K11 Owners Group

[hosehoundfr86]

So it's almost time to start getting ready for spring,, I need to clean and free up my brake calipers ,and possibly replace the brake lines , am I able to remove and clean up calipers without rebuilding them? The brake lines are original and seem to be in good condition ,, but I have read here that they break down internally,, any recommendations , things to watch for ,, and a parts supplier for this service?

Thanks::Hilton

[Scott_Anderson]

I think the determining factor is the cleanliness of the brake fluid.
If the fluid has been changed regularly, yearly/ever-other year, and is clean, you should be ok.
The problems seem to crop up when the fluid is neglected and it then starts to deteriorate the insides of the lines and the piston seals.
I've not had a calliper apart to know if you can clean it good and re-assemble. There are seal/piston kits available for the callipers, if you can find a supplier.

I put new spiegler lines on my '95 a number of years ago, but the '97 still has the original hoses on it.
_________________
Ride safe.



1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

[hosehoundfr86]

Thanks Scott,I had the back brakes apart last fall and could only change one pad and had to reuse the thickest used one,, the fluid was pretty grungy and the rear caliper was a bit sticky,, figured I would do the calipers and overhaul of the system,, just looking for any tips or hints I can get before I begin next month,, fluid and pads ,, I might get away without hoses this time,, guess I'm always looking for the worst case scenario and anything less is a bonus: Hiton

[Ernie-NH]

Good morning all.. (( $0.02 ))

Just a bit of info,,, As an old retired engineer, most of you K11OG guys know that I spent most of my adult life and all of my professional life living and working in Germany. During that time two firms I dealt with were ATE and Lucas-Girling both big stars in the brake industry..I learned from studies made by both of these firms that for brake lines that "water ingression" takes place mainly at the crimped fittings, i.e.: as much as 80+% of the water in the brake fluid at any time will have come thru the mechanical interface of hose and metal found at each fitting. A lesser amount will have been ingested at the calipers. Not just water, but also all of the chemicals that can be found on the pavement that come along with the water, such as salts and some heavy metals from tire compounds, as it enters YOUR brake system !!

Up until the early 90s nearly all brake hose, whether from Bendix (France) or Teves or Lucas-Girling, used PVA ( polyvinylalchohol ) as the first tubular extrusion on which the hose was being built..ie: the I.D. liner ! However, no one up until the findings of the "Fluid Degradation Studies" were made known via the VDE ( Verein fur Deutsche Ingineure ) considered the street-water in the fluids to such an extent. Because PVA is a water soluble polymer, it then became obvious that the hose liner had to change in order to maintain braking integrity, and thus newer high-tech more difficult and expensive materials were employed to overcome hose liner breakdown. Today liners are made from fluropolymers such as Tefzel and Teflex with subsequent secondary extrusions and wrappings of EPDM and Kevlar..sometimes with and outer of braided SSTL… HOWEVER the art of Crimping has not significantly changed and water, plus water born chemicals are STILL entering and attacking your Braking system in all other areas (metallic ) not protected by a Fluropolymer,,, and the further breakdown of the glycol-based fluid itself produces acidic byproducts which go on to degrade things such as seals, plungers, sensing diaphragms etc… SO GUYS/GIRLS PLEASE change your brake fluid often, maybe every other riding season or so !!

In Europe and in Japan,, we are more religious about Brake Fluid change out.. usually no longer than 18 months between complete system fluid exchange. Here in the USA however I have heard people say that they never change out their brake fluid.. a situation I fail to understand. Ive seen the so-called "silicone base" light purple colored fluids, and the only thing I know about them is that repeated pressure cycling of the fluid (testing done at ATE/Frankfurt after USArmy Bradley Fighting Vehicles failed in Iraq ) will eventually cause the fluid to gelatinate.. ( i.e.: become semi-solid ).. with a 100% loss of braking function. … DONT THINK I WILL EVER use this crap !

Well enough that Ive bored you to tears eh?

Regards all…. ride safe….// Ernie in NH
_________________
AMA,, American Deaf Bikers
Airhead Beemers Club
'11 G650gs
'95 K1100LT
'76 R100/7

[hosehoundfr86]

Thanks Ernie,,good information,,,do you think the 93 K's would the have the old type liners?

[Ernie-NH]

Hi Hilton….

Cold in NB ?? Wicked here in upper NH, hope you don't have to be out on Fire Duty!

Any way..re the hose linings.. I really don't know and have no way of telling. The liner is there as a structural element but also because the EPDM material of the hoses themselves, despite being elastomer, and despite being resistant to attack by brake fluid, is none the less PERMEABLE when exposed to the pressures of the internal fluid were it not for the liner, .. if/when there is an internal lining failure of the hose, and if that is the old PVA material, the hose will begin to "sweat" or have the appearance of sweating..at least in those I've seen in the lab during the late 80s, which is when Girling and Bendix at least began to use a "teflon" type material for the first step which was the extrusion of the liner tubing !

If you have original hose, if could very well be deteriorated..the quality/appearance of the "exchange fluid" will be your guide. Clear light yellow slightly viscous (DOT4) is how it should appear,, NEVER cloudy which indicates entrained water… and there should NEVER EVER be any sign of particulate matter in the the change-out fluid.

If your hoses are not Original, NOS, or BMW certified, or were perhaps replaced here in North America sometime in the last 20 years, then I have no idea how they were made and tested or even IF they were manufactured to BMW or Brembo specs. My involvement with "Brake Hoses" has been 'more/less' from the outside looking in,, my primary responsibility relative to BRAKES has been the design and materials development of the sealing elements themselves such as Primary and Secondary Brake cups, Booster diaphragms, Caliper seals etc… I simply don't know any way other than "fluid analysis" to detect a marginally failing brake hose…

So have fun NB, don't think you can go wrong if you decide to simply replace the hoses etc… I mean the only thing better that a "reliably starting bike" is one the will STOP for CERTAIN each and every time !

Ride safe, stay warm…...// Ernie in NH
_________________
AMA,, American Deaf Bikers
Airhead Beemers Club
'11 G650gs
'95 K1100LT
'76 R100/7

[hosehoundfr86]

Hey Ernie: Cold it is ,, I have been fortunate ,so far this winter, not to have been called out too many times on these cold nights this season,,
We started working 24 hr. shifts this month and that should help,,
As for my brakes ,As far as I know it is all original,,, the rear caliper was sticking and the fluid was a very grungy brown,, sounds like an overhaul is in the works ,I have pads , I see seal kits are available on e-bay from the UK, and Beemer Boneyard has hoses,, better start shopping around,,
I guessing from posts I have read that all hoses should be changed and come from the same manufacturer to keep from having ABS code troubles
Here's to warmer weather and gravel free roads,,

Thanks for the input,, :Hilton

[Scott_Anderson]

Re ABS issues and hoses....
I've not heard of anyone that has had an abs issue related to the brand of hose.

Some owners run BMW dealer hoses, some run Speigler brand(I do), some have taken their hoses to a local automotive supply store/machine shop and had custom hoses made, and have not heard of anyone having issues.

Key factor is to bleed the system very thoroughly.
_________________
Ride safe.



1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

[Ernie-NH]

Hi Scott…

You said in the first response: Cleanliness, regular change out, then meticulous bleeding… are the secrets to long life in Brake Systems ( seals, pistons, diaphragms etc ) …

Hilton mentioned "grungy" dark brown fluid, sticking etc.. I just wanted him to know what could be behind his observations and why. Certainly today, nearly 30 years after the beginning of the change away from PVA as a structural liner and the introduction of fluropolymers, no matter what replacement hose he uses, PVA and its contribution to fluid degradation will not be a problem nor even a consideration! However, as you and I both stated, one MUST still change out brake fluids no later than every other riding season.

I too like Spiegler hose products, and the $200 Front/Rear compete hose kit for K1100 is ideal. I don't know who makes their hose, but given the high standard today, I would give it no concern !

Good luck…ride safe….// Ernie in NH ( see you in May !! )
_________________
AMA,, American Deaf Bikers
Airhead Beemers Club
'11 G650gs
'95 K1100LT
'76 R100/7

[552255]

After many repeated brake fluid flushings, I went out and got a Harbor Freight vacuum pump...it makes it so much easier and less messy. Worth every dollar...bout 30 I think. Now its a quick job as well, you can see the new clean fluid at the caliper.

I have rebuilt both front calipers with new seals...pretty tough and dirty to work the pistons out, you need compressed air, etc. If they work and don't leak, I'd simply spray out with brake cleaner and change fluid, pads, etc. You can remove caliper, and then remove/inspect/clean the rubber outer seal for each piston, checking the true inner seal function, maybe add some silicon grease to the piston sides...
_________________
1997 K1100LT-SE
1996 K1100RS-SE
"Black & Silver Duo"
Lincoln, NE

[Ernie-NH]

Hey "…255",,

How did you coax the pistons back into the bores after cleaning and replacing the seals… i.e.: WITHOUT damaging the sensitive sealing lip ?? Got any advice on how to do this ??

Best regards,,,,ride safe….// Ernie in NH
_________________
AMA,, American Deaf Bikers
Airhead Beemers Club
'11 G650gs
'95 K1100LT
'76 R100/7

[552255]