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How to change bearings on a klargester BA, BA-X & BB BioDisc

Klargester BioDisc bearings are a wearable part which should be changed by a wastewater servicing engineer at your annual service as standard when signs of wear start to appear. This can be anywhere from 3 - 5 years as the rotating biological contactor discs are turning on the bearings non-stop. When bearing bushes are worn this can cause the shaft to become unstable and could cause further issues in operation and eventually cause the system to stop working.


Here are some examples of signs of wear on a Klargester BioDisc bearing 

Changing the BA, BA-X or BB BioDisc drive-end bearing (Front Bearing)


Klargester BA, BA-X and BB BioDisc are supplied with a whole drive end bearing, a one-piece bearing with complete housing and insert, often referred to as the ‘front bearing’. To replace this bearing with the same whole bearing you will need to:


1. Remove the BioDisc drive belt, loosen the locking element and remove the bottom pulley from the shaft


2. Raise the shaft with a lifting frame by 2-3 inch


3. Slide the worn bearing off


4. Slide the new whole bearing onto the shaft


5. Put the locking element and bottom pulley back onto the shaft and tighten


6. Lower the shaft back into place


7. Place the nylon and metal retaining plate back over the bearing and tighten bolts


8. Put the belt back onto the bottom and top pulley


Some engineers will opt to use two half bearings rather than a whole drive end bearing as this can be done without having to take the pulleys off. For older systems it can be difficult to get the bottom pulley off without causing damage to the locking element. Often, if the bottom sprocket is forced off old systems to replace the whole bearing a replacement locking element will be needed when putting the bottom pulley back on.


To remove the BA BioDisc whole drive end bearing without removing the bottom pulley and locking element it is possible to cut off the bearing using a grinder and chisel but care should be taken not to damage the shaft or tank in the process. When replacing with two half bearings the shaft should be raised with a lifting frame then the bearings should be secured into place with a nylon and metal retaining plate which bolts to the tank.


Changing the BA, BA-X or BB BioDisc non drive-end bearing


The non-drive end bearing is often referred to as the ‘back bearing’ of the BioDisc. Only one-half bearing is required for the non-drive end. To change this bearing a lifting frame is required to raise the shaft by 2-3 inch. The worn bearing can simply slide out and be replaced with the new bearing. The retaining plate should then cover the bearing to secure the shaft in place.


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Klargester BA-BC Nylon Retaining Plate
£4.50
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Klargester BA-BC Metal Retaining Plate
£4.25
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Klargester BC BioDisc Drive End Bearing
£36.00£29.00
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Klargester BD/BE Half Bearing
£25.00