I am trying to work some of the bugs out of this machine.I noticed today if you use left hand control to raise loader arms they will actually go down for a 1/2 of a second and then raise like they are supposed to.You can lower them slowly all the way down if you barely pull the left hand control towards the raise position and leave it at that spot.
You could have a valve problem, but the first thing I'd do is loosen one of the lines that go to the rod end of one of the lift cylinders. You only have to do one because the two cylinders have lines tee'd together. Have the bucket just a couple of feet off the ground and loosen the line, see if the arms then drift down.
The problem is most likely to be the load check valve - there are a number of different valve types in the 1845c, however they will all have load checks. Look to see which spool is the lift & the load check will be in line with the spool - usually in the middle of the valve body. The spring is usually the culprit. The valve below is a sample for you to get an idea - this is the most common type for check valve problems - due to a pathetic spring design.
That's a good possiblity Alrman. :notworthy That looks like the poppet check valves that feed oil to the power beyond chamber inside the valve. If they are, wouldn't the problem be the poppet for the bucket circuit being the problem? When you shift the spool to raise loader arms, the spool blocks the center return port and delivers oil through the poppet check for the loader spool circuit, the oil goes into the power beyond chamber to be delivered to cylinders. If the poppet for the bucket circuit isn't seated, or spring is broken, while doing this, especially with loader spool slightly opened, the oil in the chamber will leak by the poppet and go to the return port. Once you shift loader spool fully, sufficient pressure/flow develops in the chamber to counter the faulty bucket poppet check. Does that make any sense?
Your hurting my brain ATCO - it's probably easier to check both springs .........
Just practicing to challenge Digger. :tong Then again...bad idea!
Paul read your post twice and yes it made my brain hurt. Once I got my head around what you said I thought I would post this.... The way the load checks work in a nutshell.... Say the loader is 4 feet off the ground with a load in it. If the load check was not present as the spool strokes to send oil to the base end the pressure in the bucket would momentarily exceed the pressure in the valve just as the spool cracks open causing the loader to fall before it started to raise. The poppet serves the purpose by closing the port, the pressure from the load in the bucket reacts on the back side of the poppet. When the pressure on the spool side exceeds the pressure on the bucket side it opens the poppet allowing flow to the loader cylinders. The only oil flowing through the power beyond circuit is return oil or excess flow. Thats why if you want to check your load checks you just feather the spool open slightly, if the load check is bad the loader or whatever will fall before it raises. Inversely the other load check stops the loader from falling down should you have the unit raised off the ground. Bucket poppets work the same and the two are not related you can have one or the other bad and they will not effect one another. Alrman has the right idea...you're in there check all 4 poppets. Those springs were not the best, if one is bad probably the other 3 are not far behind and they're inexpensive.
Ahhh, makes perfect sense Gil. I haven't encountered these before, thanks for the tip. May I add this; when the pressure on the spool side exceeds the pressure on the bucket side, plus the additional pressure of the poppet spring , it opens the poppet allowing flow to cylinders. The additional pressure of the spring would require the spool side pressure to be slightly greater than cylinder side to open poppet. Which is why a broken spring would cause leak down upon feathering valve. Without the spring (or broken spring), the spool side would just need to be equal to the cylinder side to lift poppet, but it could leak down through the partially open return to tank port of the feathered spool. Does that make sense? (go ahead and take another asprin!) As for my above post, I see now I was referring to a different type of valve than the one on the 1845. I was referring to a control valve that has an internal power beyond chamber and related poppets, which is not what we're discussing here. My bad. ointhead :tong
The problem withe the loader dropping before raising is the load checks for sure. But before you pull your hair out trying to find 4 of the load checks there are only 2 1 for the bucket and 1 for the loader circuit. They are under the short topped plug between the cylinder ports on the respective spool.
I know this is a old thread but it is relevant to my current problem with my 1845C. The OEM springs are not available, I was wondering what have other folks used to replace the load check springs? Any length, strength info on the compression springs would be great. TIA. SimS
There are a couple of different valves used in the 1845C. Is the spring you require part # 511682?
Yes, I think so. I have an early 1845C and that should be the correct loader control valve load check spring(s). I will visually identify the control valve today and confirm the valve "matches" my machine's PIN. SimS
I have a Case125 backhoe attachment for my MTL. It does the same thing. Thanks for the info! Now to find the correct replacement springs...
I just went out and confirmed the loader control valve and checked my parts manual. Yes part # 511682 should be the correct spring for the load check springs. I just found that part number online and ordered two. Thanks for the info SimS
Hi. I am curious if replacing the springs on your load check valves solved this problem of the loader lift arms dropping slightly before raising when moving the lift control levers in the cab? Thanks for any update you can provide.
@Stephen Smith , The drooping only occurred when I was trying to lift heavy loads and trying to "feather" the boom up or down. I replaced the springs and it hasn't been as big of an issue. It still does it on large/heavy buckets of stuff, but not as severe. SimS