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Procedure: Ginetta G40 Brake Caliper Replacement

The bleed screws on the these calipers tend to seize up, especially if they've been over-tightened or not moved for a long time. For this reason, you may need to replace your brake calipers now and again. I've heard of piston failure, but not often.

Buying new calipers

You can only get the calipers from Ginetta, although they are manufactured by Hi-Spec of Kent. The calipers are four pot on the front and two-pot on the rear, with two bleed screws on each caliper (inner and outer). For more information, see: Ginetta G40 Wheels, Tyres & Brakes Info.

Procedure for replacing rear brake calipers

This is a straightforward procedure and requires the following tools:

  • Trolley jack
  • Wheel bolt socket 18mm and torque wrench (set to 80 n/m)
  • Pliers
  • Socket with 8mm Hex bit; or 8mm Allen / Hex key for the caliper mounting bolts
  • 14 mm socket and wrench for the hose union
  • Brake bleeding kit (such as vacuum pump type)
  • 8 mm spanner for the bleed screws

(Step 1) Jack up the car and remove the road wheel.

(Step 2) On the brake caliper, remove the pins that lock the brake pads in place. These pins are secured by a fastening clip through the middle hole of the pin. Pull the clips out with pliers and then remove the pins. You may be able to slide the brake pads out now, or do it in step 4 when removing the caliper.

(Step 3) On the inner side of the caliper, find the union that joins the brake hose to the caliper. Loosen it off with a 14mm socket, but don't remove it. The idea is to loosen it while you have a good purchase, which you won't have when the caliper is off the car.

(Step 4) On the front of the caliper, loosen the two bolts that secure it to the hub, using an 8mm Hex bit / key.

(Step 5) Remove the bolts to free the caliper from the mounting, then remove the brake pads and caliper. Note that there is a washer in the bolt joint and also a washer between the caliper and the mounting, so don't lose them.

(Step 6) With the caliper free, carefully loosen and remove the union bolt between the brake hose and the caliper. Fluid will leak out (slowly).

(Step 7) Carefully put the new caliper onto the brake hose union. Get a good thread purchase, as it would be easy to strip the thread in the alloy caliper. Tighten the union, but not fully tight, as you will need to adjust the position when the caliper is back on the car.

(Step 8) Replace the brake caliper and pads, reversing the previous steps.

(Step 9) Tighten the brake union bolt while ensuring that the brake hose is pointing approximately downwards and not at risk of snagging on the bottom of the coilover. I don't know the torque settings for the caliper union or brake caliper bolts, but I suggest being careful not to over-tighten the union bolt.

(Step 10) Bleed the brakes to get fluid into the caliper, and top up the brake fluid.

(Step 11) Replace the road wheel and press the brake pedal to test the brakes (with the car in motion).

Run the car for a test after this procedure, and then check for leaks to ensure you have tightened it sufficiently (or request the torque settings from Ginetta).


Caliper with worn bleed screw (stuck)