Weird and potentially stupid question regarding calipers...

[Jay]

Hi Guys.
As succinctly as possible;
My'89 1200, has been standing for more than 10 years, in the process of stripping it, to rebuild it.
Have taken off all the calipers to sort them, just wondered...
I know I can blow air through the hole with a compressor nozzle to hopefully pop the stubburn pistons out...but my gun doesnt have a rubber nozzle, so all I have to make the seal air-tight is a crappy old rag... it's not really working.
Do you know if it's possible to screw an M10 compressor quick-release adapter into the space usually housing the bango bolt? Or is the thread pitch different?

TIA gang.

[Pat Conlon]

The thread pitch on the FJ banjos (all of them) is M10 x 1.25.

When I can't use air...I have a neat little tool made by Motion Pro that clamps the ID of the pistons for extraction.

https://www.revzilla.com/motorcycle/motion-pro-brake-caliper-piston-tool

[Jay]

The thread pitch on the FJ banjos (all of them) is M10 x 1.25.

When I can't use air...I have a neat little tool made by Motion Pro that clamps the ID of the pistons for extraction.

https://www.revzilla.com/motorcycle/motion-pro-brake-caliper-piston-tool

Hello again, Pat!
Ah right, I've seen these things before, they do actually work then yeah?
Have you ever had to use it on a REALLY stubborn piston?

thanks

[Pat Conlon]

No, that tool is not for stubborn pistons.
For a stubborn piston that I can't get out with air, I use hydraulic force.
I reconnect the caliper to the brake line, then with a 1/4" plate I clamp the opposite pistons to prevent them from moving then pump up the master and use the pressure of the system to move the stubborn critter.

[Waiex191]

Do yourself a favor - buy a set of used R1 calipers and MC. Huge bolt on upgrade.
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=fz1+brake+caliper+01+05&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=+fz1+brake+caliper

[86FJNJ]

+1 on the gold dot or blue dot R1 calipers!

I'm rebuilding calipers now on my Honda I sprayed on blaster on the inside and let it soak for a few days. Then clamped it in my bench vise and heated it with a heat gun then got channel lock pliers and twisted it out slowly no problem.

[Pat Conlon]

Yea, I agree, the R1 monoblock calipers are a great upgrade for your '89.

Unless I'm doing a concourse restoration with all correct oem parts, if I had a stuck piston in my front oem FJ caliper I wouldn't even bother fussing with it and go directly to the R1 calipers.

Except the Rear caliper, yep, gotta free that piston.