Brakes are life savers and Series Land Rovers are heavy vehicles to stop. On today's roads, modern vehicles are able to stop very quickly and often in a controlled manner, without brakes locking up the wheels and causing skids. Thirty-plus-year-old brake technology cannot compete. But too often other drivers are not consciously aware of this. It becomes our responsibility to not only maintain our aged brakes to the best standard possible, but also to be aware that other road users are often not appreciative of our relative braking handicap.
Over the course of the next few months the series123.com homepages will focus upon the maintenance, repair and troubleshooting of the braking system for Series I,II and III Land Rovers.
We start with what we have all heard, if not on our own vehicle - the squealing of the brakes when they are applied. This is generally not considered a major problem as it is almost always caused by grit being rubbed against the brake drum lining. For offroad vehicles like Series Land Rovers, this is most frequently encountered after traversing mud, wading through dirty water or driving through sand. That does not mean that the problem should be ignored if it persists. Damage will be done to the lining of the brake drum by scoring marks in its surface. This in turn will reduce the effective area of contact between the brake lining and the drum lining thus reducing brake efficiency.
Grit however, is not the only possible cause of squealing; some older style brake shoes have the linings fitted by rivetting rather than the modern chemically bonded type. Infact it is still possible to obtain linings and rivets and fit them yourself to existing shoes (if the shoes are pre-drilled to accept the rivets). If your brakes have riveted linings then it could well be that a squealing sound is indicative of the linings being worn and a rivet head now coming into contact the drum lining. This will most certainly beginning to score marks in it. If drums are seriously scored then they can be machined smooth again on a lathe as an alternative to a replacement drum.
Worse case scenario is that the brake linings are the chemically bonded type and they are so badly worn that part of a brake shoe surface is now in contact with the brake drum under braking action. This will sound more like grinding then squealing.
Other similar sounds could possibly be caused by
a bent brake back plate, a damaged brake shoe or a loose wheel cylinder. These are all relatively rare causes, but increase in likelihood the more offroading you do. You need to identify which wheel is producing the sound and then remove the brake drum and investigate the cause.
It is also worth noting that the 10in dia drums of SWB models and the 11inch drums of the LWB models are not directly replaceable across the range from Series I-III Land Rovers because the splined metric wheel studs introduced in late IIA models are wider and so the holes in these drums are of greater diameter. However, if you do require to fit a later drum to an earlier wheel hub, the stud holes can be drilled out to suit.
Also of importance is the fact that 109in Series IIA and III Land Rover models with the 6-cylinder engine as standard, were fitted with 3in wide brake drums instead of the 2.25in wide as for the 4-cylinder versions. This was to provide for more effective braking with the increased power of the 6-cylinder engine.
Brake drums are cast iron, and whilst thick, they
do eventually corrode along their rims and then entry of grit is facilitated through the corrosion gaps.
Binding brakes cause the brake linings to run hotter than they should and consequently lead to brake fade. Series Land Rover brakes are not good, by modern standards, even at their best, so you don't need to compromise your safety further than necessary. Binding brakes will also significantly increase fuel consumption.
Seriously binding brakes can be identified by feeling the centre of the wheels after a short drive; they will feel warm to the touch. The most commonly quoted means of assessing binding is to jack up each wheel in turn and turn it to feel for resistance. Wheels are heavy however and slight binding will not be detected by this method. You need to remove the wheel and turn the brake drum itself to be completely sure than there is no binding.
If brake shoe location is the only problem causing the binding, then turning the appropriate brake adjuster snail cam on the backplate should solve the problem. There are other causes that may need to be investigated though.
1. A brake wheel cylinder may have partially or fully seized up, keeping a brake lining in contact with the drum. To check this, the brake drum must be removed and either each brake shoe levered away from its cylinder location to check piston movement, or someone else gently press the brake pedal A LITTLE whilst you watch for correct piston movement.
2. A brake shoe pull-off spring may have weakened or broken. Repeat the check in No.1 that requires an assistant and watch the action of the spring(s). Note that the springs should be positioned behind the brake shoes and not infront of them ( this can cause tilting of the brake shoe resulting in the adjuster cam not working correctly).
3. It's possible that there may be a restriction in a brake flexible hose. This could be caused by faulty clamping when disassembling the brakes in situ, or perished internal rubber. Again, repeat the check in No.1 that requires an assistant and consider this as a possibility if the cylinder(s) is not seized and the spring(s) appear strong.
For brake systems that do not have a servo, there should be free play of 1/16in (1.5mm) between the end of the pushrod and the piston in the brake master cylinder - adjusted by turning the nuts on the pushrod shaft.
Photo showing incorrectly fitted rear brakeshoe spring(should be behind shoe) and also uneven brake lining wear.
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