G1800 48" center blade cuts lower than outer blades

[bstauss]

Just acquired a G1800 with 48" mower deck. The center blade cuts lower than the outer two blades. I measured the blade height under the deck and the center blade is 5/8" lower than the outer blades. It does not appear to be installed incorrectly. The mower deck is way out of whack adjustment wise, and I've been tinkering with that. But with the deck on the ground, center is clearly lower. Any thoughts on way? The blade does not appear to be bent. Thanks!

 

[Buckeye Guy]

First thought is to check that all 3 blades are the same. Some mowers use flat blades, others use stepped blades (blade edge is lower than center). If they are all the same, check the spindle depth, and make sure the spindles are the same. Has to be one or the other, unless the deck itself is really damaged

 

[Brown Dog]

Loosen or take belt off : turn blade tips together & see how far they are off.

Both sides of each blade in any combination is supposed to be dead level.

Buy a new set of blades & check this same procedure.

I’ve seen new mowers with uneven spindles from the factory.

Too many shims or spacers between the two bearings will lower or raise the spindle shaft making new blades uneven.

You’ve got to start with new unused blades before making any adjustments.

 

[RickB]

Some of those older, smaller Kubota decks use different blades in different positions.

 

[seville009]

same thought process as Brown Dog above - spindle may have been replaced at some point and wasn’t seated properly when installed

 

[bstauss]

Thanks for the suggestions guys. I have another G1800 with same 48" deck and it is the same way - center blade on this one is also 5/8" lower. The Messick's parts diagram shows the same part number for all three blades. If I rotate the blades to where the tips touch/cross, they are all the same height. It's the "north/south" orientation when it is off 5/8". That suggests both decks have a center spindle that is bent forward - what are the odds of that? The previous owner gave me two extra sets of blades (now new, but not visibly damaged or bent), and installing those, no change. I do know one of these tractors was used in a lawn care service (the one with 1100 hours), so it's possible a spindle was replaced and incorrectly. The other one, with 800 hours, was only used to "mow Mama's 6 acres". Guess I need to pull one of the decks and do a closer inspection on the spindle.

 

[Brown Dog]

Have you checked all 3 shafts for up & down loose motion with belts off ??

I don’t see how North & South problem could happen unless deck flange is bent where spindle bolts to it.

I’d still buy a brand new set of blades, install & start all over with your checks IF you don’t find any up & down loose motion in your shafts.

 

[Brown Dog]

I had a New Land Pride Spindle cutting 1/2” lower than the other two.
No loose motion, brand new blades.
Nothing at all wrong.
I used washers between the deck & spindle housing to raise it the 1/2” & it’s been flawless for many years.

5/8” is a LOT BUT it can be fixed.
May have to disassemble a spindle assembly

 

[TractorGuy]

Built in lawn striping?

I have a 54" JD deck that is all out of whack. It looked like new so it probably got pulled off a mower under warranty. Unfortunately I didn't find it until I spent many hours adapting it to my F725 mower. I think I can build a fabricated deck easier than I could figure a fix for it.

 

[RickB]

Have you checked all 3 shafts for up & down loose motion with belts off ??

I don’t see how North & South problem could happen unless deck flange is bent where spindle bolts to it.

I’d still buy a brand new set of blades, install & start all over with your checks IF you don’t find any up & down loose motion in your shafts.

Exactly, it has to be a bent deck shell. New blades are not gonna help. Take the blades off and stack them, if none are bent they will nest perfectly and the blades are good to go.

 

[Brown Dog]

If blades are off 5/8” North & South : I don’t see how they could be level East & West with blade tips together

Stacking blades together is not a true way to diagnose if their bent or warped.

 

[RickB]

I

If blades are off 5/8” North & South : I don’t see how they could be level East & West with blade tips together

Stacking blades together is not a true way to diagnose if their bent or warped.

1. The blade spindle is vertical as viewed from the front or rear but not as viewed from the side.
2. 3 blades stacked together and nested perfectly means they are not bent at all or they are all bent exacty the same amount in exactly the same places which is HIGHLY unlikely. If you do not agree please explain.

 

[Brown Dog]

I’m not being ugly or trying to start an argument at all.

Think of a warped car wheel : laying it on your carport floor will most likely not show up.

Mount it by it’s center bore & turn it then it’ll show you the warpage.

Anything that’s round or turns needs to be mounted & turned / spun to check runout.

I’m no Engineer by any means : this is just my theory lol

 

[RickB]

Stacking the blades demonstrates the relative shape differences. Nothing ugly about that. Each is a template for the others. No engineering degree required.

 

[Ford850]

What's the rake on that deck? The center blade is arranged forward of the two outside blades, so if the deck is tilted too low up front it would have a lower front/center blade tip than the sides.

 

[TractorGuy]

Another way to check spindles it to put a 6in level on top of each pulley. The bubble should be the same on all if the deck is not bent.

 

[Brown Dog]

I’d bet Ford850 is barking up the right tree :thumbsup:

The OP has started a different thread about the deck being low in the front.

 

[RickB]

I’d bet Ford850 is barking up the right tree :thumbsup:

The OP has started a different thread about the deck being low in the front.

That will do it.

 

[radios1]

What's the rake on that deck? The center blade is arranged forward of the two outside blades, so if the deck is tilted too low up front it would have a lower front/center blade tip than the sides.

I was going to say the same thing..