OutdoorKing Repair Forum Forums Repairs and Maintenance Questions On Ride On Mowers Questions on Rover Ride On Mower Rover Colt 5 - Cutter Spindle Bearings

The cutting deck spindle bearings on my colt 5 are seized so I'm trying to get it apart.

I've managed to remove the drive pulley and unscrewed the pulley mounting hub.

Are the bolts underneath for the plate left hand thread ?

Hi mowall, welcome to Outdoorking.

I'm not clear on which parts you are talking about here. Here is the illustrated parts list drawing of the relevant area:



Please give the Item number of the bolts you are referring to.

I have removed 57, 2, 3, and 5 from the top of the cutting deck spindle.

The ones I'm referring to are the 3 bolts and 1 large nut (45 and 57 at the very bottom of the drawing ) that hold the cutting plate to the bottom of the spindle. Are they left hand thread ?

Note : 57 has been used twice in the drawing.

Basically, I just want to know how to get the spindle apart so I can change the seized bearings.

I think you can be pretty confident those will have conventional right hand threads. First, hex-head bolts with left hand threads are very, very unusual, and second, both of those fasteners (45 and 57) have to be undone in common service operations, not just overhauls, and those service operations are the same on this machine as on many, many others. To use a left-hand thread on a design which is just about universal on mowers, both push and ride-on, and which is always right-hand, would cause close to 100% of routine service procedures to result in stripped threads. The manufacturer who did it would be laughed out of the industry.

The reason I ask is because the spindle is just a bar threaded on both ends. The top collar (5) is threaded onto the spindle clockwise (normal for the direction of travel). If the bottom collar is also threaded onto the spindle, and I think it would be, and if it was threaded clockwise then the action of cutting grass and hitting rocks etc might tend to undo it and that's dangerous. Unfortunately, I've already snapped the head of one of the bolts (45) while trying to undo it anticlockwise.

Well they are right hand threads.
Can't get the 3 bolts out without snapping the heads off them.
I will have to either drill them out or make a new boss.

Not in this case. From the location of the discharge chute, spindle rotation is clockwise, viewed from the top. With a right hand thread on the bottom, any resistance [from grass or object impact etc] to the rotation of the collar [called a 'disc boss' by Rover] will tend to tighten the boss on the shaft, not loosen it. The centre bolt will be RH thread also, for the same reason.

And as grumpy says, LH thread bolts are extremely rare. The only cutter deck I can recall encountering them on was the old Mobilco Heavycut self propelled slashers, which have anticlockwise blade rotation.


It's very common indeed for the bolts in blade carrier bosses [on all sizes of mowers] to rust into place, and for the heads to shear off when you try to undo them. They do get wet in service, after all.
Applying a good penetrating lube, and a bit of heat, beforehand is pretty much standard procedure for removing these. An impact wrench/driver can help too, if used with care. Even then, it's still common to need to either replace the boss, or redrill offset and tap it, after the bolts all shear.

Some metal-based anti-seize compound on the bolt threads is a very good idea when assembling them, as well. Including the centre bolt.

Often it's easier to lay out three new holes on the same pitch circle as the existing ones, and just drill and tap them. 120� spacing is usual, but check this on your boss. Rover use US UNC/UNF threads on these bits.

Less mucking about than getting busted bolts out!

Yes, you are right . I was thinking backwards. It will tend to tighten.

All three snapped off.
This is a very good idea to drill new holes on the same boss.
It will certainly save a lot off trouble.
Now to see if I've got one of those taps. Might just use 6mm.

I bet getting those bearings out will be a thrill too.

The thread spec isn't that critical, but the diameter is - pick a size that will be a good fit in the holes in the blade disc. Even if you have to enlarge those holes slightly to get a good fit [say 0.5mm clearance on diameter].

Don't want too much slop there, as these bolts take the torsional shock loads when the blades hit something..

Here are links to the parts that you want to replace.

Bolt CLICK HERE

Nut CLICK HERE