Brake Hoses

What do you do if one of your brake hoses develops a leak when you’re out in the bush?

The brake systems in our 4WDs consist of a sealed hydraulic system that stores fluid in a reservoir. When you push your brake pedal, the fluid gets forced through the system and provides force to the brake callipers clamping the brake pads to the disk rotors. Or, if you have drum brakes, pushes the brake shoes into the brake drum.
Our 4WDs have brake boosters which assist in applying brake pressure, however, there are still huge hydraulic pressures passing through the brake lines to the brake components.
Imagine you are driving along and press the brake pedal, and your foot goes straight to the floor. If you ever find yourself in this situation, it’s important that you know how to diagnose the problem and get yourself and your vehicle out of trouble.

 

A brake hose fitted into the supporting bracket. The brake hose only locates into the bracket in one position and is held in place by a clip. The metal tubing is screwed in place by a brake line nut, which creates a seal.


A brake hose fitted into the supporting bracket. The brake hose only locates into the bracket in one position and is held in place by a clip. The metal tubing is screwed in place by a brake line nut, which creates a seal.
The first thing that you should do is get out, open the bonnet and check your brake fluid level. If the level is low, then you could have a leak in the system. Check around the wheels and look for dampness around the brake callipers, hoses and fittings.
One of the most common failures is a leaking or burst hydraulic hose. Once identified, you will need to clamp off the leaking hose before the leak, otherwise continual pressing of the brake pedal will force all remaining break fluid out through the leak.
To clamp off the hydraulic line you can use a number of tools. There are brake line clamps available which work really well and are a great addition to any tool box when travelling. You can also use a pair of vice grips or you could even get away with a pair of pliers and some wire.

 

The left side of this photo show a picture of the brake calliper, and closer to the top of the brake calliper the bleeder nipple. The bleeder nipple is what is used to bleed the air out of the brake system for each wheel.


The left side of this photo show a picture of the brake calliper, and closer to the top of the brake calliper the bleeder nipple. The bleeder nipple is what is used to bleed the air out of the brake system for each wheel.
It is as simple as fitting the clamp over the hydraulic line and clamping. Once this is done, it is a good idea to have someone press the brake pedal, to make sure the brake pedal is still hard, and also to check that brake fluid is not leaking past the clamp.
If it is not leaking you can continue on, but remember that wheel that has now been clamped will not brake at all. Usually when there is one wheel not working under brakes it will cause the car to pull to one side. So make sure you give yourself plenty of room to brake and also reduce your speed and have it repaired as quickly as possible.
If you are well prepared you may have another brake hose with you just in case. If you do have one, it is a relatively easy job to perform. The old brake hose will need to be removed. They usually unscrew from either end, or some have a banjo fitting with two copper washers on the brake calliper end. They will also have a clip to hold them in their locating bracket.

A brake line clamp that can be used to block off a brake hose. These clamps are cheap, readily available and are a great addition to any toolbox.


A brake line clamp that can be used to block off a brake hose. These clamps are cheap, readily available and are a great addition to any toolbox.
Once you have removed the damaged hose, fit the new brake hose into the bracket. Before you tighten the hose, check that the brake hose is sitting correctly and not twisted or kinked.

Once the brake hose is fitted, tightened and secured, the brakes will need to be bled to remove the air from the hose. If you don’t have someone to help, you can drip bleed the air out of the hose. Simply fill the brake reservoir and open the brake bleeder and let the fluid drip or run out until it is a steady flow with no bubbles.
If you do have someone with you, you can start by drip bleeding and then you will need to pump the brake fluid through by operating the brake pedal and releasing the bleeder screw while the brake pedal is held down. This will force the new brake fluid through and push out any air that may be trapped in the brake calliper. From there just top up your brake fluid level and check that the brake pedal feels correct.
The main reason for writing this, however, is that many people tend to over look some of these smaller parts of their vehicle when preparing for trips. Broken brake hoses do happen and surprisingly are quite common. I have also seen broken clutch hoses as well. So a simple check over them before any big trip will go a long way as prevention really is much better than repair!


Qualified motor mechanic Adam Adler has spent half his life under the bonnet of a 4WD and has worked for some of the top accessory companies and workshops. He knows what it takes to get your vehicle out there and back home in one piece. He runs the online aftermarket store www.nutsabout4wd.com.au.


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