Front brake partially seized

[pxm]

I was cleaning my Girly this morning and when I came to clean the front wheel rim I noticed it was stiff to turn.  I guess the calipers need freeing after standing over winter.
I tried to give it some heavy braking on my drive (not yet road taxed) & it freed off a little but is still stiff.
I won't be taxing it as it's up for sale, so without the complexity of stripping the calipers down, can anyone suggest a quick fix please? 
Would removing the front wheel & carefully pushing the pistons (1 at a time!) back in do the trick?  Would brake cleaner ruin the piston seals?

[Mustang]

You can try brake cleaner
...but it usually just a band aid .
The real fix is new seals and pistons.
Sometimes you get lucky with a cleaning though...

[Timbox2]

I was cleaning my Girly this morning and when I came to clean the front wheel rim I noticed it was stiff to turn.  I guess the calipers need freeing after standing over winter.
I tried to give it some heavy braking on my drive (not yet road taxed) & it freed off a little but is still stiff.
I won't be taxing it as it's up for sale, so without the complexity of stripping the calipers down, can anyone suggest a quick fix please? 
Would removing the front wheel & carefully pushing the pistons (1 at a time!) back in do the trick?  Would brake cleaner ruin the piston seals?

Mustangs right but for a quick fix try pouring hot water over the calipers then try pushing them into the wheel ( They are sliding calipers so should move eventually) But if they keep sticking as Mustang says. The slider pins seize up too as well as the pistons and sometimes the rubber boots need replacing( Only use grease suitable for rubber on those pins/boots)

[Tiger-G]

Hi 🙂,

My brakes are always seized after the winter lay off, so it's no big deal.

Take the caliper off, put a hand vice on one piston to stop it movingly out, press the brake lever and let the other piston come out a bit, clean the crap off the piston with brake fluid and your lass's tooth brush, put some fresh brake fluid on the piston and use a hand vice to push it back in. Swap round and do the same with the other one. Then just for good measure, press the brake lever in and out a few times to get the pistons moving freely again. Once you're happy they're sorted, put the caliper back on the disc, press the brake lever until it grips, take the caliper back off and coat the exposed part of pistons with copper slip to stop them crudding up. Then it's just a case of putting your lass's tooth brush back in the bathroom 

Having said all that, if you haven't changed your piston seals for a good few years, it might be a good idea to do them, it's quite a simple job.

Edit: I've just been overhauling my brakes after the winter lay off, and one more thing to mention is to check that the caliper carrier sliders are moving freely. They're the ones that are covered by rubber seals. All mine were seized. you can pull the caliper off the carrier completely and tidy the sliders up so they move freely.

Good luck, and keep us posted as to how you get on 😉

[pxm]

Hi 🙂,

My brakes are always seized after the winter lay off, so it's no big deal.

Take the caliper off, put a hand vice on one piston to stop it movingly out, press the brake lever and let the other piston come out a bit, clean the crap off the piston with brake fluid and your lass's tooth brush, put some fresh brake fluid on the piston and use a hand vice to push it back in. Swap round and do the same with the other one. Then just for good measure, press the brake lever in and out a few times to get the pistons moving freely again. Once you're happy they're sorted, put the caliper back on the disc, press the brake lever until it grips, take the caliper back off and coat the exposed part of pistons with copper slip to stop them crudding up. Then it's just a case of putting your lass's tooth brush back in the bathroom 

Having said all that, if you haven't changed your piston seals for a good few years, it might be a good idea to do them, it's quite a simple job.

Edit: I've just been overhauling my brakes after the winter lay off, and one more thing to mention is to check that the caliper carrier sliders are moving freely. They're the ones that are covered by rubber seals. All mine were seized. you can pull the caliper off the carrier completely and tidy the sliders up so they move freely.

Good luck, and keep us posted as to how you get on 😉

Hi Graeme
I'm having a few problems with this job.
I removed the caliper & using a G clamp screwed one piston in, pumped the other out as far as I dare, cleaned it with water based engine degreaser & a toothbrush, lubed with copper grease, screwed it back in, repeated with the other piston then did the entire job again.  Both pistons have been in & out twice.  Did the same with the other caliper.  I also pulled the caliper rubbers back & squirted some water based degreaser in.  I don't have any rubber grease. 
Calipers can't be pushed against the wheel by hand.  I have to tap it off using a rubber mallet.  This doesn't sound good!
Front wheel is rotates better but is still fairly stiff.  Certainly much more stiff than the rear wheel.
I'm also unsure about the antirattle spring.  I'm inserting flatter end first before the pads so the deep bend in it allows the retaining pin to pass above it, but it's hard to get the pads in with the antirattle spring in place.
Before I remove both calipers, strip, clean & renew piston rubbers, am I missing anything?
Cheers
Paul

[Timbox2]

Hi Graeme
I'm having a few problems with this job.
I removed the caliper & using a G clamp screwed one piston in, pumped the other out as far as I dare, cleaned it with water based engine degreaser & a toothbrush, lubed with copper grease, screwed it back in, repeated with the other piston then did the entire job again.  Both pistons have been in & out twice.  Did the same with the other caliper.  I also pulled the caliper rubbers back & squirted some water based degreaser in.  I don't have any rubber grease. 
Calipers can't be pushed against the wheel by hand.  I have to tap it off using a rubber mallet.  This doesn't sound good!
Front wheel is rotates better but is still fairly stiff.  Certainly much more stiff than the rear wheel.
I'm also unsure about the antirattle spring.  I'm inserting flatter end first before the pads so the deep bend in it allows the retaining pin to pass above it, but it's hard to get the pads in with the antirattle spring in place.
Before I remove both calipers, strip, clean & renew piston rubbers, am I missing anything?
Cheers
Paul

You must get rubber grease, Copper grease will swell the rubbers. Think your gonna have to strip and rebuild, what has most likely happened is corrosion has got behind the outer most piston dust seal and is grabbing the piston not allowing it to go back. I did mine a couple of years back, the groove that the dust seal goes into was full of crap and needed gentle but thorough cleaning out with a soft pick and dremmel.

I used these people for the rubber kits, but if feel you are not up to it they can rebuild them for you, or exchange and not silly money really

https://www.powerhouse.uk/content/motorcycle-brakes/motorcycle-brake-caliper-services.php

[Tiger-G]

You must get rubber grease, Copper grease will swell the rubbers. Think your gonna have to strip and rebuild, what has most likely happened is corrosion has got behind the outer most piston dust seal and is grabbing the piston not allowing it to go back. I did mine a couple of years back, the groove that the dust seal goes into was full of crap and needed gentle but thorough cleaning out with a soft pick and dremmel.

I used these people for the rubber kits, but if feel you are not up to it they can rebuild them for you, or exchange and not silly money really

https://www.powerhouse.uk/content/motorcycle-brakes/motorcycle-brake-caliper-services.php

When I say use Copperslip, it's just for the exposed part of the piston to stop them corroding over the riding season, it should never get in where the seals are. Rubber grease is probably better though  :icon_wink:

Paul - I would only ever use brake fluid, or something similar to clean the pistons, that doesn't swell the seals. As for the sliders, when you squirted the degreaser in them, did they move freely to the point where you could pull them off the caliper easily enough ?? That's how free they should be, or the pads will wear unevenly. The metal sliders may be corroded inside. If so, take the slider off and use some emery paper or wire wool on the metal to clean them off.

And.....as Tim said.......if you're still struggling, your calipers may be at the point where you need new seals, or need to take the pistons out to fully inspect behind them.

If you need any more help, just shout  :icon_wink:

[pxm]

Thanks for the advice Tim & Graeme.
I've ordered a set of seals & will strip & clean them both.  They clearly are past the point of no return!
Cheers
Paul

[93TigerBill-2016]

They clearly are past the point of no return!

Liked the pun....

[Tiger-G]

Thanks for the advice Tim & Graeme.
I've ordered a set of seals & will strip & clean them both.  They clearly are past the point of no return!
Cheers
Paul

Good luck with bleeding the brakes afterwards, I've always found it a nightmare !! 

[pxm]

Good luck with bleeding the brakes afterwards, I've always found it a nightmare !! 

Why are they difficult?  I have a brake bleeding kit (plastic bottle & some tubing) so I was hoping it would be straightforward.

Can any please advise on the anti rattle shims?  Which way round?  Insert shim followed by pads?

[Tiger-G]

I don't know if it's just me and my technique, but I just can't seem to get the fluid from the reservoir to go down the brake pipe to the calipers ??

I've changed my technique now for brake fluid changes, and make sure the pistons are pushed fully back in the calipers, almost empty the reservoir, fill it up with new brake fluid, and keep it filled as you pump the new fluid through the system. Works a treat for me.

[Timbox2]

After youve bled as much as you want, Zip tying the brake lever back over night has always worked for me

[pxm]

I'm pleased to report success in sorting this.
The problem was corrosion behind the dust seal causing it to be forced out into the piston.  A Dremel in the grooves sorted it.  New seals fitted anyway.
Brake bleeding was straightforward enough.
MOT this Friday so I'll test if they still work then.
Thanks to all who gave advice.   

[Timbox2]

Good result mate, glad its sorted