How To : Replace Front Caliper Dust and Piston Seals

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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.

 

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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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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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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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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.