Hi everyone, it's Eros again, Mike's contributor! Today I want to tell you about a rather invasive maintenance I performed on my car.
Before proceeding the usual disclaimer
All the operations I have performed have been carefully checked by my trusted professional mechanic, so they are not recommendations to perform rather delicate work on one's own car.
Any work should be done by trained personnel: when you are traveling with your car, you are entrusting it with your life, and therefore mistakes cannot be made!
Well, let's get going!
My passion for mechanics and cars is long-standing, I would almost say it could be called "ancestral"!
Today I will show you what I managed to do thanks to the advice of my trusted mechanic and what steps I followed to achieve the final result.
In this maintenance appointment we will proceed to the replacement of:
- Steering arms;
- Front axle discs and pads;
Before proceeding in any operation, you must set the vehicle in an absolutely flat position, and secure it with appropriate wedges. A hydraulic lift should be used to lift the car, and to keep the vehicle safe, a stand should be placed to support all the weight.
Since I did not have a bridge available to carry out the operations, I had to work first on one side then the other.
First, without lifting the car, I loosened the 5 wheel retaining bolts then proceeded to lift the car.
With the bolts and wheel removed, I had free access to the desired mechanical part: steering arms and braking apparatus.
Steering arms
Replacement of the steering arms is necessary when the front wheels begin to have play in the heads. This play can be recognized as the car begins to be inaccurate in corner entry; that is, to attack a corner the steering angle is no longer what it used to be, or corrections are needed.
To remove the arms, you must first remove the spherical head connecting to the wheel spindle, and then you have access to the arm.
Through a special tool you unscrew the arm, after which you can mount the new one.
This is the tool needed to disassemble the arms.
Source: https://www.fermectools.it/default.php?t=ecomm&el1=65&el2=65460&eid=BGS66525
In order to do a perfect job, it is necessary to have special repairers' manuals called workshop manuals, this is because each bolt must be tightened to the correct torque using a torque wrench. As you can see from the photo below, at the top of the spherical head, the fastening between the head and the hub is done by a toothed bolt. This is because the bolt must be tightened to a certain torque, and there is a hole in the threaded part where a cotter pin must be inserted to prevent the bolt from unscrewing.
This is a safety feature since the hub is subject to a number of sometimes very intense vibrations.
Very important is to keep the position of the spherical head on the arm marked, because the toe-in of the front wheels depends on that distance.
By all means, once you have marked the positions and have recalculated them with new parts, it is absolutely necessary to go to the tire dealer to do an accurate geometry, which they do with a special digital bridge.
There would also be the possibility of doing a toe-in tuning with wires (just as they did before they invented digital benches), but there are calculations and knowledge involved that may not give the optimal result.
In practice, it is not within everyone's reach.
Source: By Author
Front axle brakes
Having replaced the arms and heads, we move on to a very delicate part of brake replacement. Given my rather aggressive driving style, I opted to fit Tar-Ox whiskered discs and Ferodo F2500 (track day) friction pads.
The choice of the whiskered discs came down to the fact that the whiskers, besides dissipating fading gases, keep the friction surface always "alive" and even if you do long and light braking during city commutes, you will not vitrify the surface of the pads. I did not prefer to use drilled discs because the possibilities of small bristling of the discs are more likely, despite the heat treatments undergone by the discs.
One important note is about the whiskers: to maintain acceptable riding comfort, we need to mount them so that following in the direction of travel they go from the center of the disc outward.
If, on the other hand, we mount them in reverse, that is, with the whiskers following the direction of travel going from the outside to the inside, they become very noisy during braking and the life of the pads becomes much shorter. This style of mounting is also called "Racing," in fact all racing cars have the whiskers in the reverse direction of how I mounted them.
In order to replace the wearing compnents of the braking system, we first start by retracting the caliper rods and remove the old pads. We unscrew the two bolts of 19 that secure the caliper to the hub and keep it out of the work area by just securing it with a plastic clamp.
Now we need to remove the old disc, to do this we remove the spherical cover in the center of the disc and unscrew the bolt present. The two slotted screws located on the hub (near the studs) are removed.
Now we can remove the disk complete with hub and tapered bearing. Once all components are removed, the hub looks like this.
Source: By Author
To procdere to reassembly, the steps are performed in reverse giving some weight to 2 operations:
- Greasing the tapered hub bearing.
- Tightening of the locking bolt.
Tightening of the locking bolt must be done in 2 steps: first tighten at 1 kgm, unscrew and re-tighten at only 0.5 kgm.
This operation MUST be done very precisely and carefully because otherwise we risk seizing, and consequent rupture, of the bearing (if we tighten too much) with major problems of vehicle directionality.
I also leave you with an exploded view (taken from the workshop manual) to get a good understanding of how to proceed.
Source: https://www.zuccaricambi.it/prodotto/kit-cuscinetti-mozzi-ruota-anteriore-116-162-03-80-12-89/
Well we managed to replace the steering arms and redo the brakes on our car. Next time we will fix the rear brakes, which are very distinctive in my car as they are located at the exit of the differential!
In the photo below you see the parts I replaced: if you look closely the old discs in addition to having holes they also had whiskers ... which I "erased" by braking ...
Source: By Author
See you at the next Motors Article!