Repair and replacement of toilet cistern drain fittings

Recommendation points

• Typical device and main units
• Intake valve malfunctions
• Restoration of the drain valve
• Button and mechanism repair
• Eliminating the leak
• Complete valve replacement procedure

Breakdowns of the cistern happen quite often and are very diverse. In order not to spend money on calling a plumber, it is enough to study the device and the principle of operation of the fittings, and then independently eliminate any kind of malfunction and carry out repairs in a matter of minutes using the simplest tool.

Typical device and main units

Modern models of drain fittings are compact, simple and highly maintainable. Although there may be slight differences in the layout of parts from different manufacturers, two general theses can be defined:

1. The vast majority of drain fittings can be easily disassembled by hand.
2. All devices use the same operating principle.

The drain valve consists of two assemblies: an inlet float valve and a drain valve. The inlet assemblies can be designed for the lower and upper connection of the water supply hose, which determines only the location of the float and the scheme of transmission from it of the locking force. Unlike outdated designs, where the float is made in the shape of a pear and is prone to loss of tightness, modern products are supplied with a double glass.

The drain valve is a vertical column located exactly in the center of the tank under the button. In the lower part there is an annular saddle, which is covered by an elastic cuff. The locking force is provided by both the own weight of the stem and the mass of water in the tank. The valve opens when the stem is lifted associated with the button by a gear rack or linkage.

Intake valve malfunctions

If the inlet valve does not close tightly, the water will gradually fill the tank until the level reaches the overflow hole. Outwardly, such a breakdown is expressed in the appearance of a leak not immediately after the cessation of water supply to the tank, but some time later.

There are two variations in the design of the locking mechanism: in the form of a check valve and a simple cuff. The second option is more reliable due to the simplicity of the device. In both cases, the principle of operation is extremely simple: when floating, the float raises a lever or a rod, which exert a force on the valve with a reverse shoulder. The problem is that over time, the elastic cuff or rubber stopper takes the shape of the mating part, which does not contribute to high-quality locking.

On-site repairs cannot be performed, so the inlet valve will have to be removed. It is mounted on a threaded bushing made of plastic. First, you need to turn off the water supply tap and drain the water from the tank, then unscrew the drain button and remove the lid. With the effort of your hand, you need to unscrew the union nut, with which the entire valve structure is attached to the bushing.

The problem of any valve type is on the back of a small rocker arm associated with a boom or float arm. To make it easier for yourself, unclip the float drive and dismantle them, disengaging the drive lever from the rocker arm. Next, you need to remove the rocker itself, usually it is planted in two holes of the valve body with two pins: you just need to slightly bend the ears and get a miniature part. In the reverse-acting valves, at the opposite end of the rocker arm, there is a plastic cup, inside which a small rubber stopper is pressed, abutting against the water supply spout when closed. The plug can be pulled out and turned over to the spout with the flat side that does not have a workout. If this operation was performed earlier, you can cut the cork to form two new flat ends, and then fold and press the two rubber parts back into the glass..

In diaphragm valves, loss of tightness occurs either due to deformation of the rubber disc, or due to insufficient pressure exerted on the valve by the float. You can adjust the position of the glass and place it lower, it will also help to attach a foam cube to the bottom of the float. If it does not help, install a new membrane from the repair kit. The simple shape of this part often allows you to make it yourself from a piece of a car camera. Do not forget to thoroughly rinse the device from limestone deposits and rust before reassembling the device..

Restoration of the drain valve

The entire drainage mechanism is easy enough to remove after removing the cover, it is enough to turn its upper part counterclockwise until it clicks (1/2 or 1/4 turn). The tightness of the drain hole can be restored in several ways. If the valve membrane has a symmetrical shape and at the same time is noticeably deformed (the edges are bent up), it is removed and installed back on the other side. Previously, it will not be superfluous to restore the elasticity of the rubber by holding it for several minutes under running hot water.

If the membrane cannot be turned over or there is no point in that (the edges are even), most likely the insufficient tightness of the valve is due to the low degree of pressing. It can be recommended to increase the vertical stroke of the rod, for which it is necessary to carefully examine the place of its landing in the glass of the outer body. Usually the downward movement of the stem is limited by lateral ribs or other formations on the outside of the tube. The recipe is simple: you need to sharpen the stops by 2-3 mm with a file or a knife. The second way is to increase the weight of the piston, for which several large nuts are attached to its upper part or wrapped with 10–20 turns of thick copper wire.

Loose seating of the membrane in the seat can be the result of deposits of limestone or organic matter both on the rubber disc itself and on the counterpart. Use the coarse side of the sponge and a small amount of dish soap to remove the green organic residue. To remove limescale deposits, use a special detergent or regular vinegar. In order not to disturb the planting density, it is better to abandon the idea of ​​scraping off deposits with a knife..

Button and mechanism repair

The valve stem lift mechanism is the least problematic thing, although problems occur with it: seizure, insufficient stroke or simply no effect on the stem.

In older versions of fittings, a not very convenient and not the most reliable scheme was used: the button pushed the toothed rack, which rotated a gear with a long lever attached to it. The membrane was lifted through a chain attached to the end of the lever. The elimination of problems was solved by a higher tension of the chain, and over time, the teeth on the rack worked, and it had to be turned over with the reverse side.

Modern drain valves predominantly use a lever mechanism that is virtually trouble-free. The only problem can arise from poor alignment: after installing the bonnet, make sure the threads on the drain valve body are exactly centered on the hole. If this is not the case, the situation is corrected by displacing the upper thrust plate of the microlift by a few clicks in the right direction..

Eliminating the leak

In some situations, the appearance of water on the floor may be the result of a leaky fit of the cistern on the toilet shelf. First, you need to wipe all surfaces dry and find out exactly where the leak has formed.

If, during an external examination of the inside of the tank, the presence of rust on the bolt heads was noted, most likely this was the cause of the leak. It is necessary to drain the water from the tank and unscrew the plastic nuts from the bottom. After that, the bolts are replaced with new ones, if necessary, also replacing the washer washers. To protect the bolts from corrosion in the future, you can cover the caps with ordinary enamel or sealant, but do not use silicone for this purpose..

Looseness of the drain valve seat nut may also cause leakage. You will have to remove the tank completely and assess the condition of the sealing rings, as well as the gasket under the tank. If there are cracks or loss of elasticity, these elements must be replaced with new ones..

Complete valve replacement procedure

In such cases, as the destruction of reinforcement parts or strong depletion of the seats of parts of the mechanism, it is possible to recommend only a complete replacement of the reinforcement. The whole process will take half an hour at most:

1. Shut off the water supply and drain the tank.
2. Unscrew the button and remove the cover.
3. Unscrew the inlet valve nut and unscrew the top of the drain mechanism by turning counterclockwise.
4. If an identical set of fittings is used for replacement, it is not necessary to replace the lower parts..
5. If it is necessary to replace the lower part of the drain valve, remove the tank fixing bolts.
6. Unscrew the wide clamping nut from the bottom and remove the bottom of the drain mechanism.
7. Install a new seat with O-rings on both sides of the threaded socket.
8. Secure the tank in place.
9. Install new inlet and drain valves, center the neck under the button and complete the tank assembly.