Brakes: Part III

Follow-up on brake cable story from the last newsletter – It gets worse!

At first glance the frayed brake cable looked suspicious … something didn’t look right. There were no frayed cable ends sticking out, but the strands were damaged and gnarled. At any rate, the cables definitely needed replacing. Once they were off the car and subject to close inspection, we found the cable schwages had been tampered with. After roughly half of the cable strands on each side had frayed an enterprising repair person re-schwaged the broken strands, apparently with a chisel, certainly without the proper schwaging equipment required for such an important safety issue. Brings back memories of the time we saw a single strand of 12 gauge copper house wire used to secure the brake pedal to the cables. This was many, years ago at a local public facility. Please be sure your brakes are properly serviced on an annual basis, preferably by a trained service technician and certainly with the correct OEM quality parts.

Introduction

Golf cart brake systems are not well understood by the average user or owner. Press the brake – the car slows down … what’s to know? Many folks have harrowing stories about the time the brakes on the golf cart broke. Some, unfortunately, have injuries to show. The incident may be funny in retrospect, but very scary while careening out of control. Modern golf cart brakes are self-adjusting and pretty much take care of themselves, but they need a little human intervention from time to time.

The early systems need regular manual adjustments, but they all need regular cleaning and inspection such as we have outlined. Last time, we presented the various brake designs employed by major golf cart companies over the past 50 years. Modern designs require the brake pedal, cables, and self-adjusters to be clean and in good working order. All brake systems also require the shoes, linings, and drums to be in good condition for optimal and safe performance. There are lots of things to go bad here but the good news is these parts generally function very well. Sometimes, too well.

#1 Mistake with Brakes

DO NOT adjust the brakes at the cables!!!! Because the hill brake adjusting portion of the brake system is so obvious, most folks tighten the cable when the brakes get a little sketchy. This works ok for a little while, but what really happens is the brake shoe linings pay the price and they wear out at the very bottom instead of along their entire length. This greatly reduces brake efficiency and wears away the bottom of the brake shoe linings long before they should. Left unattended, the lining will completely wear away until the metal shoes dig into and damage your brake drum. More on this later.

Brake Shoes

When we mention the brake shoes, most people don’t realize that the “shoe” is actually the curved piece of metal to which the “lining” is attached by means of glue or rivets. When you “reline” your brake shoes, you literally attach new lining material onto the old metal shoe. This material used to be asbestos, which was basically outlawed back in the late 80’s due to serious health concerns. Since that time, the entire vehicle manufacturing industry has grappled with finding an adequate and safe replacement for asbestos. It has not been an easy task. Some materials were too hard, others too soft. Some squeak or make bothersome noises that cause golf cart owners to worry something catastrophic is about to happen. Brake noise is usually something to be concerned about, especially if it starts suddenly or gets progressively worse.

The actual braking surface of the lining will typically “glaze” over, but it also may crack and come loose from the metal shoe. The drum may also “glaze” over as the lining wears against it. “Glazing” is a smooth, shiny, finish which builds up on the lining and drum as a by-product of brake dust, and heat caused by the friction of stopping. This glaze reduces brake efficiency, but it can be removed by rubbing coarse sandpaper over the lining and drum surfaces. Under severe braking conditions such as heavy loads, quick stops or hilly terrain, the heat build up from the braking effort can become too high and the system cannot dissipate the heat fast enough. This exacerbates the glazing but even worse, it can cause the glue that holds the lining together, as well as the glue which holds it to the metal shoe, to fail. The linings can develop heat cracks and in some cases lose their adhesion to the shoe. The inner surface of the drum sometimes will develop heat cracks as well. If the factory paint on the outside of the drum has blistered and is peeling away, it indicates that serious braking heat has been present.

Brake Drums

As mentioned in Part II, modern drums are cast iron and are turned on a lathe for true roundness. They are beefier for better heat dissipation and more resistant to warping. Club Car and Yamaha use a drum that slides over the wheel hub and the brake shoes. The drum is held in place by the wheel itself. E-Z-GO uses a combination hub/drum. As the term implies, the wheel hub and brake drum are cast into one piece. It slides onto a splined axle and is secured by means of a washer and castellated nut with cotter pin. The hub/drum must be installed with the appropriate washers/shims and tightened to have long life and work properly. More on this later.

The drums are simple devices that give very little trouble as long as the shoes have good linings and the brakes are reasonably maintained. If the linings wear completely out, as will always happen with constant adjustments at the cable, then the metal shoes start to eat into the metal brake drums. NOT GOOD! Even non-mechanical folks know that metal on metal plus frictions usually doesn’t produce ideal results.
We have seen many drums worn to the point where they must be removed from the car in pieces. The customer usually comes in saying the golf cart doesn’t brake well….No Wonder! Occasionally, we will see drums that have grooves worn into the inner surface. Sometimes this can acceptable wear, but here in the mountains, we do not compromise on brakes. We replace all necessary parts unless the wear is minimal. The manufacturers recommend that the drums not be turned on a brake lathe. If you’re doing your own work, it is of course, your choice, but it’s also your safety at risk. Professionally speaking, is this the type of repair you want for yourself or your loved ones? There are many other maintenance tasks for your vehicle that you can do yourself, but be sure you are certain of your workmanship before tackling your brake system.

A last word on the E-Z-GO hub/drum… It is an excellent drum systems, but the retainer washer and nut must be monitored for proper tightness at least annually. If you can turn the flat washer between the hub and the nut with you fingers, the hub is loose! This will not affect the brakes stopping power, but $80 for a new hub/drum will certainly hurt your wallet. Not to mention that the splined hub/drum interface which mates with the axle can strip out and leave you stranded. There is a very specific hub/drum tightening procedure which should be followed to avoid these incidents.

Brake Backing Plates

The backing plate is the part that holds the brake shoes, brake shoe anchors, and the self-adjuster mechanisms. The brake cables also connect to the backing plate via their connection with the adjusters. Like the drum, the brake backing plate gives very little trouble but there are a few things to check. Be sure the anchors are tight and that the plate is bolted to the axle mounting flange tightly. Be certain that the plate is not warped and that the adjuster slides freely on the backing plate. This may be hard to determine with the shoes and springs in place. The sliding motion is important for the shoes to properly position themselves against the drum when the pedal is depressed.
A last word on backing plates – there are three raised areas at the front or leading edge and three at the rear or trailing edge. The brake shoes have three corresponding portions that rest against the plate when installed. The slight motion of the shoes when the brakes are applied and released causes the metal of the shoe itself to rub against the raised portions of the metal plate. Wear can occur here and the plate may develop grooves where the shoes have rubbed for years. When servicing the brakes, a very slight amount of grease should be applied to the raised portions of the plate. The lube quiets the brake shoe action and helps prevent the grooves from forming. If the grooves are severe, the plate may need to be replaced as the shoe will settle into the groove and not work properly.

Conclusion

This wraps up our short discourse about golf cart brakes. As well as they are designed and function, they have their limits. Please don’t overlook or ignore them, especially if you operate your golf cart in crowded pedestrian areas or on hilly terrain. Years ago, you had an entire fairway to ride out a brake failure. In today’s environment, with golf carts emerging as the multi-purpose utility vehicle of the future, brake failure can have a much greater impact, like into the side of a million dollar recreational vehicle, horse trailer, or race car. The final words … Be Safe, Check Your Brakes, and Have Fun!

Written by John C. Triolo, President, www.golfcarcatalog.com

 

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