Mower Repair

[woodlandfarms]

Sorry no photos on this but I wanted to bring you up to speed on a few mower issues.

I have the large, 90" Rough cut mower. It is by no means flawless, but it gets the job done.

To begin with I broke bolts off the mower and this time around I could not extract them no matter what I did. I went down the hill to my neighbor who had been a truck mechanic initially and now managed all the heavy equipment for the local BLM.

I think he was in it for the experience of tearing stuff apart, but I am glad we did. The bolts broken where over the Hydraulic motor (the direct drive mower blades). So we took the motor off, then removed the large collette. This is when we noticed the first and repeating issue. The bracket that hold the motor is broken again. So we continued to dissassemble, pulling the second locking system out and then the pulley. Finally we dropped the 5 bolts holding the bearing assembly and rotor and the system fell free. We then went to the drill press, and with reverse drills we extracted the bolts.

The motor bracket broke the metal this time (not the weld). So we welded up the plate, then gusseted the arm that supports the motor. My hope is these little gussets will spread the strain, but having this break 2 times leads me to feel we have a PT Design flaw that other owners of this mower should look at.

It was a reasonable simple affair to bolt back up, and my fear of tearing this apart is pretty gone. The one thing you do need, at least for the center motor, is a good pulley remover. I don't have one and it is now on the wish list.

So to a couple of mods we are making. In looking at the blades, we are going to try an expirement. We are welding little tabs to the blades that stick up just before the bolt heads. We think that maybe if the mower blade hits this steel before it hits the bolt head we can reduce the times we have to extract bolts.

Second involves looking into a new system of connecting the blades. My friend knows of a source that sells mower blade bolts that are rounded on one end (to hold the mower blade on) and have an internal hex key space on the other. To remove the blade your come through the top of the deck to get at the hex side of the bolts. I hope this makes sense.

So that is the directions we are trying. Too many hidden rocks on my property for sure.

Carl

 

[American Bulldog]

Funny that you are mowing at this time of year. Only thing to mow here is snow, lol.

The finish mow kit has fixed blades, and there are four per hub. Maybe you should get that from PT.

The mower has been a disappointment for me as well, so I don't use it a lot, as most of the time I have other options. I probably should look into reinforcing it anyway.

 

[American Bulldog]

Hey Carl if you want I can take a pic of my finish kit for you so that you can see what it looks like. Let me know.

 

[woodlandfarms]

I always want to see what the competition looks like. Can you get a pic of both the bottom and top?

I am in no way disappointed in my rough cut mower. I thickened the blades and it made a world of difference. Not sure what a fine cut mower is like, though.

Oh, one other thing I did was bend my new blades at the tips up, like the aleron of a wing. My hope was to mimick grass cutting blades that life the grass.

Ended up lifting a lot of dust.. Oh Well...

Carl

 

[Charlie_Iliff]

Funny that you are mowing at this time of year. Only thing to mow here is snow, lol.

The finish mow kit has fixed blades, and there are four per hub. Maybe you should get that from PT.

The mower has been a disappointment for me as well, so I don't use it a lot, as most of the time I have other options. I probably should look into reinforcing it anyway.

I have the 72" rough cut and have had good luck with it. I have broken some things, but those were due to actions like dropping the deck into a hole and backing down a hill.
I have the finish blade set, but don't recommend it unless it has been improved. It is a trio of rings, each with four stubby blades welded on. On my lawn, which isn't smooth, it scalped pretty badly, but, more importantly, broke a blade off and sent it out from under at speed.
John Coxon and I both replaced the original thick swiveling blades on the stump jumpers with higher-lift lighter blades. I've been using them for a number of years, with decent mowing quality and no failures.

 

[American Bulldog]

Carl, here are what the finish blades look like. I haven't put them on yet.

I think they are the same as what Charlie is talking about.

I say the mower is a disappointment because of the poor engineering. PT is fully aware that the bolts break off faster than you can say "Power Trac", yet they don't seem to care in the least. Another thing is that you can't mow when it is hot out, or you will overheat your PT, at least if the PT is in it's stock form. PT is also fully aware of this problem, yet once again they don't care. The mower really can't handle the heavy growth, and it does a lousy finish mow as well. Only things good about it is that it is quiet, and can mow pretty fast.

 

[Heavyduty]

I wonder why they didn't design the blade to be mounted on the blade carrier with just one BIG bolt instead of two little bolts? This would allow the blade to move if you hit something big.

The way it's designed now, if you hit a stump, the shock goes through the blade, to the blade carrier (some call it a stump jumper), to the hy motor. Instead of the blades taking the beating, everything else does.

 

[cqaigy2]

I wonder why they didn't design the blade to be mounted on the blade carrier with just one BIG bolt instead of two little bolts? This would allow the blade to move if you hit something big.

The way it's designed now, if you hit a stump, the shock goes through the blade, to the blade carrier (some call it a stump jumper), to the hy motor. Instead of the blades taking the beating, everything else does.

I can't really tell how thick the metal is in the 'blade carrier', but it seems one could modify it as Heavyduty suggest by trying out one of the smaller bolts only.

 

[American Bulldog]

I wonder why they didn't design the blade to be mounted on the blade carrier with just one BIG bolt instead of two little bolts? This would allow the blade to move if you hit something big.

The way it's designed now, if you hit a stump, the shock goes through the blade, to the blade carrier (some call it a stump jumper), to the hy motor. Instead of the blades taking the beating, everything else does.

That is the finish kit. it is not designed to hit stumps. More like a conventional lawn mower. The regular rough cut kit has two swing blades per turret, and then the other two mounting bolts break off when the blades hit them.

 

[woodlandfarms]

I thought the finish mower was a different beast than the brush mower...

It is no wonder it does not work. no baffeling, nor tornado effect to suck the grass up. The up tipped blades are not enough, they need a baffle on the mower to help create the suction...

Carl