Brake pipe DIY repair

In detail: do-it-yourself brake pipe repair from a real master for the site my.housecope.com.

Repair of the brake system is often not only reduced to replacing brake pads or replacing and pumping brake fluid in both circuits. More difficult, requiring accuracy and certain qualifications during installation, is the repair of brake pipes. Often this happens when through corrosion or pipe destruction due to an accident or repair of the brake caliper.

Do-it-yourself repair of brake pipes and successful connection of the brake pipe to the distributor nipple, tees, brake master cylinder and brake calipers requires high-quality processing of the tube end and the formation of a flange flange, or the so-called "funnel". It is obtained using the brake pipe flaring procedure.

There are several basic funnel options.

  1. Eurostandard fungus (center). It resembles a wheel tire in shape, it is widely used in most cars produced at factories on the Eurasian continent. It turns out the most durable connection option from the above, but it is considered one-time. Can be used up to three times if properly staged.
  2. An ordinary simple funnel, obtained by bending the walls of the end part of the tube with a special tool for flaring brake pipes.
  3. A funnel obtained by double-folding the rim of a tube or a simple funnel. It is considered the standard in American cars. This type of brake tube flaring is obtained from the fungus, upsetting its upper part with a tapered mandrel.

The time of using a simple funnel is long gone, first of all, the metal from which pipes were made on old cars has changed. Instead of soft and ductile rolled copper, a strong and hard steel pipe is often used. If earlier the driver could flare the end face with pliers, a wrench and a couple of hammer blows, now it is impossible to flare steel brake pipes without a device.

Video (click to play).

The main condition for the successful flaring of the pipe end has always been and will be the use of high-quality, and better professional, tools. For our cars, Europe-Asia, buy flare kits in metric design. The Americans look more than decent, sparkle with chrome plating, but they can slip an inch system. The old Soviet standard for copper brake pipe is 8 mm, more recent Soviet and Russian versions used 6 mm steel.

In terms of choice, the most affordable is a set for flaring brake pipes Force 656B, 906T2, you can use more elegant JonnesWay sets, or the common Biltema or Licota.

The flaring tool kit includes:

  • a screw rolling press and a clamp, with the help of which the vise strips are tightened and the metal of the brake pipe is deformed;
  • two split vise strips with six to seven holes with cones, into which tubes for flaring are clamped;
  • a cutting device that allows you to cut off the end in a strictly perpendicular direction;
  • a set of mandrels and cones of various diameters for the formation of fungi.

Please note the following points when choosing a flaring kit. First, the screw-nut of the press and the clamps should be matte black. This indicates heat treatment and hardening of the helical surface. In a cheaper version, chrome plating is used.

Second, the accuracy of making calibrated holes in the vise strips. Typically, the inner surface of the cones is coated with a protective phosphate-based oxide film.Such a coating facilitates the sliding of the wrought metal along the inner surface of the matrix.

Third, all calibrated holes are numbered with dimensions, indicating the units of measurement - millimeters or inches, punched by a stamp to a depth of 0.1 mm, without additional chrome plating or painting. Alternatively, the entire structure can have an oxidized coating. Non-working parts can be painted with a plain light paint.

The procedure for flaring brake pipes with a fungus with your own hands:

  • choose from the set a device for accurate perpendicular cutting of the end of the brake pipe, inserting it into the hole of the corresponding diameter, tighten the screw and wrap the cutter a couple of times until it stops;
  • there is also a sharp semicircular saw for removing internal chamfers and burrs;
  • after filing the end of the brake pipe with a file, we put a nut-union on the pipe and fix the end in a vice with a clamp, observing the amount of release of the end of the pipe above the plane of the vice;
  • add a couple of drops of "brake" to the end of the tube, insert a mandrel of the appropriate size and press down on the edges of the tube, getting a fungus.

If, according to the conditions of flaring, it is necessary to obtain an American version of the fitting, a cone is inserted into the clamp, and the edges of the upper part of the fungus are pressed under the cone of the matrix. Sometimes a ratchet is built into the structure of the clamps, which makes it possible to limit the force applied to the surface of the fitting.

If the flaring needs to be done quickly and in a large number of points, in the case of copper pipes, a simpler tool is used - a pliers and a swivel roller.

The ductility and pliability of copper does not require much effort to deform the metal, therefore it is faster and easier to flare the end with the effort of the hand. Due to the compactness of the device, the pliers can be used for flaring brake pipes directly on the car, in conditions when it is difficult to carry out work with a standard set.

Steel brake pipes, in contrast to copper ones, have practically no reserve of plasticity, so the fungus and the funnel can turn out with the formation of a large number of microcracks. In this sense, the rolled edge of the fungus remains less sensitive to the presence of microcracks, if, of course, they are located only in the area of ​​the hole. If cracks have formed on the periphery, at the widest point of the fitting, this option is definitely subject to rejection.

For the American double funnel, it is often possible to use only a copper brake pipe. In extreme cases, if there is an urgent need to expand the steel tube according to the American standard, the procedure is performed in two or three stages. At the first stage, after cutting and filing the end of the tube, it is expanded under the fungus. Next, the resulting version is subjected to short-term annealing by heating with a torch, which allows you to remove a significant part of the stresses in the metal. The third stage will be flaring at an intermediate angle of 25-30 °, instead of 45 °, and repeated annealing. Finally, the final flaring is performed to the desired funnel size.

If possible, before flaring the tube, it is worth practicing obtaining a steel American funnel on unnecessary trimming of a pipe made of a similar material.

The video shows the process of expanding the brake pipes:

Flaring brake pipes is a procedure that may be required at any time by someone who has their own car. Of course, the implementation of this and any other operation related to the maintenance and repair of a vehicle can always be entrusted to qualified specialists at service stations, but many motorists go the other way and try to do everything with their own hands.Each car owner has the right to decide for himself who to trust the maintenance of his vehicle, but many of these issues can be resolved independently.

Learning to self-expand tubes is a snap.

Brake pipes are an integral part of the braking system of any car, which is responsible for stopping it at the right moment. To understand how important such tubes are for the operation of the brake system as a whole, you should at least superficially familiarize yourself with the principle of its operation.

So, the process of stopping the car, for which the braking system is used, consists of the following stages.

  • If it is necessary to reduce the speed of the vehicle or to stop it completely, the driver presses the brake pedal.
  • The master cylinder piston connected to the pedal is activated and begins to act on the brake fluid.
  • Under high pressure communicated by the piston of the master cylinder, liquid begins to flow through pipes and hoses into the cylinders of each wheel, acting on their pistons.
  • Under fluid pressure, the pistons act on the brake pads, which are pressed against the brake discs, stopping the rotation of the wheels.

Car brake system diagram

Obviously, brake pipes play a crucial role in the operation of the entire brake system, and if they break, it completely fails. That is why the repair of these elements, which includes the expansion of the brake pipes, should be approached with all responsibility.

Through the brake pipes, as mentioned above, high-pressure brake fluid is supplied to all elements of the system. When the throughput of such tubes deteriorates, the entire system begins to work ineffectively, which leads, in particular, to a significant increase in the stopping distance. The fact that the elements of the brake system, including pipes, require diagnostics (and, possibly, repair), may be indicated by the following characteristic signs:

  • the appearance of extraneous sounds and pulsating movements when you press the brake pedal;
  • free movement of the brake pedal when you press it;
  • leakage of brake fluid, which leads to a decrease in pressure and, accordingly, to ineffective braking and intensive wear of the brake pads;
  • driving the car to the side when braking (this situation, although it is an indirect sign, can also indicate that the brake pipes need to be repaired).

Old brake pipes in terrible condition should be urgently replaced even if there are no leaks

However, the main sign that the brake pipes do not fully fulfill their functions and require flaring is an increase in the braking distance. The most common causes of deterioration in the performance of brake pipes are:

  • violations in the design of the hex heads with which such tubes are equipped;
  • deterioration of the quality and reliability of threaded connections, the ingress of debris or coked liquid into them.

Such malfunctions, negatively affecting the technical condition of individual elements of the brake system, significantly reduce the efficiency of its work. That is why experts and car manufacturers recommend diagnosing it every six months. If you are tied to the mileage, then this procedure must be performed every 50,000 km of run, and it is necessary to replace rubber tubes, regardless of their technical condition, every 125,000 km of vehicle run.