OUTER DISC

710 620 03 OUTER DISC is usually one of the friction surfaces in a brake pack, often found in the tramming motors or sometimes in the rotation unit's braking system. Its main job is pretty straightforward: when hydraulic or spring pressure is applied, it gets squeezed between other discs, creating the friction needed to slow things down or hold them still. Without it, you're not stopping much, and that's a problem on any rig.

When this OUTER DISC starts to wear thin or warp, you'll usually notice your brakes feeling a bit 'soft' or taking longer to engage fully. On tramming brakes, especially on an incline, you might get a bit of drift, or even a noticeable grinding noise if it's really chewed up. If it's in the rotation unit, you could see the drill rod 'creep' a bit when it should be locked solid, which is a big safety and operational headache.

Replacing these isn't rocket science, but you've got to make sure you're checking the mating surfaces on the other discs and the pressure plates too. Don't just swap out the worn disc and call it a day; if the others are scored or warped, you'll be back in there sooner than you think. And always remember to properly clean out the brake housing before reassembly – any crud in there will just accelerate wear on the new parts, making your effort short-lived.