Calipers sticking once brakes get hot

[phred]

I thought I had this fixed but as it turns out not.
Ford calipers and rotors with H-boost. Brakes work great but the calipers stick once the brakes get hot.

I've bled the brakes. Checked the calipers for movement and the brakes do not drag when cool. The slides on the calipers have been polished (both sides) and are well lubricated.

Short of replacing the calipers what else do I look for?

 

[ransil]

Mine needed a spacer ( 2 washers) between the hydro boost & master cylinder

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[Timmy390]

Brakes work great but the calipers stick once the brakes get hot.

Not sure I understand this...what's making them hot? The sticking calipers? I mean I knwo brakes get hot when stopping but unless you're really pounding on them they should cool down between stops due to the air flow over and around the calipers and be what I consider on the high side of warm. Of course different pads and rotor combinations will vary this...

If I had to guess, each time you apply the brakes your fluid bleed off/return is less and less due to a collapsed inner brake hose or as stated the HB needs a a spacer. If the pushrod is too long, it's not releasing the MC all the way thus more and more pressure is building up. My stock booster came with an adjustable rod....

Tim

 

[Broncobowsher]

It isn't the calipers that are the problem. The master cylinder isn't releasing fully. The fluid isn't venting properly back into the master cylinder because the master cylinder is slightly depressed all the time.

 

[phred]

The brakes only drag if they get hot. Meaning lots of stopping in a short period of time. Intown traffic stoplight to stoplight. On the open road no problems unless repeated braking such as a curvey mountain road.
With the truck idling and the wheels off you can spin the rotors so it appears that the master is releasing (also the master and booster are matched both from an 03 superduty).
Once everything gets cool again its all good, but you can't just run down the road to cool them because once they start dragging they just keep getting hotter.

 

[ransil]

2 washers will cost you nothing, cut and make a" c" and it will take 5 minutes to try. Been there had the same issue.

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[phred]

I'll give it a try tonight.