B21 Low Loader Breakout Force

[PointyHairedBoss]

I have a B21 with about 1900 hours - great little machine.
Recently my loader bucket tilt (I think that's called "breakout force") has become very under powered. I can barely scoop a half load of gravel. Bucket lift works fine.
When I tilt the bucket under load I get a hissing sound in the valve like fluid bypassing.
Any suggestions?

 

[Dave M7040]

Go to a Princess Auto location and buy a pressure gauge good for 0 to 3500 psi along with a male hydraulic coupling fitting compatible with your tractor's.
the gauge is $16.
0 to 3,500 PSI Glycerine Filled Pressure Gauge | Princess Auto
Install the gauge into a rear hydraulic port if you have one or into the one for the loader.
Rev up the tractor, activate the hydraulics and see what pressure shows on the gauge.
If it is around 2,500 to 2,700 psi then there is nothing wrong with your tractor.
If is is lower value then an adjustment is required which is best left to the dealer because your system likely has two relief valves to protect the hydraulic system. There is one relief valve for the 3 pt hitch and rear remote(s) and another for the loader and both need to be set.
If you have a joystick control it is possible that a cable has lost its adjustment and is not opening the valve for the loader all the way.
The gauge and fitting purchase with you doing the test is by far the cheapest first step.
Dave M7040

 

[PointyHairedBoss]

Thanks Dave,
Nearest Princess Auto is 2 hrs away so it will have to wait for next trip.
The hoe feels like it has full power so I suspect it is more likely to be the relief valve for the loader than the system pressure. I looked at the parts list for the loader joystick valve & didn't see anything labelled "relief valve". Is the relief valve for the loader located inside the control valve? The hissing noise I hear sounds like it is coming from the control valve.

And Ill check the valve for adjustment once it stops raining.

 

[Dave M7040]

Thanks Dave,
Nearest Princess Auto is 2 hrs away so it will have to wait for next trip.
The hoe feels like it has full power so I suspect it is more likely to be the relief valve for the loader than the system pressure. I looked at the parts list for the loader joystick valve & didn't see anything labelled "relief valve". Is the relief valve for the loader located inside the control valve? The hissing noise I hear sounds like it is coming from the control valve.

And Ill check the valve for adjustment once it stops raining.

Local hydraulic shops will have the gauge and coupling fitting for about the same cost as Princess.
Post a picture of the loader valve and I may be able to comment.
Since the same pump serves both the hoe and FEL and each of the relief valve are on the same circuit just close to the devices they serve, if one is blowing at too low a pressure I would expect it would keep the pressure of the hoe from building up to proper levels as well.
Trying to trouble shoot a hydraulic problem without a pressure gauge is like trying to determine how serious your child's fever is without a thermometer.
Even if you found the relief valve for the FEL, how would you know how much to change it?

Dave M7040

 

[downsizingnow48]

I don't have my owner's manual handy but I have looked this up before. I believe the B21 system pressure is in the range of 2100 psi.

 

[PointyHairedBoss]

Local hydraulic shops will have the gauge and coupling fitting for about the same cost as Princess.
Post a picture of the loader valve and I may be able to comment.
Since the same pump serves both the hoe and FEL and each of the relief valve are on the same circuit just close to the devices they serve, if one is blowing at too low a pressure I would expect it would keep the pressure of the hoe from building up to proper levels as well.
Trying to trouble shoot a hydraulic problem without a pressure gauge is like trying to determine how serious your child's fever is without a thermometer.
Even if you found the relief valve for the FEL, how would you know how much to change it?

Dave M7040

Here are some photos of the valve.

 

[Rod in Forfar]

My neighbour found a small Allen screw to adjust the remote on my B7510. It was hidden in a plain cylinder. In your case I would lie down under the valve and look up to see if there's a little Allen screw in view.

 

[Dave M7040]

I have a B21 with about 1900 hours - great little machine.
Recently my loader bucket tilt (I think that's called "breakout force") has become very under powered. I can barely scoop a half load of gravel. Bucket lift works fine.
When I tilt the bucket under load I get a hissing sound in the valve like fluid bypassing.
Any suggestions?

A simple test would be to to reverse the hoses temporarily. Connect the loader arms to the bucket and the bucket to the loader arms. See if it acts the same. Make the change at the valve or if there are quick couplings even better.
Dont try to use this configuration for any high work or you are apt to get hurt because nothing will be natural. I have seen old farmers suffocate when a large bail of hay rolled back unto them on the seat. They had reconnected the hoses incorrectly and continued to user their tractor`s FEL.
Dave M7040

 

[PointyHairedBoss]

I solved my problem. First I ordered a pressure gauge, hose & fittings from Princess Auto on line. This was my first time ordering from them. The web site is easy to use & delivery was quick - highly recommended.
I found some info in the tractor / loader manuals about how to check the pressure which I did. The relief valve was opening at about 1000 psi, correct setting is around 2000. No wonder I had no power.
The next step was to adjust the relief valve which is also described in the manual. The relief valve for the loader valve block is located under the seat on the right hand side in a very tight space. It was very dirty & looked like it might be seized. I thought this was probably the first time it had to be adjusted for the 10 year old machine so I was pleasantly surprised when the lock nut loosened & the valve stem could be turned freely. After a couple of adjustments I got the relief pressure back up to about 2000 & my loader back in operation. In case anybody has to make this adjustment, you turn the valve stem clockwise (if you were looking at the end of the stem) to increase the pressure. It doesn't take much movement for a fairly large pressure change. I think I turned mine less than one revolution to go from 1000 to 2000 psi.

 

[troutsqueezer]

Thanks for reporting back!

 

[TomSeller]

I'm looking at a used B21 tomorrow for a 2 acre sloped parcel and house on the water that I bought. I have a lot of terracing to do as well as hauling my boats out of the water (boat ramp). If it is in good shape I will snatch it up as the price is good. I figure the B21 is just the ticket?

 

[troutsqueezer]

You won't find a B21 owner who disagrees with that.

 

[TomSeller]

Well I looked at the B21 and should be picking it up Tuesday. 1600 hrs and not abused, so it looks like a good deal to me. It was owned at one time by a landscaping company. But about the only concern I have is the backhoe bucket pins have some flex, but from what I can find, the bushings are replaceable and along with new pins it should be like new. The front bucket had an inch of flex, but not too bad.

The guy had started it up to pull it in out of the rain so I did not see a cold start. Do B21s start well? Curious if the glow plugs are needed and at what temperatures.

 

[TomSeller]

I picked up the B21. When I went to load it, it had a suction leak at the pump intake which was causing the hydro fluid to foam and spit out the little tell tale vent in the back next to the orange fill plug. Simple fix, I tightened the hose clamp and put a few quarts of SUDT and good as new. Owner seemed to want to call off the deal once he saw me find the problem. But too late, already on the trailer. He had not disclosed the problem, money had changed hands, bill of sale signed, so a deal is a deal.

No 3 point arms though. I noticed the 3 pt lever feels like it isn't connected to anything. I don't have my owner's manual yet, but I am sure the 3 pt hydraulics are disconnected with the hoe on. I still would have thought the 3 pt raise/lower lever would have some friction to it. Previous owner never used the 3 pt so I need to buy some arms if the 3 pt system is working. Nice little tractor.

 

[varmint]

I love it! The guy was willing to sell it, for what we readers imagine was a good deal for you, but when he saw how easy it was to fix the secret problem, he tried to renege. Let's hope it works out for you! Maybe you can find some 3-point hardware from a junked out B21...

 

[TomSeller]

I love it! The guy was willing to sell it, for what we readers imagine was a good deal for you, but when he saw how easy it was to fix the secret problem, he tried to renege. Let's hope it works out for you! Maybe you can find some 3-point hardware from a junked out B21...

Yeah, I knew I was taking a risk because when I first looked at it last Saturday he kept saying he didn't want to put any money into it, just selling it "as is". I couldn't find anything wrong with it. Backhoe was strong, loader strong, slight fluid moisture at the backhoe pivot, but I saw nothing to worry about. I figured at $5K it could have a bad hydro and I could still be fine since at 1600 hrs they have been going for $12K around here. One even went for a crazy $17K, approx same hrs but better paint.

My theory is that while loading (bucket forward) the suction line on the pump being elevated was sucking air creating the foaming. Not sure about that but that led me to poke around at the suction line and there is a small radiator style hose partially behind a bracket that seemed to have excess movement. So about 20 min later I had the bracket off and tightened the hose clamp. On and off the trailer a few times and no foam out of the vent tube. When I first saw the foam and shut down the tractor he said that is the "first time I ever saw that". Then he said something about it being messy to keep putting fluid in it when it stops moving, but it "never leaked fluid". So this guy knew full well there was an issue. I then looked around his property and he had some pretty good slopes, so I am guessing when he drove up them the pump sucked in air and created the foam condition spilling out of the vent. When I had it fixed I could see he realized he made a mistake by not having a mechanic look at it. Or maybe he did and the mechanic didn't check the suction hose. As I was leaving he starting saying the tractor was worth more than I paid and sort of stood between me and the door to my truck like we were going to renegotiate. I figured I needed to get out of there and I could tell he figured it would be best to let it go. Made sure the signed bill of sale was in my cab and left. Anyway, filled it back up with fluid as I mentioned and have a nice little TLB.