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1Back to top Go down   Strange Caliper Bolt? Empty Strange Caliper Bolt? Thu Nov 10, 2022 12:00 pm

MartinW

MartinW
Life time member
Life time member
When Bruce had the tyres on his 75s changed the tyre fitter encountered a problem fitting his RH front caliper. As the brakes had to come off to allow the rims to be powder coated I decided to have a closer look. The LH caliper has normal bolts the RH calipers upper bolt is normal however the lower bolt is shouldered and the mounting point on the fork leg is partially tapped out. Has anyone encountered this before?
Regards Martin.
Strange Caliper Bolt? Pb100010
Strange Caliper Bolt? Pb100011
Strange Caliper Bolt? Pb100012


__________________________________________________
K75s Hybrid
    

2Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Thu Nov 10, 2022 12:19 pm

duck

duck
Life time member
Life time member
MartinW wrote:When Bruce had the tyres on his 75s changed the tyre fitter encountered a problem fitting his RH front caliper. As the brakes had to come off to allow the rims to be powder coated I decided to have a closer look. The LH caliper has normal bolts the RH calipers upper bolt is normal however the lower bolt is shouldered and the mounting point on the fork leg is partially tapped out. Has anyone encountered this before?
Regards Martin.
Strange Caliper Bolt? Pb100010
Strange Caliper Bolt? Pb100011
Strange Caliper Bolt? Pb100012

The one with the flange on it is for the front bolt of the rear caliper that also holds the bracket for the speedo sensor wire. Somebody probably got them mixed up when servicing all of the calipers.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

3Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Thu Nov 10, 2022 12:47 pm

MartinW

MartinW
Life time member
Life time member
Thanks Duck but why was the hole tapped and a standard bolt was too large to go through the hole.
Regards Martin.


__________________________________________________
K75s Hybrid
    

4Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Thu Nov 10, 2022 1:05 pm

duck

duck
Life time member
Life time member
MartinW wrote:Thanks Duck but why was the hole tapped and a standard bolt was too large to go through the hole.
Regards Martin
The unthreaded part of the "fit bolt" (parts catalog name for the flanged bolt) probably didn't go in all of the way in so whoever got the bolts mixed up probably had to drill the caliper mounting hole a little to make it fit.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

5Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Thu Nov 10, 2022 1:12 pm

MartinW

MartinW
Life time member
Life time member
The diameter of the hole on the fork leg that the shoulder went through was the same diameter as the other caliper mounting bolt holes. The threaded part of the hole was too small for the standard caliper mounting bolt to go through.
Regards Martin.


__________________________________________________
K75s Hybrid
    

6Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Thu Nov 10, 2022 1:24 pm

duck

duck
Life time member
Life time member
Got me. Both the fit bolt and the other caliper bolts have the same M10 threads. (I know because I replace all of the caliper bolts with SS bolts on my Ks.)


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

7Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Thu Nov 10, 2022 1:28 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Does the bike have ABS brakes?  I know that on my K75RT one of the front caliper bolts has that flange and that when I take the calipers off I have to keep track of where it goes. 

The MaxBMW parts list shows that flange bolt installed in the upper mounting hole of the caliper, but it doesn't say which side.  Since the only difference between the sides is the wheel sensor for the ABS, I think it has something to do with controlling the position of the ABS sensor on that fork leg.  That is where it is located on my RT.


__________________________________________________
Present:
1994 K75RT
1991 K100RS


Past:
1988 K100RS SE
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

8Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Thu Nov 10, 2022 1:38 pm

MartinW

MartinW
Life time member
Life time member
Bruce's bike did have ABS which was removed. However the caliper wasn't touched. Another mate has a 91 LT with ABS removed so I might have a look at that and see if it also has a modified bolt.
Regards Martin.


__________________________________________________
K75s Hybrid
    

9Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Thu Nov 10, 2022 1:53 pm

duck

duck
Life time member
Life time member
Yeah, the parts diagram does show a flanged bolt on the front ABS:

https://www.realoem.com/bmw/enUS/showparts?id=0572-USA---K569-BMW-K%2075%20S%20(0563,0572)&diagId=34_0637

I just went and looked at a 93 K75RT-ABS parts bike that I have and it has a flanged bolt installed in the upper bolt for the caliper on the side with the ABS sensor.  (Right)



Last edited by duck on Thu Nov 10, 2022 2:04 pm; edited 2 times in total


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

10Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Thu Nov 10, 2022 1:59 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
If the caliper wasn't touched, then the flange bolt would still be there.  If the sensor was removed, the bolt would go on the side with the notched ring.


__________________________________________________
Present:
1994 K75RT
1991 K100RS


Past:
1988 K100RS SE
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

11Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Thu Nov 10, 2022 2:12 pm

MartinW

MartinW
Life time member
Life time member
Thanks I'll do a bit more checking.
Regards Martin.


__________________________________________________
K75s Hybrid
    

12Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Fri Nov 11, 2022 6:21 am

Arlina

Arlina
Moderator
Moderator
Those bolts belong to calipers on ABS machines.
The reason is, that it's very tight fit, as you adjust the sensor (with fillingplates) the sensor will always have the same gap to the ring,
after removing and installing the caliper on the bike.
With this also it prevents damage to the sensor by installing the caliper wrong to the bike as it should have a normal bolt.

An ABS caliper has an other ordernumber than non-abs calipers Smile


__________________________________________________
Strange Caliper Bolt? Eu-log10  K1100RS/LT - R1200RT - R1100RS (RIP) - Cagiva SST 350 Ala Verde - K75LT project - K75 Schurgers - K75S
    

13Back to top Go down   Strange Caliper Bolt? Empty Re: Strange Caliper Bolt? Fri Nov 11, 2022 7:03 am

MartinW

MartinW
Life time member
Life time member
Thanks to all who helped solve the issue. I'd already come to the conclusion that that was what it was for. Bruce and the tyre fitter apparently had a hard time fitting the caliper on his last tyre change due to that bolt. So as the bike will not be having it's ABS reinstated I've modified the caliper to take a standard bolt.  I got in contact with a mate who also has a 91 K100 LT with the ABS removed and got him to take a piccie of his caliper and it doesn't appear to have that bolt. I might be seeing this bike today so I'll have a closer look.
Regards Martin.


__________________________________________________
K75s Hybrid
    

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