Brakes dragging after rebuild...

[cowman]

So, I had a stuck front caliper - rusted up piston.

Had both front calipers cleaned up and a caliper kit installed, one got new pistons, guide pins all lubed up etc.

Flushed system through (cleaned out rear calipers and refitted too) and filled with fresh brake fluid.

Bled it as best as I could, and brakes seem to work ok.

However - they drag a fair bit and the disks will get hot as well as the hubs even without using the brakes? The hubs will be hot, but you can hold onto them without getting burnt.

I can squeeze a screw driver between the pad and piston and itl retract with no issues. Its happening to both front wheels.

Could it be a bleeding problem? would air in the system cause the piston to not retract properly? do the piston seals have a right way up/down? I have done a few 100kms since refitting everything.

How much drag is ok? should the hubs be getting hot even without using the brakes? I can spin the wheel with one hand no worries but it wont go far once i let go.

Edit : truck is a nissan terrano 1992 manual

[slide]

Could it be a bleeding problem?

How much drag is ok?

No, air in system won't stop calliper retracting (so its not a bleeding issue)
What state are the wheelbearings in?
Drag/heat can be because of them being bad, or overtight.
If you can hold your hand on hub, then I don't think that'd be any problem.
And if you can spin easily with one hand, then its not very tight. (unless you're built like the hulk )

[cowman]

I just took the truck for a drive about 2km, didnt use the brakes over about 10km/h and the discs heated up to a bit over warm not quite hot. Would that be normal? Drive any further and the hub starts to heat up...

[Tarmac]

Check (adjust poss) if bearings are loose tyre disc etc may flex n rub onto pads/ grease bearings. the pads move back by themselves - if that makes sense - ie only preassure on clamping.

[klompy]

Also check you don't have the slides mixed up and on the wrong sides.

[Sadam_Husain]

putting all that hot shit aside coz the rotors and hubs will heat up...... have you jacked the truck up and turned the wheels to see if they are bound up, a bit of drag is normal

[cowman]

Yea I have jacked it up and can spin the wheels with one hand they will got about a quarter turn after I take my hand off, Im just not sure how much is normal and thought that if the hubs are heating up without even using the brakes it might be a bit excesive?

[Sadam_Husain]

If you can still hold your hand on the hub its not hot, if its binding and getting hot you'll be able to smell the oil and grease burning and you wont get your hand anywhere near the hub or rotor

[bang-thud-thump]

Saddam is right - always try the spin as you have done.

I have seen the odd old vehicle internally collapse the hoses when they are squished with a clamp when calipers are removed creating a one way valve deal - rare however but worth tucking away.

if you clamped a hose that is- if not Im talking bollix

[cowman]

nah it seemed to sort itself out in the end, either that or I just stopped putting my hand on stuff