Need some help with rear brake issue 2005

Jeff06098

.040 Over
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Mar 6, 2021
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61
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Winsted, CT
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2005 Triumph Rocket
Hey guys. So a couple weeks ago after hitting a nasty pothole I noticed my brake light was stuck on. After a stretch of bad weather kept me off the bike I’ve now been able to determine it’s the rear brake causing the light to stay on. It doesn’t always cause the issue when I use it. It definitely seems to be worse when the bike is really hot. It tends to stay stuck on for 3-5 minutes then goes out. I can see no obvious signs as to what is causing it.
So now here is where I could use some help/ advice. I’m leaning towards this being a bad pressure switch or a bad master cylinder. I suppose it could be a bad caliper but I don’t think so. The rear wheel seems to have 0 drag when the light is on so I’m thinking bad switch but it works fine other times and is definitely worse hot so would heat effect the switch? It would make more sense to me that heat might cause more of an issue with the master but again I’m not certain so I’m asking you all.
I do know that the prior owner had the fluid and at least the steel lines changed around 2000 miles ago. Bike currently has 15,200 ish miles.
If anyone can point me in the best spot to start I’d appreciate it. Would rather not change one part only to find the other was the issue. Could always change both but hate to waste the money. Thanks in advance.
 

Jeff06098

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Mar 6, 2021
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Winsted, CT
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2005 Triumph Rocket
Have you checked the wiring inside the fender to make sure it is not damaged and shorting out
It looks good. I actually have new wiring harnesses in case it does go bad because I know it’s an issue. I had a fuse blowing that ended up being headlight related but I grabbed the harness just in case as it was the last one I could find. Everything’s backordered. When I inspected it though I left the old as it seems good. Also this issue is strictly rear brake related. I can use the front all day and the light will never get stuck on. I tap the back pedal when I get home and it sticks on instantly. If I tap the back when it’s cold it works as it should.
 

Ralsmith

Supercharged
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Aug 13, 2019
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424
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Pasadena CA
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2011 Rocket 3 Roadster
If no drag on wheel but light still on I would vote for break switch as it sounds like your breaks are functioning properly.
 

Jeff06098

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Winsted, CT
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2005 Triumph Rocket
If no drag on wheel but light still on I would vote for break switch as it sounds like your breaks are functioning properly.
That’s what I’m thinking too but I’ve never dealt with a pressure switch before so I’m not certain how sensitive they are. I feel no drag and pads don’t seem to be disappearing but I’m not convinced that doesn’t mean there’s not a slight amount of pressure in the system. Again though I’m not sure what it takes to activate the switch.
 

TURBO200R4

stand up straight and grab the world by the a$$
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Jan 24, 2013
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TUCSON AZ
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Takes a very small amount to activate the switch guessing about 8 lbs.
If u want to check while brake light is stuck on losen the bleeder screw to releive any pressure. If light stays on u either have a bad switch or a short.
Have u got any extra lights that could b giving probs or shorting brakes.
Hth
 

Jeff06098

.040 Over
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Joined
Mar 6, 2021
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Location
Winsted, CT
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2005 Triumph Rocket
Takes a very small amount to activate the switch guessing about 8 lbs.
If u want to check while brake light is stuck on losen the bleeder screw to releive any pressure. If light stays on u either have a bad switch or a short.
Have u got any extra lights that could b giving probs or shorting brakes.
Hth
I don’t have any lights. I bought a one way valve for the bleeder so I can bleed them off easily by myself. I will try cracking it open when I get that. That’s a really good idea to help figure it out. I also ordered a switch since it’s only 30 dollars. I figure 16 years old it can’t hurt to swap it out anyway seeing that I’ve read about a lot of issues with them. Thanks.
 
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