Lost front brake caliper bolt

[kingmarty45]

Hi guys,

I was out riding yesterday and was pulling up at a set of traffic lights when I noticed that my front brake wasn't working.

At the light I noticed that one of the two bolts that holds the front brake caliper to the fork had shaken out and disappeared. Not sure when this happened but it was a little concerning, I am lucky I didn't need to stop quickly for any reason.

The loss of the bolt had caused the brake caliper to swing down off the rotor, so that when I squeezed the brake, the bads were no longer closing around the rotor.



Because I was trying to use the brake when it was dangling away from the rotor, the two brake pads have seized shut and I am not sure how to get them to loosen again so that I can but the brake back on.



Anyone know? Also, anyone know where I can get replacement bolts? Also, any ideas to stop this from happening, like using loctite or similiar?

I am pretty keen for this to not happen again.

Thanks for your help.

[chinabiker]

Hi King

Here is something recommended by forchetto, which has proven to be very useful.

If the bolts go through the holes and are tightened against a nut, I'd recommend the use of a spring washer under the bolt's head and a normal washer under the nut - but use a locknut. All this if spaces allows.
Important: locknuts have to be replaced by new ones once removed.

If the bolts go into a thread, I'd use a spring washer under the bolt's head and Loctite the thread. Be careful to use the right Loctite. There is link in forchetto's post, leading to a Loctite write-up.

Bolt quality should be 8.8, best for vehicle use I was told. Lower grades may be too weak, higher ones too brittle. Our company e.g., instructs for replacement of 10.9 and higher grade bolts and nuts after they have been removed once.

Andy

[forchetto]

It's a two-piston swinging calliper, meaning that it only has hydraulics on one side. Apply force to the pad on the right hand side of the second photo. You'll probably need a "G" clamp or plumbers slip-joint pliers.

The idea is to push the piston back into its cylinder a bit until there's a gap between the two pads. Then wedge something between the pads and apply a steady force. A large screwdriver or wooden wedge should do it.

Whilst the cylinder is returning to its normal position the brake fluid is being forced back into the reservoir so it's best to loosen off or remove the lid of the reservoir to avoid any pressure in there that will impede the return of the fluid.
As the piston recedes you should be able to see the fluid level in the reservoir rise.

I would reassemble the bolts using blue Loctite, but check that the threads on the missing bolt hole have not been damaged by running with a loose bolt.

An 8.8 grade steel bolt should be OK. Take the remaining one to the shop for comparison.

As a further observation, note how on Japanese bikes all vital safety nuts and bolts have been marked either with a marker pen or yellow paint. This is to confirm that they've been torqued and also acts as a tell-tale if they move. Once again I have to praise the Qingqi (Qlink) QM200 for following this wise practice. I notice your disc rotor bolts are not marked in any way, whereas my Qingqi's are.

[kingmarty45]

Thanks guys, I appreciate it.

I got the brake pads apart without any hassle and got the caliper back on the rotor.

But, Instead of shopping for a bolt, I rode over to my dealer and asked for one. He just took one off a Kinlon he had on the show room floor and that was it.

Surprisingly, even though the two bikes are the same, the bolts are different. Both fit, but one has a much larger head. No idea.

Anyway, I have bought some blue loctite, and am planning on going over the bike with it...

Any trouble spots you can recommend hitting up? Or should I just do all?

Thanks again,

Marty.

[CrazyCarl]

DO IT ALL!

Be sure to check the suspension mounting bolts (famous for being marked as checked at the factory when they actually aren't), engine mount bolts, and all nuts related to the axles.

CC

[ChinaV]

DO IT ALL!

+1

I don't know if that bolt would have been checked in China. A lot of motorcycles are shipped in a crate without the front wheel attached. My guess, maybe it wasn't torqued at the dealer when they assembled your bike.

I was wandering an assembly line in China one day when I noticed a worker marking bolts with a white dot to indicate they were torqued. She explained it was much easier to pre mark them before assembly and was quite impressed with her efficiency.

Cheers!
ChinaV

[chinabiker]

... I was wandering an assembly line in China one day when I noticed a worker marking bolts with a white dot to indicate they were torqued. She explained it was much easier to pre mark them before assembly and was quite impressed with her efficiency. ...ChinaV

You made my evening, ChinaV - Have to clean my screen now ...

Andy

[kingmarty45]

DO IT ALL!

Be sure to check the suspension mounting bolts (famous for being marked as checked at the factory when they actually aren't), engine mount bolts, and all nuts related to the axles.

CC

I should've bought a bigger bottle...