Brush Cutter Died -- The Search For A New Motor

[ponytug]

Not to beat a dead horse, but it is reasonably well known in automotive circles that because of a number of factors, synthetic oil is better at getting by orings and seals than mineral oils.

Nevertheless, a great reminder to folks thinking of changing fluids. Of course all of you with wet brakes need to be careful about the fluid not being too slippery...

All the best,

Peter

The manufacturer, M+S Hydraulic (labeled RRUSA), of the 48 inch brush cutter motors mounted directly on the deck says not to use synthetic oil in their stock products.

PT uses multi-weight motor oil in their hydraulic systems. Some people with the gas powered PTs that use this particular brush cutter have switched to synthetic hydraulic fluid or synthetic motor oil in their machine's hydraulic system.

The warning is for those folks, since they are likely to be unaware of the requirement not to use synthetic fluid in that brand of hydraulic motor.

 

[KentT]

The manufacturer, M+S Hydraulic (labeled RRUSA), of the 48 inch brush cutter motors mounted directly on the deck says not to use synthetic oil in their stock products.

PT uses multi-weight motor oil in their hydraulic systems. Some people with the gas powered PTs that use this particular brush cutter have switched to synthetic hydraulic fluid or synthetic motor oil in their machine's hydraulic system.

The warning is for those folks, since they are likely to be unaware of the requirement not to use synthetic fluid in that brand of hydraulic motor.

Thanks for the heads-up. Thankfully, I have the old-style brushcutter that uses Lovejoy connectors.

 

[KentT]

Shell Rotella motor oil, courtesy of PT.

By the way, I put several strong magnets on my hydraulic filter to pick up metallic trash. An old car of mine used to have a magnet on the drain plug, which always had some debris on it, and I thought it was a good idea.

On my latest filter change (100hr), I let the filter drain into a white pan to see how much magnetic material had been retained. When the filter drained, the oil looked black, but on standing, it all settled out. All of the black bits that you see in the photo are magnetic, i.e. pieces of metal that would have been circulating through the wheel motors.

YMMV...

All the best,

Peter

Peter -- anything unique about those magnets? Where did you get them?

 

[J_J]

Hello Kent. Some of the guys have put hard drive magnets on the hydraulic filter. You could put them directly in the tank, or put one on the hydraulic oil drain. I think anyplace you can put a magnet is a good idea. Some people also put them on gas lines to orient the molecules so that you get better performance. I really don't believe that it works, and it sounds like a con, however someone reading this will state the scientific reason behind this concept. Reminds me of the dowsing rods thingy used to find water. If that were true, you could walk out in the water of a lake and get perpetual motion. I know somebody will say that their grandpa did it. No one to date has had good repeatability.

 

[ponytug]

Nothing special about them. I just put a couple of the HF 100lb pull retrieving magnets on. They are cheap, $5ish, and strong. On the prior filter, I had some smaller magnets on. KJmagnetics have lots of cheap neodynium magnets that are a lot more powerful.

I think the magnets in the tank is a better idea, but I don't yet have a reason to remove the fill plate and punch holes in it.

All the best,

Peter

Peter -- anything unique about those magnets? Where did you get them?

 

[dfkrug]

About a month ago, my 48" brush cutter seized up. It was running fine, squealed for about two seconds, then locked solid.

I have always thought the design of this model with the motor bolted directly to the deck was suspect. Unlike the older variety, there is no Lovejoy coupler to temper the impact shocks from the cutter. On the model I have, they are absorbed directly by the motor. The cutter only had a couple of hundred hours on it. Most of those were cutting tall grass. It only had about five hours of brush cutting. This was a failure that shouldn't have happened.

Did you open up the bad motor to see how it failed? $350....ouch.

 

[SnowRidge]

Did you open up the bad motor to see how it failed? $350....ouch.

Not yet, but I will.