Badly galled rear caliper bolts

[Greb]

I just had to check didn't I? My top bolt was rusted but came out okay, bottom not so much. More money to spend this winter

I never take these bolts out when doing tire changes, I just pull the axle out and drop the entire rear brake hanger assembly.

If you have newer bike I'd pull these bolts and put anti-seize on them ASAP!

 

[08FJR4ME]

Oh well... It was worth a try, right?

Yeah, but it was an absolute epic pain in the ass to find Metric-Fine Helicoils. I could have done without that. And now I sit around trying to figure out a rig to help get a tap in straight and square.

Wynpro Machining Services?

It may be to late at this point. You will have to go with a T-sert at this point on the messed up thread. They run slightly larger than Helicoils. Somethimes you can get a double wall if its real bad.

Dave

 

[dcarver]

Anti-Seize every bolt that comes out.

 

[Greb]

Oh well... It was worth a try, right?

Yeah, but it was an absolute epic pain in the ass to find Metric-Fine Helicoils. I could have done without that. And now I sit around trying to figure out a rig to help get a tap in straight and square.

Wynpro Machining Services?

It may be to late at this point. You will have to go with a T-sert at this point on the messed up thread. They run slightly larger than Helicoils. Somethimes you can get a double wall if its real bad.

Dave

$76 w/o shipping for a T-sert kit.

New Caliper $184 w/o shipping.

Wynpro Machining Services? I'm listening

 

[jpcfjr]

Can someone post a pic of which bolts you are talking about...just to clarify.

Hmm, on second thought, I guess it has to be the two bolts that the caliper pivots or slides on. That sucks...I'm scared to pull them out now. Two years and 26,000 miles it's probably too late to lube them up.

 

[RadioHowie]

After following this thread from the beginning, I've discovered two things.....

1 - Every report of threads pulling out on a rear caliper bracket was a Gen II, and

2 - There IS a positive to having use EBC "Evapo-O-Pads" on the FJR....the lifetime of those crappy pads is SO short, the caliper bolts are never in long enough to seize up!

 

[JamesK]

I had a shop install a Helicoil in my stripped thread and it's working just fine, cost about $45.

 

[jpcfjr]

I had a shop install a Helicoil in my stripped thread and it's working just fine, cost about $45.

I've a better solution, stop using brakes! :yahoo:

 

[Fred W]

Can someone post a pic of which bolts you are talking about...just to clarify.

Hmm, on second thought, I guess it has to be the two bolts that the caliper pivots or slides on. That sucks...I'm scared to pull them out now. Two years and 26,000 miles it's probably too late to lube them up.

Yes, correct. We are talking about item #6 in the parts breakdown here.

But the buggered threads would be in the caliper body, which doesn't seem to have a part number. You'd have to buy the entire assembly (item #3).

Every report of threads pulling out on a rear caliper bracket was a Gen II, and

Hmmm...

Well the bolt itself has the same exact part number in both applications, but the caliper assembly part numbers are different, even though they look identical in the part break-down line drawings. 1st gen and 2nd gen.

Also the caliper part pricing is pretty far apart with a first gen caliper assembly listing for $413 and a second gen list is $284. :blink: You may be on to something...

 

[Aasland]

Why do these bolts seize up when the front caliper bolts don't?

 

[Geezer]

I can't figure out why you guys are removing that bolt to change brake pads. I haven't had my pads out this year, but if I remember correctly the new pads just slip right in with the caliper on the bike.

 

[Constant Mesh]

The bleed screw location is different on the two generations. On the Gen I the bleed screw is on the top pointed up. On the Gen II it's on the side next to the hose connection. There may be other differences I haven't noticed.

It might be feasible to replace the OE bolt with a standard bolt and nut. Those two bolts don't appear to be loaded all that much. Their function is to properly locate/center the piston caliper on the pads. All the braking force is transferred from the pads to the fixed caliper bracket. The pads rest on the bracket not the piston assembly. The bolts don't see any of the force from braking.

One could just drill a hole completely through the bracket and install a standard bolt and a threadlocked nut. The piston assembly would slide side-to-side on the bolt for centering about the disc.

 

[Fred W]

I can't figure out why you guys are removing that bolt to change brake pads. I haven't had my pads out this year, but if I remember correctly the new pads just slip right in with the caliper on the bike.

I believe that you are thinking of the front pads, Greg. You need to remove the caliper in the rear as the pads slide into the carrier from the sides, not the top.

The bleed screw location is different on the two generations. On the Gen I the bleed screw is on the top pointed up. On the Gen II it's on the side next to the hose connection. There may be other differences I haven't noticed.

Ah.... so it is. Good eye. Doesn't explain the price difference.

It might be feasible to replace the OE bolt with a standard bolt and nut. Those two bolts don't appear to be loaded all that much. Their function is to properly locate/center the piston caliper on the pads. All the braking force is transferred from the pads to the fixed caliper bracket. The pads rest on the bracket not the piston assembly. The bolts don't see any of the force from braking.

One could just drill a hole completely through the bracket and install a standard bolt and a threadlocked nut. The piston assembly would slide side-to-side on the bolt for centering about the disc.

Those slide pins are smooth and greased and have seals to retain the grease, so that the caliper can easily slide sideways and center itself to the rotor. Otherwise the pad will drag on the fixed side of the caliper (side opposite the piston). I'm thinking that a through bolt would not give you the nice smooth action of the slide pins.

 

[wmadoty]

I have a 2010 with 5,000 miles. After reading this I decided I needed to pull those bolts and get some anti seize on the threads. Service manual says use silicon grease on the slider shafts (long smooth part of the bolt).

I found that the bolts did have a little anti seize on the threads and very little silicone grease on the shafts. The bolts are much happier now and I hope not stripping out when I go to change pads.

On a side note: I would not hesitate to use any of the thread repair devices available to fix stripped threads on this caliper. IMO Helli-coil would be just fine.

 

[Constant Mesh]

"Why do these bolts seize up when the front caliper bolts don't?"

Although I haven't removed my rear caliper bolts one difference in these bolts and the front caliper bolts might be a "bottoming out" effect.

The ends of the front bolts probably don't bottom out in the caliper as they're tightened to the specified torque. The bolts pass through the fork lug and thread into the caliper. When the fork and caliper are sandwiched tightly together the rated torque is attained. But the end of the bolts never bottom out in the caliper.

Conversely, the rear bolts don't tighten against a sandwich of parts. They get tight only when they bottom out. After it bottoms out the bolt can't advance any farther. So if you continue to crank the bolt something has to give -- the threads in the caliper or the bolt. The caliper threads are likely the weaker of the two so they weaken and fail.

The small decorative hex wrench screws which attach the fairing to the frame are a classic example of a bolt or screw which tightens from bottoming out. They pass through a rubber grommet into the frame. If you keep cranking one of these after it bottoms out the frame threads would quickly disintegrate. Whether or not you use anti-seize the threads can be easily ruined once the bolt or screw bottoms out.

 

[Fred W]

Actually, no, they do not bottom out. The slide pins (that's what they are) have a shoulder at the head end that you tighten them up against. The pin portion protrudes out the back side of the caliper into the carrier. They tighten the same as any other bolt, except you are not sandwiching anything in there. Once they are tightened in place into the caliper these pins act to slide in the bores located in the carrier.

 

[Constant Mesh]

Oops! I shouldn't have speculated until I'd taken mine apart not knowing exactly what's there. If I wait until I need new pads I may never take mine apart.

 

[bucky]

After reading this post,I had to remove my rear caliper bolts one at a time to inspect. Each bolt came off easy with no damage to bolt or caliper. Appeared to have some grease (evidently silicone grease) on smooth sliding part and the threaded portion (adjacent to the 13mm bolt head) was not dry. I assume this was anti-seeze compound. Added a small bit of additional silicone grease to the sliding part of the bolt and a generous amount of anti-seeze compound to the threads and retorqued to 19 lb per specs. bike is an 08 AE with 4k miles.

And yes, when you torque these "slider bolts", the bottom side of the 13mm bolt head tightens against the outside of the caliper. The smooth bottom end of the slider bolt does not bottom out in the inside part of the caliper bolt hole. This allows the caliper (and pads) to always center (by sliding over the greased part of the bolt) over the disk when you apply/release the brakes.

Wasn't that one of Newton's laws..for every action there is an equal and opposite reaction?

Just wondering...since these caliper bolts only purpose is to keep the caliper centered over the rotor and do not really "hold anything together", but only keep the caliper from sliding/pivoting downward off the rotor if the bolt(s) are removed, why not just have a heli-coil or something similiar installed in stripped out threads and save some $$? As long as it is done correctly, the only purpose of these threads in the caliper and mounting bolt is to keep the bolt from loosening.

 

[FJR Flyer]

Interesting. I just removed the rear caliper for the first time two days ago. One bolt was tight and pulled a little material out in the threads. First time I've removed the caliper in 50K miles. There was almost no grease on the slider, just a dab at the end.