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Recently had new rear brake pads installed on my 2006 sportster (10 days ago) While riding down the interstate rear brake locked, stopped on shoulder of road and bike would not move in neutral, rear rotor was smoking fluid dripping from caliper, then brakeline hose exploded like a gunshot. WHY? Let rotor cool down then rode home sans rear brake. What was the problem? My shovelhead once did this in arkansas a week after I put DOT 4 fluid in front cylinder accidently.
 

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Wayward Son
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Who did the work?
Either the pistons did not fully retract or the brake was adjusted incorrectly. Not allowing the pistons/pads to fully retract.

I will figure you rode more then just today since they were replaced so my guess is the pistons hung up.
 

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Wayward Son
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Air in the brake system will also cause a lock up when it gets hot.
True.
But would cause mushy brakes as well.
That may have been happening and Johnnybeabad may have failed to mention it.
Maybe the reason for initially changing the pads? :dunno
 

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Rear sporty brakes are a hoot to change, if you don't know the exact way to do it. I BET WHOMEVER CHANGED THE PADS SCREWED UP!
 

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My guess is the pads were dragging on the rotor. As they got hotter, heat transferred to the fluid, and then the master cyl. Fluid expanded, putting more pressure on pads/rotor until you stopped, then convection continued heating the system until the brake line gave.
Why were the pads dragging? Maybe the pucks were not properly cleaned and couldn't retract enough.
 

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Wayward Son
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My guess is the pads were dragging on the rotor. As they got hotter, heat transferred to the fluid, and then the master cyl. Fluid expanded, putting more pressure on pads/rotor until you stopped, then convection continued heating the system until the brake line gave.
Why were the pads dragging? Maybe the pucks were not properly cleaned and couldn't retract enough.
"Pucks"?
That is a new term to me. Pistons?
Never worked on Sporty brakes. Just know the basics.
Trying to learn.

Am really surprised the rotor did not warp.
 

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Recently had new rear brake pads installed on my 2006 sportster (10 days ago) While riding down the interstate rear brake locked, stopped on shoulder of road and bike would not move in neutral, rear rotor was smoking fluid dripping from caliper, then brakeline hose exploded like a gunshot. WHY? Let rotor cool down then rode home sans rear brake. What was the problem? My shovelhead once did this in arkansas a week after I put DOT 4 fluid in front cylinder accidently.
Could very well be the brake fluid . If you mix DOT 4 and DOT 5 , they will form a jell and lock up the calibers .

Who did the brake job, the Dealer ???? If so..they should be held responsible for all of the damage .
 

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"Pucks"?
That is a new term to me. Pistons?
Never worked on Sporty brakes. Just know the basics.
Trying to learn.

Am really surprised the rotor did not warp.

Yea, pistons. Maybe the Canadian whisky made me write "pucks"? I haven't heard or used that term in a looong time. It's amazing what comes out of the archives of my mind at times.
 

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Could very well be the brake fluid . If you mix DOT 4 and DOT 5 , they will form a jell and lock up the calibers .

Who did the brake job, the Dealer ???? If so..they should be held responsible for all of the damage .
that's an old wives tale. you should never mix DOT4 and DOT5 brake fluids, but they do not form a gel if you do. you can easily try it and see, in a glass jar.
 

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that's an old wives tale. you should never mix DOT4 and DOT5 brake fluids, but they do not form a gel if you do. you can easily try it and see, in a glass jar.
Didn't use a jar.................used the master cylinder . Gelled in less than 200 miles .

DOT 5 is not interchangeable or compatible with DOT 3, 4, and 5.1 fluids and can cause catastrophic system failure.

Dot 3, 4, and 5.1 are glycol ether based. They are compatible, but like motor oils, you should use the recommended or higher grade fluid. Dot 4 and 5.1 also have borate ester to handle higher temperatures. DOT 3, 4, and 5.1 fluids are found in most brake and clutch systems.

DOT 5 is a silicone oil based fluid and can only be used in new, dry systems.
 

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I've been using DOT5 ( in appropriate systems) for years. Have used DOT 4 and before that DOT3 Have seen them mixed in several systems 9 old corvette systems come to mind) and never have I seen gelling. Just saying.

Never mix Dot5 WITH ANY OTHER BRAKE FLUID, but still never seen gelling.
 

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I've been using DOT5 ( in appropriate systems) for years. Have used DOT 4 and before that DOT3 Have seen them mixed in several systems 9 old corvette systems come to mind) and never have I seen gelling. Just saying.

Never mix Dot5 WITH ANY OTHER BRAKE FLUID, but still never seen gelling.
" How DOT 3 and DOT 4 when mixed with DOT 5 causes a system failure . "

""DOT3/DOT4 to DOT5 Brake Fluid Conversion
by Dave Barbieri


--------------------------------------------------------------------------------

Since I don't do 'conversions', I wanted to talk to some of our brake vendors (TX & CA) and get my facts straight. Here's the procedure recommended:


Use a turkey baster to suck all the old fluid out of the master cylinder reservoir. Fill the reservoir with rubbing alcohol. Get about 5 bottles; yer gonna need 'em. 8-P

Bleed the system, just like you would normally. Keep bleeding each wheel cylinder/caliper until only rubbing alcohol comes out. When all you see is only clean, clear rubbing alcohol, you're thru with the flushing.

Take all the brake lines loose at both ends. Use filtered, dry compressed air to blow out all alcohol. The lines must be free of all traces of alcohol.

Remove the master cylinder and wheel cylinders/calipers. Disassemble each component, clean thoroughly with either hot soapy water/hot water rinse or with a commercial non-filming brake cleaner. Dry each part and reassemble using DOT5 brake fluid as lubricant.

Components such as the combination valve will have alcohol in them from the flushing procedure. Blowing them out will be pretty touchy. Too much air and you 'blow out' the valve, too little and you don't get rid of the alcohol.

Re-install all the parts, fill the reservoir with DOT5 fluid, and bleed as normal.
There's not complete agreement on how DOT5 reacts with DOT3/4. Some tech reps said it forms a gummy residue that affects brake action. Two stated that the DOT5 would simply 'flush out' any traces of alcohol/DOT3/4 during the bleeding process. Since there's not 100% agreement, (and I'm both anal-retentive and paranoid when it comes to brakes), I listed the full procedure.

Do you really, reeeelly wanna do this? DOT5 is typically used in heavy eqyuipment, military vehicles, and (some) antique vehicles. All share the same characteristic of sitting for long periods of time. DOT5 gets rid of any concern about moisture absorption while sitting idle.

DOT5 is expensive and a PITA; I think you'll spend a lot of time and $$, only to be disappointed with the actual performance gains"

DOT 4&3 will absorb water from the air, then when mixed with DOT5 ( a 100% silicone oil ), it'll form a brown gel like sludge .
 

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In a brake system, with a large amount of moisture laden DOT3 or4 , adding DOT 5 will cause the DOT 3 or 4 and any moisture it contains to separate and you will see a brownish mix of DOT 3 or 4 and water, but like I said before I've never seen the stuff Gel.

The flushing you mention can be done with fresh DOT 3 or 4 instead of alcohol. The 3 or 4 absorbs the moisture and then the 5 which will not mix will push the 3 and 4 and moisture out as the system is bled.

All this said, DON"T MIX 3 or 4 with 5, and never change from one to the other without making sure all old fluid is removed from the system first.
 

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If they where not OEM shoes they may have been a cheap imitation that are not quite right. I had an issue with a pair I got off Ebay for a 93 and the shoes where missing a very distinct taper at the top and because of that the shoes would ride up and bind between the caliper and the disc and cause excessive squealing and friction leading to a lock up from overheating
 
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