Hi, my car has been sat idle for so long the front right hand brake calliper is blocked. Can anybody tell me how to unblock it?

You're going to have to rebuild that calliper. Get the best penetrating oil you can find - I prefer Deep Creep from Sea Foam. Soak the nut attaching the brake line to the calliper and unscrew it. If necessary, apply heat to help, but don't damage the nut! Block the brake line with a nail or something similar that's metal. Don't use a toothpick! Then remove the calliper from the hub. Buy a calliper rebuild kit which should include the inner sealing ring and a dust boot. Remove the old dust boot and soak the periphery of the piston with your penetrating fluid. Apply high pressure compressed air to the brake line attachment hole and stand back. The piston should pop out, maybe violently. If it doesn't, apply more penetrating fluid and wait. Once you have the piston out, remove the old sealing ring and clean the cylinder and piston as well as you can. They should be shiny. Now reassemble the whole thing and bleed the brakes - all of them. When you test drive, if the car is pulling to the left under braking, rebuild the left front.

Hi, thanks for the detailed reply. I'll try and get it sorted using your instructions. The weather over here is France is pretty awful now so I have a month or two ahead of me to get the car on the road. Charles

Rebuilding the front caliper would be the ideal solution, perhaps both sides and maybe even the rears. However, I have had some sticky calipers that "fixed" themselves after a bit of driving and braking. Use caution if your brakes are pulling to one side or not fully effective, of course.

On the other hand, if it's the brake line that is blocked, that's a different problem. Could be a defective flexible hose from the wheel well to the caliper.

-Bryan

I should have mentioned that the brake hoses and pads are brand new. The car has just not moved in so long it might well be worth trying to ease the blocks disc free on the road. I am still some way off being able to drive it as I need to replace the soft top 3/4 windows and install the new top. I've owned the car for 29 years and hardly ever driven it, so I'm looking forward to some summer drives in the French countryside.

I have had pretty good luck removing the caliper from the caliper bracket. Then remove the dust seal, support the caliper so the piston is pointing up. Spray silicone around the piston and let it sit. Use a "C" clamp to push the piston into the caliper base. Then I put a piece of wood in the caliper so the piston can't move very much (5-10 mm) and push on the brake peddle. This pushes the piston out to the wood. remove the wood and again use the "C" clamp to compress the piston. I repeat this a few times. The silicone lubricates the fluid seal/piston and is safe in brake systems. I believe the same process using brake fluid would also work. Replace the dust seal and caliper into the bracket.

Hi, just to let you know that I managed to get the calliper working properly using a C clamp. Thanks for the advice. Charles