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Discussion Starter #1
Has anyone done an overhaul of the brake calipers on the K1300GT?

Thinking of new pistons and seals,,,

Is it hard to do?

I see kits are available...


Thanks

Dave :grin
 

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Thinking you need new pistons is a leap of (non)faith, pistons don't usually get replaced in an overhaul. See post #2, why?

I "overhauled" the calipers on my K100RS, or my BMW 3.0CS, forget which, because at least one piston was stuck from rust. It isn't a physically demanding job, but if your piston(s) is(are) stuck, you may need to carefully apply compressed air through the fluid port to move the piston(s). Be careful when you do this because they can let go suddenly and there will be a helluva force behind them. Put a wood block in place of the pads to catch the released piston and so it doesn't go flying out and into something soft, like yourself. The piston may make a loud POP when it releases.

Better than the air method is to use hydraulic pressure of the brake system to get the piston to move. Sometimes this is not possible, leading to bench work with the piston in your vise.

There are those who say to never scuff the bore or piston with anything abrasive, as this will damage the coating/plating there and lead to further trouble(s). There may be crud stuck to either, and solvent plus elbow grease is the best way to get that off. However, expediency may lead you to wet-dry sandpaper, steel wool, scotchbrite pads.... Just get the piston and bore really clean prior to reassembly.
 

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I split my calipers this winter for a respray, glad i did not purchase any seal or pistons, just took it all out and after a good clean they looked like new, so i reused all parts when reassembling. Worked fine for 2 months now. The pistons were a bit stiff and binding before the clean and it was due to brakedust. Think they never been apart before, my bike is an 2009 k1300s.
Most likely you will get away with just removing the pistons and seals and cleaning, no need to split them for just a clean, if you have a ultrasonic wash use it to get them clean inside.
 

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If you have tokico calipers be wary about splitting them as they can have a tendency to warp. Some kits ie Motorworks, don’t include the inner seal in the refurb kit for this reason.
 

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I got at least 20 people saying the same about Bmw brembo, "they will warp", "they will leak" "you will never get them sealed again" "you dont have the correct torque for the caliper half bolts" and so on.

Nothing warped, nothing leaked (using the same seals and O-ring), torquenumbers are easy, just look up the standard for the size bolt you have and materials used, lubed or dry, torque in sequence, i started out like this. first to 15nm, then another pass to 30nm, standard for M8 bolt is 33nm but since calipers are made from aluminium i considered them lubed and backed off 10% as standard tell's you to.
 

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All I’m saying is be aware. Apparently there have been problems with Tokico calipers

From Motorworks
With anti squeal insert. Silicon oil is provided in the kit for fitting the pistons to the calipers and should be used in order to avoid damage during assembly.
Please note, we do not recommend splitting these calipers, as the caliper halves are prone to distortion when doing so, which makes them leak on re-assembly.

This is why the caliper half o rings are not provided in this kit.
However, if you absolutely MUST split these calipers (which you do at your own risk), the Tokico caliper half o ring BRA58389 is the one you need to reassemble the two halves. Two required per caliper.
 

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All I’m saying is be aware. Apparently there have been problems with Tokico calipers

From Motorworks
With anti squeal insert. Silicon oil is provided in the kit for fitting the pistons to the calipers and should be used in order to avoid damage during assembly.
Please note, we do not recommend splitting these calipers, as the caliper halves are prone to distortion when doing so, which makes them leak on re-assembly.

This is why the caliper half o rings are not provided in this kit.
However, if you absolutely MUST split these calipers (which you do at your own risk), the Tokico caliper half o ring BRA58389 is the one you need to reassemble the two halves. Two required per caliper.
Tokico? K1300gt uses brembo calipers just like the S models.
 

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Brake caliper repair kit front Brembo | BRA38257

Fits K1200S (09/2003 - 08/2008), K1200GT (09/2005 - 08/2008), K1300S... Show All...

Associated BMW part: 34112338257 (34 11 2 338 257)

With anti squeal insert. Silicon oil is provided in the kit for fitting the pistons to the calipers and should be used in order to avoid damage during assembly.

Please note, we do not recommend splitting these calipers, as the caliper halves are prone to distortion when doing so, which makes them leak on re-assembly.
read more...
This is why a caliper half o ring is not provided in this kit.
However, if you absolutely MUST split these calipers (which you do at your own risk), the standard caliper half o ring FUA54739 is the one you need to reassemble the two halves.

Again - All I'm saying is be careful. Obviously some have experienced warpage.
 

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Discussion Starter #10
Brake caliper repair kit front Brembo | BRA38257

Fits K1200S (09/2003 - 08/2008), K1200GT (09/2005 - 08/2008), K1300S... Show All...

Associated BMW part: 34112338257 (34 11 2 338 257)

With anti squeal insert. Silicon oil is provided in the kit for fitting the pistons to the calipers and should be used in order to avoid damage during assembly.

Please note, we do not recommend splitting these calipers, as the caliper halves are prone to distortion when doing so, which makes them leak on re-assembly.
read more...
This is why a caliper half o ring is not provided in this kit.
However, if you absolutely MUST split these calipers (which you do at your own risk), the standard caliper half o ring FUA54739 is the one you need to reassemble the two halves.

Again - All I'm saying is be careful. Obviously some have experienced warpage.
No, Respectfully, I don't think that applies to the Brembos.....- There is no warning on the Motorworks site not to split the Brembos. And they don't mention the o ring.

Dave
 

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Discussion Starter #11
Brakes

By the way.... if anyone has a manual or can reference an online one that includes a caliper strip I'd be hugely grateful.

The BMW Motorrad one does not include this procedure.:grin

Thanks

Dave
 

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Discussion Starter #12
Brakes

And if someone has a manual that covers the caliper strip I'd be hugely grateful.:grin

The BMW Motorrad one I have doesn't include this.


Many thanks

Dave
 

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No, Respectfully, I don't think that applies to the Brembos.....- There is no warning on the Motorworks site not to split the Brembos. And they don't mention the o ring.

Dave

Brake caliper repair kit front Brembo | BRA38257

Fits K1200S (09/2003 - 08/2008), K1200GT (09/2005 - 08/2008), K1300S... Show All...

Associated BMW part: 34112338257 (34 11 2 338 257)

With anti squeal insert. Silicon oil is provided in the kit for fitting the pistons to the calipers and should be used in order to avoid damage during assembly.

Please note, we do not recommend splitting these calipers, as the caliper halves are prone to distortion when doing so, which makes them leak on re-assembly.

Hey Dave
The above is from the Motorworks site referring to Brembos
 

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Discussion Starter #14
Brake caliper repair kit front Brembo | BRA38257

Fits K1200S (09/2003 - 08/2008), K1200GT (09/2005 - 08/2008), K1300S... Show All...

Associated BMW part: 34112338257 (34 11 2 338 257)

With anti squeal insert. Silicon oil is provided in the kit for fitting the pistons to the calipers and should be used in order to avoid damage during assembly.

Please note, we do not recommend splitting these calipers, as the caliper halves are prone to distortion when doing so, which makes them leak on re-assembly.

Hey Dave
The above is from the Motorworks site referring to Brembos

There must be two versions of the site, because on the version I access this warning does not apply. Nothing at all about splitting the Brembos.


I'm not worried about splitting them if necessary - plenty of cheap second hand units are available if it goes wrong. However I have a piston extraction tool and compressed air so it should be possible to do without splitting.

Anyway I will post a video when done for your amusement...:grin
 

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I’m sure there won’t be a problem. The purpose in posting that warning was to think about only splitting the caliber if there was a problem. I noticed the warning from Motorworks as I was going to split mine but as there were no issues, decided to wait until it became necessary to do so
 

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Discussion Starter #16
I got at least 20 people saying the same about Bmw brembo, "they will warp", "they will leak" "you will never get them sealed again" "you dont have the correct torque for the caliper half bolts" and so on.

Nothing warped, nothing leaked (using the same seals and O-ring), torque numbers are easy, just look up the standard for the size bolt you have and materials used, lubed or dry, torque in sequence, i started out like this. first to 15nm, then another pass to 30nm, standard for M8 bolt is 33nm but since calipers are made from aluminium i considered them lubed and backed off 10% as standard tell's you to.
That's helpful, thank you.

Well I've split them and will be resembling when my new lines arrive back and they are on the bike.

I see standard torque is indeed 33 nm less 10% would give 30.

However similar calipers on other bikes seem to be more in the range of 20-22 nm.

Think I'll go to 7, then 14, then 21, then 28nm .

If it all goes Tits Up then it'll be 'new' second hand calipers and start again. :rolleyes:
 

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That's helpful, thank you.

Well I've split them and will be resembling when my new lines arrive back and they are on the bike.

I see standard torque is indeed 33 nm less 10% would give 30.

However similar calipers on other bikes seem to be more in the range of 20-22 nm.

Think I'll go to 7, then 14, then 21, then 28nm .

If it all goes Tits Up then it'll be 'new' second hand calipers and start again. :rolleyes:
why not do them to 30nm as supposed, why invent something new out of the blue?
 

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Brake caliper repair kit front Brembo | BRA38257

Fits K1200S (09/2003 - 08/2008), K1200GT (09/2005 - 08/2008), K1300S... Show All...

Associated BMW part: 34112338257 (34 11 2 338 257)

With anti squeal insert. Silicon oil is provided in the kit for fitting the pistons to the calipers and should be used in order to avoid damage during assembly.

Please note, we do not recommend splitting these calipers, as the caliper halves are prone to distortion when doing so, which makes them leak on re-assembly.
read more...
This is why a caliper half o ring is not provided in this kit.
However, if you absolutely MUST split these calipers (which you do at your own risk), the standard caliper half o ring FUA54739 is the one you need to reassemble the two halves.

Again - All I'm saying is be careful. Obviously some have experienced warpage.

very sensible post....

of course you need to replace the pistons they get stone chips / damage and it impacts the seal / allows crud to get in where it shouldn't

if you can't press the pistons back in by hand you need to get an overhaul kit and pull the pistons out. What happens on many bike callipers is corrosion sets in in the bottom of the seal cut out... the corrosion slowly gets worse distorting the piston seal and jamming in the piston. Pop them out and clean all the rubbish out of the seal slot and they'll work much better...

modern rubbish uses phenolic plastic pistons and they seem to play up more than the good old days
 
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