The front driver’s side brake on my 1999 Land Rover Discovery 2 TD5 started to occasionally bind on causing the brake and wheel to get hot.  I expected to find that the slider mechanisms had rusted and seized, but they were still in good order.  I then thought that the calliper pistons must have corroded so I pumped the pistons out nearly all the way and folded the dust covers back.

The pistons were not in bad condition, certainly not rusty.  You can see in this photo that there were a few sticky marks on the pistons, but these cleaned off easily by rubbing them with a strip of cloth.

I re-fitted the calliper, hoping that the problem would have gone.  However the brake was still occasionally binding on.  Once again I removed the calliper, but not before buying a new calliper seal kit from a Land Rover dealer.

I once again pumped the pistons nearly all the way out while connected to the car. 

Removing one of the pistons was a lot more difficult than the other.  The binding brake was caused by a build up of rust behind one of the outer dust covers, which forced the rubber hard against the piston.

I cleaned out the slot using a small cutting disc and cleaned the calliper using a needle de-scaler and wire brush.  I then painted the calliper before reassembly using the new seal kit.

I had followed the same procedure previously on my other Discovery, as can be seen by clicking here.