step will come out with the spool. It usually does. Stick you pinking into the hole on the back of the valve and get the old seal out. I allways install the seal onto the spool then slide it back into the valve. Again when putting the seal on the spool make sure the larger part of the OD is facing inward toward the center of the valve. Most of the time all you need are the four green lip seals. I keep a dozen or so on my service truck all the time. JJ

WMSHOOKE I have the same machine and did your just leak fluid? Mine likes to do right hand circles on its own. But if i hold the left stick back slightly it will stop. but when i pull it backwards it wants to do circles backwards. As its looking taking apart the valve body looks like to much fun for me! Not to hijack your thread ( I can't post any thing yet and need to get my machine runnig soon) If any one has any idea whats wrong any help would be great. Thanks

Yes the valve being discussed here is the bucket lift bucket curl and aux hydraulics only. The drive curcuits are seperate. Sounds like you have a loose worn aluminum padle that sit on top of you drive pumps that actuate the pumps or the spring return to nuetral adjustments are off. JJ

 

[SuperDirty77]

I looked at it and the left stick defintly move around more and is not as firm as the right. the the left aluminum padle is loose on the shaft but when i went to tighten the bolt on the side it is already tight. maybe there is another tighting bolt? there is a lage plate on top of the body that moves with the controls. does that come off easily for easier acess . Thanks again guys.

 

[mrfixitpaul]

You can remove the top plate(centering plate) by removing the bolt that holds the long spring. Then the plate should come off or at least move out of the way(some models have a hydraulic line going through a hole in the plate). If the aluminum arm won't tighten the square hole is probably damaged and you'll need a new arm.

 

[SuperDirty77]

Ok Thanks for all the help I will look at it on Friday and get back with you

 

[Hardline]

Yup. they have loctite on them so make sure that you can actually move the bolt. Back it out just a bit then try to tighten it up. If not the arm is wallowed out and needs replacement. JJ

 

[bernie oconnor]

can anyone please tell me when replacing the seals in the spool and orings on the valve on a 743 is there anything there that fly apart and can it be done in the machine without removing engine etc,any help would be greatly appreciated.

 

[willie59]

It's been a long long time since I've done one on a 743B so I don't recall the particulars myself.

 

[Bumpsteer]

It's been a long long time since I've done one on a 743B so I don't recall the particulars myself.

Been a long time since I've been into mine.....don't recall having to chase any flying parts.

Pretty simple other than no damn room to work.

Ed