Brake Spring Removal and Installation
HOLD-DOWN SPRINGSPurpose
Hold-down springs hold the shoes/linings against the backing-plate. The springs provide a flexible grip so that the shoes/linings will still be able to slide back and forth across the surface of the backing-plate.
Tools Needed
- Specialized brake spring tool or
- Pliers / needle nose locking pliers
- Duct Tape (optional)
Removal
- The hold-down spring must first be compressed so that the tip of the retaining pin is cleared of the spring.
- The spring is then rotated so that the slot in top of the spring lines up with the tip of the retaining pin.
NOTE: Be sure to hold the retaining pin from the rear of the backing-plate to prevent the pin from rotating with the spring.
- The hold-down spring can then be released and the pin should slide through the slot in the top of the spring.
- A specialized brake spring tool makes the job very simple. The tool firmly grips the surface of the hold-down spring while providing a clear view of the pin/slot relationship.
Hold-down Spring Tool:
- Conventional pliers or needle nose locking pliers will work if a brake spring tool is not available.
- Grasp the top the the spring with the plier, compress, and rotate.
CAUTION: Excessive pressure can easily distort the top of the spring. Any distortion widens the slot which can cause the pin to pop out during normal operation. If the slot appears distorted or widened it must be replaced.
Installation
- While holding the brake shoe against the backing-plate, insert the retaining pin from the rear of the backing-plate through the appropriate hole in the brake shoe webbing. Verify the shoe is resting squarely on the contact pads of the backing-plate.
NOTE: A strip of duct tape placed across the backside of the pin and backing-plate will help keep the pin from inadvertently falling falling out and will free up a hand to help steady the shoe during the next step.
- Place the hold-down spring and washers over the pin.
- With the thumb of one hand hold the shoe steady while reaching around the backing-plate to hold the retaining pin steady.
- Use your other hand to simultaneously compress and align the slot of the hold-down spring with the pin.
- When the slot and pin are aligned, further compress the spring to clear the tip of the pin and then rotate the spring 90 degrees.
- The slot and tip of the pin should now be opposing each other at a 90 degree angle.
- Verify the tip of the retaining pin is locked into the indents on the surface of the hold-down spring. This will keep the retaining pin from twisting and inadvertently popping out.
RETURN SPRINGS
Purpose
Drum brake systems maintain a constant residual pressure on the wheel cylinders. Return springs overcome this residual pressure and keep the shoes/linings from contacting the drum when not in use. Return springs also overcome the resistance encountered by the shoes/linings as they are retracted across the contact pads on the backing-plate.
Return springs can be separated into two categories, shoe-to-shoe and shoe-to-anchor pin.
Tools Needed
To remove and install return springs, three separate tool are useful. These three tools are often combined into a single pair of "brake pliers".
Return Spring Tool:
Shoe-to-Anchor Pin
These springs are attached at the brake shoe webbing (two 90 degree bends in the shank of the spring slide through and under webbing) and hook around the anchor pin.
Removal
- A brake spring tool is inserted over the top of the anchor pin and rotated
- As you rotate the tool a notch on the bottom side of tool slides under the spring and lifts it up and over the anchor pin.
- The other end of the spring should now just pull up and out of the hole in the brake shoe webbing.
NOTE: Carefully note the color of the spring and which hole it came out of. Liquid typewriting eraser or nail polish can be very useful in marking the appropriate hole for later installation.
Installation
- Install the spring into the brake shoe webbing first. The two 90 degree bends should slide into the hole and lie flat, locking the spring to the webbing.
- Slide the brake spring tool through the looped end of the spring and then hook the notched end of the tool over the anchor pin.
- Pivot the tool upwards to stretch the spring over the anchor pin (a light film of grease on the backside of the brake tool will help the spring slide over and onto the anchor pin).
- Be careful not to over-extend the spring.
WARNING: Do not attempt to help the spring over the anchor pin with your fingers. Should the return spring slip off the tool it could seriously lacerate your hand.
Shoe-to-Shoe Return Springs
Removal
- Note the color and relationship of the spring and the holes in the brake shoe webbing it is attached to.
- Using a pair of brake spring pliers, slide the hooked end of the pliers around and under one end of the spring.
- Place the pointed tip of the pliers onto the brake shoe lining surface directly across from the spring (if the shoes are to be reused, place the tip into a rivet hole or place a thin sheet of wood between the linings and pointed tip).
- Squeeze the pliers and lift the return spring from the hole.
- Release the pliers slowly and remove the other end of the spring.
Installation
- Use the same technique for installing the spring as was used for removing it.
- If a rivet hole is not available, place a thin sheet of wood between the lining and pointed end of the tool.
- A pair of needle nosed pliers may be helpful for guiding the end of the return spring into the hole.
WARNING: Do not attempt to help the spring into the hole with your fingers. Should the return spring slip off the tool it could seriously lacerate your hand.