So, I've got contaminated brake pads and rotors - not sure why so going to go through process of finding out whether its seals in the callipers or contamination from oil etc...
Question is..since I don't want to buy new pads to instantly waste with leaking seals...if I clean as best possible with swarfega (pads) and isopropyl (rotors) and do a decent test ride on the road..will any contamination left on the knackered brake pads hide the fact it could be a seal leaking or is a seal leak obvious compared to contamination from outside oil?
Hope that makes sense...Cheers for any help...
I've previously sorted out contaminated sintered pads by putting a blowtorch on them for a short while. Not sure if the same would work for organic, kevlar etc.…
Quick tip boys. Wrap one of those green recycling bags (the ones you get free with your council tax subscription) round your rotor/rotors and calipers when spaying oil about, no more pads for the fire treatment.
If the brake judders and makes a horrible squawk as you roll to a stop it's definitely contaminated. Clean the rotors with IPA or glass cleaner and stick the pads in the dishwasher. Leaking piston seals are unlikely because the pistons are a friggin' tight fit in the seals. The only time it's happened to me it's been when I've split the calipers and there's been brake fluid oozing out of the seam or I've been clumsy bleeding the brakes.
pull brakes with current pads hard and see if anything leaks from pistons. if not then clean discs with fairy or some other detergent then sand before installing new pads.
IMO Your wasting your time with chemical cleaners, heat pads slowly with until they stop smoking, when cool refinish the pad surface with dry wet and dry.
Disks should be scoured with soapy water and wet and dry then brakes bedded in again.
The above has never failed unlike so called brake cleaners.
For pads, brush off dust, wipe with disc brake cleaner, put on a concrete floor, add a bit more disc brake cleaner, set light to it.
Not sure about Swarfega, that itself may contain contaminating stuff.
First thing is put some tissue between the pads and rotor and zip tie the levers closed, if the tissues damp with fluid the next day your seals are leaking and no amount of scrubbing/baking/dishwashing will make any difference..
It's a bugger when you do all that faffing and then find out that your seals are leaking..
I've rescued contaminated pads in the past using a blow torch to heat the pads until they smoke then sand papering them. Just remember to let them cool down before you pick them up to sand back 😳
Cheers all for tips...so I've isopropyl the rotors and cleaned and sanded pads..test ride on road outside house and they're working great...reckon next step is your point @khani...zip tie lever closed and see if tissue paper gets wet. If it doesn't I'm good to go and must have been nunptiness getting pads contaminated some how....
As I wrote above, the pistons are an extremely tight fit in their seals so I doubt they leak. People think the pistons move through the seals but they don't; the seals deform under braking pressure then spring back and the pistons only creep through slowly as the pads wear.
The seals leak, usually when you've reset them and pushed some cack back through the bore.
Other than that, spot on.