Question: I have a '74 Blazer that I have been working on for 15 years now. The body, front axle, brakes, and hydraulic steering with four-wheel steering are the last things left to do. The body will become an Urban Guerrilla Wagon.
The brakes: I have trouble getting enough stopping power in the front end. I can lock up the back tires but the front brakes feel like they are just sliding. Would I be able to upgrade to a 1-ton or 3/4-ton brake master cylinder to get more pressure, or would I have to upgrade the whole front brake system?
Jeff D. Sommer
Answer: No, going to a 1-ton master cylinder is not going to give you more braking pressure. In fact, it just might take more pedal pressure to stop the vehicle. I am not sure of the bore size between a 1-ton and your Blazer, but if I had to guess, I would say it had a bigger bore to compensate for the larger calipers and wheel cylinders. This means that it will displace, or move, more fluid for a given amount of stroke than one with a smaller bore. In other words, with a larger cylinder-bore master cylinder-let's say, a 1-inch versus a 7/8-inch diameter-the pedal requires less travel to move a given amount of fluid, but will require more pedal-pushing power to gain the same amount of line pressure to stop the vehicle. The reverse happens when a smaller-bore cylinder replaces a larger one. It takes less pedal-pushing power but more pedal travel as the piston must make a longer stroke to move the same amount of fluid as the large bore cylinder. Something to keep in mind: a larger-bore master cylinder doesn't push any more fluid down the brake lines than a smaller-bore cylinder does because the brake lines and the wheel cylinders can only accept a given amount of fluid in a direct proportion to their given total capacity in cubic inches of volume.
There are several things that could be causing the lack of front braking. The first thing that I would do is to closely inspect the front brakes. Make sure that there is no rust and corrosion on any of the components that slide in and out. Excessive wear on the mounting brackets could also cause the sliders to bind and not move freely. Clean everything up, and apply a proper high-temperature lubricant to all moving parts.
It also could be that it's time for some replacement calipers. Corrosion and wear could allow the pistons to cock in the bore and not fully expand properly. Rotor finish is very important. Have a shop turn the rotors, and be sure to choose one that does a lot of brake jobs, not the local auto parts store that turn only a few a week. Chances are a shop will have a newer and better machine that will give a much better finish. Be sure to clean the rotors with soap and water before reinstalling them. Quality pads are very important, as well as following the manufacturer's break-in procedures.
Then again, it could be that all these components are just fine. I have seen brake problems where the combination valve was not allowing enough fluid to flow to the front brakes or that the master cylinder itself was leaking internally and bypassing fluid. One of the strangest complaints of lacking braking ability was caused by the simple fact that the brake line had been pinched by a rock and prevented fluid flow.
Now if you feel bucks-up, there are several companies that offer aftermarket brakes ranging from a completely new system to just rotors. An Internet search under "Chevy 4x4 brakes," or something of that nature, should bring up some information. One company that comes to mind is Stainless Steel Brake Corporation (www.stainlesssteelbrakes.com). They also have an inexpensive gauge kit that I have used where you can pull off a brake line and attach a pressure gauge to that line. It's a fairly quick test to make sure you're getting adequate line pressure to the brakes.
Question: I was wondering if you guys have ever heard of filling a flat tire with a broken bead away from the rim with starting fluid? I saw a guy change a tire on the rim and then spray it with starting fluid and then light it, which in turn sets the tire and fills it with enough air to drive on. Was wondering if this a good idea or if it is dangerous?
Answer: Yes, we have witnessed it first-hand. It's not something we would do or recommend as it can be quite dangerous. Why? First, just how much starter fluid do you inject into the tire? Not enough, and the bead will not seat; too much, and you could in theory blow the tire off the rim or cause a portion of the tire to break. What would happen if the tire went flat and came off the rim because of damage to the sidewall and you used the starter fluid method? How would you like a piece of tire in your face? Remember, you're not putting air into the tire but an explosive gas. What if the tire does seat before all the explosive gas burns up? Now you have a tire that is full of explosive gas. Not something that I would like to drive around with.