Nissan Qashqai - One overheating brake disc - SiC

After approx 5 miles on A road + 1 jn on Mway, braking was juddery enough for my wife to come home. So I had a look at the caliper expecting to find it seized or binding in some way. Disc was hot enough to turn water to steam. Left it a bit & caliper came off fine, pads came out grubby but also fine except for the groove in them chock full of dust & debris. All cleaned up, regreased & I managed to push the piston back in by hand. This is not a seized caliper! Great. So why is it still overheating????? Any ideas / suggestions welcome.

Nissan Qashqai - One overheating brake disc - bathtub tom

Sticking slider?

Nissan Qashqai - One overheating brake disc - SiC

Thanks, will give that a look tmw. When I've got a bit more time to think straight... what do you recommend? Wet n dry, brake cleaner, WD40, then copper grease?

Nissan Qashqai - One overheating brake disc - edlithgow

Thanks, will give that a look tmw. When I've got a bit more time to think straight... what do you recommend? Wet n dry, brake cleaner, WD40, then copper grease?

I recommend nothing.

Or at least nothing that you've mentioned, except perhaps the WetNdry.

IF its a sticking slider, I would

(a) De-rust the caliper, especially the area behind the stainless steel abutment clips. I use an abrasive disk made from a flattened beer can for this, then I apply a little sunflower oil and grind some more, produ8cing a durable aluminium finish.

Wire brushes, grit wheels, files and grease would be more conventional and less, but still, effective.

(b) Clean and polish the stainless steel clip surface. I use soapy water and aluminium foil but I might use Brasso or Silvo if I had some.

(c) I now think liquid lubricant on the pad ears is probably a mistake, because its likely to attract brake dust (I used to apply a trace of Aluslip) so I just wrap them with PTFE thread tape.

Next time I might scribble on them and the clip surface a bit with a soft pencil as well.

Edited by edlithgow on 29/10/2020 at 01:30

Nissan Qashqai - One overheating brake disc - SiC

Sticking slider?

Sorted. Lower slider pin was a bit of a pita to get out. All done & much happier brakes.

Nissan Qashqai - One overheating brake disc - edlithgow

Terminology can be tricky..

If your caliper pin was stuck then I'd say it WAS a seized caliper.

If your piston was stuck (which it wasn't) then it would be a seized piston.

I took "slider" to mean the surface that the pads, like. slide on, or not, if stuck

Should have checked.

Nissan Qashqai - One overheating brake disc - SiC

Terminology can be tricky..

If your caliper pin was stuck then I'd say it WAS a seized caliper.

If your piston was stuck (which it wasn't) then it would be a seized piston.

I took "slider" to mean the surface that the pads, like. slide on, or not, if stuck

Should have checked.

No problem. I'm sure they will need a complete overhaul at some point during the winter....there's that much muck & water on the N Yorks rural roads. Thanks for your input, it gave me more confidence /determination to sort it out myself??

Nissan Qashqai - One overheating brake disc - edlithgow

4WIW, on caliper pins I've had good results abrading the pin and the hole it moves in with aluminium foil, then lightly applying silicon grease to the pin, wrapping it tightly in PTFE thread tape and applying a little bit more grease on top before fitting. The tape was still where I put it when I stripped them again a few years later.

Silicon grease allegedly has poor corrosion resistance. It has been OK here in Taiwan but might not be where .the roads are aggressively salted in winter. I also have some red rubber grease and some Bendix Ceramlube but havn't used them yet.

Copper antiseize is a popular alternative, but should not be, since it isn't designed as a lubricant and isn't rubber compatible.

I use Brake Clean if I get grease or oil on the disk surfaces. For general cleaning and removal of brake dust and road grime a few buckets of hot water (optionally with detergent and a stiff brush) is more effective and economical, and less of a potential health hazard.

For routine de-greasing, old brake fluid (kept after brake flushing) applied with an old toothbrush, is effective and free, guaranteed compatible, and can be washed off with hot water.

Edited by edlithgow on 03/11/2020 at 13:14

 

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