Lamborghini 105 Hydraulics Air Sucked In?

[DrWazzock]

After reassembling the tractor following the work on the gearbox I replaced the two main hydraulic oil suction filters and the steering pump filter. I filled each filter with clean oil before refitting.
Now after a couple of hours running there is still a buzzing noise from the hydraulic system. I tweeked up the jubilee clips on the short piece of flexible hose between steering pump and filter and thought I’d cured it but now it’s back, most noticeable on start up and fading as it warms up.
I suppose I’ll just have to work my way through the joints on the suction side of both pumps but just wondered if anybody knew of a usual point where this system lets air in/ cracked pipe/ joint failure. It might even be trapped air that eventually clears itself.

 

[njneer]

Jubilee clips on the suction pipes would be the first port of call,or the o rings on the flat faces where the pipe flanges bolt to the pump.

 

[Mur Huwcun]

If your steering is working fine you don’t have much air in system, is the buzzing not a steel pipe vibrating?

 

[DrWazzock]

If your steering is working fine you don’t have much air in system, is the buzzing not a steel pipe vibrating?

The steering and everything hydraulic is working fine. The main pump suction pipe feels as though it’s vibrating at quite a high frequency when you put a hand on it. There are a pair of things that look like small filter housings on LHS of hydraulic unit. Are they some kind of system vibration attenuators? Can they “wear out”? They leaked for years but finally cured their leaks.
anyway the noise isn’t too serious and is intermittent depending on engine speed. Sometimes disappears at certain revs which would point to a resonating pipe as you say.

 

[njneer]

The steering and everything hydraulic is working fine. The main pump suction pipe feels as though it’s vibrating at quite a high frequency when you put a hand on it. There are a pair of things that look like small filter housings on LHS of hydraulic unit. Are they some kind of system vibration attenuators? Can they “wear out”? They leaked for years but finally cured their leaks.
anyway the noise isn’t too serious and is intermittent depending on engine speed. Sometimes disappears at certain revs which would point to a resonating pipe as you say.

Yes they are silencers to quell the resonance of oil passing through metal pipe work, was a fault on the early tractors with hydraulic noise they were fitted in-line to interrupt the pulse effect you get from a gear pump Especially on the steering circuit used to transmit into the can through the steering unit,