Technical Brakes again...

[xf1ref]

My stupid phone will not play 4K video I had to download them and convert to a lower resolution

Sorry for this, the videos uploaded on HD resolution.
Before removing pads

After removing the pads

Pads in the carrier and sliders

Are both the pads the same thickness?

Yes

I guess your car will have an ABS unit?

Yes

Are you sure you have a brake problem

Not sure, I'm seeking the answer if is normal the temperature on rims and bolts. Masured on outside -1 Celsius degrees, after a 20 km journey the temperature of front is 55 degrees Celsius.

 

[koalar]

Not sure, I'm seeking the answer if is normal the temperature on rims and bolts. Masured on outside -1 Celsius degrees, after a 20 km journey the temperature of front is 55 degrees Celsius.

Thanks for the videos, they work on my phone now

Too many variables to be 100%

Wheel bearing give off some heat as well as the friction from braking

No discolouration of the discs
No noise
No smell
I can't see any grease melting out

For context
57 degrees is the hottest day
40 degrees is an average bath

55 does not sound excessive to me,

I'd be more concerned if one side was different to the other

See what others think

 

[vexorg]

55°C on the rim of the wheel? That's toasty warm - too hot. The disc should olny be about 55 degrees

 

[jackwhoo]

Hi,

A post stated new caliper square rings , are they the seal rings in the caliper between the caliper and piston to seal in the brake fluid?

J

 

[xf1ref]

55°C on the rim of the wheel? That's toasty warm - too hot. The disc should olny be about 55 degrees

Yes, on the rim and on the bolts. I can't do the measurement on discs because it's a shiny surface and the pyrometer do not detect the real temperature. I regret that I did not measure five months ago when were 35 degree outside.

 

[jackwhoo]

New caliper to piston brake fluid square section seals?

If piston seals have too much lubricant the seal cannot grip the piston to pull it back into caliper when brakes released.

If piston not retracted by seal brakes Will drag.

The groove the piston seal sits in must be free of dirt and corrosion, if groove is clogged and so incorrect shape the seal cannot pull piston back after brakes released.

 

[koalar]

Surely it depends how you measure it, how you drive it,

2 or 3 minutes then pulled up to a heavy stop, and immediately measured, not a panda but vented discs, brakes in good order


145C fronts
100C rears

Even a slightly sticking I would expect 300 or more after a 40 minuites drive

 

[MrMagoo]

If you haven't got brake fade or if they are not binding, then I wouldn't be concerned. It is normal for brakes do get very hot.

 

[xf1ref]

Hi,

A post stated new caliper square rings , are they the seal rings in the caliper between the caliper and piston to seal in the brake fluid?

J

The groove the piston seal sits in must be free of dirt and corrosion, if groove is clogged and so incorrect shape the seal cannot pull piston back after brakes released.

Yes, new caliper square rings. The piston and the caliper without any corrosion or dirt. Everything was cleaned and also dirt seals are new on the calipers, new brake hoses and new brake fluid.
Maybe the heat is quickly transferred to the wheels and that's why the wheels are getting hot.
Does anyone know the torque for the nut of CV axles? I what to tighten the nut to the right torque.

 

[vexorg]

Surely it depends how you measure it, how you drive it,

I know on mine for a typical drive too or from to work then touching the disc for about half a second before getting too hot usually mean somewhere in the 50°C to 70°C range. You can feel if the think is too hot to touch before you get too close.

But he's saying the outer wheel rim is 55°C! not disc.

 

[koalar]

I know on mine for a typical drive too or from to work then touching the disc forabout half a second before getting too hot usual;y mean somewhere in the 50°C to 70°C range. You can feel if the think is too hot to touch before you get too close.

But he's saying the outer wheel rim is 55°C! not disc.

Outer wheel rim? I read it as at the rim near the wheel nuts

Not sure, I'm seeking the answer if is normal the temperature on rims and bolts. Masured on outside -1 Celsius degrees, after a 20 km journey the temperature of front is 55 degrees Celsius.

165C is where wheel nut flags are designed to fail, 55C dose not sound excessive, it's at the point where the everything is touching the disc. It all depends on useage

55°C on the rim of the wheel? That's toasty warm - too hot. The disc should olny be about 55 degrees

There is no normal temperature for the disc. If you measure it straight after pulling up it will measure much more but will fade quickly over time. The whole idea of brakes is to convert the forward momentum to heat


Which is why I said way back you need to drive for about 1/2 a mile without braking and coast to a stop, then measure

Even slightly dragging brakes get to 2-300 degrees C quite quickly as they are continually pumping the heat in

The centre of the hub would be yellow and the pads would be wearing down, grease running out of the bearing, smell as soon as you open the door and so on

I don't see any evidence so far of a problem yet

 

[jrkitching]

Which is why I said way back you need to drive for about 1/2 a mile without braking and coast to a stop, then measure

Exactly.

Note well the part that's in bold. Any use of the foot brake will make this exercise pointless. But it's permissible to (carefully) use the handbrake to bring it to a final stop.

It's also a waste of time to do this if it's raining, or there is a significant amount of water on the road surface.

The only thing I'd do differently is to drive it for 10 miles at a steady speed before coasting to a halt. Most folks could fit this in as part of a normal journey.

If you were to do this on repeated occasions at the same steady speed and record the results, you could find out what's normal for your car. You can then repeat the exercise periodically as a check that you don't have a binding front brake.

 

[vexorg]

My wheels are cold on the average drive, any dragging brake is easy to tell from the centre of the wheel. and using the burny finger way. I'd say braking is needed though, they might stick on slightly and free off again as you drive rather than peranement dragging.

 

[xf1ref]

Today after a normal jurney of 27km, in the city.
Left wheel hub is hotter than the right one. 67.5 vs 63

 

[vexorg]

measure the brake disc!

 

[koalar]

4 degrees is nothing

You don't know if the cool one is doing slightly less work

Even the side of the sun makes a difference if it's out

15 miles of stop start is not a good test

The whole point of the brakes is to convert forward motion to heat. There's a lot of energy to be lost in a lump of metal travelling at 30mph to a stop in a few feet

If you want to see if the brakes are dragging, you need to drive without using the brake, so any heat build up is due the dragging

Hammering it from leek to Macclesfield is enough to get brake fade 350C (13 miles)

Yet when driving slow Crewe to Telford and they are below 40C (40 miles)

And everything in between

 

[xf1ref]

measure the brake disc!

I tried but because disc shiny surface my pyrometer is not reading the real temp. Next time I will try in a different way.

If you want to see if the brakes are dragging, you need to drive without using the brake, so any heat build up is due the dragging

I will try also this but is hard to drive without braking in my area, especially if I want to do a longer journey.

 

[koalar]

Have you got any axle stands

 

[xf1ref]

Have you got any axle stands

Yes, I do.

 

[AnthonyH]

Pads in the carrier
View attachment 434533

Why are these moving like this? Doesn't it have any spring clips?