Some cyclists feel unsafe with spongy mechanical brakes. Until hydrologic disc brakes become cheaper mechanical disc and rim brakes will remain common on budget bikes for the time being.

If a mechanical brake bike has done many kilometers (or miles if you like) of braking there is an on going problem of worn out break pads and brake springs becoming week with time.

There are various types from racing bike side pulls to various mountain and commuter bike counter lever designs.

If your bike is a side pull type examining new side pull brake bikes indicate the mechanical fit what these brakes should be. The same is true if your bike is any of the designs. One of the biggest problems home fix it yourself will come across in some counter lever types is adjusting screws on each brake arm.

New counter lever adjusting screws of the type fited to your bike are an indication of what they should be. Using a new one as a guide examine the old one. If he condition of the old one looks a little squashed at the stop end there is a good chance it is not effectively acting as a proper stop causing week spring problems.

Theses are usually machine screws. Cross threads is a major consern. They can cause adjusting problems caused by forcing in crocked, wrong machine screw thread type or wood screws also cross threading the lug too. We can feel by how hard we have to presure to move the screw.

New screws show what the threads should be. Unhook the spring from the spring arm. Good threads screw inall the why in  lugs easily with fingers. New bikes are always a good indication of what everything should be,

If you examine closely and find the lug bent slightly can cause the tip of the stop to miss alight the spring causing week spring tension. Examine the lug to check if it's bent. Different models have different designs. Some designs are easily assessable. Some are not.

It is delicate work to straighten out assessable brake arm adjusting screw lugs without uneven twisting forces bending the lug improperly. Eventually breaks off rendering adjustment useless.

An effective method is between the jaws of a shifting spanner. For fix it yourself it is a mistake to use cheep shifting spanners, old well worn ones that have sloppy jaws. Slack moments are not safe.

Movement will twist the lug uneven just as bending at the tip the worst thing you can do. For proper support the spanner must cover over the whole lug with no sloppiness between the spanner blades. Any slack movement is dodgy taking the risk of not bending straight improperly.

Jiggle the spanner adjusting feeling for solidness before you bend. A major problem in bending is often overdoing it. Careful. Easy she goes.

Jiggling for a feel of solidness then gently bend the lug back into proper straightness. Make sure when refitting the spring make sure it is pressing properly on the stop of the screw.

Examining the inner wire cable anchored on the brake arm of any new bike gives a good idea of what they should be and an important clue to proper reassembly practises. The inner wire cable connecting brakes arms is always straight. There are no bends or kinks in the wire cable. If any will cause slack cable operation both rim and mechanical disc brakes.

The inner cable needs to be disassembled, relocated so it is as straight like new bikes are. Missing inner cable end caps on the tip of the inner wire cable cause fray problems. End caps are always on new bikes. They stop the ends of the wire cable from becoming fayed. They are an important anti fray device. Clamping down without them helps to fray the ends of unprotected cable ends.

Following new bike examples the proper anchoring of the inner wire cable should be. A mistake is to arrange a rap round eyelet technique under the lock nut. As new bikes tell us it doesn't work that way.
Even end caps won't stop fraying tightening on the wire cable.

The fiction of tightening is going against the wind crushing the strands apart unraveling them at that point. It only takes about a couple of fine tuning adjustments to crush apart individual strands eventually severing unraveling the strands beyond any safe use anymore. Following the a new bike example goes with the strand winds as you tighten.

If the fray is minor with a missing anti fray tag even following new bike correct way you will have your work cut out for you with a lot of time consuming fiddling trying to avoid making the fray worse on reassembly. If the end cap is connected you will have no problems.
If you have any antic fray caps missing it's recommended to fit one to good cables before it's too late.

You will need an anti fray cap, and a method to clamp it on hand before you start clamping.
Squealing and slack handle bar feel problems is often attributed to ignoring the importance of adjusting screws located on the brake arm designs.

Side pulls don't need them. Checking out a new bike that has your braking system you will observe these adjusting screws each brake arm They adjust the spring tensions centralizing the arms vertical between the rim properly. With out them the spring tension of one arm pulls both arms lope sided to one side.

Without theses adjuster screws one pad is to close to the rim and the opposite pad to far away braking. This often happens if one of the springs has become weaker. The stronger spring pulls the pair to one side. The weaker one hasn't the strength to move the pair straighter. If these screws are negated or missing it is this that will happen.

Unscrewing one side relives tension where the opposite spring pulls both arms straighter. The pads are level with the rim. Screwing inwards strengthens the tension acting the same way. If you haven't got theses screws in place replace them.

Loosen the inner wire cable anchor bolt enough you can slide the inner wire under the acorn or Allan key nut to allow both arms to spread apart on there own leaving the nut attached. The brake springs should release the tension spreading rim brake bike arms wide or in the case of disc bake models to no tension.

You will need to determine if you are left or right handed these jobs like these. Following a new bike example thread under the loose nut to the most covenant left of right hand position that suites you best. With one had clamp the brake pads to the rim. Holding them there, with the other hand pull the tial of the inner wire cable straight making sure there is no bends or kinks as a new bike.

Left or right handed you should manage to hold the brake arms with one hand and at the same time with the other hand manipulate the inner wire cable and clamping bolt at the same time.
Next is to adjust with the brake arm adjusting screws. You will observe unscrewing one side moves both arms over and if unscrewing will do the same. In this way fine tune the the two arms.