Removing and Replacing the Shoes
The following text refers to Girling HL3 drum brakes which were fitted to Morgans from 1956 - 1993. They are not self adjusting and should be checked regularly for adjustment and hydraulic leaks. If visual checks of the shoes are not made regularly, the drums may become difficult to remove without a puller. It is surprising how a little rust between the hub and brake drum can act as an effective adhesive.
1 Jack up the rear of the car and support it on axle stands.
2 Remove the rear road wheels. If the car has wire wheels with centre lock hub nuts, remember to turn the nut clockwise when removing a wheel on the right side of the vehicle. Turn the centre lock nut anticlockwise when removing a wheel on the left side of the vehicle.
3 Remove the four small screws retaining the brake drum . DO NOT remove the four large screws.
4 Slacken the ( brake adjuster) on the backplate and remove the drum.
5 Use pliers to push down the washers on the brake shoe retaining springs and turn them through ninety degrees, enabling them to be released fom the shoe retaining pins (as shown in Figure 1 )
6 Note of the position of the brake shoe return springs and disengage the handbrake lever from the leading shoe. Lift the shoes from the slots in the adjuster and slave cylinder, then remove them complete with the springs. Place an elastic band around the slave cylinder to prevent the piston from coming out.
7 Examine the shoes for contamination and wear. If the shoe lining is level or almost level to the rivets, they will need replacing. If the linings are bonded, they must be thicker than 1/32nd inch at the thinnest part of the lining. If this is not the case, new linings will be required.
8 The adjuster should move freely. If any brake parts need lubricating, only use copper brake grease and ensure it does not contaminate the brake linings or drum. Copper grease can stand temperatures of up to 1,150 degrees centigrade. Use disc brake cleaner to clean the friction surface of the drums
9 Replacing the shoes is the reversal of the removal procedure. It is wise to purchase new return springs, which should be put on the same way as the originals came off. If you did not make a note when removing them, refer to ( Figure 1). The spring with the gap in the middle belongs on the slave cylinder end of the shoes, and the long spring belongs to the adjuster end. The springs should be mounted between the shoes and backplate.
10 After replacing the brake drum, press the brake pedal a few times to centralise the shoes.
11 Finally adjust the brakes and road test.
Removing the Slave Cylinder
Removing the slave cylinder on the rear brakes of many cars is often quite easy, because after removing the brake drum, shoes and the hydraulic line, there are only two bolts securing the slave cylinder to the backplate. Girling HL3 brakes on Morgans however, have 3 little clips securing the slave cylinder to the backplate, which allow the cylinder to slide up and down. If you have never come across these before, they can be a little fiddly to remove. Whilst I do not profess to know the official way of removing them, the following method worked for me. In Figure 2 I have drawn them in seperate colours for clarity . The spring plate is nearest the backplate and the distance plate is farthest from it.
1 Remove the brake drum and shoes.
2 Cut a short length of clear brake bleeding tube and seal one end with an oil tight bung. Undo the union on the cylinder hydraulic pipe and push the short length of prepared tube on the end of it to minimise loss of brake fluid.
3 Remove the split pin and remove the clevis pin from the handbrake lever.
4 Prise the rubber backplate dust cover from between the backplate and the spring plate.
5 Work a screw driver between the spring plate and retaining plate.
6 Lever the retaining plate forward enough to clear the lugs on the bottom of spring plate and use thin nosed pliers to pull the retaining plate outwards and downwards (see Figure 2).
7 If the handbrake lever is pushed out of the way when the dust cover and retaining plate have been removed, there should be enough room to extract the distance piece. There are two holes in the top of the distance piece. A hook or wire can be inserted through the holes to assist in removing it upwards.
8 The spring plate can now be removed by sliding it upwards to free the wheel cylinder, allowing it to be removed from the backplate.
Servicing the Slave Cylinder
1 Remove the wheel cylinder clip and dust cover, then examine the wheel cylinder for leaks.
2 If brake fluid has leaked past the piston, it will have to be removed.
3 Having extracted the piston, examine the wheel cylinder bore for signs of wear and corrosion. If the sides of the bore are not perfectly smooth, the wheel cylinder will have to be replaced. They are readily available on the Internet for around thirty pounds.
4 If the cylinder bore is perfect, then clean the inside of the cylinder with fresh brake fluid and fit a new piston seal with the flat side facing the shoulder on the piston. Smear new brake fluid on the seal and cylinder bore, then carefully insert the piston into the bore.
5 If the backplate dust cover or spring clips are damaged, a replacement set can be found on the Internet for around ten pounds .
6 Refitting the cylinder is the reversal of the removal procedure. Use copper brake grease when reassembling the retaining clips.