Brake piston problem 1999 V40

You will have to use a c-clamp or brake piston compressing tool to get that piston back in, while you have the brake master cylinder fluid reservoir cap off.

Get a C Clamp large enough to fit from the back of the caliper to the piston. Put a piece metal across the the piston and tighten the c clamp onto the piston as far as it will go. This will push the piston in to put the pads on the caliper and to be able to fit the caliper back onto the brake rotor after installing the pads.

normally, you need to remove a small portion of brake fluid from the master cylinder before doing this procedure, then after you remove the brake caliper, and brake assembly, then take your c clamp, and a small piece of a 1/1 wood and lay the 1/1 across the piston area, and put the 1 end of the c clamp onto the piece of wood, and start turning the c clamp handle , the piston should go back into the caliper, if not, then it sounds like the piston has froze. when this happens, there are times a person has to replace the caliper, if piston can not be pushed inward.

If the piston was not compressed completely back into caliper, ( I use a large C-clamp,) then the caliper/brake pads will not fit over the Rotor. Also when you compress the piston back into the caliper be sure the brake fluid resevoir doesn't overflow when the fluid returns during the compression process.

will try to help. 1st remove the wheel, then remove the 2 caliper bolts that hold the brake caliper on. after removal of brake caliper, [it should just pull off after the 2 bolts are removed] replace the brake pads[be sure to apply anti squeal lube to the outer side of the pads..not the pad itself,the one not contacting the brake rotor] install the pads, the you will need a C clamp to push the brake caliper pistons back into the caliper. i've used this installation easily. use the old pad ,place it against the caliper piston,then apply the C clamp and push the caliper piston back into the brake caliper, then the brake caliper will slide back over the new pads easily, no need to bleed the brakes if you use this solution. replace the brake caliper bolts, then go to next side and repeat the process. after the replacement of the front brake pads,pump the brakes with engine running!!! it's really a simple process. be sure the brake pads are facing the brake rotors with the [pads] facicing the rotors. no metal facing metal. easy! if you have added brake fluid recently, do not be alarmed if you see fluid coming out of the brake master cylinder,when you use the C clamp to collaspe the brake caliper back into the recessed position. [as always when you have to add brake fluid to the brake master cylinder,it only means your brakes are wearing naturally. if you have a vibration in front wheels or steering wheel when braking, you have a brake rotor or both front brake rotors that need replacement with your brakes also. hope this helps and as always, please get a second opinion if you have doubt. an expert will be happy to help. thank you for choosing fixya.com

1. Remove 2/3 of the brake fluid from the master cylinder.
2. Raise and support the vehicle.
3. Mark (index) the relationship of the wheel to the hub.
4. Remove the tire and wheel assembly. Install 2 wheel nuts in order to retain the rotor.
5. In order to push the piston into the caliper bore and provide clearance between the pads and the rotor, complete the following steps:

5.1. Install a large C-clamp (2) over the top of the caliper housing (1) and against the back of the outboard pad. 5.2. Slowly tighten the C-clamp (2) until the piston pushes into the caliper bore enough to slide the caliper (1) off the rotor.

1. Remove the caliper bolts (2).

1. Remove the caliper (2) from the rotor and caliper bracket. Suspend the caliper from the strut using a wire hook (1).

1. Remove the pads (2, 3) from the caliper bracket (5).
2. Remove the 2 retainers (1) from the caliper bracket (5).

1. Inspect the following parts for cuts, tears, or deterioration. Replace any damaged parts:

• The bolt boots (1)
• The piston boot (7)

1. Inspect the caliper bolts for corrosion or damage. Use new parts, including bushings, when installing the caliper if any corrosion is found. Do not attempt to polish away corrosion.

INSTALLATION PROCEDURE

IMPORTANT: Before installing new brake pads, wipe the outside surface of the caliper boot clean. Use denatured alcohol.

1. Bottom the piston into the caliper bore. If installing new brake pads, use a C-clamp (2) in order to clamp the piston at the same time. Use a metal plate or wooden block across the face of the piston. Do not damage the piston or the caliper boot.

IMPORTANT: Lift the inner-edge caliper boot next to the piston. Press out any trapped air. The boot must lay flat below the level of the piston face.

1. Install the 2 retainers to the caliper bracket.

IMPORTANT: The wear sensor is on the inside pad. The sensor is positioned at the leading edge (upward) of the pad during forward wheel rotation.

1. Install the pads (5) to the caliper bracket (3).

NOTICE: Use care to avoid damaging pin boot when rotating caliper.

1. Install the caliper (2) to the bracket (3).

NOTICE: Refer to Fastener Notice in Service Precautions.

1. Install the caliper bolts (1).

• Tighten the caliper bolts to 31 Nm (23 ft. lbs.) .

1. Remove the wheel nuts securing the rotor to the hub.
2. Install the tire and wheel assemblies. Align the index marks on the wheel and the hub.
3. Lower the vehicle.
4. Fill the master cylinder to the proper level with clean brake fluid.
5. Apply approximately 778 N (175 lbs.) of force to the brake pedal 3 times in order to seat the pads.
6. Burnish the pads and the rotors.

Can't believe three people helping without a visual aid.

Loosen the bleeder valve open on the caliper. Take a C Clamp and use that to press thei piston back in. Very simple. Tighten the bleeder valve shut when doe with sombody holding the brake pedal down firmly as you tighten the valve. That prevents air getting into the line

You will need a larger sized C clamp to slowly push the caliper back into its boot. Make sure your brake fluid reservoir kid is OFF,..allowing for the fluid to go back into the reservoir. Once you have placed the C clamp around the caliper, take an old brake pad and place it across the round piston...place part of the clamp over this pad and tighten the clamp..Do not place the clamp directly on the piston, you may damage it or compress it in crooked. so place a used pad across it. Push the piston back in untill its almost flush with the boot, making sure no dirt is on the silver exposed piston..u dont want dirt to go back inside the boot. Once its in, refit the caliper to its mount with the new pads.

Rear pistons need to be rotated anti clockwise when pushed in.
There is a special tool to do this with, but you could try rotating it with a vice when pushing them in.

This is a verry common procedure for cars with rear disk breaks.
Otherwise the handbrake would not work it they could push themselves in.

Have fun