Precautions against broke failures

Press, Volume CXV, Issue 33934, 29 August 1975, Page 12

Precautions against broke failures

Looks like an obstruction up ahead, better nip down a gear. A gentle touch of the brakes. Funny! Try a bit harder. There’s something wrong! Try pumping the pedal. Grab the handbrake. Too late. . . .

Any driver who has had this sort of experience is likely to be a little neurotic about the state of a car’s brakes. But it is the sort of neurosis that keeps you alive. Let us have a look at what can go wrong with the brakes on your car.

Adjustment faults are probably the most common. These days, with the cost of servicing, many owners try to defer it for a few weeks. Combine with this the fact that you could well have the wrong linings fitted to your car — easily possible if it’s secondhand — and you might well be running out of brakes. You tend to compensate naturally for long pedal travel and it really is possible one day to end up with the brake pedal flat on the floor — praying that those slipping, skimming, slowly working brake linings are going to bite before you hit the car in front.

Do not rely entirely on brakes being self-adjusting either. Front disc brakes usually are not too bad. They do stay in adjustment and apart from a sticking caliper piston — which could quickly turn you in a circle when you use the brakes — pads which are entirely worn out are the biggest danger. Self-adjusting rear drum brakes often do not self adjust. If they get far enough out of adjustment because of ordinary wear, you could quite easily end up with that pedal-on-the-floor situation and no signs of slowing down. If the brake pedal feels spongy and resilient, you could have air contaminating your brake fluid. You can, of course, compensate for this one with a quick “one two” up and down on the pedal. Up it comes hard and once again effective. But do not get in the habit. The day will come when you will forget to pump the pedal or there just may not be time. It is much better to tackle the original fault and get the air bled out of the system. If you are a “do-it-yourself” type make the time and get down to it. If not, get your garage to do it soon.

There is only so much wear that can be taken up. At some time pads are going to be worn to the dangerous point where there is only 3 m.m. of lining thickness left. Brake shoes on drum brakes can be down to the brass rivets on one end and already starting to chew into the smooth bearing surface of the brake drums.

If you do your servicing, you will know how vital it is at every service to check lining thickness and pad thickness. If your servicing is done by the garage, you could still check the pad thickness yourself and it might be a good idea to check the brake linings as well. Brakes that fail suddenly and. completely feature in most drivers’ nightmares. Fortunately it is not a frequent occurrence, but when it does happen, more often than not it is one of the wheel cylinders that is responsible. A small rubber seal fails, fluid dribbles out and the driver forgets to check the level of brake fluid in the master cylinder reservoir for a couple of weeks. Then one day — no brakes. At the slightest sign of dampness around the end of the wheel cylinder, get the trouble checked. A new wheel cylinder is the best bet. If one cylinder has sprung a leak, the probably the same age, could be about to fail. A thorough check should be made. Change any doubtful cylinders. If your brake reservoir fluid level has already started to drop more than it should, it is the first sign that should make you check inside the brake

drums. While you are going through the hydraulics, do not forget the master cylinder itself. It too can develop leaks, and they can pass unnoticed for some time. It could drip fluid down behind sound-

proofing on the engine bulkhead or the fluid could be oozing down behind the carpets on .the driver’s pedal side of the bulkhead. Many other odd things can go wrong with the master cylinder too and if you are suspicious about wheel cylinders, remember the master cylinder will be the same age and just as vulnerable.

Flexible hoses are part of the hydraulic system where old age is probably not the most important factor. Because of the steering and suspension design, they can easily chafe on some projecting part. Particularly suspect are cars with a good lock. Finally think about the rest of the hydraulic circuit. This is the part that is fixed under the car and which joins the flexible pipes from the wheels to the four-way pipe union which is usually associated with the brake light switch and'is fairly near the master cylinder. It is not really leaks you should look for with this part of your braking system — something much more sinister — rust. To find out how the thin metal pipes are doing, you will have to brush off all the mud. They should be smooth shiny and unpitted. Any piece of pipe that is loose and flaky with rust -or which has a rough pitted surface needs changing. There is no way of telling by eye how deep the corrosion goes. Do not risk it,' fit a new part. With most cars rusty brake pipes are limited to specific, par-ticularly-exposed sections. Have them renewed.