Click image to see step by step process

Brake Venting by Bruce Simurda

A Cool Solution for Hot Braking Action!

There certainly isn't a shortage of performance components to increase the speed of your VW, just look through the advertising pages of Hot VWs! You can find everything from simple, bolt on carburetors to full-race 2330cc 400 horsepower turbo motors. In fact, it's possible to drop a check the mail on Monday, and have an engine delivered on Friday with double, triple or even quadruple your stock engine's horsepower! Instant performance may be the name of the game, but before  bolting in that big engine for some weekend racing, an enthusiast should stop and take a few minutes to consider whether or not his current baking system can handle all the increased load.
    For stock use, the VW is equipped with an "adequate" braking system. However, it doesn't take much to find their limits. Just bolt-up a performance engine and head to the local drag strip, or do a little slalom racing, and you may discover that the binders are no longer up to the task . . . especially early model beetles with their narrow drums.
    That's why one of the most popular brake updating mods has been the conversion from stock drum to disc brakes. Although discs were OEM equipment on Karmann Ghias, later model buses and type 4s, the Beetle never featured these better binders. Yes, Ghia drums will fit the ball joint Bug front end, but since this conversion became popular the parts have become scarce. For those wanting the ultimate in stopping, several companies sell disc brake conversion kits, but they require that you convert early 5-lug wheels over to the newer 4-bolt pattern.
    But there is another, less expensive approach to improved braking. According to Vince Bunting, owner of C.H. Topping & Company, 520 W. Esther St. Long Beach, CA 90813; (562) 432-0901, drum and disc ventilation - the actual drilling of small holes in drums or rotors - can greatly improve the braking action and life of any braking system. Combined with high-quality shoes and pads, even the stock VW drum brake system can handle the increased load of drag, slalom or heavy duty street use.
    Now, before we get into the particulars of brake venting, it must be stressed that the drilling process should not be attempted by the home mechanic. There  are many variable, such as hole size, placement and pattern, that are critical for proper brake operation. Improper drilling of drums and rotors can cause imbalance, noise, and possibly breakage. C.H. Topping has spent over ten years perfecting this procedure . . . do not attempt to drill drums and rotors yourself!
    So what is the purpose of venting? Just its name implies, it allows the air between the shoes/pads and drum/rotor to escape. Without venting, a cushion of air can develop between the shoes/pads and drum/rotors, reducing braking efficiency. Venting also helps cool the drums and rotors, reducing heat which is a major cause of brake fade. According to Vince, this also results in an average of over 50% longer brake life. Another benefit of venting is that it practically eliminates water-fade, because water is thrown out of the drums by centrifugal force.
    In the ten years that C.H. Topping has been venting brakes, they've done everything from a moped to 2-ton trucks, from off-road cars to Lamborginis, commercial truck fleets and even one Rolls Royce! The secret to the process, and one that Vince declines to give much detail to, is the size and pattern of the ventilation holes, which is dependent upon the type and use of the vehicle. We did, however, discover that all patterns are designed so that the entire width of the drum/rotor is covered. In other words, if you were to draw lines around the inside of the drum, or circles on the face of a rotor, every circle would touch a vent hole. Patterns on drums and rotors are quite different. There is also a difference in the patterns on the right and left wheels, and putting them on the wrong side results in a very noisy brake! While not divulging specific numbers, hole size varies according to use. For example, Vince will drill drag car drums/rotor with many smaller holes while an off road car or sand buggy gets fewer, but larger holes.
   We had the opportunity to the brakes on our own Westfaila camper vented, and if there was ever a VW that needed good braking this 3200 lb. bus is it! Vince started by disassembling the brake system, checking all components for wear, and then measuring the drums and rotors for size. Although you should get over 50% longer life from vented brakes, it's a good idea to purchase new drums or rotors before venting if your present units are close to worn out - you don't want to have to throw your vented drums/rotors away come next brake job.
    Next comes a thorough cleaning, and the actual drilling of the drums/rotors. Vince personally does all drilling, carefully by hand, after marking out a special pattern on the outside. The process us a slow one, as he spent nearly 30 minutes per drum/rotor. According to Vince, some drums and rotors take considerably longer, especially larger vented rotors with vanes in the center or drums with cooling fins on the outside.
   With the drums/rotors drilled, they are refinished on brake lathes and then sanded to remove any grooves. For the drums, new high-quality organic Italian Fren-Do shoes are then arced to match, and then installed on the car. Vince recommends Fren-Do shoes and quality metallic pads for the best performance with vented drums and rotors.
    While Vince said that we would notice a big difference once the new brakes seated in, we could feel a difference right away. Pedal feel was much more sold than before, and we didn't experience any fade even after an hours drive home in stop-and-go LA traffic. The true test of these brakes will come later this summer when we head up (and down) to the high Sierras, we'll keep you posted on their performance. The only negative we experienced was a slight hissing noise when the brakes were applied, although Vince noted that this wasn't a common occurrence and is often a result of the wheels used.
    The cost of drum and disc ventilation ranges between $25 and $35 each, depending upon the type of drum or rotor. Most standard VW drums, because of their simplicity, will be in the $25 bracket.
    If it's a little hard to believe that vented brakes really work, just take a look at some of the top sports car manufacturers such as Porsche or Ferrari, or at any of the "concept car" making the show scene. As technology moves forward, vented brakes appear to be a wave of the future.


C.H. Topping & Company
520 W. Esther St., Long Beach, CA 90813
(562) 432-0901