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Collection, Preservation and Display of Old Lawn Mowers

atco B30 rear roller

The centre roller on my B30 is not free wheeling on the main shaft, no clickety click ratchet (just squealing!)

Can't push the mower forward.

The 2 outside ones are fine and working independently.

Anybody done this job and whats involved?


wristpin Sat, 16/04/2022

I think that you will find the centre roller contains the differential which is keyed to the main spindle and transmits the drive to the two outer rollers while allowing them to move independently without scuffing the turf when the machines turns.  The centre roll is keyed to the main spindle and can only turn when the chain drive is either powered or the main plate clutch is disengaged. Before dropping the roll out and pulling it apart, it may be a good idea to remove the final drive chain so that the whole roller can roll with no interference from the drive . With the chain removed the machine should push and pull freely. If there is any serious resistance or noise , it would suggest a problem with one of the bearings that the main spindle rotates in. If there’s no nasty noises or resistance to either forward or back movement , push it forward and execute a sharp left and right turn. At that point, assuming a reasonably grippy surface you should see the outer rollers moving independently to the centre one. If either doesn’t move or you get your squealing noise it will be time to drop the roller from the chassis. The squeal may be coming from the diff which has various shafts and pinions with bushes , one of which may be in need of lubrication.

You mention the “ click, click ratchet noise. That would be from the 20 and 24” machines where the rollers are driven from their outer ends by independent ratchets. As above, the 30” machine has a proper diff with no ratchets to make that noise. 



Andrew Pritchard Sun, 17/04/2022

Thank you Wristpin!

I have now found the sqealing. Its those 2 small rollers on the clutch fork behind the coupling plate.

Haven't sorted yet, but hopefully easy enough.

So with the main drive chain off, the rear roller seems sillent and good, 2 outers working independently. 

But the outer main pulley turns as well, locked to the centre roller.

So this is fundamentally different to the b24.

You cannot manually push it forward without the drivetrain/cylinder going as well?

(unless you disengage the cylinder)

Makes it a bit more tricky to manouver, but at least it sounds like its all working correctly.

wristpin Sun, 17/04/2022

Quote “I have now found the sqealing. Its those 2 small rollers on the clutch fork behind the coupling plate.”

Those Bearings should only turn with the clutch disengaged. With the clutch engaged they should be just clear of the withdrawal thrust plate.  You may be able to carefully pick one seal out of each bearing , insert some grease and then refit the seals. With those thrust bearings rotating freely you may find the machine easier to push. The bearings may be partially seized and skidding on the withdrawal plate.



wristpin Sun, 17/04/2022

Just seen your image of the bearings. Possibly past re- greasing! They are 

a standard bearing , either rubber or steel sealed. Stock item from someone such as Simply Bearings.

Andrew Pritchard Mon, 18/04/2022

An easy fix!

The clutch fork mounting bracket was mis-aligned (unbelieavable that previous owner did not sort this)

So the one side bearing retaining shaft was bottoming out on the centre pulley shaft (metal on metal)

A simple adjustment and all good. Bearings cleaned and greased.

Squealing has gone!

Mower moves slightly better. But of course will never be like the B24 and free wheel.