Hey ya'll, I made three posts so now I can finally start a thread and hopefully get some help. I have a 2000 Bobcat 753, and I'm currently rebuilding the control valve on it. I bought a service manual and followed the procedures in it and removed the entire control valve/BICS valve assembly. What a pain. My machine was very dirty on the inside and was impossible to clean everything off when I removed the control valve - so I'm worried that if I don't clean out the control valve blocks, that there is some mud, grit, etc. that might have fallen into the passages that will undo all the work I'm doing to rebuild it. I need some ideas on how to clean the passages out to make sure that they are very clean when I put the parts back together. If anyone would be willing to share some ideas or suggestions it would be greatly appreciated. Thanks. Here are a couple pictures. _____ Dennis
Were you getting leaks from the control valve? I will be doing the same in my 763 which has a leak from its control valve. Generally I don't worry too much about getting dirt in as I am going to disassemble totally and rebuild. I clean parts with diesel and/or degrease with lye first. Rusted parts get submerged in a solution of lye, washing soda or baking soda and water and connected to a battery charger for electrolysis. Final cleaning of castings is usually by pressure washer. Once cleaned I simply drop part in diesel and let the water seperate. During assembly I use generous amounts of hydraulic oil and then tape up or cap inlets. After a brushdown with paint thinner and the part dries I paint it. Last but not least, I install it on the machine. My 863 is still all apart so every piece gets cleaned, rebuilt and painted seperately. Once assembled it's like new.
Yeah, it was leaking pretty bad. I checked the fluid one day before I started it up and noticed it was barely touching the bottom of the dipstick. First thought was that it was a motor seal and it had drained into the chaincase. I removed the chaincase plug expecting to see all the missing fluid coming out, but nope, in fact, it was low on fluid as well. Finally, I found the fluid all sitting in the bottom of the machine. Apparently the previous owner operated the thing in some nasty clay and it completely clogged the drain holes, and continued its way into the machine. I have a feeling it was a spool valve that was leaking, but there were lots of other bad seals that I've discovered as well. All the leaking fluid just pooled up inside the machine. Thank you for the tips.
what is this costing you if you dont mind me asking?
Oh yeah...this will muck up a hyd system's operation! As for cleaning it; drop it in a 5 gal bucket with some mineral spirits and clean the oil/grime off of it. Then dry it down with compressed air. For general "spot cleaning", like when you go to install a spool and want to make sure the bore is clear of debris; a can of starting fluid. Starting fluid is a mechanics best friend, not so much for starting engines, but for cleaning. It cleans oils great and evaporates really quick. Spray a good bit inside the bore, blow it out with air, and it will be clean and dry. Then spray some WD40 into the bore to give a light lube for installing the spool.
$109.05 for the seal kit for the control valve, a lot time and frustration and several layers of skin off my knuckles. I figured I might as well rebuild the BICS valve while its off as well. The problem is there isn't a kit available for the BICS valve, so everything will have to be ordered separately, and the dealer didn't have any of it in stock. All the parts to reseal the BICS valve will cost less than 50 bucks. So I still need to order and pick up all of those. I sure wish there was a place you could order and have it shipped to your address, because my dealer is about an hour away. The only other thing is the manual shows a special tool that is used to install the detent balls (which by the way, be sure to wrap a cloth around them, the manual isn't kidding, the spring sent one of mine into orbit but thankfully it landed on my trailer bed). I asked the lady behind the parts counter how much that tool cost, and I think it was around $120!! So... I haven't figured out what I'm going to do when I get to that step yet. Thanks everyone for all the great advice, and please keep it coming. Is there a way I can make my pictures from PhotoBucket show up like the one above, or do I have to upload it to this site?
I don't take apart those Bobcat detents unless I'm forced to kickin' and screamin'! It's been a while since I've had one apart and I don't have it in my head of what you need to do to re-assemble it, sorry 'bout that. As for pics? Yes, there's a handy little feature to do this. Go to the top of the page and click the FAQ link. Click on Reading and Posting Messages. Then click on Attachments and Images. This will give you the steps to take.
Thank you. Let me see if this works. Well, guess it didn't . Maybe I can't link an image from a different site and instead it has to be uploaded as an attachment here?
I haven't tried to upload an image from another site, I just upload images I've saved on my computer. That's what I did with your image; opened it, saved it, then upload. There may be a way to do it from other sites, I just haven't tried. Try saving one of your images on your computer, then upload it, just to see how it works.
mineral spirits and blowing things out with compressed air is the answer.
Thanks for the helpful advice everyone. I started with the BICS valve since its smaller and let it soak in a tub of mineral spirits overnight. Then I cleaned off as much of the dirty grime as i could with a toothbrush in a laundry sink in my garage. Then I hosed everything out and *think* I got any extra dirt/grime that could possibly be inside the passages of the BICS valve out. Now its been soaking in diesel fuel for a while, haven't had time to work on it over the past day or so. It appears that all the water has settled on the bottom. Should I soak it in mineral spirits one more time, then let it dry out?
Sure, mineral spirits will evaporate, diesel tends to hang around.
One of the old mechanics at the dealer where I worked had made a simple but effective tool for installing the balls & spring. It was a c-shaped piece of plate about 3/8"thick, the 'c' was sized to go around the denent holes, had one hole drilled and tapped to 1/4 x 20 that you lined up over the hole, insert the parts, and hold in place with an allen screw. then push detent cap into place, pushing tool off the balls at the same time. Looked fairly simple to make and worked with the valve still in the machine. Wish I had 'borrowed' one when I retired from there but will definitely make something when the need arises. sorry no pictures either, I'll try and draw a picture and post it.
Sounds like a pretty slick trick! I learned on the first 743 that I changed valve seals with the valve installed, that it's not wise to pull the detent cage apart. Those little balls disappeared in the belly of that machine. I learned to remove the screws that hold the centering spring cap on and pluck the whole spool out of them, then slide new seal on the spool. I don't mess with the detent unless it has a problem.
Hi doesnt want to hijack the thread, so will post here. right, after reading this and some earlier posts about resealing control box on BC, and knowing that mine leaks some oil, went to the dealer and ordered a reseal kit for my 863 BC. on friday got this one delivered: now i wonder if thats the right kit, doesnt looks like it has all o-rings etc, and there is only one rubber cap. so now, before i tear the control box out, can someone confirm if its the right sealing package? just want to avoid extra downtime, if it will turn out its not the one. thanks!
You've got the kit to reseal one spool. A lot of the control valve leaks come from the spools leaking, not the fittings, etc. Do both spools at once and you'll be trouble free. If you only try to do one spool, say the lift spool, your tilt spool will start leaking soon there after, and vice versa.
there should be three difrent kinds of seals in there a black quad ring the orange seals and the green seals the black quad rings where on the old 743 843 853 and the orange seals i have only come acrossed one set and they where on a 7753 the green are on all about all of the newer g series and above machines. the kits just come with new bolts and boots but unless you strip out the bolts you dont need them the factory recommends that you replace them any time you take them out but then again they recommend people do alot of stuff to prolong the life and assembly of things but you dont see that getting done on alot of guys tuff run er till she blows then gripe about the bill pay me now or pay me later as my old instructor used to say. don't take the four to six hours to remove and reseal the control valve it can be done in the machine and should cost about 25 dollars or so in parts around here in missouri just get the seals balls spring and stud and call it good take it apart before you go to the dealer to see if you are going to need new allen bolts because occasionally the do strip out dont loock tight them back in because the next time you go to pull it apart you will wish you had not done that tighten the bolts evenly on the caps to keep them from binding up in the cap and bore
Yep, like BCmec said, I have a 763F and I replaced the seals in my control valve while the unit was in the machine. It took about 2 or 3 hours (I never did one before) and the parts were cheep also from the dealer, I don't think it was much more than the above quote. Good luck!
Thanks pals! makes sense though i am a bit confused about "balls, spring and stud", local dealer gives me that weird "what do you want" expression on the face when asked for them Bobcatmec, maybe you could help me out, i could PM you s/n and paypal you the amount for seals/balls/springs/stud + shipping + 6 pack of beer? that way i would save a lot of time running arround town to and from the local, which is an hour away anyways
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.
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
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
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
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
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.
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 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 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
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.
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.
Ok Thanks for all the help I will look at it on Friday and get back with you
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
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.
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