2022-05-09 Front Caliper Rebuild

published by dcarver on Tue, 05/10/2022 - 09:08

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1981 Honda CBX SuperSport

2022-05-09 CBX Front Caliper Rebuild

Front brakes sticking after installing new pads LHS. Had to use clamp to push pistons back in bore, should have been my first clue..

Found a complete kit from BrakeCrafters, and it's a *very high quality* kit, well worth the $$$.

Pieces and Parts. Pistons are SS, organic grease, everything you need!

Caliper off.

Pad retaining clip held by 10mm headed bolt.

Sliding mount configuration.

Future reference picture.

All in all, not that bad. As Found condition.

Not sure if Ray was in these when we did a mechanical refurb. The cross hatch doesn't look factory to me?

Pistons came out pretty clean too.
BTW, I used compressed air to extend one piston while keeping other piston captive using wood working adjustable clamp.
And for the last little bit, used elec tape on the piston and vice grips to pull it completely out.

Removed square rings. They were not as flexible as new ones, but not too bad either.
Once again, don't know if Ray replaced these are or not.

Let the cleaning process begin.

Bought a small brass wheel for the Dremel. It was too large to fit the dust seal groove, so used a hand brass brush there.

Some built up gunge in the grooves were removed.

Declared clean!

New seals installed using just a tad of special grease.

This worked well to seat the piston. Gently rocked it back and forth until she slid right in.

Organic pads, easier on the rare and $$ stock rotors as compared to sintered pads.

50% loaded.

Tape to remind me... calipers need be 'centered' on rotor by applying front brake before tightening caliper to forks.
I haven't bled brakes yet, so thus a reminder....

New speedo cable! Same as XR 200, 250, 350, 400, 600, 650 etc

Used this to keep dripping away!

Off to RHS caliper.

After this pic, finished loading and installing the caliper, bled the brakes.

That's all the pics I have, but here's a couple of videos...

2022-05-10 Not my first FAIL

Permalink Submitted by dcarver on Tue, 05/10/2022 - 21:33.

I knew yesterday I had failed. Front brakes too sticky, still. No real improvement, even after new caliper pistons, seals.

Improper install? Something else? E.g. crud in brake lines or Master Cylinder not relieving pressure.

So today, removed both calipers, removed piston.

Found install damage to dust square rings, my bad. Traces of 'cut' material trapped between cylinder bore and piston.. Probably enough to cause drag?

Thing is, not sure what I could have done better!

Removed 'trace elements', cleaned, greased pistons, re-installed, both calipers.

Marked improvement, and I 'exercised' the pistons using 40 psi air source and a 'block' to keep pistons from exiting. Did this 5x or so each piston, each side.

Decided to clean master cylinder.

BUT... could not figure how to remove rubber boot from piston without destroying it.... have new parts on order but not here yet... so oh well, later.

Decided to clean MC best as can. I knew the little relief hole was open, and the CBX has a plastic cover over the 'holes' to prevent a 'fountain' effect.

So shot suspension cleaner best I could into 'big' and 'small' hole at reservoir bottom, chased with compressed air.

Put all back together, bled brakes, and this time, did NOT depress brake lever prior to torquing calipers to fork.

And... it WORKED! What fixed it? Working caliper pistons again? Cleaning MC? Don't know, Don't Care!

Rotation after initial 'fix'