Thread: Too close?

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I'm wondering how close is too close for a brake pressure (brake light) switch to an exhaust system? I have about 1-1/2" between the muffler and the switch. Is a heat shield in order or am I over thinking it?

Just as an insurance from heat, I would put a shield on the aluminum like something from DEI or Dynamat.

With the heat shield you should be good just the way it is. That corner of the muffler will get warm, but not near as hot as the exhaust pipe.



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Remember, aluminum conducts heat, while it can disparate heat, it can collect it as well. JMHO, I believe stainless (or even sheet metal) to be a better heat reflecting (shield) material, or insulate the aluminum on the inside as chopt50wgn suggested.

Why don't you just move the switch a few inches?

Originally Posted by jerry clayton

Why don't you just move the switch a few inches?

X2 Just move it. No big deal.

Not to step in and be the smart butt new guy, but your brake switch is mounted upside down, leaving a blind cavity above the main line which WILL hold an air pocket and make you pull your hair out. Flip the T and switch over so the brake fluid runs down into the switch and the air goes up.

Also, I've found that these switch last a lot longer if they're used to trigger a relay rather than switch the brake light power directly. Might not be as big an
issue now with LED lights that draw a lot less power.

Originally Posted by tdkkart

Not to step in and be the smart butt new guy, but your brake switch is mounted upside down, leaving a blind cavity above the main line which WILL hold an air pocket and make you pull your hair out. Flip the T and switch over so the brake fluid runs down into the switch and the air goes up.

Also, I've found that these switch last a lot longer if they're used to trigger a relay rather than switch the brake light power directly. Might not be as big an
issue now with LED lights that draw a lot less power.

Welcome, and thanks for the comment that makes a ton of good sense but is not obvious at first glance. I'm all but sure that my brake switch is mounted straight up, and while the tiny air bubble may not affect the overall system pressure much it's the reason that it takes a stronger pedal push to light the brake lights. I expect that there will be several "T's" being quietly flipped.

Great comment!

Can the line be moved to the outside frame rail and off the X-brace to get it away from the heat?

Gut an old hairdryer, and glue the mica sheet to the outside of your heat shield

I'm with Mike P, considering the flow path in the muffler that corner will be hot, but it won't be anywhere near the temperature of the exhaust pipe. I'd feel comfortable with the heat shield as you've got it, but swapping it to a piece of thinner SS like Ray suggested so the aluminum's not holding heat is not a bad idea if you're still concerned.

Why not just move the switch? as in KISS method?

Originally Posted by jerry clayton

Why not just move the switch? as in KISS method?

Well lets see, time, more work, more money? Not your fault because you don't know; but I'm a single income guy trying to build 2 hot rods and all these little things build up (in both time and money) I'm 4 years in and getting real close to the 30K mark. To me it's easier, cheaper, and faster to just grab some aluminum and drill a couple of holes and bolt it on. Hindsight is 20/20 I wish I could have put the mufflers somewhere else but there again the pieces I ordered didn't allow me to move it back farther (Pipes not long enough). I also could have turned the muffler on it's side a bit to get it away from the switch but my OCD says they have to be flat and level (sorry it's in my head and I have to live with it). Even if I wanted to turn the mufflers now, it's too late. If I turn them it will mess up the angle of the tail pipes that I worked days to get even (again my OCD). For once I'm not over engineering it. I could build a small enclosure and hook a computer case fan to it to keep it cool! Your right it is just a couple small sections of line and (for me not most people) a couple hours work. I am slow at everything. Truth be told I'm pushing 50 and I'm just over 400 pounds. I don't get down and up like I used to and in fact the running joke with my buddies is whether or not I'm actually going to fit in the car once it's done.

I have sometimes laminated a piece of sheet gasket material like you by from Oreillys between 2 pieces of aluminum and whitney punch them and put some rivets through the sandwich, the gasket material stops the heat transfer, you can hold your hand on the other aluminum plate and I have used them closer than your current setup when you can't relocate. I got the idea off the carb isolation stack they use to insulate the carb from the manifold, works good

Might be doing the same on the truck, have to go and check it's orientation out!