Arwibon Electric Scooter Mechanical Brake Caliper Iron Part and Brake Pad Assembly Guide

If the mechanical disc brake on your Arwibon scooter has worn brake pads, excessive lever travel, abnormal metal noise, or a loose internal piston contact piece, the brake caliper can be disassembled and rebuilt with the correct internal parts.

This guide follows the official arwibon brake caliper assembly procedure. It covers the round magnetic iron part, the two brake pads, the spring clip, and the retaining cotter pin used in the F160/R140 mechanical brake caliper shown in the video.

Tools and Parts Needed

Prepare the following before assembly:

• Needle-nose pliers
• Protective gloves
• Mechanical brake caliper body marked F160/R140
• Round magnetic iron part / piston cap
• Two brake pads
• U-shaped spring clip
• Split pin / cotter pin

Work on a clean table so the small internal parts cannot be lost.

Identify the Caliper Parts

The mechanical brake caliper shown in the official procedure contains several separate pieces.

The main parts are:

• Black mechanical caliper body
• Round metal piston contact piece
• Two brake pads
• Metal return spring
• Cotter pin

Lay all of these parts out before starting.

Do not begin assembly if the retaining pin, spring clip, or round internal iron part is missing.

Install the Round Iron Part

Step 1: Locate the Moving Piston Side

Hold the brake caliper with the rotor slot facing you.

Look inside the caliper and identify the round recess on the moving piston side.

This is where the small round iron piece is installed in the procedure.

Step 2: Place the Iron Part Into the Recess

Take the round metal piece and position it over the circular piston seat.

Press it into the recess.

The video shows the part being held in place magnetically.

Press it flat with your finger and confirm that it sits evenly inside the circular seat.

It should not remain tilted or partially outside the recess.

Check the Iron Part Before Continuing

Tilt the caliper slightly and inspect the part again.

It should remain seated against the piston area.

If it sits at an angle, remove it and check for dirt or debris underneath before reinstalling it.

The brake pads should not be installed until this piece is correctly seated.

Assemble the Brake Pads and Spring Clip

Step 3: Position the Spring Clip

Take the U-shaped metal return spring.

Hold it in the orientation shown in the original procedure, with the upper retaining hole aligned toward the pad retaining-pin area.

Step 4: Fit the First Brake Pad

Place the first brake pad against one side of the spring clip.

The metal backing plate should sit against the spring.

Align the retaining hole in the pad tab with the hole in the spring.

Step 5: Fit the Second Brake Pad

Place the second pad on the opposite side of the spring clip.

The two brake pads should face each other with the spring positioned between their backing plates.

The friction surfaces should face outward toward the rotor-contact sides of the assembly.

Compress the Pad Assembly

Step 6: Squeeze the Pads Together

Use your thumb and index finger to compress the two brake pads around the spring clip.

The spring should remain centered between them.

Align the holes at the top of:

• First brake pad
• Spring clip
• Second brake pad

All three holes need to form one clear passage for the retaining pin.

Insert the Brake Pads Into the Caliper

Step 7: Slide the Pad Assembly Into the Caliper

Keep the pads compressed.

Guide the complete pad-and-spring assembly into the rotor slot of the caliper.

Push it inward gradually.

Each pad should slide into its corresponding side of the caliper.

Do not force the assembly if one pad catches on the caliper body.

Align the Retaining-Pin Holes

Step 8: Check the Side Hole

Once the brake pads are inside the caliper, look through the retaining-pin hole in the side of the caliper.

Move the pads slightly until the following holes line up:

• Caliper outer hole
• First brake pad hole
• Spring clip hole
• Second brake pad hole
• Opposite caliper hole

You should have one straight path through the complete assembly.

Install the Cotter Pin

Step 9: Insert the Split Pin

Take the metal cotter pin.

Insert the straight end through the side of the caliper.

Push it through the first pad, spring clip, second pad, and out through the opposite side of the caliper.

The looped head should remain against the outside of the caliper body.

Make sure enough of the split end extends from the opposite side to be secured.

Lock the Cotter Pin

Step 10: Bend the Pin Ends With Needle-Nose Pliers

Use needle-nose pliers to grip the exposed split ends.

Bend one side outward.

Then bend the second side away from the first.

The purpose is to prevent the pin from sliding back through the caliper during use.

After bending, pull lightly on the pin.

It should remain securely retained.

Check the Pad Assembly

Step 11: Inspect the Pads From the Rotor Slot

Look through the center slot of the caliper.

The two brake pads should sit opposite each other.

The spring clip should remain centered between them.

The pads should not be twisted or trapped at an angle.

Step 12: Check Pad Movement

Press the pads lightly.

The spring clip should allow the pads to move and return within the caliper.

If one pad is stuck, remove the retaining pin and check the spring orientation and pad seating.

Assembly Quick Reference

Keep the Friction Surfaces Clean

Handle the brake pads by the metal backing plates or upper tabs whenever possible.

Do not touch the friction surfaces with oily or greasy gloves.

Oil contamination on a brake pad can reduce braking performance and may cause abnormal noise after installation.

If the friction material becomes heavily contaminated, the pad may need replacement.

Make Sure the Round Iron Part Sits Flat

The round internal iron part shown in the official procedure must sit flat inside its piston recess before the brake pads are installed.

If it is missing or installed incorrectly, the caliper will not be assembled in the same configuration shown in the source procedure.

If the part repeatedly falls out or does not seat correctly, inspect the piston recess and the part itself before continuing.

Do Not Leave the Cotter Pin Straight

The cotter pin retains the brake pads inside the caliper.

After insertion, the exposed split ends need to be bent so the pin cannot slide back out.

Do not reinstall the caliper on the scooter with an unsecured retaining pin.

After bending the pin, confirm that it cannot be pushed back through the mounting hole by hand.

Inspect the Pads Before Installation

Before putting the rebuilt caliper back onto the Arwibon electric scooter, inspect both brake pads.

Do not reuse pads if:

• Friction material is worn away
• The material is cracked
• The backing plate is bent
• The pad is contaminated with oil
• The retaining hole is damaged

Both pads should sit properly in the caliper before the rotor is inserted between them.

Final Check Before Installing the Caliper

Before mounting the caliper back on the scooter, confirm:

• Round iron part is installed
• Two brake pads are present
• Spring clip is centered
• Pad retaining holes are aligned
• Cotter pin passes through the complete assembly
• Cotter pin ends are bent and secured
• Friction surfaces are clean
• Pads are not jammed inside the caliper

Once these checks are complete, the caliper is ready for installation and subsequent cable-tension and rotor-clearance adjustment.

Arwibon Mechanical Brake Compatibility

This procedure is based on the mechanical disc brake caliper marked F160/R140 shown in the official Arwibon service video.

Use the same assembly method on another Arwibon scooter or Arwibon e scooter only when the caliper uses the same round internal iron part, two-pad spring arrangement, and cotter-pin retention system.

Similar-looking mechanical brake calipers can use different pad shapes, springs, or retaining hardware.

Official procedure: Brake Mounting Iron Parts | arwibon