I think it is to do with the drum brake. The tube itself looks like the outer housing for the brake operating shaft. I haven't seen anything like that before.

Cheers

Greg Locock


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That looks like the hydraulic wheel cylinder and return spring from a drum brake that's somewhat larger than the one in the picture, set up to actuate something within the brake through the sort of torque shaft and lever that's normally used to actuate the 'snail cam' in air operated drum brakes for trucks.

I too have never seen anything quite like the device in the picture.

It appears that the axle is rigidly bolted to the frame through the plates shown.
A serious vehicle manufacturer would interpose some kind of spring or bumper in order to limit the forces applied to the frame at any speed; I infer that the assembly was put together by an amateur, or possibly an agricultural manufacturer, where the design speed is assumed essentially zero.

Mike Halloran
Pembroke Pines, FL, USA

It's a picture from an agricultural trailer. I was wondering whether it is some sort of braking system or suspension system. In almost all agricultural trailers, I have seen, there are no suspension system!! I wonder why!!

as the others have said, it's very likely a part of the braking system.
The shaft operates a cam, which then pushes the brake shoes apart.
It used to be a quite "common" solution for airpressure operated truck brake systems many years ago, not sure what the current state of the affairs is in this respect.

In all likelyhood, it will look something similar to this inside the brake drum.



for agricultural trailers, you also find complete mechanical solutions, which use the inertia of the trailer, pushing against the braking tractor, to generate a braking force at the trailer - see below.


other agricultural solutions:

Suspension doesn't matter at normal tractor speeds. Tractors normally don't have suspension, either. The deflection in the tires is all the suspension you get.

Brake actuator bar or brake actuator rod.

Thnx to all. Your answers were helpful