B21 problem

MarkV · Nov 6, 2001

I had a problem this weekend that I had not experienced before and thought some of you might be able to shed some light on what happened. After about 5 hours of continues use of the backhoe and loader on my B21 the hydraulics gave out. The backhoe would not respond at all and the loader would rise in about 6” increments and then stop. The tractor temp gauge read normal, hydraulic fluid showed full (best I could tell on that silly yellow dip stick), could not find any leaking, the fluid did not feel abnormally hot and the fluid looked normal. (Changed less than 50 hrs ago and no foaming visible) After about 20 minutes of looking and checking the tractor ran fine for another 2 hrs of work.

Any ideas? Would air in the system do something like this and if so, how would it get there?

MarkV

TWINKLE_TOES · Nov 6, 2001

Mark,
Sorry you're having a problem. I don't have any answers/w3tcompact/icons/frown.gif but I do have a question. When this problem occured was operation of the HST and steering normal or was it affected also?

Al

MarkV · Nov 6, 2001

Al,

Good question and I should have added that in my first post. The steering was fine and the HST was working the best I could tell. I had lowered the backhoe and could not raise it so my test was limited.

If I have a problem I am not sure what it is. After looking things over, checking fluids and reconnecting the lines to the backhoe things worked fine the rest of the day. It was strange and I thought someone might point out something I am missing.

Thanks for your interest.

MarkV

TWINKLE_TOES · Nov 6, 2001

Mark,
I plan a trip to my dealer tomorrow to pick up some mower blades. I will
drop out in the shop and see if the mechanic may have some ideas. One of his is worth more than ten of mine.
Al

TWINKLE_TOES · Nov 6, 2001

Mark,

I pulled out the hydraulic schematics and the only single failure I see that is common to the loader and hoe and not HST and steering is the relief valve. If this is the problem it's no big deal, easy to remove and no big ticket items inside. Perhaps a spring, obstuction in the seat?? This is my best guess other than your idea. I will check with the mechanic tomorrow.

DarinRay · Nov 6, 2001

Let us know how you make out because I have the bigger brother and may someday also run into this....Hopefully not but that's whats great about this site because if you need something you can normally find it out here. /w3tcompact/icons/smile.gif Goodluck with your project.

Darin

allmobile · Nov 7, 2001

One of the quick couplers came disconnected even though they looked connected. I've had this happen many times over the years.

Brian

Anonymous Poster · Nov 7, 2001

Sounds like the drive to the pump may be slipping. We had an instance where the hydraulics worked intermittantly, and when turning the pump by hand ,everything looked OK.

It may be possible that the drive splines just slip on a worn section of the drive, and then make just enough contact to drive again.

The only other possibility I can think of is an interruption to the oil supply. Dirty strainer or similar problem.

MarkV · Nov 7, 2001

Al,

Thanks for taking a look at your service schematics. If the problem continues I will be looking at the relief valve first.

MarkV

MarkV · Nov 7, 2001

Brian,

Your thoughts and experience are always valued so thanks for jumping in. I had thought about the quick connects as we were looking for the problem. I did disconnect and reconnect them and one did feel a little strange. At the time I thought, these things are either hooked up or not and we had been running for a good while so that can’t be it. If you have seen connectors break their seal while still looking connected it may be that simple. I’ll take a closer look this weekend and make sure there isn’t any dirt in there.

MarkV