Mowing Pt425 Brush Cutter starts a loud bang

[Clumber]

I used my new 48' brush cutter for the first tine yesterday. With tractor running at full throttle, I switch-on the PTO switch to hear a loud bang as the hyd motor engaged. It run smoothly and quietly after starting. Is the bang normal? The bang happens every time it starts.

I shutdown to look under the deck and it looked okay so i continued It does a very nice cut for a brush cutter on the overgrown lawn and plows through thick brush easily. There are two swing blades on the "turret". But there are four bolts. Is that a normal setup? Is it possible to add two more blades? I would not think more blades are necessary, since it cut so well with two.

 

[KentT]

I used my new 48' brush cutter for the first tine yesterday. With tractor running at full throttle, I switch-on the PTO switch to hear a loud bang as the hyd motor engaged. It run smoothly and quietly after starting. Is the bang normal? The bang happens every time it starts.

I shutdown to look under the deck and it looked okay so i continued It does a very nice cut for a brush cutter on the overgrown lawn and plows through thick brush easily. There are two swing blades on the "turret". But there are four bolts. Is that a normal setup? Is it possible to add two more blades? I would not think more blades are necessary, since it cut so well with two.

That is the blades hitting the bolt heads of the "stops" (or alternate bolt holes) on the stump-jumper hub. Those other bolts serve two purposes...

Always, always, engage the PTO for the brush cutter with the engine speed as low as it can be without killing the engine (ususally slightly above idle) and THEN speed up the engine to full throttle. It won't completely eliminate the "bang" but makes it "livable."

If you engage the PTO at full throttle, you risk the blade hitting so hard that it jumps over the bolt head, ending up 45 degrees away from where it should be, and you have one heck of a vibration issue until you can get it shut down. Then, you have a PITA to sometimes get it back over the bolt head where it belongs... Yep, been there... :laughing:

BTW, I don't think you'd want 4 of the heavy stump-jumper blades on it -- would take too much power to spin them... JMO...

 

[Clumber]

Thanks, Kent.

I did begin to start slower then rev up full power after being surprised the first time. As you said it does not fully eliminate the bang. Seems like a strange design, but what else is new?

 

[BobRip]

Kent speaks with great wisdom.

 

[washita]

I ruined my blades on the brush cutter after about 8 hours of service, once the blades start to wedge on the second set of bolt heads it becomes a constant headache and if you are unlucky the bolt that holds the blade will bend or worse case shear off (been there ) I use the disk conversion kit on mine with swing away style blades, 12+ hours and so far I am pleased, the smaller blades are inexpensive in comparison to the brush hog blades (special order in my area)

 

[MossRoad]

As others have said, throttle your engine back to near idle before engaging the main PTO switch when the brush hog or mower is attached. Once it is spinning smoothly, increase your throttle to MAX!

On my larger IH tractor we had a brush hog on the three point hitch. The blades were very similar to the PT setup and I also had to start it with the throttle way down. That is a LOT of weight to get spinning, so take it easy.

Also, be very aware of the dangers of the brush hog attachment. Never brush hog towards people, your house, car, etc... it can and will fling debris a hundred feet and forward seems to be the most common direction. If you hit the bolt that holds the blade on with a large buried rock, or extremely hard tree stump, the bolt will shear off and that blade will fly out with great force. It could easily kill or maim someone.

When the blade bolt snaps off, the blade will bury itself somewhere and the bushing that goes inside the bolt hole that allows the blade to swing freely will be lost.

Do yourself a favor and get a second set of blades and some extra bushings from PT. Order them with your oil filters so you can make the minimum $$ for shipping. Then get some replacement bolts from a local company. Also, an air compressor, impact wrench and impact sockets make for a much easier blade replacement.

This brush hog is a real beast. It eats everything. And, unfortunately, we as operators tend to get a bit over confident in its abilities and we push it to see just what it will do. We push it until it breaks. And, yes, sometimes we just hit a buried rock 5 minutes after we get the tractor off the trailer and then have to go home. It happens. :laughing:

 

[cqaigy2]

And, yes, sometimes we just hit a buried rock 5 minutes after we get the tractor off the trailer and then have to go home. It happens. :laughing:

That rates an Arg! in pirate parlance.

 

[MossRoad]

That rates an Arg! in pirate parlance.

It happens so often to me that I am contemplating an air compressor for my Suburban to run an air ratchet at the remote property.

 

[Gravy]

Or maybe a nitrogen tank? 12VDC compressors that will fill a small tank and run an impact at a reasonable rate are pretty pricey.

 

[washita]

moss;
there are some decent 12vdc air compressors capable of running an impact we used to install them in the customers service vehicles, usually about the size of a lunch box and not cheap, seen a few ''smog'' pumps converted but low pressure high volume and you would need the opposite