GT85 on brake disc.

[nmfeb70]

https://www.toolstation.com/holts-brake-cleaner/p43710?searchstr=holts If you have a Toolstation near you, this stuff is very good value.

This is NOT a recommendation, but over the years I've cleaned WD40 off motorcycle tyres with brake cleaner. No ill effects. With anything porous like rubber tyres, brake pads etc, it's usually ok if you do it quickly, but especially with brake pads I'd not even try and clean them if they've had contaminants on them for longer than a few minutes.

Thanks, I have just bought the product and will give it a go.

 

[nmfeb70]

I'll explain more. I am currently riding with a front brake only, the rear brake is hardly having any effect. When I lift the rear wheel off the ground, spin the pedals and then apply the brake, the wheel takes a couple of rotations before coming to a halt.
After riding in wet weather I occasionally spray a little GT85 on the rear derailleur. I suspect the spray has strayed onto the rear disc because the rear pads are gripping the disc but the wheel isn't stopping. I can't imagine worn pads are the problem (the front ones are fine) but is there any other explanation for this other than solvent on the disc? Thanks again.

 

[derrick]

Nail varnish remover.

 

[DaveReading]

I always believe in a bit of trial-and-error when attempting to get my brakes working.

I mean, what could possibly go wrong?

Bin them.

 

[nmfeb70]

I always believe in a bit of trial-and-error when attempting to get my brakes working.

I mean, what could possibly go wrong?

Bin them.

Good advice with a touch of sarcasm!

 

[ColinJ]

Bin them.

Put them to one side and put new ones in. If the new ones don't work either then something else is wrong and you haven't thrown away perfectly good pads! (If the new ones DO work, THEN bin the manky old ones.)

 

[si_c]

I'll explain more. I am currently riding with a front brake only, the rear brake is hardly having any effect. When I lift the rear wheel off the ground, spin the pedals and then apply the brake, the wheel takes a couple of rotations before coming to a halt.
After riding in wet weather I occasionally spray a little GT85 on the rear derailleur. I suspect the spray has strayed onto the rear disc because the rear pads are gripping the disc but the wheel isn't stopping. I can't imagine worn pads are the problem (the front ones are fine) but is there any other explanation for this other than solvent on the disc? Thanks again.

That's a classic contamination issue. Clean the rotors and pads - if that doesn't fix it, new pads and clean the rotors again. When using spray solvent anywhere near disc brakes I use a plastic bag (the same one!) to cover the caliper and pads - this keeps the risk of contamination down.

Of course I've also contaminated pads by riding through a puddle which had oil/diesel on the surface so it might not be the GT85.

 

[I like Skol]

Just a side note for the OP. Spray lubes have no place in bicycle maintenance. The only time they get used is when trying to flush crud out of something where the pressure and solvent effect can be quite useful. Even on a derailleur lubrication should be applied as oil with a spot dripped onto each pivot point (there are 8 of them on a typical Shimano parallelogram derailleur).