How To : Replace Front Caliper Dust and Piston Seals

Action Jackson

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If you've ever changed your brake pads, you might notice a rip or tear in the dust piston seal like the picture below.
 

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What to do? Replace those seals.
If you can change brake pads, then it's a matter of a few more steps and equipment.

Here's what you'll need (you may use something else but this is what I used):

- Socket Set
- Wrenches
- Allen Keys
- A OEM Front Caliper Seal Kit # GAYR 33 26Z [I'd suggest getting 2 of these in case you screw up like I did]
- Jack and stands
- New Brake Fluid
- Disc Brake Spreader Tool [works better than a C Clamp]
- Brake Parts Cleaner Fluid/Spray
- Good Lighting
- Good Ventilation
- Bin to Catch Used Brake Fluid
- Several Clean Lintless rags
- Someone to help bleed the brakes (and maybe the clutch) unless you have Speedbleeders :)
- Gloves If You Wish
- A Small Thin Tool to Remove Piston Seal like a Dull Putty Scraper
- Air Compressor suggested
- Brake Slider Lube of Your Choice
- Eye and Ear Protection If You Wish.
 
Below are pictures of some the tools and equipment.

One is the brake spreader tool. You'll probably need either an old brake pad you don't need, or a thin piece of metal to help compress the piston.

The other picture is the seal kit from any Mazda dealership.
Cost is about $48 CDN + tax.
Each kit is enough to do both front calipers.
 

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Here we go:

1.
- Spray everything down with Brake Cleaner. Wipe if necessary.
- Have something ready to catch the brake fluid.
- Remove the Brake Lines from the back of the caliper :
 

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2.
- It's just like changing the brake pads, so I'll skip some of that explanation, but in a nutshell it takes an Allen Key to do that part.
- You'll need to slide up the caliper:
 

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3.
- This part is like changing the rotors. Remove the caliper off it's slider:
 

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4.
- The air compressor will come in handy. You might recognize this as an air nozzle to blow off debris.

- The 2nd picture shows that you'll need to remove off the tapered nozzle.
 

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5.
- It's a good idea to clean the caliper that you removed with Brake Cleaner.
 

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  • 09 Rear Of Front Caliper Ready To Be Blown.jpg
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6.
- Don't use pieces of wood shown here. Instead use a whole bunch of rags b/c the piston will blow out with a bang.
 

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7.
- Gently insert the air nozzle
- using short bursts, gently blow air into the hole
- Be careful as it can blow out with a real bang!
 

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  • 11 A Perfect Fit - Nozzle and Caliper.jpg
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8.
- don't know if the piston seal was already damaged, or damaged from having the piston popped out with air, but here it is:

- The 2nd picture shows when it's removed:
 

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9.
- 2 shots of the caliper piston:
 

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  • 15 Rear Of Front Caliper Piston.jpg
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10.
- After cleaning out the caliper, insert the new seal. I used some fresh brake fluid to lube the seals:
 

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11.
- and clean off the piston as well. Lube the piston with fresh brake fluid:
 

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12.
- Lube up the new dust seal with fresh brake fluid. This photo shows the supplied grease, I don't use it anymore, just fresh brake fluid.
 

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13.
- slide the dust seal near the end (but not off) the piston:
 

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14.
- if you're wondering, installing the seal this way makes it extremely difficult to install so I don't recommend it.
 

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15.
Now for the way I recommend which is a bit easier.
- carefully insert the piston with the seal near it's bottom into the caliper:
I'm showing a repeat picture to show you the positioning of the dust seal.
 

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16.
- gently use your hands to push the piston into the caliper, but there came a point where I had to use the brake spreader to help out:
 

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17.
- I had to gently offset the spreader and manually help push in the piston. I had to change the position of the disc spreader varying from dead centre to offset numerous times in order to inch in the piston.
 

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