Seized Disc Brakes
Discussion
Hi guys
First time I've posted in the Pedal Powered section - haven't been on a bike (except my unicycle) for years.
I've just had my mountain bike returned to me after lending it to a family member for the last year or so. The bike is a Giant Terrago 2007. The bike has been sat in a damp garage all of this time and hasn't been used
Basically the wheels are very stiff to turn and I think it could be something to do with the brakes being seized - it has hydraulic discs.
Any ideas how to fix it/get it working again? Also, if it has sat unused for this long will the brake fluid need changing too?
Thanks in advance!
First time I've posted in the Pedal Powered section - haven't been on a bike (except my unicycle) for years.
I've just had my mountain bike returned to me after lending it to a family member for the last year or so. The bike is a Giant Terrago 2007. The bike has been sat in a damp garage all of this time and hasn't been used
Basically the wheels are very stiff to turn and I think it could be something to do with the brakes being seized - it has hydraulic discs.
Any ideas how to fix it/get it working again? Also, if it has sat unused for this long will the brake fluid need changing too?
Thanks in advance!
Welcome to a fellow unicyclist!
I'd start by checking it is the brakes seized on. If you unbolt the calipers can you slide them off the disc? If not then you're right and it's the calipers seized on. If the calipers come off OK and the wheel is still stiff then you need to investigate the hubs.
I've not stripped bicycle calipers so I'll leave someone better qualified on how best to sort them but I'd expect they'll need a strip, clean up and potentially new seals - hoping the pistons aren't corroded.
Stick to Uni's - much simpler!
I'd start by checking it is the brakes seized on. If you unbolt the calipers can you slide them off the disc? If not then you're right and it's the calipers seized on. If the calipers come off OK and the wheel is still stiff then you need to investigate the hubs.
I've not stripped bicycle calipers so I'll leave someone better qualified on how best to sort them but I'd expect they'll need a strip, clean up and potentially new seals - hoping the pistons aren't corroded.
Stick to Uni's - much simpler!
Brake fluid is hygroscopic so this means it increases in volume - due to water absorption - which will force the pistons out.
Or the pistons could have seized in the bores, which will require a strip, clean, and possibly new seals.
Having just done a set of Hope 6 pots I can honestly say it is a horrible job with zero satisfaction - unlike most bike fettling jobs. My advice is take it to a bike shop.
Or the pistons could have seized in the bores, which will require a strip, clean, and possibly new seals.
Having just done a set of Hope 6 pots I can honestly say it is a horrible job with zero satisfaction - unlike most bike fettling jobs. My advice is take it to a bike shop.
Edited by rhinochopig on Wednesday 25th April 20:48
XG332 said:
I would pop the calipers off and push back the piston. Refit and give it a squeeze.
Usually just gets stuck and needs a little movement.
This is the first thing you should try. Take the wheel out of the bike and pads out of the calliper. Then using the flat 'side' of a flathead screwdriver carefully push the pistons back in a bit. Don't push too far and be gentle. Usually just gets stuck and needs a little movement.
Depending on your technical/mechanic skills, this is probably a good time to take it to a bike shop if it is still sticking.
Jayyylo said:
This is the first thing you should try. Take the wheel out of the bike and pads out of the calliper. Then using the flat 'side' of a flathead screwdriver carefully push the pistons back in a bit. Don't push too far and be gentle.
Depending on your technical/mechanic skills, this is probably a good time to take it to a bike shop if it is still sticking.
After that my technical skills run out quite quickly! I've got a few friends who are very good with bikes who I'm sure would be happy to take a look. Plus I don't know of any decent and trustworthy bike shops in my area. Could anyone recommend one in Sunderland/Durham area?Depending on your technical/mechanic skills, this is probably a good time to take it to a bike shop if it is still sticking.
GPS M-Jet said:
Thanks for the replies fellas! I also forgot to mention that the levers are very stiff and have little movement in them - not sure if that helps diagnose it?
Typical symptom of moisture in the fluid. Take it to your LBS and get them to change it, and they *should* work. The moisture increases volume, pushes the pistons out, which clamp the disc and lock up the lever.Shouldn't cost you too much to get done. You can do it yourself, but you'll need a bleed kit, and it can be messy if you get it wrong. I tend to do my own mineral oil brakes, but let the LBS do the DoT 4 fluid ones as it's unpleasant stuff.
As the brakes are Giant MPH have you tried turning the master cylinder adjuster on the lever?
The design was taken from the early Hope C2 system and they have a large barrel master cylinder with a brass adjuster cap (about the same size as a £1 coin).
If this is turned the system (which is a fully closed one) pushes the pads at the caliper end onto the disk. This can lead to the brake appearing to seize on.
Regards
J
The design was taken from the early Hope C2 system and they have a large barrel master cylinder with a brass adjuster cap (about the same size as a £1 coin).
If this is turned the system (which is a fully closed one) pushes the pads at the caliper end onto the disk. This can lead to the brake appearing to seize on.
Regards
J
Forgot to say the point about moisture from the others is still valid, although unlikley due to the design.
Forcing the pistons in at the caliper end wont work as being a closed system they will pop back into position straight away.
I would just find a local Giant dealer and they could tell you in 10secs!
Good Luck
J
Forcing the pistons in at the caliper end wont work as being a closed system they will pop back into position straight away.
I would just find a local Giant dealer and they could tell you in 10secs!
Good Luck
J
For stopping power, what did you use on the gears WD40 nooooo
or GT85/TF2 teflon or lube etc?
Some of this has proabably got onto the discs!
Get hold of a new cloth and some isopropanol (circuit board cleaner) and clean the discs.
You may have contaminated the pads - which means new ones.
as for the squeaking - ahh they all do that sir.
ways to sort can be but not always
alignement of the caliper
more use of the bike
cleaning of the discs
or later and harder braking
although the best cure is an I-Pod
or GT85/TF2 teflon or lube etc?
Some of this has proabably got onto the discs!
Get hold of a new cloth and some isopropanol (circuit board cleaner) and clean the discs.
You may have contaminated the pads - which means new ones.
as for the squeaking - ahh they all do that sir.
ways to sort can be but not always
alignement of the caliper
more use of the bike
cleaning of the discs
or later and harder braking
although the best cure is an I-Pod
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