Brake fluid transfer from front to aft chamber in master cylinder.

[Chryco Psycho]

lot os answer here , not sure why I missed it so long
 you can drill a balance hole higher up in thte reservoir , this will allow the fluid to balance but if one side went low it would nto drain the other chamber .
 The rubber behind the brake flaer is the residual pressure valve , the keeps the seal expanded so they do not leak , only drum brakes have this problem .
 Front is rear & rear is front always , the most important brakes / fronts do most of the work & are closest to the pedal .
 Often missed is under hood air flow , it is easy to get air under the hood but it also has to have a way out . The Shaker seems to add / retain a lot of under hood heat , you are not the first to encounter this . the air has to get out under the car but with the large tube headers this may be an issue also . We had a similar problem with a 340 stuffed into a D50 pick up , we did add louvered vents to the hood & solved the problem but I am not suggesting you do that .
 Build a heat sheild , a piece of sheet steel between the master & headers , this will drop temps dramatically to the master as long as there is an air gap between the sheild & master cyl .
 You need to make or have the factory heat sheilds near the fuel tank also , one of my customer has fuel boiling in he tank & we narrowed it down to the tank being flat black , enough light was reflecting off the concrete to boil the fuel , we put a light coat of silver on the tank & no more boiling fuel !

[johannes]

(A1)..... but if one side went low it would nto drain the other chamber ..... 
 
(A2)
 You need to make or have the factory heat sheilds near the fuel tank also , one of my customer has fuel boiling in he tank & we narrowed it down to the tank being flat black , enough light was reflecting off the concrete to boil the fuel , we put a light coat of silver on the tank & no more boiling fuel !

Thanks for the info CP.   
I have done some thinking, and here are some more thoughts;

(A1) You're right.... THE BRAKE FLUID WILL NEVER MAKE IT FROM ONE CHAMBER TO THE NEXT.
The reason I was convinced this was happening, was the combination of see through glasses and extreeme under hood temperature.
....parking the car with just a small tilt angle, will fool you if you look at the brake fluid level in the see through glasses....
.....and I am pretty sure there WAS brakefluid seeping from under the reservoir top gasket....
Is THIS possible, due to extreme underhood temp

(A2) The heat shields near the tank IS in place..... The innerside of the tank is coated with sealer,...reducing heat tranfer.
     

I could start looking into ways of heat insulating /re-routing the fuelhoses....and make a shield for the master cylinder.
......but I'll first start looking for ways to reduce the underhood temp... some sort of heatshield for the headers...
...hence my questions in previous posting...
ALL INPUTS WELCOME...

[Chryco Psycho]

typically  fluids expand when heated & fluid do not compress, specifically brake fluid used for transfering pressure so if the fluid expands it has nowhere to go but push through the seal in the lid .
 If the headers are coated they should have a decent thermal barrier , you could buy insulating wrap to try to reduce heat more , creating more air flow through the engine compartment helps too , front air dams can create  more vacuum under the car & tend to pull more air down out of the engine compartment , removing the rubber wheelwell seals may help too . I don't have a lot of other suggestions to get more air flow

[johannes]

Thanks for your input CP.
......even if the reservoir is not completely filled with fluid,... the expanding fluid and air might lift the lid,...and the seeping air might bring some brake fluid hanging from the gasket with it......hence my observation....

I removed the rubber wheelwell seals,.....and are toying aroud with alu sheets.....

By the way,...what is front air dams

I had a better look at the original heat shields at the exhaust resonators......seems they are designed for shielding UPWARDS more than shielding sideways = NOT protecting the fueltank much...so some improvement can be done there.....
ANYONE making better heatshields that original??

Also, some "expert" friend claims that stuff like jackets and sheets are no longer used in dragracing, because of firehazards...any comments to this claim??  Sure I can relate to abrobsion of oil into the fiberglass material, and the obvious risk of shortcircuit the startermotor power input causing a hazard,...but are they no longer used ?   are they illigal

[Chryco Psycho]

Jackets & sheets ??
I think the old header wrap was asbestos based , I have seen insultaed alum foil for protecting things from heat but ti would never survive on the headers , but might help the master