Problem with front disc brake
Ponyup
Posts: 9
Hey guys,
Warning lots of words!
TL;DR brake piston sticky, is it a matter of insufficient oil or faulty caliper? Please advise/help!
My bike is brand new, bought it last week and have ridden it properly once.
The bike in question is a Scott Scale.
I noticed that my brakes were rubbing slightly when leaning the bike (left to right while out of the saddle) and I tried aligning the caliper by undoing the two 5mm bolts and actuating the brakes while re-tightening.
At first it made it worse! After 10mins I managed to align them to how they were and cycled down the road and it still rubbed when the bike was lent left or right.
So I decided to take the wheel & pads off and tried pushing the pistons back fully and re-assembled and actuated etc still rubbing.
Second time while pushing the pistons back I started squeezing the brake lever and noticed that the piston closest to the hub was coming out much more than the other.. So.. I've got a sticky piston.
Tried spraying muc-off silicone shine/mo94/disc brake cleaner all to no avail to get the sticky one to move like the opposite one.
So I can only think of two things it could be, one maybe not enough mineral oil in the system hence only one coming out much further than the other? Or that the caliper & piston are faulty. Which I've been told by Evans Cycles being Shimano hydraulics & brand new that is quite unlikely.
So yeah if anyone can help/suggest anything it could be or how to fix it please go ahead
Warning lots of words!
TL;DR brake piston sticky, is it a matter of insufficient oil or faulty caliper? Please advise/help!
My bike is brand new, bought it last week and have ridden it properly once.
The bike in question is a Scott Scale.
I noticed that my brakes were rubbing slightly when leaning the bike (left to right while out of the saddle) and I tried aligning the caliper by undoing the two 5mm bolts and actuating the brakes while re-tightening.
At first it made it worse! After 10mins I managed to align them to how they were and cycled down the road and it still rubbed when the bike was lent left or right.
So I decided to take the wheel & pads off and tried pushing the pistons back fully and re-assembled and actuated etc still rubbing.
Second time while pushing the pistons back I started squeezing the brake lever and noticed that the piston closest to the hub was coming out much more than the other.. So.. I've got a sticky piston.
Tried spraying muc-off silicone shine/mo94/disc brake cleaner all to no avail to get the sticky one to move like the opposite one.
So I can only think of two things it could be, one maybe not enough mineral oil in the system hence only one coming out much further than the other? Or that the caliper & piston are faulty. Which I've been told by Evans Cycles being Shimano hydraulics & brand new that is quite unlikely.
So yeah if anyone can help/suggest anything it could be or how to fix it please go ahead
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Comments
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If bike is only a week old and you are not happy then take it back to the shop you bought it from, simples0
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That would be simple, apart from the bike shop being 250miles away
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Sounds like wheel movement. And or fork flex.
But there is all ways some rub don't worry about it. You will also get some rube every time you remove and refit the wheel.
That is life. It gets better the older the pads but then they need changing.
Ps telling us what brakes would be better than saying what bike."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Sounds like wheel movement. And or fork flex.
But there is all ways some rub don't worry about it. You will also get some rube every time you remove and refit the wheel.
That is life. It gets better the older the pads but then they need changing.
Ps telling us what brakes would be better than saying what bike.
I see, this is my first mtb afterall.
I guess I'll just get used to it, coming from a road bike which is very quiet!
Of course sorry they are Deore m447 callipers.0 -
Sounds like wheel movement. And or fork flex.
^^^^THIS^^^^ Wheel movement more than anything check spoke tension. Had it on a few new bikes, the wheel is flexing causing the rub.
And do not use this muc-off silicone shine stuff anywhere near the brakes. Asking for trouble.
Also seems as you have been messing with the pistons, and I don't know why. Push them back and put the yellow block in the calliper and and squeeze the lever a few times. This will put the pistons equal again.0 -
Sounds like wheel movement. And or fork flex.
But there is all ways some rub don't worry about it. You will also get some rube every time you remove and refit the wheel.
That is life. It gets better the older the pads but then they need changing.
Ps telling us what brakes would be better than saying what bike.
I see, this is my first mtb afterall.
I guess I'll just get used to it, coming from a road bike which is very quiet!
Take a logical approach, putting silicon (reduces friction) next to a part that requires friction...well you can work it out.
MTB has two wheels pedals brakes and gears just like a road bike.0 -
[url=http://www.bikeradar.com/forums/viewtopic.php?p=19708750#p19708750]Clockworkmark31[/url] wrote:Sounds like wheel movement. And or fork flex.
^^^^THIS^^^^ Wheel movement more than anything check spoke tension. Had it on a few new bikes, the wheel is flexing causing the rub.
How? The rotor is fixed to the hub. The caliper is fixed to the fork. Movement at the rim won't cause rubbing.
Movement at the hub will.I don't do smileys.
There is no secret ingredient - Kung Fu Panda
London Calling on Facebook
Parktools0 -
[url=http://www.bikeradar.com/forums/viewtopic.php?p=19708751#p19708751]Clockworkmark31[/url] wrote:Sounds like wheel movement. And or fork flex.
But there is all ways some rub don't worry about it. You will also get some rube every time you remove and refit the wheel.
That is life. It gets better the older the pads but then they need changing.
Ps telling us what brakes would be better than saying what bike.
I see, this is my first mtb afterall.
I guess I'll just get used to it, coming from a road bike which is very quiet!
Take a logical approach, putting silicon (reduces friction) next to a part that requires friction...well you can work it out.
MTB has two wheels pedals brakes and gears just like a road bike.
Most road bikes don't have hydraulic discs though, do they!
I thought I did take a logical approach.. I put silicon (reduces friction) into the pistons (which move)
I did also write that I'd used disc brake cleaner which was the last thing I did to get rid of most of the silicone in/around the caliper to avoid contamination.
Good call with the yellow disc block however, picked one up today and it seems to have solved it just about. A lot less rub when leaning.
Maybe a good bleed just to be safe wouldn't be a bad idea either.0 -
It may seem logical but putting lube anywhere near brakes isn't even if it's only the pistons. Brake fluid for that. It may also seem logical to use brake cleaner, but again it's not. Water is better, IPA best.0
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Glad that sorted it.
I can't comment on road bikes and what they use as I like getting dirty.
Have learnt from experience anything near the brakes accept from IPA and water will just ruin the pads.
And wheel movement or flexing caused rub on my Talon had to get the wheel re-tensioned.
Also a bleed on such a new bike I would avoid. Any more problems I would contact the seller. But use it and let everything bed in.0 -
[url=http://www.bikeradar.com/forums/viewtopic.php?p=19710314#p19710314]Clockworkmark31[/url] wrote:Glad that sorted it.
I can't comment on road bikes and what they use as I like getting dirty.
Have learnt from experience anything near the brakes accept from IPA and water will just ruin the pads.
And wheel movement or flexing caused rub on my Talon had to get the wheel re-tensioned.
Also a bleed on such a new bike I would avoid. Any more problems I would contact the seller. But use it and let everything bed in.
Thanks again. So far, so good.
I see, I'll have to get some IPA and use that from now on. ebay best bet?
Just wondering, why would you avoid a bleed on a new bike?0 -
It can cause more problems than it solves0
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Bleeding is used to remove air from the system. If there is no air in the system, which there shouldn't be with new brakes, bleeding is totally pointless.[url=http://www.bikeradar.com/forums/viewtopic.php?p=19710314#p19710314]Clockworkmark31[/url] wrote:Glad that sorted it.
I can't comment on road bikes and what they use as I like getting dirty.
Have learnt from experience anything near the brakes accept from IPA and water will just ruin the pads.
And wheel movement or flexing caused rub on my Talon had to get the wheel re-tensioned.
Also a bleed on such a new bike I would avoid. Any more problems I would contact the seller. But use it and let everything bed in.
Thanks again. So far, so good.
I see, I'll have to get some IPA and use that from now on. ebay best bet?
Just wondering, why would you avoid a bleed on a new bike?I don't do smileys.
There is no secret ingredient - Kung Fu Panda
London Calling on Facebook
Parktools0 -
Bleeding is used to remove air from the system. If there is no air in the system, which there shouldn't be with new brakes, bleeding is totally pointless.[url=http://www.bikeradar.com/forums/viewtopic.php?p=19710314#p19710314]Clockworkmark31[/url] wrote:Glad that sorted it.
I can't comment on road bikes and what they use as I like getting dirty.
Have learnt from experience anything near the brakes accept from IPA and water will just ruin the pads.
And wheel movement or flexing caused rub on my Talon had to get the wheel re-tensioned.
Also a bleed on such a new bike I would avoid. Any more problems I would contact the seller. But use it and let everything bed in.
Thanks again. So far, so good.
I see, I'll have to get some IPA and use that from now on. ebay best bet?
Just wondering, why would you avoid a bleed on a new bike?
I appreciate that, but just because they are new doesn't mean there wont be any air in the system, surely?
A new bike is only as good as the person who built it, brakes included? Or would the brakes have come completely sealed/pre-bled and just needed bolting on?0 -
It is not unusual for the piston action to be slightly different, if it is alot take the bike back to the shop.
The undo the bolts and pull the brake on approach doesn't work well normally. You need to undo the caliper bolts and adjust by eye so the pad gap is the same either side when looking directly down. When tightening the bolts keep a good grip on the caliper as it will move as you tighten. Also before this make sure the rotors are bolted on properly.
Then use the brakes a few times and look again. If the action is slightly off you may need to adjust a little to one side to compensate. Unless you have cheap brakes this should stop them rubbing even after you remove and reseat the wheel. If you have QR wheels make sure the springs are on both sides and the right way round as this helps the wheel go in consistently. Bleeding should make no real difference.
My XT brakes don't rub even when i remove and replace the wheels. My previous elixir brakes were really bad and rubbed / squealed.0 -
The best thing to do with brakes, especially new ones, is leave them alone and just ride.I don't do smileys.
There is no secret ingredient - Kung Fu Panda
London Calling on Facebook
Parktools0 -
It is not unusual for the piston action to be slightly different, if it is alot take the bike back to the shop.
The undo the bolts and pull the brake on approach doesn't work well normally. You need to undo the caliper bolts and adjust by eye so the pad gap is the same either side when looking directly down. When tightening the bolts keep a good grip on the caliper as it will move as you tighten. Also before this make sure the rotors are bolted on properly.
Then use the brakes a few times and look again. If the action is slightly off you may need to adjust a little to one side to compensate. Unless you have cheap brakes this should stop them rubbing even after you remove and reseat the wheel. If you have QR wheels make sure the springs are on both sides and the right way round as this helps the wheel go in consistently. Bleeding should make no real difference.
My XT brakes don't rub even when i remove and replace the wheels. My previous elixir brakes were really bad and rubbed / squealed.
I'll do that from now on then, when I pulled the brake on and nipped the bolts up it didn't really solve it. I'll do it by eye.
Thanks0 -
Read all the posts and know a lot more now than I did beginning of the week.
Thanks for all the help!0
