What worries our brother repairman most of all is the quality of the parts on which traffic safety directly depends. Today let's talk about those in the brake system.
Here is the first story. The owner of the VAZ 2106 asked to prepare the car for inspection. In the eyes of anxiety: the car began to slow down worse, the left rear wheel "does not take." The locksmith habitually removed the brake drum, but did not find any visible faults - everything is in working condition. Brake pad linings still look like. What about the wheel cylinder? Together we checked: with a light pressure on the pedal, both pistons diligently advanced a millimeter and a half - alive! Having thoroughly cleaned everything, the mechanic assembled the car. We tested the brake … Alas, the left wheel is still "not taking"! What is the matter?
A locksmith changes a suspicious cylinder to a new one. Tested: cheers! It works great. The owner departed on his own, and we have a mystery! When the old cylinder was dismantled, the picture became clear.
Remember how the automation of the working cylinder works, maintaining the correct gaps between the block and the working surface of the drum? The entire working stroke of the piston is approximately 1.2–1.6 mm, but it “dances” from its “stove” - a sliding stop, for the movement of which along the cylinder a force of at least 35 kgf is needed. This emphasis is a steel split ring, with an interference fit inserted into the cylinder. If the block is worn, the driver presses the pedal harder, and when the force with which the piston presses on the ring becomes sufficiently large, the emphasis will move outward, compensating for the wear of the block. Simply? Yes. Reliably? Don’t rush with this!
The fact is that we knocked out the pistons and stops with a heavy hammer (photo 1)! The rings sat dead in their places - and the "machine" could not bring the worn out pads to the drum. The owner would have to press the pedal harder, but it is not known what the result would be: the cylinder has already begun to rust, "grabbing" the thrust rings. This was confirmed by the darkened liquid, which the owner did not change!
Here I have to remind you that Tom, Dew and similar liquids based on ethylene glycol are extremely hygroscopic - they eagerly absorb water vapor from the atmosphere. And for this reason they are subject to regular (see instructions!) Replacement. Do not save on this, do not wait until the brakes fail!
The second story! Once replaced on "Samara" back pads. New - a well-known company with protective holograms. Two weeks later, the client called and shamed: “Well, how so, Anatoly Mikhailovich! "The replacement order is indicated in the order, and you left the old ones!"
I invited the client to come. We examined the pads: here they are - holograms, clearly visible! This means that the client is not always right. However, his claim to the brakes is valid. Of the four pads, three are normal looking, slightly worn. And the fourth you see in photo 2: a piece of the lining came off, the rest barely holds. And the material is strange, malleable - something in between rubber and paronite. We were probably faced with a fake.
On a photo 3 - a block for "classics" from a well-known shop in the Moscow Southern port. But how she “sailed” to the port is again a mystery. For a scruffy product, the outer radius of the lining is much larger than the inner drum - try sticking it in without sawing the edges almost to the piece of iron! And look how the pad is glued: a few drops of glue promise exciting adventures to a brave buyer!