SKANDIX - Your quality choice in VOLVO and SAAB car parts

This is a general note on floating caliper brakes of the design used in the form of the Girling caliper in the Volvo 940.
If brake pads in such calipers are worn diagonally (picture) or have worn down on one side, something is wrong. This usually happens due to the stuck guide bolts.
While driving, this often results in more or less strong vibrations when braking, sometimes even while driving, because the pad is still stuck in contact with the disc. Also, the car does not roll freely, higher fuel consumption and brake pad wear are the result. If the pad constantly grinds, this can of course also lead to damaged break discs.

The fact that the guide bolts start to sag at some point is caused either by defective sleeves or by rust on the exposed part of the bolt, the rust of course passes under the sleeve after some time and makes it useless. As a general rule, you can say that this always happens with Girling saddles as the vehicle ages.
In the case of the broken guide bolt shown here, the collar has already rusted away to such an extent that a new collar would no longer fit anyway.
It makes no sense to grind it clean, as there would be nothing left of the guide collar afterwards.

In the worst case, this is how it ends if the bolts are not replaced in time. Because the bolt could no longer be removed, it simply tore off after a few attempts to loosen it. This means that a new saddle bracket is needed, because the repair would be at least very complicated or even impossible. Please do not experiment with drilling out the bolt, as this usually only damages the saddle bracket. In addition, the guide bolt has a strength of 10.9, which would make drilling a torture anyway.

In this situation, the saddle bracket should be replaced. The picture shows a pre-assembly of the bolt set 1015454 and the saddle bracket 1010859, the bracket is always delivered without the bolt set.

If, however, rusted guide bolts are replaced at an early stage, the saddle bracket can usually still be used. Nevertheless, it is important to make sure that the bore is clean, that fresh grease is applied and that the sleeve seat is intact.
Attention: The bolts have a slight play even in a new saddle bracket, this is how it should be.

With other floating caliper systems, such as those from ATE, where the guide bolts are screwed into the caliper bracket or steering knuckle and the guide is in the caliper, other jams occur after a certain period of use, which usually have two causes. These systems exist, for example, on the Saab 900, 9-3 (-03) or 9-5(-10) and on the Volvo 850 (picture) or V70.
The first reason is that the guide bolts on the screw connection side become dirty as the brake wears down, as they are usually uncovered there. If the caps are missing on the side of the hexagon socket or are not present due to the design, dirt and water will naturally penetrate there. This dirt is collected on the bolts and prevents them from sliding cleanly in the plastic bushing. For this reason, the bolts should be removed and cleaned or, if necessary, replaced at every brake service The plastic sleeves and collars must be intact and clean.
The second reason for sagging with this system can be corrosion on the caliper in the guide bore. This corrosion causes the guide sleeve to jam more and more, so that it eventually sticks onto the guide pin.

The picture above shows such a bore without the plastic sleeve. Here it is dirty and slightly corroded, but still usable.
If corrosion is more severe, a repair kit is unavoidable for the experienced mechanic, as the sleeves have to be removed from the saddle in order to clean the bore and bring it back to its original size. The sleeves are usually destroyed in the process, if they are not already damaged. After hollowing out (ATE offers honing brushes for this, shown in the next picture) and cleaning, the sleeves are refitted with a grease compatible with the plastics, such as Plastilube, and the caliper can be used again, as long as everything else is OK.
If you don`t have the confidence to carry out this repair, which requires some expertise, it is better to buy a new saddle or a replacement saddle. Everything will be preassembled and the hydraulic part will also be new.
It should be noted that the bolting of the caliper to the steering knuckle or the caliper bracket requires a certain amount of care: Often, the sliding bolts are placed crooked and the threads are damaged or they are tightened too much with mostly the same result. Please be sure to observe the manufacturer`s instructions when tightening the bolts; in the worst case, depending on the type, this may require a new steering knuckle!

Here is the process of honing an ATE caliper with the repair kit already mounted on the other side.
In general, all moving parts on floating caliper brakes require a certain amount of maintenance. The sliding surfaces for the brake pads must of course also be cleaned and may not show any obstructive corrosion. Before fitting, these should be greased with Plastilube (1049363), for example.
Checking the guide bolts before changing the pads is relatively simple: remove the wheel, unscrew one guide bolt and fold down the caliper. You can then check the mobility of these parts. However, if in doubt, replacing parts when the condition is uncertain is always the better solution.
It is worth it, the pedal feeling of a correctly repaired brake is completely different.
Often a certain habit has crept in before. Some people only realize how bad the brakes really were when they are replaced.
And always remember: brakes are safety-relevant parts! Unprofessional repairs have no place on such vehicle components.