Keeping the wheels turning

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PSV parts distributor Imperial Engineering offers advice to operators about the importance of regular component maintenance

Propshafts transmit the rotational torque from the engine via the transmission to the drive axle, and compensate for the relative movement between the gearbox and drive axle. Also known as driveshafts, they can vary in length and incorporate a universal joint (UJ) at each end. Some also feature a splined sliding joint to compensate for relative movement. UJs are typically the weakest links in the propshaft as they have to accommodate severe loads in terms of torsion and stress. Open to the elements, propshafts are also exposed to dirt and water; consequently, they demand regular checks that are appropriate to a vehicle’s duty cycle. It is recommended that buses operating in cities have propshaft checks at intervals not exceeding 25,000km, or every three months.

To help operators avoid potential problems, at Imperial Engineering we recommend the following routine propshaft maintenance checks for buses:

  • Check the main tube body of the propshaft for damage and ensure the balance weights are present and secure. Dents, damage or missing weights could cause excessive vibration through the drivetrain and result in bearing failure or increased wear on the UJs.
  • Inspect the two main yokes on the UJs to ensure they align.
  • Ensure that all of the main mounting flange bolt assemblies are tight. Signs of corrosion around the bolt assembly could indicate a loose assembly.
  • Check the assemblies for excess rust from the bearing caps or seals, as this could be a sign of water ingress and reduced lubrication to the roller bearings.
  • Test the UJs for excess movement. From the underside, lift the UJ to ensure there’s no excess movement at both ends of the propshaft. Check for excess movement on the sliding splined joint.

Some UJ assemblies are sealed units and do not have the capability for re-greasing, while others have greasing points to allow for this. Clean the greasing point and apply the correct specification grease until it emerges from around the seals of the roller bearings. In some instances, propshafts have a protective cover over the splined sliding connection. Ensure the cover is present and has no damage which could allow dirt ingress.

If the propshaft has been removed for any reason, it is recommended to inspect the rear axle and gearbox drive flange bearings for excess play. Inspect the mounting flanges of the propshaft, gearbox and rear axle for any corrosion build-up and damage.

As one of the UKs major PSV propshaft suppliers, Imperial Engineering is an authorised distributor for Dana Spicer Driveshaft and GKN Driveline, offering brand-new OEM units and a comprehensive range of propshaft parts. We also provide a propshaft repair service using OEM service kits and UJs and stock a wide range of service exchange units to minimise lead times and vehicle downtime.

Proper maintenance is essential to ensure components have long lives, says Imperial Engineering. IMPERIAL ENGINEERING