Brake Reservior Heat

[Railroad]

I have been noticing the triple reservoirs on the frame rail get pretty hot after a couple of hours of driving.
I think a metal shield between the headers and the reservoirs will get the job done. I am just kicking the various solution ideas around in my head right now. Anyone else have concerns or addressed this issue?

Here are couple of photos. 1 shows relation to headers and 2 location under the hood with new reservoirs.

150777150778

[rich grsc]

Why? Define pretty hot, able to hold your hand on them, or too hot to touch. Brake fluid is able to operate at temps over 300*, so the temps at there reservoir, unless at that temp or higher isn't an issue.

[NAZ]

I'm with Rich, there is hot and then there is too hot. Brake fluid is formulated to operate at higher temps than most engine bays get. If you can touch the reservoirs with your hand that is definitely not too hot. If do a crackle test (spit on them and it sizzles), you might want to move them.

As for blocking radiant heat, a heat shield is very effective. But maybe not so much for convection heat transfer in an engine bay.

[Railroad]

Why? Define pretty hot, able to hold your hand on them, or too hot to touch. Brake fluid is able to operate at temps over 300*, so the temps at there reservoir, unless at that temp or higher isn't an issue.

What drew my attention to the issue was the pin hole in each cap, had a drop of brake fluid on it. The caps are baffled, so the first incident did not worry me. After the last trip all three caps had the same. I guess there is some residual fluid above the baffle, do not know why. While wiping off the caps, I noticed how hot the bottom of the reservoirs was. I would not say too hot to touch, but surprised at the high temp.
I had the same thought about fluid temp. Probably much, much hotter at the calipers.
I considered just putting some heat barrier on the bottom of the reservoirs, but thought I would pick the brain trust first.

[Jim1855]

I agree with Rich & Naz, brake fluid is designed to get hot but... If you can keep it cooler there may be a benefit. But I don't believe that the benefit will be realized on the street, may in road racing.

Now for the problem. The heat shield is a good plan if you have the means to separate the reservoirs from the engine bay heat and keep a circulation of outside air around the reservoirs, this will be difficult. Everything will heat soak given time and temps.

In the past and on my current build I've used a Tilton 3-chamber plastic reservoir mounted high on the firewall. Short of directly over the headers this is one of the hotter spots in an engine compartment.

I'm guessing that the majority of builders place the reservoirs in the same place on the side of the engine compartment w/o problems or concerns.

Jim

[rich grsc]

You said the caps had a drop of fluid on them, are they too full? I leave a small airspace for fluid expansion

[Railroad]

You said the caps had a drop of fluid on them, are they too full? I leave a small airspace for fluid expansion

I do not have them over filled, but need to keep them in the upper range due to the height location of the reservoirs compared to the master cylinders, not good by design.

[jiriza84641]

I have the same issue with heat with the coyote. I used heat reflective tape on the bottom of the reservoir and the front and sides. I also used hear reflective tape to taper over the hoses. I just recently used header wrap on the headers that helps.

[Railroad]

I pulled the caps and had more fluid than normal?, between the cap and the baffle seal. I cleaned all the caps and baffles of fluid. That should stop the drops on the bleed holes, unless it is pushing past the lip and getting on the open side of the baffle.
I found some peel and stick heat shield. After feeling under the reservoirs, it was obvious to me, I was not going to remove the reservoirs and fight the peel and stick getting it around the fittings and hoses. I cut a 1.5" strip by 7" and got the engine side of the bottom covered.
We will see if I notice a difference. Thanks for the tips.
I would suggest putting the heat barrier on before mounting, to get results like jiriza84641.

150791150792

[Nigel Allen]

What others have said, plus

1. Heat will evaporate moisture that might condense in the reservoir, so that should be a bonus.

2. Once all air is bled out of the hose from the reservoir to the master cylinder, then it doesn't matter if the fluid level or reservoir is lower than the MC.

Cheers,

Nigel

[Railroad]

What others have said, plus

1. Heat will evaporate moisture that might condense in the reservoir, so that should be a bonus.

2. Once all air is bled out of the hose from the reservoir to the master cylinder, then it doesn't matter if the fluid level or reservoir is lower than the MC.

Cheers,

Nigel

How would the master cyl get brake fluid to compensate for pad wear. I think the reservoirs should be able to gravity feed the master cylinders. Maybe I am missing something.

[David Williamson]

The brake fluid will be pushed into the master cylinder by atmospheric pressure the same way a siphon works. Zero absolute pressure in the master cylinder and 14.7 psi on the brake fluid in the reservoir.
David W