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Model 405000x8

So one of the spindles decided to go bye bye. Well I figured I would just replace them both. Everything was working great for 2 minutes when I heard what I thought was a bad bearing. So I parked it and loosened the belt and when I checked the blade was loose. So if I tighten and spin it by hand the nut comes loose. And if I tighten it more the whole spindle won't move. I'm lost right now. Also anyone know if the washer should be flat or cupped. My thought is maybe the washer got warped.

There are quite a few different spindles used by Murray over the years and it would help if we knew which one you are having trouble with.
So please start with the mower model number from under the seat.
Then the make & number of the replacement spindles you fitted & where you got them from

I am guessing and it is a pure guess that you are missing the spacers that go between the bearings so the bearings crush closed before the blade nut gets tight enough

The model is 405000x8

I bought a whole assembly since the aluminum was broken. So I decided just to replace both Assemblies.

One side I have no issues with but the left side is giving me the issues.

Also the large washer is Belleville type (dished) so it must installed the correct way to extra clamping force. Make sure the outside rim of the Belleville washer is against the blade then the large flat washer and nut.
Also the blade nut torque spec is 35 foot-pounds (47,5 N–m).

If the Belleville washer has lost is cup ie spring action then it must be replaced.

Plus I have had problems with Rotary spindles not being assemble right.

I possibly put it in backwards. I will try that tommorow and see. Wouldn't be the first time I put something backwards

That housing has a step machined into the top & bottom to seat the outside race of the bearings
This housing uses the same bearing top & bottom
However there is no lip on the shaft to locate the inner race of the bearing
In place of that there is a tube to prevent the inners being crushed into the outers & locking the bearing when you tighten up the blade or pulley nuts.
Knock one of the bearings out and check that the sleeve is there.
Over the years I have only ever had the one where the wrong sleeve was fitted so the bearings would lock up befor the nut was tight enough to hold the blade firm.

Pull your old ones apart and see how it goes together .

If the Rotary ones are good then they should be exactly the same as the originals so if your housing is missing the spacer then you can use an original one.

Most mowers now days do not sell individual spindle parts, just complete assemblies so it is hard for owners to know what is inside of them.
Some of my suppliers will sell each part as an item so I can rebuild them some only do assemblies.

The mistake most people make is to hold the pulley nut while trying to tighten the blade nut.
This is wrong because the pulley nut will turn & crush the bearings
You must hold the blade while tightening the blade nut so you are clamping the blade between the nut & the flange / boss forged into the spindle shaft.

Yeah I held the blade and I order a new Belleville washer as this one was warped out and didn't sit level.

In that case what you have posted makes no sense unless you have the spindle fitted upside down .
There should be a raised flange on the bottom of the spindle for the blade to tighten up against and hold the blade tight.
Tightening that nut should have no effect on the spindle turning because you are just clamping between the nut & the flange.

bertsmobile1 said:

In that case what you have posted makes no sense unless you have the spindle fitted upside down .
There should be a raised flange on the bottom of the spindle for the blade to tighten up against and hold the blade tight.
Tightening that nut should have no effect on the spindle turning because you are just clamping between the nut & the flange.

Click to expand...

I meant the washer upside down. But I put new washer on and it still is coming loose. I took apart the spindle and it all seems ok. But when I tighten the blade it stops it from spinning. Maybe it's a bad spindle still. I'm not sure at this point.

OK just to be sure we are talking the same language here.
When you say the blade stops spinning do you mean spinning on the shaft or the blade and the shaft stops spinning in the mandrel ?

The blade shaft and pulley all stop. So I called Amazon and they gave me a refund for it so I ordered a new one which will be here Saturday. So I'm going to replace it and see what happens. I spent hours trying to get it to work so I feel like something isn't right because the other one just bolted on with no issues after I put it together. I took the whole thing apart and didn't see anything but who knows.maybe the blade attachment is hitting something. There's resistance on the shaft when I tighten the blade. And if I tighten to much it locks it in place I'll just keep it to have as a parts spindle I guess.

Good call
There is definately something very wrong if tightening the blade tightens the spindle when you are not touching the pulley nut which does tighten the spindle .

I'll post how it goes with the new one once I get it.

bertsmobile1 said:

Good call
There is definately something very wrong if tightening the blade tightens the spindle when you are not touching the pulley nut which does tighten the spindle .

Click to expand...

So now that it stopped raining I put the new spindle on and no issues. I'm guessing that other spindle is damaged somehow but I'll steal the bearings off of it for the future.other than that it will be trash. Thank you for your help.