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Does anyone make a bolt on master cylinder brace for 4th gen f-body's? I was looking under the hood and noticed that the firewall is flexing a lot when pressing on the brake pedal. The firewall flex is bad enough that the brake fluid cap is actually making contact with my after market hood (vfn sunoco hood), and the sticker on the cap is peeling off now . I looked online but I only found one, but it was for an aftermarket master cylinder.
A master cylinder brace would give you a more solid brake pedal and also give you better feel of the brakes since there won't be any flex. You guys will be surprised how much firewall flex there is when getting on the brakes. If you want to see for yourself pop open the hood and look at the master cylinder while someone else steps on the brake pedal, the pos has a lot of flex.
Here is a picture of a master cylinder brace for an import vehicle. With the way the master cylinder sits over the shock tower on the 4th gens, it looks like it would be easy to make something similar that would bolt on to the shock tower and hold the master in place. Perhaps a vendor can step up to the plate and make a bolt on master cylinder brace for 4th gen f-body's..... maybe bmr, umi, strano or mwc.
Maybe make one out of steel or aluminum angle stock?
After monkeying around with various brake and clutch options, I ended up with a big hole in my FW, which I covered with a 1/4 inch aluminum plate. This, incidentally, also firmed up the firewall. Maybe you could do something similar. Ignore that arrows, those were for illustrating a point in my build thread.
I do want to make a plate, but I do not feel like doing it until I have to replace the booster. For the time being I would like to get a bolt on brace, but it seems like we really have no options out there.
The pic you posted is from an STI, I have one that REQUIRES that brace. The brace is not because the firewall flexes, they all do.
This particular chassis (08+ WRX/STI) has a class action suit going on because the firewall and pedal assembly separate when the pinch welds crack. The brace is a Band-Aid as I know from experience. The only way to really fix the Subaru problem was to pull the dash, pull the pedal assembly, weld the broken pinch spots, then BOLT the pedal assembly and firewall back together. Fun stuff driving when the clutch pedal slams itself to the floor but doesn't release, and brake pedal travels all the way to the floor without applying pressure to the calipers.
In case of the fbody, there aren't as many bracing points in the engine bay to run off of that will effectively hold the master in position. Add plates to the firewall or find something to triangulate off of in the engine bay. Might need to weld brace points to the upper strut tower, then another down on the fender, then something against the cowl overhang for lateral support.
I've actually found this interesting and made a mock-up brace for the 4th gen. I have the mock-up sitting in the garage right now and it's waiting to be drawn up on Solidworks, just whenever I get the chance to at school I could draw it up to spec and 3D print it out right at school. My car would be the test subject and I might finalize it from there.
I've also found a local metal plant in town that will custom-make stuff for whatever you have on Solidworks and I could send in my little project to them and have them weld up a brace for me. Honestly I don't think it'll dramatically improve pedal feel a whole lot, but it'll be a cool project for me when winter hits. Maybe if others are interested as well I could get a head start...
I was having someone bleed my brakes the other day and noticed this as well. It was a little alarming though obviously it's nothing new, just something new to me. I would prefer it being braced. I may make something up....
07-30-2015, 10:46 PM
Bolt on master cylinder brace (vendors welcomed) 
. I looked online but I only found one, but it was for an aftermarket master cylinder. 
