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Replacing Your Brake Calipers
 
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Pelican Technical Article:

Replacing Your Brake Calipers

Nick Czerula

Time:

3 hours3 hrs

Tab:

$200

Talent:

****

Tools:

Socket set, 7mm Allen bit, 14 mm line wrench, flathead screwdriver.

Applicable Models:

BMW E46 3-Series (1999-06)

Parts Required:

Brake caliper, brake fluid

Hot Tip:

Bleed entire brake system

Performance Gain:

Shorter stopping distances

Complementary Modification:

Replace brake pads and hoses at same time.

BMW E46 service brakes consist of hydraulic brake calipers, one at each wheel. When the brake pedal is pressed, brake fluid is forced out of the brake master cylinder and through the brake lines to each brake caliper. Pistons in the calipers push out and clamp the brake pads against the brake rotors (or discs), thus slowing down the vehicle. As it ages, the brake caliper can leak fluid from the piston seal and may also become corroded or restricted, resulting in poor brake performance. 

If a brake caliper is not performing at 100%, you may notice a slight pull to one side when braking. You can service each brake caliper individually or both at the same time. Corrosion from road salt and grime may affect moving parts of the caliper other than the hydraulic piston. Sometimes you can clean the sliding mechanical parts of the caliper, including the 7mm Allen sliding bolts (see replacement procedure below), and this results in the caliper operating smoothly again. But if this does not work, I recommend replacing the calipers in pairs to maintain an even brake feel. If one caliper is failing, the other will not be far behind.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches. 

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you are working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability. 

Our vehicle may vary slightly from yours as models do change and evolve, as they grow older. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

Lift and support the axle of the vehicle you are replacing the brake calipers on. 

Next, remove the wheels on the axle you are replacing the brake pads on.

See our Pelican Parts technical article on Replacing Your Brake Pads for more information.

There are two ways to reduce the amount of brake fluid loss when you are replacing your brake caliper. One way is to clamp the hose with a hose clamp tool to prevent fluid from leaking. This method could lead to a damaged hose if done incorrectly. 

I prefer to use the second method, depress the brake pedal half way and hold it in place with a stick or brake pedal depressing tool.
Figure 1

I prefer to use the second method, depress the brake pedal half way and hold it in place with a stick or brake pedal depressing tool. This will keep fluid in the master cylinder from leaking.

Working at the brake caliper using a 14mm line wrench, loosen the brake hose.
Figure 2

Working at the brake caliper using a 14mm line wrench, loosen the brake hose. Do not remove it though, as you will unscrew the hose from the caliper later. You can use a regular 14mm open end wrench, however you risk damaging the hex on the brake line.

Using a flathead screwdriver, remove the brake caliper anti-rattle spring by prying it out, while securing it with one hand.
Figure 3

Using a flathead screwdriver, remove the brake caliper anti-rattle spring by prying it out, while securing it with one hand. The spring can pop off and go flying, be sure to hold it steady.

Using a flathead screwdriver, slowly press the brake caliper piston in.
Figure 4

Using a flathead screwdriver, slowly press the brake caliper piston in. This allows brake caliper to be pulled off brake rotor easily. I like to pry between the outer brake pad and brake rotor. This way there is less chance of damaging the caliper piston. Be careful not to damage brake pads if you intend to reuse them

Remove the rubber plugs from the brake caliper mounting fasteners (green arrows).
Figure 5

Remove the rubber plugs from the brake caliper mounting fasteners (green arrows).

Next, using a 7mm Allen bit, remove brake caliper mounting fasteners (green arrows).
Figure 6

Next, using a 7mm Allen bit, remove brake caliper mounting fasteners (green arrows).

Remove the brake caliper from the mounting bracket and unscrew the brake hose from the caliper.
Figure 7

Remove the brake caliper from the mounting bracket and unscrew the brake hose from the caliper. Screw the new caliper into the brake hose then install the caliper in the mounting bracket. Tighten the caliper mounting fasteners and install the plugs and anti-rattle clip.

Now tighten the caliper brake hose.
Figure 8

Now tighten the caliper brake hose. Bleed the brakes.

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Comments and Suggestions:
Rick Comments: BW1 had a question below not a tip. Can you provide the answer.

If doing all 4 calipers, is it better to:
1. remove and replace one at a time, then bleed after all new calipers have been installed, or
2. remove/replace Right Rear RR first, bleed RR caliper, then remove/replace LR, bleed that one, then RF, bleed that one, then LF, and bleed that one.

Thanks
September 25, 2017
  Followup from the Pelican Staff: Go with 1. Replace all, then bleed system. - Nick at Pelican Parts  
Chris Comments: I'm getting ready to do this repair and I'm just wondering why it's rated as hard as it is 4/5?
It looks fairly straightforward and easy.
Is there something I'm missing?

Thanks for all the tutorials. They really are a lifesaver!
June 16, 2017
  Followup from the Pelican Staff: Due to having to jack vehicle and it being a safety repair, brakes. Not very difficult though. - Nick at Pelican Parts  
BW1 Comments: If doing all 4 calipers, is it better to:
1. remove and replace one at a time, then bleed after all new calipers have been installed, or
2. remove/replace Right Rear RR first, bleed RR caliper, then remove/replace LR, bleed that one, then RF, bleed that one, then LF, and bleed that one.

Thanks
April 10, 2016
  Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
 
John Comments: Hi, I own a euro 325ci, at 70-80mph I seem to be suffering from pad knockback of some form on one wheel. Could this be caused by faulty calipers? I do not have any leaks of brake fluid
February 15, 2016
  Followup from the Pelican Staff: If the pads are moving, more likely the caliper mounting bracket is worn. - Nick at Pelican Parts  
Chris Comments: Figure 6 - These are T45 Torx on some models 2002 onwards I think rather than allen bit.
December 12, 2015
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 

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Page last updated: Tue 11/21/2017 02:20:26 AM