Author Topic: Thwaites Two Ton Dumper Leaking Steering Valve  (Read 2066 times)

Offline awemawson

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Thwaites Two Ton Dumper Leaking Steering Valve
« on: June 16, 2022, 08:15:32 AM »
My Thwaites 2 ton dumper has been leaking for a long time from the 'steering valve'. It's not the original valve but one I rescued from a 'Bank Mower' that I scrapped. Same fittings and mountings but the swept volume doesn't match the steering ram resulting in MANY turns from lock to lock - but heck it works. The leak is from the upper central shaft seal and is annoying rather than debilitating. Slowly but surerly oil leaks into the steering column itself and back out as the column isn't sealed to it's mounting flange.

The proper solution is to strip the unit and replace the seal but life is too short and I'm still hoping to find a proper ex Thwaites dumper steering valve!

So today stripped out the unit from it's mountings, made a few measurements,  I fired up autocad, draw up a flange gasket, ported the DXF to my laser cutter, cut a gasket, dragged out an old tube of Blue Hylomar and stuck it all back together.

Early days but so far no leak - I'll wait for the oil to come out of the top of the steering column but I don't think the leak is on the pressure side so it should only fill up to the level in the hydraulic reservoir !
« Last Edit: June 16, 2022, 01:12:47 PM by awemawson »
Andrew Mawson
East Sussex