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Discussion Starter #1 (Edited)
I took the wife on a quick ride. We smelled a burning smell, and we were having to give it way more gas to keep it going. We pulled into our driveway, and all of the sudden, the bike flew out from under us. The front right brake caliper sized up completely. I tried bleeding the brakes before, and right brake caliper bled normally; but the left brake caliper doesn’t let out any fluid. When I cracked the bleeder valve, a tiny bit came out of the left brake, but nothing more would bleed out. The right caliper shot fluid 10” and then trickled out normally, allowing the bike to move again. I am just glad we were going less than 5 mph. Previously, I undid the banjo bolt at the manifold and only a tiny bit of brake fluid dripped out of the right side. Can I pick up some universal brake lines at like autozone and swap them out? We got damn lucky we weren’t going 30 or 50. Now the wife is scared to ride on it.

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First, glad you weren't more badly injured.

Second, sounds like you've got two problems. Probably a clogged line on the left caliper (might be in the caliper itself), and possibly a bad/clogged master cylinder that wasn't releasing pressure in the lines when you released the brake lever. Sure, replace the lines, but take a hard look at the calipers and master too.
 

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Discussion Starter #3 (Edited)
First, glad you weren't more badly injured.



Second, sounds like you've got two problems. Probably a clogged line on the left caliper (might be in the caliper itself), and possibly a bad/clogged master cylinder that wasn't releasing pressure in the lines when you released the brake lever. Sure, replace the lines, but take a hard look at the calipers and master too.


I undid the banjo bolt going to the left caliper, a couple small drips, then nothing. I undid the banjo bolt at the manifold (not sure what it is called), and it dripped steadily. I will try taking apart the master cylinder and clean everything. Is there anything special I should look at while I have it all apart? Can I just shove something in the return hole? I drained the fluid when I first got it, so I could see the return port functioning at the bottom, and there was no sediment. Thank you for your help.


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I've never rebuilt a master cylinder, but it's my understanding that there are seals on a shaft that move back and forth across internal ports. If the return/vent (?) port is clogged (either with sediment or by a stuck seal), then the pressure just builds up in the lines and you wind up with locked brakes. I replaced the whole unit on my truck when it went bad, just so I wasn't rolling the dice on missing something critical. (oh, EVERYBODY knows that you have to grease part X with product Y before you reassemble).
 

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I'm thinking since one caliper was locked and the other wasn't, it's not the master? Collapsing hose on the.. left? If that's the one that was locking. I would try to get it locked again and see how it behaves when you open the bleeder. If it unlocks, it's the hose, if it stays locked, it's a sticking caliper.

You won't get these hoses at Autozone.
 

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Discussion Starter #6
I'm thinking since one caliper was locked and the other wasn't, it's not the master? Collapsing hose on the.. left? If that's the one that was locking. I would try to get it locked again and see how it behaves when you open the bleeder. If it unlocks, it's the hose, if it stays locked, it's a sticking caliper.



You won't get these hoses at Autozone.


The left caliper doesn’t function, and the right one is the one that seized. The guy that I bought it from said the left one was completely seized, and he cracked the bleeder valve to get the bike to move. So both time it seized, the bleeder valves were cracked and it went back to operational. Is there any way to test it without the tires locking up again? I have new Galfer lines coming: https://www.ebay.com/itm/KAWASAKI-1986-2005-VN-750-VULCAN-GALFER-STAINLESS-STEEL-FRONT-BRAKE-LINE-KIT-/251459421803 hopefully these will are decent ones.


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The left caliper doesn’t function, and the right one is the one that seized. The guy that I bought it from said the left one was completely seized, and he cracked the bleeder valve to get the bike to move. So both time it seized, the bleeder valves were cracked and it went back to operational. Is there any way to test it without the tires locking up again? I have new Galfer lines coming: https://www.ebay.com/itm/KAWASAKI-1986-2005-VN-750-VULCAN-GALFER-STAINLESS-STEEL-FRONT-BRAKE-LINE-KIT-/251459421803 hopefully these will are decent ones.


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Then the line on the right is collapsing internally, holding hydraulic pressure. Cracking a bleeder won't release a seized caliper piston.

Can't test without getting the caliper to lock up. The new lines should fix it.

That leg! Mine would've just snapped. ATTGATT. All The Gear All The Time
 

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As always, I've got to agree with Spockster. If the left is blocked due to extreme hose degradation, the right could be partially collapsed, acting like a one-way valve.
 

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Discussion Starter #9
I am worried I could’ve warped the rotor. It was smoking badly. Do I just put it on a flat surface to check?


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