Hot brake disc, warm alloy and lug nuts - Mazda 6 MPS

[jackdg93]

2006 Mazda 6 MPS - 80,000 miles

Went to change both rear brake pads. Driver side caliper piston was a mess so I ordered a rebuild kit and let the car stand on a jack for a few days. Caliper rebuilt (new piston, seals, greased sliding pins), piston went into caliper real easy, installed to car perfectly, bled etc.

With the pads and caliper off however, there was a pretty strong resistance to turning the hub, I could still turn it by hand, but compared to the offside it was much tougher, and would not spin freely for any degrees.

I believe this resistance is causing my wheel and brake disk to heat up.

Why I don't believe its brakes dragging;

After pumping brake pedal hard and then releasing, I can still move the wheel by hand.
After 30min drive at 60mps the rotor wasn't glowing red hot and I do not smell burnt pads

Is there any better course of action than to just buy a new hub/axle assembly? (probably same price as bearing job?)

[E-bmw]

All pads drag slightly for a few hundred yards or so after letting off the brakes, not a problem.

[jackdg93]

E-bmw said:

All pads drag slightly for a few hundred yards or so after letting off the brakes, not a problem.

Yes, however I am suggesting my hot wheels/brakes are not being caused by the brakes, but by the hub/bearing?

Rebuilt calipers and I'm not seeing anything that would cause the brakes to drag and I know that my hub is difficult to turn with caliper / brakes removed

[sparkythecat]

Is there any play in the wheel bearing, or any bearing noise?

A complete new hub and bearing is only around £50

[anonymous-user]

If the wheel wont spin even with the caliper removed as you suggest, then I think you need a new hub bearing / hub assembly as obviously it's not working correctly (assuming this is an undriven wheel?)

[jackdg93]

sparkythecat said:

Is there any play in the wheel bearing, or any bearing noise?

A complete new hub and bearing is only around £50

No play. No noise when driving. In fact the only reason I was aware of this issue is changing pads first time I paid attention to the wheel.

[jackdg93]

JimSuperSix said:

If the wheel wont spin even with the caliper removed as you suggest, then I think you need a new hub bearing / hub assembly as obviously it's not working correctly (assuming this is an undriven wheel?)

Yeah for 60 quid I may as well swap out the hub.
It is a driven wheel as the mps is 4wd/awd

[anonymous-user]

jackdg93 said:

JimSuperSix said:

If the wheel wont spin even with the caliper removed as you suggest, then I think you need a new hub bearing / hub assembly as obviously it's not working correctly (assuming this is an undriven wheel?)

Yeah for 60 quid I may as well swap out the hub.
It is a driven wheel as the mps is 4wd/awd

I suppose in that case you need to try to remove the driveshaft and then see if the hub still feels reluctant to turn.

[Digby]

I know this isn't your issue, but also never rule out brake flexi pipes as a cause of hot discs / wheels and binding calipers. Quite often you can add a new caliper, only to find out a perfect looking flexi hose has broken down internally and will not release fluid.

[anonymous-user]

jackdg93 said:

JimSuperSix said:

If the wheel wont spin even with the caliper removed as you suggest, then I think you need a new hub bearing / hub assembly as obviously it's not working correctly (assuming this is an undriven wheel?)

Yeah for 60 quid I may as well swap out the hub.
It is a driven wheel as the mps is 4wd/awd

You are trying to turn it in neutral yes? Not with the car locked in first whilst jacking it up.

Not taking the piss just always put a car in gear when jacking up and couldnt work out initially why rear wheels wouldnt spin on a bmw

[jackdg93]

CP12 said:

You are trying to turn it in neutral yes? Not with the car locked in first whilst jacking it up.

Not taking the piss just always put a car in gear when jacking up and couldnt work out initially why rear wheels wouldnt spin on a bmw

Haha yes. I think in a depowered state the car doesn't couple the rear driveshaft anyway so the rears should rotate in gear if the car is not powered. Either way I did make sure to try it in neutral and no difference there!

Reading these messages I think I will investigate the bearing/hub route. Even if the flexi is an issue (I think its not), it wouldn't be causing resistance with the brakes/pads not installed.

Thanks everyone for the replies and I'll update if I make some progress

[Boosted LS1]

Lug nuts on a mazda? Ffs get real, it aint no yank tank. More triumph spitfire :-)

[jackdg93]

Just an update in case someone somone else is searching for hot brake problem;

Upon close inspection of the new piston I used to rebuild, there was a 'burr' or sharp bit on one of the edges of the groves, it was just large enough so that when you install the caliper to the guide pins is was jamming the pad onto the disc. 2 min with a file and everything is back to normal.

Thanks everyone for your advice on this