Rear Caliper Stuck Shut On New 2021 TBR7

[Tomkay44]

When I took the rear brake caliper off its mount, I turned it a little to look at it and the caliper gently jiggled shut. Now it's shut tight as a drum. There's no prying it apart because you can't get a screwdriver in there. Do I need to bleed them? If so, can someone provide me a link that shows me how because I don't have a clue. Never bleed brakes of any kind.

[Magician16]

[Emerikol]

I would carefully open the bleeder screw and then very carefully try to push the piston back into place. What may have happened is that the piston moved forward far enough to come out of the bore, and if you get a huge pry-bar and go crazy it's possible you can damage something. Also, don't forget to open up the lid on the reservoir so the fluid that doesn't come out the bleeder screw has somewhere to go. Generally speaking, a piston should never come out of the caliper on it's own. There has to be a leak somewhere that allowed that to happen. Please let us know what you find.

[Thumper]

If you have a plastic or rubber/nitrile tube that fits on the nipple on the bleeding nut, put it on so that when you open it, you can have it drain into a jar instead of all over the floor and your hands or the tire itself!. The tube also helps prevent air from going back into the caliper's cylinder(s).

[Tomkay44]

Thanks again Magician16. I ordered the mini bleeder tube suggested in the video.

[Tomkay44]

Originally Posted by Emerikol

I would carefully open the bleeder screw and then very carefully try to push the piston back into place. What may have happened is that the piston moved forward far enough to come out of the bore, and if you get a huge pry-bar and go crazy it's possible you can damage something. Also, don't forget to open up the lid on the reservoir so the fluid that doesn't come out the bleeder screw has somewhere to go. Generally speaking, a piston should never come out of the caliper on it's own. There has to be a leak somewhere that allowed that to happen. Please let us know what you find.

Thanks Emerikol. I'll guess I'll lightly bolt it to the outside of the mounting bracket since I can't put it where it's supposed to go (on the disc). That way it'll be kinda in the right position/place relative to the reservoir and the master cylinder.
Luckily, since it's shut so tight that I can't get the smallest screwdriver in there, I haven't gone crazy on it as to damage it yet.
The reservoir is barley filled to the bottom level so maybe there's not a leak, just not enough brown China brake fluid that caused this. I'll report back to y'all and let you all know. Again, thanks for the advise everyone. Couldn't do this without y'all.

[CheapThrills]

If you have the motorcycle on a lift, sometimes it puts pressure on the foot pedal engaging the brake. Check if the jack is engaging the rear brake.


hth,

[Tomkay44]

I sure appreciate all of you taking time to turn me on to you all's wisdom that certainly far exceeds mine.
Btw, I did take it off the Jack just to make sure Cheap Thrills suggestion wasn't happening (great question).
I'm thinking back 2 or 3 months ago when I first took the wheel off, after I unscrewed the caliper from the mount, it took what I thought was a gentle hit/fall. When I picked it up, the calipers seemed lose and, just kind of fell or, gently slipped closed. I figured they would open right back up soif I wiggled the pedal or something but they haven't budged since. My mini bleeder should get here today and tomorrow I should have time to bleed/flush the brakes while I try to ease the calipers apart. Saying all that to ask these questions.
1) Do y'all think I trashed the rear calipers? (I guess they're a lot more gentle than I thought maybe.)
2) Have y'all seen anything like this happen before?
3) If I did trash them, can I just buy the caliper assembly or do I need to buy the whole rear brake system (master cylinder, reservoir & caliper.)?
4) Depending on what you all's answers to 1 & 2 are, could you provide a link to what might fit that's, hopefully, the most affordable?

Again, thanks so much for you guy's help. My 2021 TBR7 would have to be an anchor for the boat I wish I had if it wasn't for y'all.

[severely]

Originally Posted by Tomkay44

I sure appreciate all of you taking time to turn me on to you all's wisdom that certainly far exceeds mine.
Btw, I did take it off the Jack just to make sure Cheap Thrills suggestion wasn't happening (great question).
I'm thinking back 2 or 3 months ago when I first took the wheel off, after I unscrewed the caliper from the mount, it took what I thought was a gentle hit/fall. When I picked it up, the calipers seemed lose and, just kind of fell or, gently slipped closed. I figured they would open right back up soif I wiggled the pedal or something but they haven't budged since. My mini bleeder should get here today and tomorrow I should have time to bleed/flush the brakes while I try to ease the calipers apart. Saying all that to ask these questions.
1) Do y'all think I trashed the rear calipers? (I guess they're a lot more gentle than I thought maybe.)
2) Have y'all seen anything like this happen before?
3) If I did trash them, can I just buy the caliper assembly or do I need to buy the whole rear brake system (master cylinder, reservoir & caliper.)?
4) Depending on what you all's answers to 1 & 2 are, could you provide a link to what might fit that's, hopefully, the most affordable?

Again, thanks so much for you guy's help. My 2021 TBR7 would have to be an anchor for the boat I wish I had if it wasn't for y'all.

Patience, young man. You'll be able to move the caliper pistons when you crack open the bleeder valve. The brake most likely was applied when the bike fell over, thus closing the brake pads. When pushing the pads apart you will want to pry on the steel edge of the brake pad rather than the pads themselves so as not to damage the pads themselves and go from one side to the other so as to depress the pistons back evenly. Once you get the pads apart you can GENTLY pry on the pads to get enough clearance to install the caliper over the disc and start the bleeding process. Good luck. The good news is you'll be quite the experienced mechanic by the time your bike is put together and running properly.

[China Rider 27]

Once you get it all done, you will be a go to guy on the TBR7! Ha Hah and will be providing help for others! You always learn the most from the stuff that gets messed up and is difficult. At the time it is no fun but later you realize how much it helps you get better and avoid similar issues to get things right. We have all been there!

[Tomkay44]

Originally Posted by severely

Patience, young man. You'll be able to move the caliper pistons when you crack open the bleeder valve. The brake most likely was applied when the bike fell over, thus closing the brake pads. When pushing the pads apart you will want to pry on the steel edge of the brake pad rather than the pads themselves so as not to damage the pads themselves and go from one side to the other so as to depress the pistons back evenly. Once you get the pads apart you can GENTLY pry on the pads to get enough clearance to install the caliper over the disc and start the bleeding process. Good luck. The good news is you'll be quite the experienced mechanic by the time your bike is put together and running properly.

Thanks for that reassurance and words of much needed inspiration severely & China Rider 27.
I didn't actually drop the bike. It was the caliper that got away from me.
Couple of more questions please:
1) The cable/line running from the master cylinder to the capiler runs directly over the bleeder valve not leaving enough room to get the tube on there without kinking it. I definitely can't get the Motion Pro Mini Bleeder on it. Will I hurt anything if I loosen the bolt on top of where the line connects to the caliper, move it over just a little, and then tighten it back up so I can get the tube on? I'd put it right back afterwards.
2) Severely wrote, "you will want to pry on the steel edge of the brake pad rather than the pads themselves". Is that the two shinny chrome looking bars/rods I'm seeing under the pads? It doesn't seem like there's enough room to get to them to move them. I guess I could put a piece of rubber over a thin, flathead screwdriver to do it.

[severely]

Originally Posted by Tomkay44

Thanks for that reassurance and words of much needed inspiration severely & China Rider 27.
I didn't actually drop the bike. It was the caliper that got away from me.
Couple of more questions please:
1) The cable/line running from the master cylinder to the capiler runs directly over the bleeder valve not leaving enough room to get the tube on there without kinking it. I definitely can't get the Motion Pro Mini Bleeder on it. Will I hurt anything if I loosen the bolt on top of where the line connects to the caliper, move it over just a little, and then tighten it back up so I can get the tube on? I'd put it right back afterwards.
2) Severely wrote, "you will want to pry on the steel edge of the brake pad rather than the pads themselves". Is that the two shinny chrome looking bars/rods I'm seeing under the pads? It doesn't seem like there's enough room to get to them to move them. I guess I could put a piece of rubber over a thin, flathead screwdriver to do it.

Question 1 Go ahead and loosen the line bolt to reposition the line, then retighten. Question 2 No, it's not the shiny chrome bars, they allow the caliper to center on the disc. I'm referring to the steel plates behind the pad material itself, that actually fit in the pad holder brackets to pry on. Edit to add I think we're saying the same thing only differently. the pads metal surface is probably shiny when new, they should be the distance between the pads thickness apart, crack the bleeder valve and pry on the metal to separate the pads far enough to get a smooth flat pry between the pads and open them far enough to fit over the rear disc rotor BTM, with the bleeder valve open you'll lose some fluid so be prepared. You' can pry the pads apart without opening the bleeder valve but it's much more difficult to pry apart without the pressure relief. After assembly go ahead and bleed the system well, checking for excessive drag or sponginess of operation.

[Tomkay44]

Originally Posted by severely

Question 1 Go ahead and loosen the line bolt to reposition the line, then retighten. Question 2 No, it's not the shiny chrome bars, they allow the caliper to center on the disc. I'm referring to the steel plates behind the pad material itself, that actually fit in the pad holder brackets to pry on. Edit to add I think we're saying the same thing only differently. the pads metal surface is probably shiny when new, they should be the distance between the pads thickness apart, crack the bleeder valve and pry on the metal to separate the pads far enough to get a smooth flat pry between the pads and open them far enough to fit over the rear disc rotor BTM, with the bleeder valve open you'll lose some fluid so be prepared. You' can pry the pads apart without opening the bleeder valve but it's much more difficult to pry apart without the pressure relief. After assembly go ahead and bleed the system well, checking for excessive drag or sponginess of operation.

Hallelujah! Houston we have one less problem! he caliper's on the disc!
Look out gentlemen. The animated emojis are out of control!
I appreciate y'alls awsome help more than words and animated emojis can describe.

Sorry but I still have questions though.
1) Does anyone know what those 12mm caliper mounting bolts should be torqued at?
2) Not that I went crazy spreading the pads apart but, would it have been possible to spread them too far?
3) For some stupid, inexperienced reason, I tried to bleed/flush the brake fluid before spreading the pads. It got to the point where there wasn't any spongy-ness to it. The pedal would just bottom out and no fluid was really coming out. The fluid in the reservoir wasn't depleting either.
Any suggestions?
Again, I appreciate and value you all's help so much

[Magician16]

1. On a Bashan, it's 18-22; I assume it's the same. I don't torque them. I just put loctite on them and tighten them to where they feel tight.
2. You could possibly break the pad, but you'd have to beat your lever with a hammer.
3. You pulled a vacuum in the line caused by the check valve in the mini bleeder.

[severely]

Originally Posted by Tomkay44

Hallelujah! Houston we have one less problem! he caliper's on the disc!
Look out gentlemen. The animated emojis are out of control!
I appreciate y'alls awsome help more than words and animated emojis can describe.

Sorry but I still have questions though.
1) Does anyone know what those 12mm caliper mounting bolts should be torqued at?
2) Not that I went crazy spreading the pads apart but, would it have been possible to spread them too far?
3) For some stupid, inexperienced reason, I tried to bleed/flush the brake fluid before spreading the pads. It got to the point where there wasn't any spongy-ness to it. The pedal would just bottom out and no fluid was really coming out. The fluid in the reservoir wasn't depleting either.
Any suggestions?
Again, I appreciate and value you all's help so much

I agree with Magician16 on the torque values. You just need to bleed the system, you've got air in the system cracking the bleeder valve and repositioning the line. Again, patience is your friend, you're almost there.