I recently bought the machine at auction (sight unseen of course) which was described as having a brake issue, but ran ok otherwise. The machine looked relatively clean with a little over 6900 hours on it so I took a chance. When the shipper picked the machine up he reported that it wasn't moving and had no brakes. The engine did run after a boost. Shortly after he reported a large oil spill on his deck and nothing on the sight glass. It got delivered late last night and during the initial inspection I found a tag indicating that the machine needed me drive motors. This afternoon I started looking the machine over. Sure enough no oil left in the tank. I lifted the cab up and found a whole bunch of absorption pads in the belly pan under the motors. I also found a disconnected electrical connector on a solenoid ob what seems to be the parking brake manifold. I reconnected that, put 5 gallons of oil in the machine and fired it up to see. The drive motors moved a little and the lift cylinders worked, but I shut it down quickly. I relifted the cab and found hydraulic oil flowing out the side of the right side motor housing. It almost seems as though this is the brake end of the motor. My question, how much of a pain is it to pull the motor? And what's the best recourse for repair? Rebuildable myself? Cat rebuild is about $4800 plus taxes. SN HEN08192
Hard to see from your photo but it might be a leaking park brake cover. From what I can see your machine was built as a 2-speed. All the info that follows is based on that. In the case of it being single speed the motor parts info will not be correct. Parts and R&I info attached.
You are correct, it is a 2 speed machine. And yes, its leaking out of the park brake cover from what I could see. I tried attaching a video, but it was too big. Does a leak from this area indicate a complete failure?
After taking a second glance at it, it's not coming from the cover itself, but between the housing the cover bolts to and the main motor housing.
You have to host videos on YouTube first then link them to a post. Could still be a seal, unless you can see that the housing is cracked somewhere.
Here's the link to the YouTube video, it would be great if it were just a seal! https://youtube.com/shorts/-lemLlD35ZQ?feature=share
I'm sorry I've never been inside the guts of one of these motors. It might be the park brake piston seal leaking, or possibly a seal further into the motor because there does not seem to be a seal/gasket between the park brake housing and the motor housing, at least not one that is listed separately. However in Step 13 on Page 19 of the attachment above it states "install O-Ring seal (12)" and that looks like it fits between the motor and park brake housings. This is the step right before the installation of the park brake housing.
I'd suspect that's what's leaking, #12 in the picture. It doesn't seem to come up with a part number though. I'm waiting on a call back from our Cat Rep at work to see what my options are. I think either way it's coming out though, so I'll start prepping for that. It just seems odd that a seal would just suddenly let go on a part that is stationary, unless it was subjected to greater pressures than it would typically see.
I'd guess that it's part of one or both of the Seal Kits listed at the bottom of the Parts list. I can't find a breakdown of the individual part numbers of either one.
I talked to our Cat Rep, from how I've described it he thinks it's just an o-ring seal failing from age. He also thought that the brake solenoid being disconnected could be an indication that it was acting up, causing extra heat which could have cooked it. I'm going to try and take things apart in the machine, instead of pulling the motor completely. I'll definitely keep you guys updated.
I dunno about anyone else but that might be a bad idea. Disassembling the motor when it’s standing on its end (as per the service manual procedure) is one thing. Trying to hold everything in place while all the time fighting gravity in an extremely restricted space has disaster written all over it IMO. But don’t let fear stop you.....
I'm just going to go as deep as o-ring #12, if nothing is obvious up to that point, I'll stop and pull the motor completely.
Pulling the motor is really not a huge task. About an hour or 2. Have to jack the machine up and slide the axle assemblies slightly to de-tension the drive chains. Re-tensioning them is a bit of a pain without the tool but it is doable. Easier with some help.
YIKES!!!! DOUBLE YIKES!!!! TRIPLE YIKES!!!!
Got things apart, the brake is fried as suspected. From the manual it should have 10 steels and 9 clutches, I counted 12 discs of some sort. I'm thinking I'm going to drag the machine over to a better spot and pull both motors and go through both brakes. If the first one is shot, the second is likely not far behind.
The oring that was leaking was pretty hard, and one area had an ever so slight deformation to it.
The machine isn't in a good spot right now so I couldn't get it up on stands. As mentioned above, I think I'll be moving it over so that it can go up on jack stands then pulling the motors out completely.
Taking another look at the parts diagram, it appears as though the spring (3) mentioned in step 2 of the disassembly process is missing. When I removed the cover there was nothing there, just the piston. It doesn't look like this part is available on its own either, so I might be in for a whole new motor after all...
Not sure but I think those motors were manufactured for Cat by Rexroth. I think the model was an A6. I have no idea if a Rexroth dealer might have parts available.
You're correct, the Cat ID tag actually has a Rexroth number on it. I'm in discussions with a hydraulic motor shop now for parts and/or a rebuild. He's looking for a detailed parts breakdown to see if the spring is available or not.
I've found a shop that deals in Rexroth and they got me a parts diagram for the motor. Looks like the spring and seals required are available from them. Next step will be disassembling the 2nd motor to see if that brake is damaged at all.
Got everything cleaned up with the big Landa pressure washer, that took about two hours. Also got the second motor apart, no surprise the brake mechanism has been mostly removed by the previous owner and things reasealed. I got an ORFS cap and plug kit and removed the lines from the motors to stop the bleeding. Still talking with the Rexroth shop trying to figure out exactly what I should order, but it's looking like this might be a cheap fix (fingers crossed).
This thread deserves an update. I ended up ordering the parts for the motors from a Rexroth dealer shortly after my last post. I was expecting the parts early December, but didn't get them until January 5th. I also purchased a new parking brake solenoid from Cat along with a new hose and hydraulic filter, those were ready next day lol. Since it's the dead of winter here I ended up building a shelter around the machine with insulated tarps and setting up a construction heater to make things barrable. I already had everything cleaned up so with the parts in hand I put the machine back together in less than 8 hours. The machine fired right up without any issue, and no leaks to be seen! I tore down the shelter and took it for a spin around the yard and it ran well. Fast forward to this weekend, I fueled and greased the machine before cleaning up snow from the last storm. I put about an hour and a half on the machine and just had to top up the hydraulic fluid one more time. The machine runs great and seems very strong. I got it to operating temps and no leaks to be found. I bolted the cab back down, fixed a broken bolt on the fan cover and called it a day. There are still a few small things to fix on the machine, it'll be a work in progress. There are a handful of hoses that could be replaced along with the pins and bushings that connect the arm to the quick connect plate. Thanks everyone for the help and insight. The repair wasn't per the book per say, but I think it'll work out just fine.
That's awesome you could repair it yourself. You must have saved a bundle. Be curious to know what the previous owner was doing inside the motors and removing parts for? It's a nice looking machine.
It's a good looking machine considering the hours that are on it, that's what attracted me to it in the first place. The parts to repair the parking brake side of the motors was around $400, but that's only part of it. All in all I'll be into the repair for about $1500, which is pretty cheap vs. new motors at nearly $5k each. I believe the previous owner took things apart to the diagnose initially, and then abandoned the repairs after they saw the carnage. I'm planning on getting the service history from the Cat Dealer, and maybe even the suspected rental house that was the former owner.
I've put about 10 hours on the machine since the repair clearing snow around the yard. It looks like the repair was successful, the machine runs really good and I'm happy with it. I'm having issues with the auxiliary rocker switch on the RH controller, but I think I might have it figured out (bad switch). I'll be doing a few more repairs here and there, mostly cosmetic. I'm starting to look at a tracked machine now which means selling this one in the near future.
Good luck with that. Unless the dealer did all the servicing the only thing they will have on file is any warranty work or product upgrade programs that were performend on it, and even then they aren't obliged to hand over that information. Do you mean the thumbwheel roller.?
Turns out it was owned by a construction company that shares the same name as a rental house. I talked to the dealer/ rental house (Cat Rental) and they gave me some information on its life services preformed and dates. It's a bit of work to get a complete service history out of the system so I didn't bother. Yes the thumbwheel roller. Cat really doesn't want you to just replace the switch. I cleaned up the switch, but it looks like it's partially melted inside which caused some damage.
This thread may be of some assistance to you, especially the last couple of pages - Cat 226b thumb wheel switch replacement 257B2 My thumb switch is a little stiff, is there a lubricant that can smooth out the action? If there are any updates on an available replacement switch I’d like to keep updated. i would just leave it, as long as it works. if you spray any lube in there, you risk dislodging whats left of... HeavyEquipmentForums
That's the thread I've been on the lookout for, I knew I wasn't the only one with this issue! Thanks!
Turns out the issue with the thumbwheel was broken wires at the base of the joystick. Once those were repaired it worked perfectly. I put about 25 hours on the machine doing snow clearing and some work around the yard and it performed flawlessly. I put a hydraulic breaker up for sale and long story short, the guy bought the machine with the hammer. Here are some pictures right before it left. It was a great machine but the hours were a bit high for my liking and I was after a tracked machine. Thanks for the help all!