Brake Caliper Not Fully Releasing

I purchased the vehicle with this issue. I am having difficulty resolving said issue. The first thing I did was bleed the brake system from furthest to nearest. Then I replaced the brake caliper and caliper mount bracker including the brake pad slides. I then replaced the brake hose from the caliper to the engine compartment. This is the front driver side brake caliper. Nothing is bent, the caliper slides as it should. Master Cylinder or ABS related maybe? Ideas? Things to check?

A new caliper has fully retracted Piston(s). Put pads in and wheel rotates. Old rotor, old pads?
You pump brakes and wheel will not rotate?

Everything is new…this includes the rotor, pads, caliper, caliper bracket and brake hose. The piston pushed out, but doesn’t retract causing the inner brake pad to not release pressure to the rotor. The wheel will rotor, but not freely or as it should.

Open the brake bleeder screw.

Does brake fluid shoot out?

And does wheel now turn easier?


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I opened the bleeder valve on all 3 calipers, no difference. The original caliper, the first new caliper and also the second new caliper to ensure the caliper wasn’t the issue. I didn’t do much with testing the original caliper. I just went straight to installing new rotors and pads on both sides and caliper on drivers side. The strength of the brake fluid stream seemed a bit weak when opening the valve, but it does come out.

The problem may not be serious if you turn the wheel three times and it becomes normal. If the brake isn’t getting hot things may be OK.

The wheel definetely gets hot, smells and smokes lol. So definately serious :slight_smile:

You may have gotten a bad rebuilt brake happens.


The caliper on it now, is the second new caliper as stated in a previous comment. I thought that also, but nope…unless it’s going to turn into 2 bad new calipers lol, the world today!

When the right front is sticking , jack up the left rear. If the left rear is sticking too but not the other two wheels, you have a problem on one half of the master cylinder. It could be from crud clogging the return port.

I agree, unlikely to get two bad calipers. But, to rule that out, can the left and right calipers be swapped? If so, and the left still does not release that would prove sticking is not caliper related.

Questions for the real mechanics on the forum and to expand my own knowledge:
Can the hard brake lines corrode internally to creat this problem? As Oldtimer-11 noted, crud in the lines.
AciDDreamZ mentioned the ABS, does that system require a scan tool to reset? Would not the ABS light be on?
As AciDDreamZ asked, can the master cylinder create a problem with one wheel? I can not see how that would happen.

Are you saying use pass caliper on driver side as test? The bleed screw will be down, not up if caliper even fits. Can you bleed it with downward pointing bleed screw?

I will double check today, but I believe that the rear brakes (drum) work fine, wheel moves freely.

No, the calipers cannot be swapped. Yes, it would point the bleed screw down and also the brake hose would not reach. I’ll look at that today also, but I question the bleed screw in the downward position as well?

An ABS Wheel Sensor or control valve unit (if vehicle has one)?

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Just a thought… are you sure it is the brakes and not a bad wheel hub bearing stopping the wheel from turning?

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Sorry, I should have mentioned it, but this one is 4WD and when in 2WD it is rear wheel drive. Yes, I am sure it is not the hub.

Depending on the age of the vehicle, the rubber brake line to the caliper may be failing interally not allowing fluid to flow back.

Are you seeing cracks on the exterior of the rubber?

OP said he replaced it with a new one.

This is quite a conundrum. Diy’er-me, I’ve had weird brake problems before, but never had that particular problem. hmmmm … when you retracted the calipers to install new pads did you first loosen the bleed screw? If not, forcibly retracting the caliper piston could have forced old brake fluid into ABS unit and damaged it. Still, seems pretty unlikely as the explanation.

If I had that same problem I’d probably go in this order:

  • Remove pads (& caliper if necessary) and make sure piston moves freely in caliper bore.

  • Inspect caliper rubber seal where piston comes out, make sure it isn’t binding piston. If unsure, if such a thing is possible w/your configuration, remove rubber entirely, test if it changes situation, as a temporary experiment. (Note: I’ve done this temporary test with drum brake wheel cylinders, but never with disc calipers, may not be possible with calipers)

  • Lube the caliper slides, make sure caliper slides freely on them

  • Replace the brake master cylinder.

  • Remove rubber hose to caliper, make sure it isn’t blocked.

  • Bleed the entire system, making sure to bleed the ABS unit thoroughly as well, per manufacture’s spec. This may require a specialized scan tool in order to open and close the ABS valves during the bleeding process.

  • Still a no-go? Time for a pro shop. ABS unit may be the problem.

I’ve had pretty good luck with the gravity bleeding method. Seems to produce an excellent quality bleed, but takes quite a bit more time. But if there’s other stuff needing doing anyway, consider to gravity bleed while you do the other stuff.

Problem solved! 2 brand new, not rebuild, calipers…both bad :-/. Oh well, push on right lol. Thank you all for your input! Very much appreciated.