Brakes jamming in the cold.

[yuri2085]

Sorry if its kind of long
TLDR: Brakes are stiff if they are cold.

When my bike is cold (not cold engine, but the whole bike cold from weather) my brakes appear to be always on, once the pads have warmed up its problem solved.
In the winter if I were to leave the bike outside overnight it would bhe very difficult to move the bike and limited testing made me think that driving the bike for a short period (slowly) often lightly holding the brakes on would eventually loosen it up, although I cant rule out weather just leaving it after moving it round a couple of times was fixing it.
If the bike was on the center stand I could without too much difficulty move the wheels around but they would no freewheel at all, same with front and back.
As its not so cold I dont have the same problem but sometimes in the morning the wheels dont spin quite as easily and if its been a cold night I can tell (vaguely) that the bike slows down faster when freewheeling.
During cold nights (winter) the bike would come to a stop from 10 mph within seconds, and i would have to wait 10 mins or so before setting off (Because I try to keep it inside overnight I didnt get to test too much how to resolve the problem, or I was in a rush when the problem occurred)
I had assumed it was something to do with freezing, but it seems to also occur to a lesser extent when it isnt that cold (maybe i imagine it?) and also thought I might have some oil + dirt meaning the wheels arent properly lubricated. But it causes a pretty big effect when very cold so I thought this unlikely.

Just hoping for some educated guesses on what is causing it and how to fix it, its not really causing me any hassle atm.

[bikedemon99]

You can sort this by stripping down the brakes and giving everything a very good clean, get a G clamp on the pistons and push them right in but remember to open the brake fluid resevior master cylinder and watch it doesnt overflow, apply your brake several times til your happy the pistons are moving freely, clean around them so theres nothing stopping there travel and it should be good when you put it all back together, if your rear brake is a drum then remove the brake cam ( rod ) and clean completely plus the hole it came from and lightly grease it. good luck
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Ride safe

[yuri2085]

I've had a look around and it seems I can just unclip the calipers without disconnecting the hydraulics (to make it easier to work with), and then I am removing the pads and using the G clam pto hold the pistons in?

After this I just poke around making sure things are clean with mucoff.
There was mention of 'silicone brake grase' is this needed and what could be used in its place, I am assuming no to 'mucoff bike spray' (the stuff they want you to spray on after cleaning), and I am also assuming I am not applying this to the discs -_-.


Thanks for your help.

[user]

Take the calipers off the disks, remove the pads (if they're held in with pins it's a good idea to loosen these before you remove the calipers) and clean all the dirt off the exposed part of the piston. You can buy special brake cleaning fluid which is fantastic stuff, well worth the money IMO. When the pistons are completely clean push them back into the caliper like bikedemon99 said.

Silicone brake grease is used on the seals when the brakes are completely rebuilt, you won't need that. It's a good idea to put a little copper grease on the back of the pads and on the pad retaining pins to stop them sticking though.

[yuri2085]

Ok thanks for your help will be on it tomorrow morning .

The only thing I am unclear about is the opening the break fluid resovoir master cylinder, this isnt the little clear filler box? How would I identify this and does it really need to be opened.
I think I will just use mucoff spray, a least the mucoff disc brake cleaner only has additional things to 'rehydrate the brake pad' -_- unless thats really worth buying another product for i wont bother.

Thanks again
Chris

[Noxious89123]

[user]

There's a few threads explaining how to do this in the workshop guides here which explain better than I can.

You will need to take the top off the resevoir, the front one will be attached to the brake lever/master cylender assembly, the back one is often tucked away somewhere, depending on the model of bike.

Good luck

[yuri2085]

Alright read the guides and it looks like I know what to do, but its not covered whether its actually worth using a 'disk brake cleaner' rather than just general muc-off.
Other than that I think its all covered, breaking brakes is scary!

Thanks once more for the help:)

edit: And I am guessing its safe to use either copper grease or a high temp silicone doodaa when lubricating pistons and such?

[Noxious89123]

I used some proper brake cleaner and got a couple of small paint brushes from Wilco's for about 65p. Got them lovely and clean.

You can use a little copper grease on the backs of the brake pads, to stop them squealing. You can use a little silicone grease aroun the edges of the pistons to make them slide in and out easier. I used some silicone grease on the backs of the pads, because i didn't have any copper grease.

Don't use copper grease on the pistons though. I don't know what it'll do to the rubber seals, and it's also a rather viscous / coarse, so not great for lubrication. It's used more for putting on bolts to stop them seizing in things.
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[ms51ves3]

[Noxious89123]

Pah, stop being picky!

If you open a container of brake fluid, your meant to use it and then chuck it, because once the container is open it can absorb moisture and all that jazz.

If your just cleaning them up etc, I'd rather use a little silicone grease rather than open a container of brake fluid.

Same difference at the end of the day, both will do the job lovely.
____________________
'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[ms51ves3]