Car Suspension Diagnostics
(without stands and expensive equipment, written for car owners)
There is such a conflict in the world: the least information about the most obvious things. And if you ask in a car service, then the answer most often sounds like this: “Everything is obvious right away!”, Which doesn’t bring much closer to understanding the issue.
If you ask Google: “Suspension Diagnostics” – there will be a lot of copywriting and similar texts on car service sites, but little practice. Therefore, for those who are interested in doing this on their own, who have little or no trust in the car service in the neighborhood, I’m telling you how we make this diagnosis in a garage without a lift. The presence of a pit simplifies the task a little, but in general it is optional. Immediately make a reservation that in the first place I mean the front suspension of the MacPherson type, as the most common in our practice.
First, what Wikipedia says and the general visual presentation:
MacPherson strut, it’s also MacPherson suspension (MacPherson suspension) or suspension on guiding racks, “swinging candle” – a type of automobile suspension, the main element of which is a shock absorber strut (Eng. McPherson strut).
Now by car:
Here is the sequence of diagnostics:
1) On a standing car, pull the steering tips and thrusts (tie rod on the screen below) with your hands for play.
2) On a standing car, shake the wheel left and right, while the partner controls the presence of play in the hinges.
3) Visually check the condition of the anthers of the ball bearings of the steering tips and the anthers of the rack. By the way, it is worth paying closer attention to the anther strips, for example, when the seals wear, the hydraulic fluid starts to leak into the anther, and from there it will quietly pour out. That is, the anther is whole, but slightly in oil outside. As an extreme case, one can cite an anecdotal, but real story, when, with very substantial wear of the gland, the anther of the rail was filled so that even the “corrugation” was not visible – it was just a kind of bubble inflated with hydraulic oil. Sorry, this photo has not been saved..
A typical ragged boot of a reiki (the rail, by the way, is already flowing, the gland has come to an end):
Steering tip and boot:
If at first glance the boot is in the “normal, why look!” Condition, then I can recommend this: since you got to it, do not spare a couple of extra minutes to wipe the rubber from dirt and examine the boot from all available sides: it happens that there is an invisible hole or impulse that can only be seen from a different angle. It does not hurt to “gently mash” the rubber (where possible) – damage can be detected and so.
First, a general view from Wikipedia for understanding (highlighted in red):
1) On a standing car, check the backlash of the stabilizer struts (twitch them with your hands) and the integrity of the anthers:
2) If there is access to the stabilizer bushings, as on the Peugeot 206 (see photo), then look at them. If not, then pull the stabilizer as much as you can. It should not shift left and right.
Levers and Ball Joints
1) Visually check the anthers of the ball joint and the silent blocks of levers.
2) Next, you need to “hang out” the wheel and pull the lever down. On the posted wheel, the ball bearing is pushed up, therefore, if there is play in it, this will be detected when the lever moves down. From the pit or from the lift, you can directly pull the lever, and on the jack with the wheel removed it is more convenient to insert a wiring between the steering knuckle and the lever, just be careful not to damage the boot.
In the image below, this is Wheel bearings. External and internal.
Here the options begin. If there are no complaints, then checking the wheel bearing is reduced to hanging the wheel and pulling it in a vertical plane “on-off.” So the backlash will be revealed. If there are complaints about a “sound, such as a howl”, then this situation cannot be reproduced by hand. In this case, it is necessary to raise the car, start the engine, engage the gear and turn it to the speeds at which this is manifested. But the method only works for driving wheels. It is usually impossible to determine exactly which side “howls” are coming from, so hanging the wheels one at a time is an ideal diagnostic method. The main thing here is to be sure that the machine does not have self-locking differentials. Well, the reliability of backups is also very important..
In general, except for backlash and howling, there are no particular complaints about bearings, and their wear is most often caused by drying of the lubricant, after which increased wear begins.
And by the way: when I wrote this material, then at the forum of the Legion-Avtodat company the issue of increased fuel consumption was just discussed: MMC Lancer 1996 4G92 1.6_consumption 25l / 100km_ http://forum.autodata.ru/264/28309/
Incidentally, the serviceability of wheel bearings affects fuel consumption!
This, of course, is not the only reason, but the checklist “If the car eats a lot of fuel” should be put.
CV joints and drive shafts
Each CV joint should be carefully examined for anther integrity. A torn boot is a moisture hit, and the SHRUS lubricant does not like moisture very much.
She from moisture turns into an abrasive and begins to nibble SHRUS. From this, he wears out quickly. Therefore, at the sight of a ragged anther – run to change, “without waiting for peritonitis.” If you have time, then he will live. If you do not have time – well, the CV joint assembly for replacement. Well, if this is an external CV joint, it is for almost everything as a separate spare part. But the internal SHRUS may not be a separate spare part, in this case you will have to order the shaft assembly.
Next, you need to check each CV joint for the presence of backlash. This is done as follows – with one hand you need to grasp the shaft at the entrance to the constant velocity joint, and with the other hand, take the shaft at its output, and then try to twist them in opposite directions. Here there should not be any backlashes. If they are, then most likely they will appear clanging with a sharp change in the sign of acceleration (on a sharp discharge of gas after a sharp acceleration, for example).
Another characteristic malfunction of external CV joints is a crunch when driving with the wheels turned out. This is a typical problem, only determine the side – and replace the SHRUS assembly.
Finally, the last typical problem is vibration at speed, which manifests itself with significant wear on the internal CV joints. It is similar to vibration from an imbalance of wheels, but it simply grows in proportion to speed (from an unbalance of wheels, usually the maximum vibration is reached at 80-90 km / h, and then it decreases slightly). Checked in the same way as the howling of a wheel bearing.
Pads and wheels
Everything is simple here. Ideally, you need to measure the thickness, but visual control is often enough. It is customary for dealers to write the percentage of wear or balance, or write the actual and allowable thickness.
Brake Disc Thickness Measurement
In real conditions, there is a larger gradation into three categories: “still dofiga”, “you can ride so far, it’s better to replace it with MOT,” “change urgently!”
If there are complaints about a squeak / creak during movement – you need to remove the wheel, evaluate whether the disk rotates easily. Often soured or pads in the bracket, or grease in the caliper guides. In both cases, the pads do not leave the disk and rub against it, issuing a mournful squeak. It is treated by cleaning the staples with a cord brush and a file, or by updating the grease in the caliper guides. And better, of course, both.
The design is quite complicated.
There are not so many “default” checks: you just need to look for the presence of strong leaks (a slight oil “fogging” is acceptable) and the integrity of the rod boot. By and large, the rest of the checks will do little – the canonical “Soviet” test “rock the car and see if the pump stops quickly” will not work if there is at least something left in the shock absorber. And completely empty shock absorbers, most often, will be tangible and so.
If there are complaints of knocks or other problems: we pull the wheel on ourselves in a standing car (monitoring the condition of the shock absorber supports), and in a standing car we drive left and right, trying to feel the “rifts” of a worn out support bearing (the partner can hold his hand at that moment for reliability on the spring – such rifts are given to it). In the same case, we look (try to make out) the integrity of the gum under the lower coil of the spring – it on Mitsubishi, for example, often breaks.
On this, the set of standard checks usually ends, and a more detailed search is carried out only if there are specific complaints.
Failure of the ball joint of the suspension arm: diagnostics and replacement – Tips for repairing a car – A variety of tips for motorists – Everything for a car in St. Petersburg
Malfunction of a ball joint of the suspension arm: diagnostics and replacement The ball bearing of the suspension arm is a very important element of the…
How to save a suspension from death in spring pits in the asphalt
How to save a suspension from death in spring pits in the asphalt In our country, asphalt goes off the road, usually with snow. Potholes in the canvas…
How much is auto diagnostics
Without keyword I will share: before writing this article, I had to refresh my memory and remember something. I went into the archive of articles on the…
What do the clicks and knocks in the car suspension mean?
What are the clicks and knocks in the car suspension? During the continuous operation of the car, its individual components and mechanisms will sooner or…