About That Brake Booster…

I thought I’d take a brake from complaining about the checklist to talk briefly about the power brake booster.

Power brake boosters are a clever way of using the difference between atmospheric pressure and your car’s intake-manifold-created vacuum to provide extra pressure against the master cylinder’s piston when you press the brake pedal. This extra pressure means the air around you is actually doing most of the work of engaging the brakes.

This video describes how a power brake booster works in nice detail:

Speaking of my power brake booster, you may recall the significant effort it took to remove it from the Mustang originally. As we get ready to put it back in, we’re taking a few steps to avoid a repeat performance.

We’ve applied anti-seize lubricant (the gray stuff that looks like paint in the picture below) to the studs that fasten the booster to the car. These studs are inserted through the firewall into the passenger compartment under the dash.

Previously, it required wrenches to tighten or loosen the nuts. Now, they pretty much go on by hand.

We’ve also acquired more of the Right Tools For The Job ^(tm)

When we pulled the booster out, we couldn’t use a socket wrench due to the lack of space under the dash…

…and the really long studs on the booster. All we had that we could use was a standard box wrench that looks like this:

With just a standard wrench, the process for removing the nuts went like this:

• Wiggle the wrench until it locked onto the nut
• Rotate the nut an eighth of a turn
• Wiggle the wrench off the nut
• Repeat by going back to step 1 for an hour

These nuts did not want to move and were stuck behind  “sharp, painful, engineers-laughing-at-the-mechanics-as-they-designed-this sharp”. It took us an hour a bolt to get the thing off.

Thankfully, we now have a set of these:

That is a picture of a ratcheting wrench. This wonderful invention allows us to have all the benefits of a socket wrench but still work in spaces a socket wrench can’t get to. With this guy, the process for putting the brake booster back on reduces to this:

• Wiggle the wrench until it locked onto the nut
• Turn as many times as necessary to tighten the nut – no removal necessary
• Wiggle the wrench off
• You’re done!

This wrench is so choice. If you have the means, I highly recommend picking one up. If all goes well soon, it’ll get another chance to prove its worth putting the brake booster back on.