To troubleshoot, replace parts and assemblies, the suspension is subjected to complete or partial disassembly
Removing the springs from the car
The front and rear springs are removed in almost the same sequence
For this you need:
- loosen the nuts of the ladders;
- detach the lower end of the shock absorber;
- jack up the front of the car to remove the front springs or the rear so that the springs are unloaded;
- place technological supports of the appropriate height under the raised end of the frame and lower the car on them;
- unscrew the nuts of the bolts of the rubber-metal hinges of the spring.
Remove the bolts.
If it is difficult to remove them, knock them out with a copper drift so as not to spoil the thread;
- unscrew the nuts of the ladders and remove the ladders;
- raise the car with a jack so that the front end of the spring comes out of its bracket, and the rear end comes out of the earring.
Remove the spring.
Disassembling the springs
Fig. Checking the spring deflection
Before disassembling the springs, clean them of dirt and determine their technical condition.
If all the parts are suitable for further use, then it is necessary to check the spring deflection arrow in a free state, for this you need to pull a thread or thin wire between the axes of the lugs and measure the distance from the thread to the upper surface (near the center bolt) of the first root sheet, which should be:
- for small-leaf (2 sheets) front springs - (147±10) mm;
- for small-leaf (3 sheets) rear springs - (150±10) mm;
- for multi-leaf (4 sheets) front springs - (135±5) mm;
- for multi-leaf (5 sheets) rear springs - (135±5) mm.
The difference in the dimensions of the deflection boom of the springs of the same name installed on the vehicle should not exceed 10 mm.
Fig. Checking the deflection of the additional spring
Measurement of the deflection of the additional springs in the free state must be made from a stretched thread applied to the ends of the ends of the top of the main sheet, to its surface at the center bolt
This size should be for a single-leaf additional spring (1165) mm, for a three-leaf - (815) mm.
The difference between these dimensions for the left and right additional springs should also not exceed 10 mm.
If, as a result of a preliminary inspection, breakdowns are found, then the spring must be disassembled in the following order:
- clamp the spring in a vice in the immediate vicinity of the center bolt;
- unscrew the nuts of the clamp bolts, remove the bolts;
- unscrew the nut of the center bolt and carefully release the vise, as the sheets in the tightened spring are in a stressed state.
Rinse all spring leaves with kerosene, wipe and inspect for cracks.
Replace broken sheets and sheets with cracks.
Fig. 3 Mandrel for pressing the rubber-metal hinge out of the spring ears. Material: steel 40X, HPC 30-34
In case of rubber separation from the metal fittings in rubber-metal joints, they must be replaced.
To press the hinges out of the spring eye, you must use a mandrel, as shown in the figure
Fig. Pressing the joint out of the spring eye
Weakened clamp rivets must be re-riveted.
To increase the deflection of the spring sheets, it is unacceptable to straighten them with hammer or sledgehammer blows, as this leads to quick breakage.
It is allowed to straighten sheets by rolling between rollers.
Fig. Mandrels for pressing rubber-metal hinges into the eye of the spring and brackets. Material: steel 40X, HPC 30-34
Fig. Hinge press-in sequence
When replacing rubber-metal joints, they must first be lubricated with liquid soap.
Pressing the hinges into the eye of the spring must be done using mandrels, as shown in the figure
Then select the required set of sheets.
For multi-leaf springs, slip clean the surface of the sheets with graphite grease.
For small leaf springs, insert plastic spacers between the leaves.
Springs must be assembled in the following order:
- pick up the sheets in the appropriate order and insert a technological rod into the hole for the center bolt with a diameter equal to the diameter of the center bolt;
- in a vice, squeeze the central part of the spring as close as possible to the rod and remove it;
- insert the center bolt head down instead of the rod and tighten the nut;
- insert the bolts of the clamps and tighten them with nuts for multi-leaf springs and bend the clamps for few-leaf springs;
- release the spring from the vise and wipe it from excess lubricant;
- check the spring deflection in a free state, as mentioned earlier;
- hang the spring vertically and paint it black.
Installing springs on a car
Fig. Device for installing springs: 1 - spring; 2 - jack; 3 - beam; 4 - ladders; 5 - finger; 6 - latch
When mounting, the shorter end of the spring must face forward. for the correct operation of rubber-metal joints, the nuts of their bolts should be tightened with straightened springs.
This operation can be performed with a fixture using a standard jack.
Installing the spring on the car should be done in the following order:
- lower the car so that the front end of the spring enters its bracket, and the rear end enters the lower end of the earrings;
- install two conical and one flat washers on the bolt of the front end of the spring;
- install the bolt assembled in this way into the front bracket and screw the nut onto it;
- insert the bolt into the earrings and the rear eyelet of the spring, put on the lock washer and screw the nut onto the bolt;
- straighten the spring using the tool, tighten the nuts of the hinge bolts to 120-150 Nm (12-15 kgcm) and remove the tool;
- on the front spring, as well as on the rear spring of the buses, put an overlay on top, and on it stepladders, the threaded ends of which are inserted into the holes of the beam, then fix the stepladders with nuts and lock washers;
- on the rear spring, if it is small-leaf, it is necessary to install an additional spring and pad;
- if the spring is multi-leaf, then a gasket should be installed on it, then an additional spring and an overlay on it.
Then, stepladders are installed on the lining and in the holes of the rear axle cushion.
Lock washers are installed on the threaded parts of the ladders and nuts are screwed on;
- if the car has wheels, then it is necessary to remove the stands and the jack;
- finally tighten the nuts of the ladders to a torque of 120-150 Nm (12-15 kgcm);
- attach the lower end of the shock absorber.