Hello all. Back again with another problem. !986 Cat 426 Back Hoe SN 7BC00580. Recall i just finished the inframe overhaul with great results. THEN, the front TILT cylinder started leaking as soon as i put it to work.!!! Guess all that new extra power did it. LOL Anyway, question is, since it is just pouring out around the rod, which seals/orings do i replace to make it operational again? And just how much of a task will this be? There are numerous items on the drawing that could be replaced and i probably should do that but the cat prices are very high and i need to minimize my costs. BTW the rod is nice and shiny with no pits or other abnormalities. Also, i searched all over and can not find any cylinder rebuild tutorials on that particular cat model, so if anyone has done one of these before i would appreciate any advice you can give me.
Doesn’t matter what it is.... if you repair a cylinder, you need to replace them all. I would not even attempt to half replace the seals. It will end up costing you more money than doing it right the first time.
To replace the seals in the gland you need to take the cylinder apart. Replacing seals is done as a set. If one is bad they all are. If the cylinders have not been repacked in a long time you will end up doing all of them one at a time. This is why I rebuilt all my cylinders and replaced all the hoses. I bought my seal kits here. https://hwpartstore.com/collections.../cat-426-loader-bucket-tilt-cylinder-seal-kit
it's manageable, there are tricks to make it easier, it takes a LOT of torque to get some loose. Replace all the seals, even if you have to measure and order them all separate. The wear rings in the piston and gland can be reused if they're not worn.
Isn't this a coincidence, I normally replace all seals when I have one apart but.... Just yesterday I rolled a new packing gland (cap) in one because I had one in the truck and put it back in service. Am I going to HE hell for doing so?
There is probably a Part Number for a complete kit of seals that may be priced better than individual P/N's. At least it will give you another option when searching for parts. Agree with the "replace them all while you're in there" suggestions. By your Serial Number the bucket tilt cylinder is a 9T-5371 as shown in the illustration below. The Seal Kit is Part Number 228-1778 that services to 376-9011. The kit contains Reference Numbers 3 thru 6, 8, 9, 11, & 12.
Great and thanks. I have concluded that the kit is best way forward and replace it all. The problem i am having is getting the gland nut off, its really stuck on there. Must be 2oo to 300 lbs torque.
Yes, i have found that out. That nut is tight and am now looking for 3 foot pipe wrench to take it off with. I wonder if one could heat the barrel up to help? Or would that ruin something?
Thanks for the info. I did look that up and it is half the price as cat has. Probably same quality too. I can not get the gland nut off as it is really on tight. Looking for a new idea on removing it.
More than that - tightening spec is 450. And you will need a lot more than that to get it apart, probably around 600. So that will be at least 150 pounds on a 4-foot bar. I don't know how you are attacking this job but IMO it would be better to loosen the nut before removing the cylinder from the machine
Heating the barrel will ruin the seals, maybe distort something? Peeing is another way to get glands loose: HeavyEquipmentForums Wrap the rod with aluminum if you're using a pipe wrench especially. Don't want to nick the rod. If a pipe wrench doesn't work, you can fabricate a wrench to fit that gland with a section of plate, a section of pipe and four keys for the slot. A ratchet strap, or small chain will hold the wrench from slipping, and then it's just a matter of adding a long enough lever to get the torque you need.
Peeing is always good, however, peining works as well...lol Get one of these and hit where the gland threads are in the tube. This will stretch the metal a tad and often aid in the gland removal.
Ut-Ohhh Better get a 4 foot pipe wrench. After close inspection it appears someone tried to get it open before and messed up the gland nut. Yes, i left the cylinder on the bucket and it looks like i better take it off and take to a shop where they do these things. Turns out that finding a 3 or 4 foot pipe wrench here in the city is next to impossible.
Wow. It might be better for me to take it to the shop where they have all the right tools. mI checked one place her and they will do it all for $200 bucks. If i messed up that rod that would be several hundred to replace it.
Great pictorial. Always helps to see it/hear it from someone who has done these things. I actually was tapping on the gland nut already but i can see that was wrong and futile. I was using a short piece of 1 inch pipe and a 3 lb sledge trying to get it off and it wont budge. Shop time.
Piening works wonders...don't be shy with the hammer on the cylinder!!!...It works over 99% of the time.
$200 is a bargain, even if you supply the kit. It's easier to do them on the machine, but if you're stuck, you're stuck. Another method would be to cut a wrench from plate to go over the rod, against the gland, and WELD it to the gland. $200 is cheap.
I would pay the 200 and be happy IF i could just remove that cylinder EASILY. BUT, taking it off is a lot of time and work BC all 4 arms and remaining 2 pins must come off. I like the idea of making a gland wrench and may just try that BC one of my stabilizers is leaking at the seal too. Can you send me a drawing of how to do that method you describe above? I just can not picture how that can be done and need more to go on.
I had my loader bolt cylinder off. Just take the 2 bolts off those plate on both sides. You can get it out with out taking off the linkage. I was able to. For $200 I would would drop it off with a dozen donuts and not even bother trying to do it myself.
Get yourself a piece of scrap steel about 1/2" thick, 5" by 12" and cut it into a open end wrench that will fit over the cylinder rod and sit against the face of the gland, with the "handle" end big enough to just fit inside a 3" pipe, or with holes to bolt to a beam or whatever steel extension you have. Position it so it's not touching the rod, and will be just above vertical with a 10' extension on it, weld it to the gland. Looks like you can move that cylinder enough to remove the gland with the wrench attached, then replace the seals and put the cylinder back together before grinding off the weld and breaking the wrench off the gland. You'd have to figure out how to do the wiper seal with the gland in place, either remove the old wiper first and make sure the new one will fit and fit the new wiper to the rod, or leave enough room around the rod to replace it with the wrench in place.
That would work but for $200 he can get it repacked. If that includes the seals it is silly to even waste time trying.
OK. So if i take those bolts off i can then lift the cylinder out? I thought there was a shaft that extended from one side to the other and the only way out was to take the arms off. I will do that today, thanks for the tip.
No, i have to bring seals to them. m200 is for the labor etc.
Great idea. I am leaning on taking it off and to the shop. I furnish seals and they do the work.
Here's the procedure from the Service Manual in case it helps you at all. I'm not saying it's the only possible way it can be done though.
This is exactly the procedure that i had pictured to take place just using a logical approach. However, edgephoto in post #20 says he got his off just by taking the retainer bolts off at the arm pivot. I will take those bolts off today and have a look but i believe for that to work one would have to have lots of play in those arms and pins.
Sometimes it's possible to fit things on a worn machine that aren't possible on the new one that the dealer has to work on. i would try to pry the cylinder out without removing all the pins and linkage.
i was able to buy a used 36 inch ridgid pipe wrench from a pawn shop for a few bucks and decided i would try your method just for the experience. I banged on the area in your pics with a medium size ball pein hammer for several licks and then latched on with that pipe wrench with a rigged 6 foot lever and that thing will not budge. So my question is, what did i do wrong and am on the right track? What can i do to break it loose now? Maybe some heat? Seems to me that they are really overdoing it by putting those caps on so tight.
The more I think about the more I may have given you incorrect info. I may have taken the linkage pivot pins off. It was a year ago or more that I did this and I don't have pictures.
It takes more than "several" licks. You want to work down the cyl in a row, then do it again an inch away both sides of your original row. Then again, all the way around if necessary. It'll come eventually. That 3' wrench & a 10' pipe, it'll come. Put something over the rod and duct tape the **** out of it in case you slip. Joe H
Great, i was wondering what the correct procedure was. I know that if other people have done it using the hammer thing there must be something i was doing wrong. I will try using your method this weekend and if that does not do it then on Monday i will take it off and to the shop.
Could be that those arms and pins can wear enough to allow that cylinder out without taking it all loose. But on mine there is little wear and those pins have to come out.
Peening a cylinder barrel to remove the gland has never been known to fail. IIRC Willie59 was the creator of the method many years ago. The method is in this thread. HeavyEquipmentForums
This is exactly right...if the 10" pipe doesn't work, get someone else to help you pull down...if that doesent work, add another row of piening. Don't be afraid to hit really hard with the hammer...remember, you are trying to slightly stretch the tube on the threads. There is a possibility that someone put locktite on in the past, or that there is rust on the threads. With the above in mind, they didnt make them crazy tight, but the rust or locktite changes all that.
Wow, that is exactly the information i was looking for. I know it would be easier for me to just remove that dang thing and take it to the shop and let the "experts" do the job. BUT, it has become a challenge to me and i am determined to whip its butt. I am looking forward to the gratification of knowing this method can be employed with success. Thanks for that thread location. Wonder why is did not pop up when i was looking for help?? Maybe i did not use right key words.
Now see that was what i did not know, ie hitting it hard. I was actually just bouncing the hammer off the barrell BC i was afraid i would damage the metal. Now i feel i can beat the hxxx out of it and feel safe. I will not re-install with locktit BC they seem to have a way of staying tight by themselves.
Many on this forum do use the locktite, and I do understand it for a commercial application where the cylinder will see tens of thousand or even a million cycles. For me, mine is only used personally, and will not see the cycles, and I am the one that has eyes on the machine and I will see if the gland backs off. You can mark the position of the gland with a marker that will tell you if the gland is moving. On my machine, I clean the threads and apply never sieze to the gland nut threads. I have never had a gland back off. I would rather have the gland nut come off easy next time and worry about making sure the gland is tight than struggle trying the crack the nut loose.
Progress report!! I got it!! I did just what you all said to do and pounded the heck out of that barrel and laid that pipe wrench on it with the 6 foot cheater and it reluctantly came loose. It was slow going with resistance all the way out. Then the rod would not come out of the barrel and had to pull it out with a come a long. Put the rod back on the pivot pin and took that big bolt out that holds the end on and then the nut was stuck on the rod. Again had to use the come a long to get the nut off.
Here are some more pics of the gland nut and its seals.
NICE!!! Persistence pays!!
My seal kit will be here on Monday and i figured now is the time to get more information on re-assembly. Recall i had trouble getting the rod out of the barrel and then the gland nut was hard to remove. This tells me that if these parts which are old and used were that hard to remove THEN putting the new back are gonna be harder? So question one is how do i put the seals into the nut. It looks like i have to drive the old seals out the front? That metal retainer looks pretty much solid stuck in there. What is best tool to do the driving? Number two is how do i replace the rod with the new seals on it? It was difficult to get out and i assume with new seals it will be worse to put back. Its gonna take lots of force to put it back? There must be some way to rig up a press of sorts to force it back?
Nice job!!! That gland has had some action. I only had one gland I could not get off on my machine and it was not a Cat cylinder. Must have been replaced at some point. I feel your frustration. It is awesome once it comes apart. I had one piston bolt I could not get free. I exploded a Snap-On 3/4 drive breaker bar. Tried heat to see if it was the Locitite holding things. My brother has a friend who works in a heavy truck shop. Brought it to them and he had to fire up the trailer compressor and use a 1-1/2" drive impact to get it free.
A tip for installing rod/head seals is to soak them in boiling water beforehand - all except the steel-cased ones anyway. It makes them more pliable and easier to install.
I had heard that the piston nut would be hard to remove and was very apprehensive about it. Once it was out of the barrel i turned it around and re-pinned it back to the bucket and used a large crescent wrench and 3 foot cheater and it came loose easily on first try. I will replace it with lots of loctite. LOL
Great idea!! I would never thought of doing that BC water and seals are not a common combination. I will do that but still visualize some trouble getting head back on the rod and rod in the barrel. I am gonna need some kind of press to do that.
Lots of lubricant and patience. Wrap any exposed threads in duct tape for protection.
Be sure to orient the seals in the correct direction. The rod wiper usually has a metal carrier that you tap in with a hammer. The large wiper lip out. The u-cup seal has an o-ring in a groove. That side will face the oil...As oil pressure builds, it forces the o-ring deeper and seals the rod. Note orientation of all seals before you remove, even the bearing...there is usually an angle to the way it is cut.
Also, for the piston seal, protect it, then put a worm clamp on it the compress it...leave it on till just before you try to insert it...and as Nige said, don't be shy with lube. I use Vaseline, but others work. Vaseline will dissolve into the hydraulic oil the first time it gets warm.
Don't need to use "lots" Loctite. A couple drops is all you need to do it's job. Too much just makes a mess of things. You may need to take this apart again someday.
They slide back together easier than come apart due to the new now flexible seals Did you crack the hyd lines loose trapped air can fight you A ratchet strap to put a solid pull on while you wiggle it in can help but for a smaller cylinder like that not usually necessary
Was just thinking...u did losen the hose on the blind side of the cylinder before trying to pull it apart, right?
Did not crack that line and in retrospect i can see i should have.
No, i did not and i now realize i should have. That is probably why i could not pull the rod out, had lots of suction.
Ok good idea on that clamp thing. I have some Lucas oil here somewhere and i will use it on the whole thing.
Now this is the kind of tutorial that i need. This will be the one that helps me reassembly that head.
Forgot to ask. Do i drive those seals and metal carriers from the back end? Or just insert the screwdriver from the front and use leverage to pry it out?
I do it from the front. Once you drive in under in a couple places, just turn the handle and they will come out.
You really need a seal pick to hook the non-metal-cased seals out. Much easier than a screwdriver because it gives you leverage. Something like this.......
Yes, that is why you had to use a come along. Make sure you loosen or remove prior to the install or it will never go in. To Nige's point, here is a pick set for $2.00 and it works. I actually have a Snap-on pick set at the house I live at, but have the one linked below where my equipment is. Have used the Harbor Freight picks several times with good results. https://www.harborfreight.com/mini-pick-and-hook-set-63697.html
Nige, i do have these in stock. They are handy for so many things.
Ok, thanks. I too had a snap on set and could not find it so went to HF and got one those cheap ones. They are useful for so many things.
If you can possibly stand the cylinder on end when you reinstall the rod and piston it is likely that there will be no damage to the piston seals from being dragged over the barrel threads. An engine hoist is quite handy for doing it that way.
I do have an engine hoist but my plans are to keep the barrel attached to the bucket and rested on that sawhorse as in my pics above and push the rod into the barrel in that way. If i need to i can attach the come along to the bucket frame and push the rod in that way. This is so much fun i will probably tackle the one stabilizer that is seeping oil. I never knew rebuilding these things was so easy but thanks to all of you here, i was able to get thru one with no real problems.
If you're really into this, go ahead and get the seal installer set, they're not that expensive, and they're fun to use, even if you could do it with your fingers and a wood dowel in most cases. The twisty pliers thing is what I'm thinking of.
Alright, new twist here. LOL Did not know they made such a thing. So where can i get one and which ones are best? I try to stay away from the really cheap stuff if i plan to use it more than once or twice.
3Pcs Hydraulic Cylinder Piston Rod Seal 0.87" Up U-cup Installation Tool sml | eBay
Great. Weird looking contraption. But it looks like it will do the job. Do they make a tool for driving in those seals that have a metal shield? I usually use the ball pein hammer but if there is a tool made for that purpose it would be easier.
A small steel plate works quite well to prevent distorting the seal. Pound it down until the seal is flush with the top of the gland.
Here is my progress report. All seals went in fairly easily , thanks to all the tips i received here on this forum. The replacement seals barely resembled the ones that came out. The only ones that were identical were the flat split ones. The rest fit but were not identical. The thick one in the middle gave me the most trouble as it was stiff as heck even after warming it up. I finally managed to kind of fold it by squeezing it in the middle and forcing part of it in the groove and then worked the rest in somehow. I was surprised it actually went in. The rest were easy. There is one rubber ring that has to go in a certain way , it was NOT like the one that came out of that slot. Thanks to Nige for the drawing on how it went back and thanks to Swetz for alerting me to the fact that some of them do have a beveled lip that must go a certain way. Otherwise, i would never have seen that bevel. I had trouble getting the head to slide on the rod. It went on just enough to allow me to attach the piston. Once the piston was attached i shoved the rod into the barrel and it stopped at about 3 to 4 inches in. So i rigged up that come a long system and pressed it the rest of the way in. Reassembled it all, cranked it up and started moving dirt. Hooray.!!
It is funny but when i pulled the engine sleeves i purchased a wheel bearing puller kit that had the 4 inch round plate that was perfect to pull the sleeves with. The kit had tons of little round discs and other stuff that came with it. I had forgotten about them until i started trying to drive that outer seal in. Then i searched around and found one that was exactly the right size and , like you said, works like a charm.
That is great news!! Thanks for the update!! Happy Tractoring!! This is the u-cup installer I have....there are many others at similar price on e bay, and they do, as previously noted, work like a charm. https://www.ebay.com/itm/223486453439
Yes, and i am ordering one today. They are cheap and will be available for the next one i do. Thanks for your help.