Hot discs!!!

Robthepiano · Derestricted Danger Joined: 22 Mar 2020 Karma :

Hi guys,

My FZ6 hasn't been ridden for 6 months or so. Initially the wheels would hardly go round, I took the callipers off and brushed the pads and put some copper grease on the pin at the top but a 2km ride has still left the disc too hot to touch. Any advice would be greatly appreciated. I'm a beginner to mechanics but learn quickly. The bike is under lifetime warranty with Yamaha but they're closed at the moment so I just need the bike to run as I'm a key worker.

Thanks
Rob
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Rob

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

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Robthepiano · Derestricted Danger Joined: 22 Mar 2020 Karma :

Robthepiano · Derestricted Danger Joined: 22 Mar 2020 Karma :

Bhud · World Chat Champion Joined: 11 Oct 2018 Karma :

Brakes need rebuilding as they're beginning to bind. I would go for new seals and new pistons, depending on the pistons' condition. If you just pop them out, clean them up and stuff them back in, there's a chance it could happen again, and then you're just duplicating work.

Robthepiano · Derestricted Danger Joined: 22 Mar 2020 Karma :

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

In fairness, it could just be excesive stiction on the seals from being sat meaning the pistons aren't returning.

Might be worth taking the pads off, pumping the pistons out a bit, giving them a fucking good scrub with brake cleaner and a toothbrush, pushing them back in again then reassembling (not forgetting to pump them back out again before riding off).

Be really carefull though because with them binding like that, one of two things will happen. 1) They will eventually bind on all the way and you'll crash. 2) The brake fluid will boil and the brakes will stop working altogether and you'll crash.

So cautious test ride after and check if they are still overheating. Use them a couple of times then ride for a while without touching the front brake, stop without using it and see if it's hot. Don't touch the discs. Not even with gloves on because they can get hot enough to burn you through leather gloves in a fraction of a second. Spit on them and see if it hisses.

Last time I dropped my bike (on the road) it was due to a binding brake (it had a twisted seal on one piston). I felt the steering getting heavy and pulled in to stop. Then hit gravel and the front wheel locked itself just before I stopped.
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steve the grease · Crazy Courier Joined: 26 Jan 2018 Karma :

Lets have a look at a quick fix. If it's been stood for 6 months the pistons will have become stiff , probably not yet siezed properly , but part of the way there. There are a number of solutions some better than others , but you could try this:
Get an old butter knife and push it between the disk and the pad , if it will go , then try and twist it ( pliers?) so that the piston(s) slide back in. Then pump the lever until the pad is touching the disk again. Repeat a couple of times and then do the same on the pad on the other side of the disk. This might ...... free it up enough so that it will last until bike shops are open properly . Probably worth a try, costs nowt.
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All the above is my personal opinion, you can see my lips move, but I'm talking out of my arse.
I've been riding, and fixing , bikes for 50 years, in that time the more I learn, the less I am absolutely sure of.....

steve the grease · Crazy Courier Joined: 26 Jan 2018 Karma :

Lets have a look at a quick fix. If it's been stood for 6 months the pistons will have become stiff , probably not yet siezed properly , but part of the way there. There are a number of solutions some better than others , but you could try this:
Get an old butter knife and push it between the disk and the pad , if it will go , then try and twist it ( pliers?) so that the piston(s) slide back in. Then pump the lever until the pad is touching the disk again. Repeat a couple of times and then do the same on the pad on the other side of the disk. This might ...... free it up enough so that it will last until bike shops are open properly . Probably worth a try, costs nowt.
____________________
All the above is my personal opinion, you can see my lips move, but I'm talking out of my arse.
I've been riding, and fixing , bikes for 50 years, in that time the more I learn, the less I am absolutely sure of.....