I currently had a Thunderheader installed on my 2010 Fatboy LO. We used exhaust wrap and the clearance between the rear Master Cylinder pivot point (where the lever connects) and the Thunderheader was very close. I drove the bike for about 400km when the back brake began locking up. I changed out the entire brake system Master cylinder, line, caliper. Im starting to believe that the exhaust is eating up the fluid through the pivot point of the master cylinder. Has anyone on here ever had this issue ?

 

my 2003 fatboy has no issues with the thunderheader,

 

Sure I've heard of it. But I doubt that heat on the pivot is enough to boil the fluid all the way back to the caliper with all the wind blowing on it while you ride. I'd be more concerned that your brake lever is holding pressure on the mc piston or that your pipes are too close to the brake line in some other location.


Pics of the pivot area and the whole exhaust system Would help. Any chance heat from the pipes or the exiting exhaust is heating up the caliper or the line running along the frame?

 

Hey Man

I was 100% under the same impression as you, I said there is no way it can heat up that much with the wind passing it. I rode the bike 400km in one trip without out an issue. I replaced the whole brake system and ensured the line is nowhere near the exhaust. Now after changing the master cylinder I can see the pivot point has actually wore through the heat wrap and its touching the bare thunderheader now. I am new to the page and am currently out of the country. I'll try and have pics put up to show you soon. I appreciate you responding to my thread.