Td5 defender brake fade

[Pinkfoot]

My brake pedal has little pressure , sinks to the floor .

I can pump it up but it fades away again.

With the engine stopped the pedal is hard with no fade.

No noticeable leaks .

Any ideas?

[TreeswingerPerth]

Pads seized in calipers ?

[Pinkfoot]

It is filthy under there and I do get a right hand tug sometimes ( you know what I mean)..

[TreeswingerPerth]

Get the pads out , clean and coppaslip them so they are nice and free , then see how your pedal feels , pull to one side usually means seized pads or caliper .

[Pinkfoot]

Will do .

[Logdaft]

I would check first what Treeswinger suggests, I replaced my rear pads recently & one side of each caliper was seized & needed freeing before I fitted the new pads.

[Pinkfoot]

Any idea why the pedal is firm with the engine off?

[GA Groundcare]

In most vehicles the brake servo runs off vacuum pressure and requires the engine running.

[GA Groundcare]

I'd pull the pads out, clean everything up, use copperslip on assemble and bleed the whole system.

Normally if you can pump the pedal up it's air in the system.

[TreeswingerPerth]

When the engines running the servo gives more power to the brakes . If the pads are seized they flex more in the caliper giving a softer pedal .

If all is free they move easy and contact on the disc making the pedal a bit harder .

They test your servo at mot by pumping the pedal till it's hard then start the engine and the pedal should sink . But not to the floor .