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How to change brake caliper repair kit on a car – replacement tutorial

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Brake caliper repair [AUTODOC TUTORIAL]

How to change brake caliper repair kit on a car – replacement tutorial

To carry out the replacement you will need the following:

                      a repair kit and related brake system components
                    
                      a set of suitable tools
                    
                      brake cleaner and a brush
                    
                      a brake hose clamp
                    
                      guide pin grease
                    
                      brake fluid suitable for your car
                    
                      a brake bleeder kit
                    
                      a piston wind back tool
                    
                      a torque wrench

Buy tools

AUTODOC recommends

Look at the design and fasteners of the brake caliper
Any brake caliper has a piston dust boot and oil seal, which ensure leak-tightness

1.

To repair a brake caliper, you should access it by lifting the car and removing the wheel
2.

Use a car lift or a jack with jack stands and wheel chocks
3.

Clean the working area, especially where the hose is connected to the caliper, and the fasteners
4.

Unscrew the brake hose fitting

Important!
Before doing that, pinch the hose with a clamp to prevent brake fluid leakage
5.

Unscrew the brake caliper fasteners
6.

If the caliper cannot be detached, insert a suitable tool between its housing and the brake disc
7.

Press on the piston with the tool
8.

If this doesn’t work, pry the caliper housing off, supporting the tool on the caliper bracket

Be careful!
Do not leave the brake hose clamped for too long to prevent its deformationIf possible, use a brake line stopper
9.

Secure the caliper reliably and prepare a suitable wood block to prevent the piston from shooting out

10.

Press the air nozzle to the opening where the brake hose is connected

Important!
Do not create a fully tight connectionA little air bleeding will allow you to adjust the force that will push the piston out
11.

Supply air intermittently, watching the piston movement

Be careful!
The piston is going to pop out of its seal abruptly
12.

Pry up the boot and slide it off, then demount the piston

Please note!
The piston might be difficult to remove due to corrosionIn this case, you can also use the fluid pressure in the system to apply force to the piston
13.

Pinch the brake hose and prepare a container to collect the brake fluid
14.

Put the caliper in the container and connect the brake hose to it

AUTODOC experts recommend:
To carry out this procedure, you’ll need someone to assist youOne of you will control how far the piston is moving out, and the other will press the brake pedal
15.

Remove the clamp from the hose to allow the brake fluid to work while the pedal is pressed
16.

To prevent the piston from popping out abruptly, place the brake pads in front of it
17.

While pressing the brake pedal, check the brake fluid level in the reservoir. This is necessary to prevent air from getting into the system
18.

When you hear a distinctive sound or see traces of brake fluid, check whether the piston can be removed easily
19.

Pinch the brake hose to prevent brake fluid from leaking
20.

Remove the brake pads, extract the piston, and disconnect the caliper
21.

Check the condition of the piston and caliper
22.

Examine the way the dust boot is attached to the caliper housing

Please note!
It might be secured with a retaining ring or simply fitted into the mounting seatFor more reliable fastening the dust boot may have a metal base
23.

Remove the seal located between the caliper housing and the piston
24.

Dismantle all the parts included in the repair kit, like guide pins and their fasteners and dust boots
25.

Clean the brake caliper body and all mounting seats
26.

If the dust boot is fitted inside the component, clean its mounting seat thoroughly

Important!
Some pistons have a factory-applied anti-corrosion coating and are usually a uniform dark colourThe working surface of the piston must be smooth and free of corrosion and damage
27.

If there are any defects, replace the piston
28.

Before reassembling, prepare a small amount of new brake fluid
29.

If the dust boot is located on the outside of the caliper housing, first put it on the piston
30.

Then insert the piston into the caliper housing and install the dust boot
31.

If the dust boot is mounted on the inside, install it first
32.

Next, install the piston

Caution!
Proceed with caution so as not to damage the parts
33.

Install the dust boot and make sure it is fitted tightly into the mounting grooves

Important!
Do not use any lubricant when installing the dust boot as this might make mounting more difficultLubrication will be required during the piston installation step
34.

Lubricate the piston and fit the dust cover on it
35.

Apply some lubricant on the seal

Please note!
The process of installing the dust boot on the piston can be quite complicated, and in some cases you may need an assistantSpread the dust boot evenly while inserting the piston into the caliper housing
36.

If you don't have an assistant, use compressed air
37.

Blow compressed air from below while mounting the piston. The air will expand the dust boot, making it easier to install
38.

Carefully place the piston in its mounting seat and push it slightly until it contacts the seal
39.

While continuing to push the piston carefully, insert it into the housing. Use a special brake caliper piston wind back tool

Be careful!
Avoid misalignment to prevent the piston from jamming and damaging the seal
40.

Reinstall all the elements that were removed
41.

Check that the tapered seat of the bleeder screw in the caliper housing is free of corrosion and damage

Please note!
If the brake caliper is badly damaged and using a repair kit won’t help, you can always buy a new caliperRepair kits often include guide pins and guide pin boots
42.

As the mating surface of the guide pins is inside the bracket, it must be cleaned thoroughly
43.

After cleaning the mounting seats of the guide pins, install new boots. In most cases, they snap easily into place
44.

Apply a small amount of special grease to the guide pins and install them

Be careful!
Do not use excessive amounts of lubricant as this will prevent the guide pins from working properly
45.

Check the condition of the brake discs and pads and replace them if necessary
46.

Make sure that all connections are clean
47.

Tighten the fasteners with a torque wrench to the manufacturer's recommended torque
48.

Loosen the bleeder screw and remove the clamp from the hose to allow the brake fluid to flow into the caliper
49.

Bleed the brake system so that the fluid displaces air from the brake caliper

AUTODOC recommends:
Use special equipment and follow the car manufacturer's recommendations
50.

Connect a brake bleeder device to the bleeder screw
51.

The check valve in the device prevents air from getting back into the system when the brake pedal is released
52.

Press the brake pedal to pump the brake fluid
53.

Fill the brake caliper with fluid by pushing the air out through the bleeder screw

Important!
Check that there are no air bubbles left in the brake hoses
54.

Tighten the bleeder screw and disconnect the equipment
55.

Remove any traces of brake fluid from the surface of the component
56.

Make sure the system is leak-tight by pressing the brake pedal several times in a row

AUTODOC recommends:
Check that the surface of the brake disc or wheel hub that will contact the wheel is smooth and clean
57.

Treat the surface with an anti-corrosion agent
58.

Clean the working surface of the brake disc
59.

Tighten the wheel fasteners one by one in a criss-cross pattern
60.

Press the brake pedal several times until you feel significant resistance

61.

Check the brake fluid level in the reservoir and adjust if necessary

Comments – 2

@user_114289

20.10.2024 08:24

Member

Item 23.remove piston seal.
What item number to replace piston seal?
Only text later on refers to lubricate piston seal.
Could someone follow these instructions and fail to replace piston seal located in piston housing.
Is the piston seal manufactured with a taper on the inside diameter?
If so in which direction does the taper face? Font or rear of the piston housing for correct fittment.
Please could you inform me of your findings.
Regards Trevor.
- Graziana Venturi
  
  21.10.2024 12:32
  
  @user_114289
  
  Moderator
  
  Hello! Our Customer Support team is always ready to help you to find compatible car parts for your car and you can get in touch with us via email - [email protected] or form here: https://www.autodoc.co.uk/services/contact
  When replacing the piston, it is recommended to replace the sealing ring as well. In this case, the ring has a square cross-section, so you can install it on either side. You can find more precise information in the repair manual for your particular car.