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Collection, Preservation and Display of Old Lawn Mowers

Atco Balmoral 17SE - More Rear Roller Issues

I, like many, am having a problem with an Atco Balmoral 17SE in that the rear roller keeps locking up.  Thanks for the Atco/Qualcast Service bulletins that have been posted on to dropbox, they have helped a bit.  I've replaced the ring gear & pinion as well as the internal roller toothed gears. The rollers rotate in opposite directions OK, and run together when the pinion drive is removed.  When in situ, the roller moves a bit and then locks up (backwards & forwards).  Spinning the rollers when the pinion gear is removed seems to show that the ring gear is not running completely centrally, so the locking up is where the pinion gear is very tight to the ring gear.  Can't see there is any opportunity for any adjustment (other than securing it at the 3 different positions where it is screwed to the shaft).  Have to perhaps assume that the shaft has been bent, but it doesn't appear to be, and there is no discernable wear to the shaft.  Am considering replacing the large white toothed gears/plastic bearings in each half of the rollers, although there doesn't seem much wear/movement.  With the pinion gear in situ, there is a lot of end float of the pinion itself, no side movement (wear), just end float (must be over 1/4 inch) is this usual?  

I am not sure of the production date of my machine as a previous owner has removed the silver label.  I believe though that it is probably a 2000 onwards model, perhaps F016L80599 as it doesn't have the gear support bracket (F016102378), rather it has this as a welded plate onto the machine body 

Would also appreciate advice as to which way around the end roller bearings should be fitted to the machine sides.  Some pictures seem to have the flat surface facing the machine side frames and others, including the blown up parts diagrams seem to show them the other way around.  Does it matter?



c145hoo Mon, 20/04/2020

The answer to the orientation of the end bearings has been cleared up in Service Bulletin 139 of July 1997, in that the bearing flat face should not be attached to the machine body, but the open side (where the bearing is completely visible) should face the machine body....

Next, there is reference to 'body flex' which can cause the rear rollers to lock-up and this being resolved with a body stiffener kit (in my 17SE case = F016102025) which could be retro fitted to affected (earlier) chassis. The bulletin makes reference to all new chassis are now fitted with a tie rod and stiffening bracket.  This bulletin is dated 1997, so as my machines are both 1998 onwards machines, I can see no tie rod or stiffening brackets in place, so did they redesign the chassis to avoid having to fit the tie rod and stiffener bracket etc to prevent body flex.  Does anyone know? 


c145hoo Wed, 22/04/2020

Little surprised that no one has an opinion or is able to comment.  Is the Balmoral 17SE just to new for members on here?  

wristpin Thu, 23/04/2020

The main problem is the difficulty in offering a "spoon fed" solution without the benefit of having the machine to look at. A little analysis is needed.

The most likely causes of the locking up are belt grab or a miss-mesh between the pinion and ring gear.

Belt grab. Does the problem still occur with the belt removed?

Pinion / ring gear binding. What causes that?  ,Worn pinion, worn ring gear, worn pinion bearings, worn roller bearings , worn roller shaft.

Eliminate all the above and it leaves chassis flexing which is fairly extensively covered in the service bulletins.



c145hoo Thu, 23/04/2020

There is no issue with the belt, and the problem exists when the belt isn't attached.  The pinion is new, as is the ring gear and there is no movement in the pinion bearing (other than end float - as mentioned).  There appears little movement in the roller shaft and no groves are found on the shaft itself.  The big issue seems to be that the ring gear doesn't appear to be rotating completely centrally (viewed with the pinion shaft removed), but it is always 'out of true' at the same point, indicating that it is not the bearings.....and it is probably this that is making the pinion shaft tight at this point and therefore unable to rotate.   

Agree that the service bulletins discuss chassis flex, but from what I can see, these all relate to 1997 and earlier chassis, so what did Atco do to chassis going forward to remove chassis flex, as later machines do not appear to have the stiffening plates and bar as standard? 

Appreciate though, your response.

wristpin Thu, 23/04/2020

So is the tight spot due to a manufacturing inaccuracy in the ring gear, its mounting on the roller or is the roller itself not concentric with the dead shaft?

The ring gear is screwed to the roller so you could mark its position and then reposition it a third of a turn  (or what ever the screw positions allow) and then see if the tight spot moves with it or remains where it was . That will give some indication of whether its the gear itself or its mounting on the roller. I see that the two rollers share the same part numbers so it should be possible to swap the rollers round and move the ring gear to what was the rh roller. If that makes a difference it would suggest either an inaccuracy in the mounting of the gear on the original LH roller or in the roller itself .

Any permutation from X !!