Brush Hog Question

[redharley]

I purchased at a sale a 4ft landpride brush hog model 15-48,after getting it home I found both blades are fast to the center disk.Most that I have seen rotate on the disk or stump jumper as some may call it.Before I take it apart I was wandering if any one knows for sure if this is the way it is or should they be free to swing on the disk?Thanks for your input , Bill

 

[TedLaRue]

Bill,
If the blades were designed to not pivot on the stump jumper, there'd be no use in having the stump jumper. The stump jumper is to prevent the non-pivoting bar from battering against a stump or large rock. Solid blades would still do that, so why bother with the stump jumper?

Most likely they're just frozen up. It could also just be rust, or, if it's been used, there may be some grass or something wrapped around the pivot pins making the blades tight.

Spray a little of your favorite penetrating oil on the joints. Then start the engine, engage the PTO and rev the engine up to the rated speed for 540RPM at the PTO. Then, leaving the PTO engaged, quickly drop the engine RPM. That may be enough to get the blades to loosen up. (If you have an overrunning clutch this won't work.)

If that doesn't work, then with the engine off, engage the PTO so the shaft can't rotate, and then seen if you can jerk on the blades and get them to move.

Of course, don't get under the unit unless it is solidly blocked up.

If the brush hog is not on the tractor, you can probably block the PTO shaft from turning by running a length of pipe or rebar through the u-joint on the PTO.

 

[redharley]

thanks for your answer Ted,I should have included in my post that I have used this for several hour's now in brush and sapplings up to 2".I have even lowered it on some small stumps and some larger rotting stumps which have not freed up blades.Either they are really stuck or wore not meant to rotate.I am familiar with bush hog brand and they have always rotatedthis unit looks very similar underneath.Any other thoughts

 

[Wombat125]

Here is the manual for the Landpride RC1548

Page 23 states:

Blades (2): 1/2" x 3" Heat Treated Alloy Steel Free-Swinging Suction Blades

 

[TedLaRue]

I'm not sure 2" saplings nor rotting stumps would put that much of a load on the blades. The tips of those big thick heavy blades are moving about 250 feet per second (close to the length of a football field in one second) so they have lots of momentum.

And if they're just tight, they could have swung back some when necessary, but straightened out before you parked it.

If you have a "stump jumper" disk in the middle, ........oh never mind. Wombat just posted proof that they should be free swinging.

If you try to move a blade by hand, lift up on it a little at the same time to reduce the friction at the pivot.

 

[Wombat125]

I just had a thought. It kind of hurt.

I'm guessing that the previous owner (re)attached the blades without a shim, thus sticking them fast to the stump jumper. This is from page 17:

Blade shim (#30), must be installed to insure a tight and proper fit between the blade bolt and blade. Too tight a fitmay cause blade to not swing back into proper cutting position after striking obstacles.Too loose a fit will cause play between blade bolt and blade resulting in excessive wear on blade carrier, blade bolts and blades. Three sizes of shims are available: 16 ga., part no. 312-075D; 18 ga., part no. 312-082D; & 20 ga., part no. 312-089D

 

[TedLaRue]

I just had a thought. It kind of hurt.

I'm guessing that the previous owner (re)attached the blades without a shim, thus sticking them fast to the stump jumper. ...

Or more likely with a too-thick shim. Leaving out the shim would make the blades too loose, wouldn't it?

Good observation, Wombat!

 

[Wombat125]

Or more likely with a too-thick shim. Leaving out the shim would make the blades too loose, wouldn't it?

Ya, that sounds like a better theory. I'm definitely not an expert here as I've never even seen the bottom of a Land Pride cutter. I'm just thinking that one way or another, the previous owner didn't assemble something correctly.

 

[TedLaRue]

Ya, that sounds like a better theory. I'm definitely not an expert here as I've never even seen the bottom of a Land Pride cutter. I'm just thinking that one way or another, the previous owner didn't assemble something correctly.

I've not seen the bottom of a Land Pride cutter either, and you may well be correct about the previous owner making the blades too tight. Hopefully redharley will let us know what the problem was so other readers can benefit from our posts.

 

[redharley]

Thanks guy's you have been a help for sure,hopefully this weekend will allow some time for disassemly as I have not been able to get them to free up.With manual in hand I'll try to get them apart,unless the wife want's to go for a cycle ride then I'll have to keep the miss's happy.Rainy days does let me get some work done in the summer.I'll try to post after the weekend with some results.