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The 2-Stroke Garage => Turning Wrenches => Topic started by: SoCal250 on May 14, 2025, 08:22:41 PM

Title: Front brake system service - Yamaha RD400F
Post by: SoCal250 on May 14, 2025, 08:22:41 PM
I'm in the process of servicing the front brake on my Daytona which was in need of a full teardown as the caliper was dragging badly. So, today's project was "get the stuck piston removed". After removing everything from the bike and breaking everything down, I couldn't get the piston out of the caliper with air. I went up to 75psi and it wasn't budging after it got to a little more than halfway.
20250509_161717_resized.jpg

I decided to use Ken's (kpke) trick of wedging sockets into the ID of the piston and twisting it out with a ratchet and socket extension, but even that didn't work.
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So I went to the method that I used on my TZR last year which takes Ken's trick one step further. I heated up the caliper in the BBQ at 225F for about 20-30 minutes and then melted a couple ice cubes in the ID of the piston. After draining the water out, I then went to Ken's trick and the piston came right out with some easy twisting. :thumbs:  :cheerleader:
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After several round in the ultrasonic, detailed clean up, and masking, I'm off to the next step tomorrow - paint and then bake in the BBQ.
20250514_155858_resized.jpg
Title: Re: Front brake system service - Yamaha RD400F
Post by: dgorms on May 14, 2025, 11:53:37 PM
Nice Russ, I just stored that trick into my data base.
Title: Re: Front brake system service - Yamaha RD400F
Post by: 1976RD400C on May 15, 2025, 09:29:54 AM
Looking good. I just did the grease gun method on my RZ calipers. Oh what a mess that makes.