Left front caliper Lower bolt

[easy rider]

Hi Everyone

I am not really an expert when it comes to DIY mechanic but during the covid 19 situation and being a key worker and still needing to be on the road i am having to learn fast with
garages closed everywhere.

Just when i think i am all sorted after replacing
broken brake light switch, spark plugs, new battery, coolant leak fix, vac leak and 5 way t blockage

This happens -


I don't generally touch my brakes but i have noticed movement at the front when braking and sure enough when checking the left side front caliper it moves slightly.
So the the lowest bolt that goes through the lower part of the front forks of the bracket sub assembly appears tight but when you grab the bracket it moves along with the caliper.

My worst fear is the bolt has snapped inside and now i am wondering how its going to be removed.

i have ordered brake pads and a new bolt but i am starting to worry about this bolt.

I think when going to the garage they have used the bolt that many times it has become weak and when the brakes are being used it has eventually snapped.

Brakes are the one thing i don't touch but it looks like i have no choice with there being nowhere open.


any advice

Thanks

 

[Mophead]

Have you tried to remove the bolt? They really don't have much torque applied to them if they were installed properly.

 

[W0QNX]

Yes it will be "loose" feeling. It's the pivot point of the SMC system so it does have some freedom of motion. When you apply the front brake the caliper clamps down on the disc. This causes the caliper to rotate upwards with the disc as the disc rotates. This moves the entire SMC assembly forward (pivots about that lower bolt) and forces the small piston pin into the SMC brake cylinder (the part on the assembly with the brake fluid line) which pressurizes the line going to the piston in the rear caliper.

Short version it will seem loose. Very doubtful the socket head cap screw "bolt" is broken. If it's broken it would fall out.

If it will make you feel any better you can check the bolts tightness with a 6mm hex wrench (Allen wrench). Do NOT use an imperial hex key as it is metric 6mm. It won't hurt to check the tightness or even remove and replace the socket head cap screw (pivot bolt #23) as long as you get it back in tight.

Yes it should be installed with a torque wrench.

Part 23 and part 24 below are the bolts that hold the entire left brake assembly to the fork. They are both "pivot points" and will have some movement. They should be tight but would more than likely fall out if broken.

 

[easy rider]

Have you tried to remove the bolt?

Hi
Not yet i am waiting for my new bolt to arrive along with some new pads
I have this bad feeling the end of the bolt is all that will come out.
Also when loosing caliper bolts am i right its not left for loose and right for tight its the other way round counter clock wise?

Thanks

 

[Whooshka]

Hi
Not yet i am waiting for my new bolt to arrive along with some new pads
I have this bad feeling the end of the bolt is all that will come out.
Also when loosing caliper bolts am i right its not left for loose and right for tight its the other way round counter clock wise?

Thanks

Read the post above yours. Have you actually tried to loosen the bolt yet? You seem to be in panic mode for no reason.

 

[easy rider]

Its the bolt in the attached picture is this bracket supposed to have movement in it?
The bolt i am pointing to is solid and does not move but the bracket its securing moves around the bolt slightly left to right which gives movement to the caliper.

Thanks

 

[SMSW]

The caliper bolts tighten like any other bolt - clockwise looking at the head of the bolt to screw it in and tighten it. If you have an installed bolt on the bike - counter clockwise to loosen it. Depending on which bolt we are talking about on the front right brake, (if we are all talking about the same one), the caliper part that surrounds the bolt has a needle bearing inside. As already described, the caliper pivots slightly. Someone hop in here and correct me about where exactly the bearing is located if I misstated. Its been a year since I had the calipers off the bike. I strongly suggest you use a torque wrench on brake bolts - they are important - unless you are a mechanic and have a trained wrist. (As an aside, my auto mechanic, who has been wrenching for over 30 years and was initially GM trained, uses his torque wrench a lot, but certainly not on every nut and bolt.)

edit: Just looked at your finger.....oops, picture. I'm pretty sure this is the spot with the needle bearing inside. If you pull the bolt, you should check and grease this bearing. What is the best grease to use? That answer, grasshopper, is what separates the locusts from the cicadas.

 

[Whooshka]

Yes it will be "loose" feeling. It's the pivot point of the SMC system so it does have some freedom of motion. When you apply the front brake the caliper clamps down on the disc. This causes the caliper to rotate upwards with the disc as the disc rotates. ............................

Its the bolt in the attached picture is this bracket supposed to have movement in it?
The bolt i am pointing to is solid and does not move but the bracket its securing moves around the bolt slightly left to right which gives movement to the caliper.

Thanks

.................. As already described, the caliper pivots slightly. ..................

Yes that bolt may feel loose because the SMC rotates forward as the brakes are applied. If you torqued that bad boy down to where the SMC cannot rotate forward you would lose your linked brake function. And probably bend some hardware in the process.

 

[easy rider]

Yes it will be "loose" feeling. It's the pivot point of the SMC system so it does have some freedom of motion. When you apply the front brake the caliper clamps down on the disc. This causes the caliper to rotate upwards with the disc as the disc rotates. This moves the entire SMC assembly forward (pivots about that lower bolt) and forces the small piston pin into the SMC brake cylinder (the part on the assembly with the brake fluid line) which pressurizes the line going to the piston in the rear caliper.

Short version it will seem loose. Very doubtful the socket head cap screw "bolt" is broken. If it's broken it would fall out.

If it will make you feel any better you can check the bolts tightness with a 6mm hex wrench (Allen wrench). Do NOT use an imperial hex key as it is metric 6mm. It won't hurt to check the tightness or even remove and replace the socket head cap screw (pivot bolt) as long as you get it back in tight.

Yes it should be installed with a torque wrench.

Thank you for your help I am just over thinking everything at the moment with the way things are.
People are relying on me and we have a field hospital to support as well and my trusty bike is having problems at a time when i need it to just work but that is always the way.
Just need to get new brake pads fitted.

The bolt is perfectly tight and in place the sub bracket just moves slightly which is why i thought it may be loose or damaged.

I suppose thinking about it the ABS light would come on if the caliper was moving more than it should if the caliper bolt was loose.
Really appreciate your help.

I am replacing the headlight motor on Saturday as that is going off on its own randomly on turning the ignition on.
Wondered what the noise was at first then i realised it was the headlight motor behaving erratically so i have just disconnected it for now to solve the problem.

Please stay safe everyone during these difficult times.

Best wishes

Martin

 

[W0QNX]

Whooshka if you overtighten the bolt it won't lock the pivot up. There is no "floor" under the outer side of the pivot bracket. The bracket just pivots about the head of the socket head cap screw #23.

Bolt 23 tightens down onto the bearing which forces the bearing race against the inner side of the bracket where bolt 23 threads into the bracket.

 

[Andrew Shadow]

The best thing that you can do is remove the caliper. You will find a bearing in that hole. Clean everything up real good including the bolt head, clean the bearing out and re-grease the bearing as well as the bolt before you re-install it. Then everything will move even more freely, as it should, and freak you out even more.

 

[Whooshka]

Whooshka if you overtighten the bolt it won't lock the pivot up. There is no "floor" under the outer side of the pivot bracket. The bracket just pivots about the head of the socket head cap screw #23.

I realize that. Hence my comment about bending hardware.

 

[dduelin]

I'm late to the party but slight movement of the caliper and the bracket it is mounted on is normal. The lower bolt is a pivot axis for the caliper bracket - the bolt threads into the inboard side of the bracket - there is no nut on the end of it. The bolt passes through a bearing with a collar and the collar prevents the bolt from being tightened to the point of restricting movement about the pivot axis. In the parts diagram posted above the bolt #23 passes through the thing looking like a tube. It's actually the needle bearing others talked about.

 

[SupraSabre]

When you ordered a new bolt, did you order a new spacer?



Take a look at this picture. Does it help to see how it is attached?

I was in the process of rebuilding the SMC. And yes, the SMC, is still working 5 years later...just fine!

 

[easy rider]

I'm late to the party but slight movement of the caliper and the bracket it is mounted on is normal. The lower bolt is a pivot axis for the caliper bracket - the bolt threads into the inboard side of the bracket - there is no nut on the end of it. The bolt passes through a bearing with a collar and the collar prevents the bolt from being tightened to the point of restricting movement about the pivot axis.

When you ordered a new bolt, did you order a new spacer?



Take a look at this picture. Does it help to see how it is attached?

I was in the process of rebuilding the SMC. And yes, the SMC, is still working 5 years later...just fine!

Thanks for this much appreciated.

Yes i have ordered a new bolt plus the spacer along with front and rear brake pads.
It looks like it is all fine if the sub bracket is not supposed to be fixed solid without movement.
I over think things too much.

I have not attempted to do anything yet.

just waiting for new pads, bolt and spacer to arrive along with my new headlight motor which should be her Wednesday.

I even had fuel injection light for mapping sensor coming on but i think i have sorted that with the 5 way T i just put a new 5 way joint in with new hoses.
Touch wood its been fine up to now.

 

[wjbertrand]

If you over tighten that bolt you'll either strip the threads in the bracket or break the bolt.

 

[kenG]

Hi Everyone

I am not really an expert when it comes to DIY mechanic but during the covid 19 situation and being a key worker and still needing to be on the road i am having to learn fast with
garages closed everywhere.

Just when i think i am all sorted after replacing
broken brake light switch, spark plugs, new battery, coolant leak fix, vac leak and 5 way t blockage

This happens -


I don't generally touch my brakes but i have noticed movement at the front when braking and sure enough when checking the left side front caliper it moves slightly.
So the the lowest bolt that goes through the lower part of the front forks of the bracket sub assembly appears tight but when you grab the bracket it moves along with the caliper.

My worst fear is the bolt has snapped inside and now i am wondering how its going to be removed.

i have ordered brake pads and a new bolt but i am starting to worry about this bolt.

I think when going to the garage they have used the bolt that many times it has become weak and when the brakes are being used it has eventually snapped.

Brakes are the one thing i don't touch but it looks like i have no choice with there being nowhere open.


any advice

Thanks

it sounds very much like overthinking, iv replaced my pads a couple of times amd i just remove the lower calliper bolt and change the pads. its meant to move, even rock slightly wont take any hurt. i'd check if you think its broke with a torx tool, and a little pressure, if its broke you will know in seconds.
even removing the calliper for an overhaul doesnt include loosening this bolt.
a little maintenance squirt of wd40 round it occasionally will keep it working.

 

[Gus1300]

a little maintenance squirt of wd40 round it occasionally will keep it working.

Not really relevant to the thread, but watch using too much WD40 around a greased bearing...it might tend to remove the grease and then you'll be left with an unlubricated bearing. Not good!

 

[W0QNX]

Not really relevant to the thread, but watch using too much WD40 around a greased bearing...it might tend to remove the grease and then you'll be left with an unlubricated bearing. Not good!

And a Torx tool isn't going to work either..........kenG's post........

 

[T_C]

And a Torx tool isn't going to work either..........kenG's post........

Right size torx, just a little bigger then the allen key for the head, a BFH, it'll work. As a bonus, it will always be where you can find it!