Brake caliper seized

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TOOL
Posts: 2509
Joined: Thu Sep 01, 2011 10:30 am
Location: Var, France (ex NZ, ex UK)

Brake caliper seized

Post by TOOL » Thu Oct 20, 2016 8:24 pm

Not RX7, but the principal is the same. This is the front left caliper off my orange RX2.

It was seizing up last year and my MOT tester noted it, so I swapped it out for a spare one I had lying around.

Here it is with the piston removed:

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I had to pop it out using compressed air.

The piston is in great shape.

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You can see marks where I have had it in the vice, but that is not a sealing surface and nothing to worry about.

Here's the as found:

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The dust seal is held in by a piece if wire. Here they are removed:

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The outer recess is for the dust seal. The inner recess is for the main seal.

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You can see the main seal in place and on it's way out.

Here's the culprit:

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Lots of grit. Hopefully it'll clean up.
Back in sunny France

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DKWW2000
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Joined: Sun Jul 06, 2014 10:16 pm
Location: English Riviera - South Devon

Re: Brake caliper seized

Post by DKWW2000 » Thu Oct 20, 2016 8:36 pm

I just love the basic component rebuild posts, simple, plenty of pictures & easy to follow. They give you confidence to get on with those jobs you been meaning to do, Thanks & keep up these great posts Andy W(p
RX7 FB S3 - RX7 FC TII Vert
Rotaries Previously Owned:-
2 x NSU Ro 80s - 2 x S2 RX7s - Suzuki RE 5 - DKW(Hercules) W2000 - Norton (Krauser) Commander

codge
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Re: Brake caliper seized

Post by codge » Fri Oct 21, 2016 9:37 am

Yep, great post, great pics.

KiwiDave
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Re: Brake caliper seized

Post by KiwiDave » Fri Oct 21, 2016 1:28 pm

0-0

th:
1985 Sunrise Red S3 TWR
2003 Mercedes E320 CDI Estate AMG

TOOL
Posts: 2509
Joined: Thu Sep 01, 2011 10:30 am
Location: Var, France (ex NZ, ex UK)

Re: Brake caliper seized

Post by TOOL » Fri Oct 21, 2016 4:38 pm

Cleaned up:

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The damaged bore:

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This isn't an issue as the bore only holds the piston in position. The seal is in the bore and seals against the piston, which is in good shape.

After running the hone over it:

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The Girling repair kit

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The remnants of the repair kit

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The seals didn't fit properly and got pinched when I tried to put the piston back in. I'm not sure they were right as there was no part number on the box.
The dust seal ring also didn't fit well. I reused the old one.

NOS Mazda parts always fit. A big difference when putting it into the caliper.

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All done. Should be good to go.

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I've done the same thing on master cylinders and slave cylinders without issue.
Back in sunny France

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Hobbawobba
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Joined: Tue Nov 01, 2011 9:44 pm
Location: Worcester - UK

Re: Brake caliper seized

Post by Hobbawobba » Fri Oct 21, 2016 6:42 pm

It's not as hard as you think to rebuild the brakes aye! I've done my fronts already and got an OEM Mazda rear rebuild kit with all the seals/boots/springs from Atkins. Mazda UK might have some though? It wasn't bad pricing

Nice work though bro. I thought the damage was much worse when I saw that picture ha. Cleaned up well th:

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