Ripping with Hyd Top Link

marty · Nov 12, 2003

I have a hyd top link and when using the box blade ripper, the cylinder will retract and allow the teeth to go further into the ground. Is there any easy way, from the operator seat, to prevent this from happening? Thanks in advance for your advice!

Marty

Bird · Nov 12, 2003

Marty, if you have a hydraulic top link and it's retracting without you doing it with the lever, then I would assume you have a leak; either internally in the cylinder or the valve isn't properly closing and sealing. I'd suspect the valve first. I never had that problem with my hydraulic top link.

Slamfire · Nov 12, 2003

That or air in the system somewhere.

DocHeb · Nov 12, 2003

I agree with Bird about a possible leak. Although not ripping, I have used my Landpride 72" tiller with a hydraulic top link. I have seen the cylinder retract like a shock absorber whenever the tiller chewed something hard and bucked around, but the cylinder always went back out. After a couple hours of tilling hard clay, the cylinder hadn't retracted and was still in the proper position.

jinman · Nov 13, 2003

Marty, how long are your hoses, and are they the premium 2-wire hoses? It's possible your hoses are ballooning slightly. This would be more pronounced the longer the hoses. My toplink cylinder moves less than 1/2 inch under load. I have it attached with short hoses to a set of remote quick disconnects near the toplink attach point. I find I can counteract any movement with the control valve at the operator's platform. Do you have fine control with your valve? If you correct for the movement, does the cylinder then expand when the load goes away?

If you don't have quick connects, you might try plugging your cylinder's supply and return with the ram slightly extended. Then use your boxblade and see if the cylinder changes position. If it does, it's most likely an internal leak across the cylinder seal. Another way to check this is to run the cylinder all the way out or all the way in and remove the return side (remember this changes with direction). Apply pressure and there should be no constant leakage from the cylinder.

If I had to bet on this from the info you gave us, I'd bet your hydraulic lines are ballooning just enough to cause your problem.

ScottAR · Nov 13, 2003

Premium hoses have 4 wires.

diggerjim · Nov 13, 2003

Marty

Do you have a by-pass valve in your top link system? It sounds to me that the box blade pressure on the top link may be causing the fluid to by-pass thru the valve assy. You should be able to hear it by-passing.

Jim

jinman · Nov 13, 2003

</font><font color="blue" class="small">( Premium hoses have 4 wires. )</font>

Excellent! Thanks for correcting me; that's even better. Those should have very little ballooning whatsoever. On something really critical, it's probably better to use the best hose you can find.

slowrev · Nov 13, 2003

You are right, 4 wire is better for most all applications. Good 2wire hose will work fine for all small to mid sized tractor applications. I doubt that any CUT's come with 4 wire hose, Could be wrong on that though. Just never seen any 4 wire hose on any newer small to mid size tractors. I usually have seen it on larger and industrial grade stuff.

John_Mc · Nov 13, 2003

I've had the same problem with my toplink. It's a Tisco cylinder, and I've not been particularly impressed by it. I believe I do have an internal leak (bypassing the seals?). It also compresses under load. Some of this is due to air in the system. If I run the cylinder all the way in and hold the control there, then all the way out and hold it, this seems to purge the system and lessens the compression for a while.

I'm intrigued by the idea of the hoses ballooning. I'm sure the dealer just used the cheapest hose rated for the PSI they could get when my system was installed. I'll probably take a look at that, once I've resolved the leaky seals.

John Mc

JerryG · Nov 13, 2003

Like Slowrev said, I don't think that any standard compact comes with 4 wire hoses, at least I have never seen 4 wire hose on one.

ScottAR · Nov 14, 2003

Some of mine are. I put 'em on. /forums/images/graemlins/tongue.gif I need to change out a couple more, starting to weather crack. The parts store I use only carries 4 wire hose in my size. They say it's cheaper for them only carrying the one style. I don't mind the slightly higher price.

HayDR · Feb 8, 2004

You need a piloted check valve and this will cure all you movement problems.

JRP · Feb 13, 2004

Get some cylinder stop blocks. These are round things that clip over the top link cylinder rod and limit retraction.

You may have to get on and off to install them.

These are available from tractor dealers.

_RaT_ · Feb 13, 2004

I can rip all the live long day and never have my hydraulic top link budge. It makes me wonder about the reason for his having problems and not mine or any other tractor I have ever been on. Must be an issue on some as CCM has a piloted top link

Glenn9643 · Feb 13, 2004

As you said, it's an issue with some. I bought my top link from Prince Direct and I've never had any problem with it leaking down or "giving" under pressure. However, my tilt cylinder is driving me nuts. It won't hold up very long without having to readjust. When making rounds in a 15 acre patch with a bush-hog I'll be dragging one side of the cutter after a few rounds if I don't! I'm going to take it to a local hydraulics shop and see about getting the dual piloted checkvalves added, but if this is too expensive I'm going to replace it. I'm not sure of the manufacturer for the tilt cylinder, as it was one the dealer came up with when I bought the tractor.

JerryG · Feb 14, 2004

It can be, because of the valve or the cylinder. In either case, it depends on the tolerance stack.

_RaT_ · Feb 14, 2004

Your right Jerry and quite often it can be the valve that leaks more then the cylinder. This was explained at a website that in order to make the valve "leak proof", you would have levers so tight they would be difficult if not almost impossible to move.

MadReferee · Feb 14, 2004

Surplus Center has the double pilot operated check valves for $29.50. All you would have to do is plumb it to your cylinder like the CCM one does. See the link below for more info.

Surplus Center check valve