US3648352A

US3648352A - Method and device for removing disk brake pistons

Info

Publication number: US3648352A
Application number: US857290A
Authority: US
Inventors: Silas E Simmonds
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-09-02
Filing date: 1969-09-02
Publication date: 1972-03-14
Anticipated expiration: 1989-03-14

Abstract

Each of the brake pistons within a disk brake caliper is removed therefrom for overhaul by increasing liquid pressure applied thereto until the piston is released from the caliper. When more than one piston is mounted in a caliper and the pistons are liquid connected to each other, all of the pistons except one are retained within the caliper by suitable means so that only the one piston can respond to the increasing liquid pressure.

Description

[ Mar. M, i972 United States Patent Simmonds Kuniholm......................

Miaskiewicz...................:......

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211 App]. No.: 857,290

Primary Examiner-Charlie T. Moon Attorney-Kinney and Schenk Related US. Application Data [63] Continuation-impart of Ser. No. 764,423, Oct. 2,

ABSTRACT Each of the brake pistons within a disk brake caliper is 1968, abandoned.

removed therefrom for overhaul by increasing liquid pressure 29/200 applied thereto until the piston is released from the caliper. I427 188/72 5 When more than one piston is mounted in a caliper and the pistons are liquid connected to each other, all of the pistons except one are retained within the caliper by suitable means so that only the one piston can respond to the increasing liquid pressure.

mh "c r. um r m d Ld .m F .l] .l 18 6 55 5 [l l.

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References Cited UNlTED STATES PATENTS McKay.......t........ ................29/427 X 15 Claims, 15 Drawing Figures PATENTEDMAR 14 m2 SHEET 1 (IF 7 INVENTOR. SILAS E. SIMMONDS PATENTEDMAR 14 1912 3, 648,352

SHEET 2 OF 7' .IIVVEN TOR. SILAS E. SIMMONDS PATENTEUMAR 14 m2 3, 6A8 3 5 2 SHEET 3 UF 7 awso AHHHHII SILAS E. SHMMONDS Pmmwmm m2 3,6d8,352

SHEET or 7 INVENTOR. SILAS E. SIMMONDS I ATTORNEYS;

PATENTEDMAR M 1972 3, 6A8 352 SHEET 5 OF 7 INVENTOR ATTORNEYS PATENTEUHAR 14 I972 SHEET 8 [1F 7 INVENTOR FEGDW SILAS E. SIMMONDS ATTORNEYS PATENTEDHAR 14 m2 3, 648 352 SHEET 7 [1F 7' INVENTOR SILAS E. SHMMONDS ATTORNEYS METHOD AND DEVICE FOR REMOVING DISK BRAKE PISTONS This application is a continuation-in-part of application Serial No. 764,423, filed Oct. 2, 1968, now abandoned.

In disk brakes, the friction pads or shoes, which engage the rotating disk, are removably carried by a caliper. In one type of disk brake, the caliper has a pair of oppositely facing pistons disposed therein for acting on the friction pads that are on opposite sides of the rotary disk. As a result, when liquid supplied to the caliper, both of the pistons are simultaneously moved toward each other to urge the friction pads against the rotary disk to produce the desired braking action.

When overhauling this type of disk brake, it is necessary to remove the oppositely facing pistons after the friction pads have been removed from the caliper. This is necessary to inspect the piston to determine if it needs replacing due to having become pitted, for example. Likewise, it is desirable to replace the external seal on the piston.

Because each of the pistons has the external seal cooperating with the wall of the cylinder in which it is disposed, it is difficult to remove the pistons from the caliper. This is particularly true if the piston has rusted within the caliper and become frozen therein.

A present method utilized for removing the disk brake pistons from the caliper has been to apply air pressure to the pistons simultaneously. However, because relatively low air pressure is used, this is time consuming and has required as long as 6 hours to remove each of the hollow brake pistons. This is also because the hollow piston may tend to rust within the caliper so that a very high pressure is necessary to remove the piston from the caliper.

Frequently the pistons are so tightly engaged in the calipers that they cannot be removed by compressed air normally used in service stations where air pressures are deliberately low to avoid injury to bystanders.

For instance, in many cases between 500 and 1,000 pounds pressure is required, but if this pressure is applied from a com pressed air source, the piston would release with such explosive force that it might easily injure or kill a bystander or damage property.

By contrast, when a liquid is used the pressure force is not explosive and the pressure is released without explosive action when the piston is removed from the caliper.

The present invention satisfactorily overcomes the foregoing problem by providing a method and device for easily removing disk brake pistons from a caliper. Thus, even if the piston has rusted within the caliper and become frozen therein, the present invention easily and satisfactorily removes it in a short period of time such as to minutes, for example. Accordingly, the time required when using the method and device of the present invention to remove the rusted piston is only about 4 percent of the time required when using the previously available method.

In another type of disk brake, the caliper has two pairs of oppositely facing pistons disposed therein for acting on the friction pads that are on opposite sides of the rotary disk. In this type of disk brake, the supply of fluid to the caliper causes all of the pistons to be simultaneously moved toward each other to urge the friction pads against the rotary disk to produce the desired braking action.

In this type of disk brake, the present invention is equally satisfactory. When the caliper has two pair of oppositely facing and fluid connecting pistons, only one of the pistons may be responsive to the increasing liquid pressure applied to the caliper at any one time. The present invention satisfactorily meets this requirement by providing a pair of cooperating members that prevent the other three of the four pistons from being responsive to the liquid pressure.

In some disk brakes, only a single piston is mounted in a caliper. Again, the present invention satisfactorily enables this type of piston to be removed from the caliper by applying an increasing liquid pressure to the piston.

An object of this invention is to provide a method for removing a disk brake piston from a caliper.

Another object of this invention is to provide a method and device for removing oppositely facing disk brake pistons from a caliper.

Another object is to create a device for removing pistons from the calipers of disc brakes which will be safe to use by the ordinary mechanic.

Other objects, uses, and advantages of this invention are apparent upon a reading of this description, which proceeds with reference to the drawings forming part thereof and wherein:

FIG. 1 is a side elevational view of one form of the device of the present invention for removing oppositely facing disk brake pistons from a caliper.

FIG. 2 is a front elevational view of the device of FIG. ll.

FIG. 3 is an enlarged top plan view, partly in section, of the device ofFIG. 1.

FIG. 4 is an enlarged sectional view illustrating the reservoir and pump means of the device of FIG. l. v

FIG. 5 is a side elevational view, partly in section, showing the check valve that prevents reverse flow of liquid from the caliper to the liquid reservoir.

FIG. 6 is an enlarged perspective view showing a clamp for retaining one of the oppositely facing pistons within the caliper while the other is being removed.

FIG. 7 is a sectional view illustrating the mounting ofthe caliper on the support structure of the device.

FIG. 8 is a side elevational view, partly in section, showing the mounting of a liquid collection or drain pan.

FIG. 9 is a top plan view of another form of the device of the present invention in which two pairs of oppositely facing disk brake pistons are removed from a caliper.

FIG. 10 is an enlarged perspective view showing a clamp for retaining two of the four pistons in the caliper of FIG. 9 while one of the other two pistons is being removed.

FIG. 11 is an enlarged perspective view showing another clamp for retaining one of the other two of the four pistons within the caliper of FIG. 9 while the remaining piston is being removed.

FIG. 12 is a side elevational view of one form of connector between the liquid pressure line and the caliper.

FIG. 13 is an elevational view, partly in section, of another form of connector between the liquid pressure line and the caliper.

FIG. 14 is a top plan view of a caliper in which only a single piston is employed with the caliper having a liquid pressure line connected thereto for removing the single piston from the caliper by the method of the present invention.

FIG. 15 is a top plan view of another caliper having only a single piston mounted therein with the caliper having a liquid pressure line connected thereto for removing the single piston from the caliper by the method ofthe present invention.

Referring to the drawings and particularly FIGS. 1 to 3, there is shown a caliper 10 that has been removed from a motor vehicle. The friction pads or shoes also have been removed from the caliper 10.

The caliper 10 has a space 11 (see FIG. 1) formed therein between spaced portions of the caliper 10 to allow the rotary disk to rotate therethrough when the caliper 10 is mounted on the motor vehicle. Oppositely facing pistons 12 and 13 (see FIG. 3) are slidably mounted in cylinders within the caliper 10. The caliper 10 has liquid passages therein to provide liquid communication between the two cylinders within which the

pistons

12 and 13 are slidably mounted.

The

pistons

12 and 13 extend into an enlarged recess 14 i (see FIG. 3) within the caliper 10. The lower end of the recess 14 communicates with the upper end of the space 11 so that a portion of the rotary disk rotates through the bottom of the recess 14.

Accordingly, when liquid is supplied to the caliper 10 through a fitting when the caliper 10 is mounted on the motor vehicle, the

pistons

12 and 13 are moved simultaneously toward each other. Since each of the

pistons

12 and 13 moves a friction pad (not shown), which is mounted within the recess 14, into engagement with the rotary disk, application of liquid through the fitting 15 results in the rotary disk being engaged by the friction pads. The caliper has a bleed valve 16 (see FIG. I) mounted thereon to permit removal of any air from the liquid system of the caliper 10.

When the caliper 10 is to have the

pistons

12 and 13 removed therefrom for overhaul, the method of the present invention contemplates mounting the caliper 10 on a frame 17, which may be fixedly secured to a work bench 18, for example, by a vise 19. Thus, the frame 17 is fixedly supported. Of course, any other suitable means for placing the caliper 10 in a fixed position may be utilized.

The caliper 10 is mounted on the frame 17 through having an ear 20, which is utilized in mounting the caliper 10 on the motor vehicle, attached to the frame 17 by a bolt 21 and nut 22. A threaded sleeve 23 (see FIG. 7) is disposed between the ear 20 and the frame 17 to space the caliper 10 from the frame 17.

A reservoir 24 is fixedly attached to the frame 17 beneath the caliper 10. As shown in FIG. 4, the reservoir 24 has a filler pipe 25 with a cap 26 thereon. Thus, brake liquid may be supplied to the reservoir 24 by removing the cap 26 whereby he desired amount of liquid is provided within the reservoir 24.

As shown in FIG. 4, the reservoir 24 has a chamber 27 therein communicating with the filler pipe 25 through an opening 28 in one end of a wall defining the chamber 27. A spring 29 is disposed within the chamber 27 and continuously urges a piston 30 to the right (as viewed in FIG. 4). A rod 31 is connected to the piston and extends beyond the frame 17. Liquid leakage is prevented by a seal 32 at one end of the chamber 27; the rod 31 extends through the seal 32.

As shown in FIG. 1, the piston rod 31 has its other end connected to a lever 33 through a pin and slot arrangement. Thus, when the lever 33, which is pivotally mounted on an ear 34 of the frame 17 by a pin 35, is moved toward the frame 17, the piston 30 is moved toward the left (as viewed in FIG. 4) against the force of the spring 29. This pumps liquid from the reservoir 24 through a hose 36 that communicates with the fitting of the caliper 10. Thus, the liquid, which is pumped from the reservoir 24 by the piston 30, is supplied to the liquid passages in the caliper 10.

As shown in FIG. 5, the hose 36 has a valve 37 mounted therein to prevent reverse flow of liquid to the reservoir 24. A spring 38 continuously urges the check valve 37 to a closed position to prevent liquid flow to the reservoir 24 from the caliper 10. When liquid from the reservoir 24 isbeing pumped to the caliper 10, the check valve 27 is not effective since the pressure of the liquid being pumped from the reservoir 24 overcomes the force of the spring 38.

The frame 17 has a collection or drain pan 39 mounted thereon beneath the caliper 10. The pan 39 collects liquid when the

piston

12 or 13 is removed from the caliper 10. The pan 39 is removably mounted on the frame 17 by a spring clip 40.

In order to retain one of the

oppositely facing pistons

12 and 13 so that it cannot respond to the liquid pressure supplied to the liquid passages in the caliper 10 from the reservoir 24, a clamp 41 (see FIG. 6) is utilized. The clamp 41 includes a U- shaped portion 42 on one end. The U-shaped portion 42 has

legs

43 and 44 with pointed ends thereon. The U-shaped portion 42 is adapted to be disposed within the enlarged recess 14 in the caliper 10.

When the U-shaped portion 42 of the clamp 41 is disposed within the recess 14 in the manner shown in FIG. 3, the U- shaped portion 42 has its surface 46 bearing against the piston 13. Since the castings, which form the caliper 10, may be rough, the pointed ends of the

legs

43 and 44 permit the U- shaped portion 42 of the clamp 41 to be forced into the recess 14 if necessary.

As shown in FIG. 6, the U-shaped portion 42 has an upwardly extending portion 47 connected at its upper end to a longitudinal support portion 48, which rests on a portion of the caliper 10. The longitudinal portion 48 has a connecting portion 49, which is substantially parallel to the portion 47, attached thereto.

The clamp 41 also includes a handle portion 50, which is parallel to the support portion 48 and connected to the lower end of the connecting portion 49. Thus, the clamp 41 may be easily handled for insertion and removal from the recess 14.

In carrying out the method of the present invention, the caliper 10 is first removed from the vehicle and is cleaned. Next, the hose 36 is connected to the fitting 15 of the caliper 10. The caliper 10 is then mounted on the frame 17 by the bolt 21, the nut 22, and the threaded sleeve 23.

The clamp 41 is then installed within the caliper 10 so as to retain the piston 13 in the retracted position of FIG. 3. The reservoir 24 is next filled with liquid. The lever 33 is then actuated to pump liquid from the reservoir 24 to the liquid passages in the caliper 10. If there is any air within the liquid passages in the caliper 10, the bleed valve 16 is opened to bleed the air therefrom.

With the collection or drain pan 39 positioned beneath the caliper 10, the lever 33 pumps liquid from the reservoir 24 to the caliper 10 by means of the piston 30. As the pressure in the liquid passages in the caliper 10 increases, the piston 12 is eventually removed from the caliper 10 even if the piston 12 is frozen within the cylinder in the caliper 10. Through the lever 33, the pressure acting on the piston 12 may be increased to 850 or more pounds pressure. With only the piston 12 being movable, the effective pressure on the piston 12 is greater than during braking when both of the

pistons

12 and 13 are movable.

When the piston 12 is pushed out of the cylinder within the caliper 10, the liquid within the liquid'passages in the caliper 10 and in the hose 36 escapes through the removed piston 12 and is caught by the pan 39. The pan 39 is then removed from the frame 17 and liquid discarded.

With the piston 12 removed, the caliper 10 is cleaned and the piston 12 is inspected. If necessary, the piston is replaced. Then, the old or new piston is installed within the cylinder in the caliper 10 with a new seal.

With the piston 12 installed within the cylinder in the caliper 10, the clamp 41 is removed from retaining the piston 13 in its retracted position. The clamp 41 is now positioned in the opposite direction to that shown in FIG. 3 so that it retains the piston 12, either new or reconditioned, in its retracted position. Then, the method is repeated for removing the piston 13 from the caliper 10. Thereafter, the caliper 10 is removed from the frame 17 and again installed on the motor vehicle.

Referring to FIG. 9, there is shown a caliper 51 that has been removed from a motor vehicle. The friction pads or shoes also have been removed from the caliper 51.

The caliper 51 has a space formed therein between spaced portions of the caliper 51 in the same manner as the caliper 10 has the space 11 to allow the rotary disk to rotate therethrough when the caliper 51 is mounted on the motor vehicle. Four pistons 52-55 are slidably mounted in cylinders within the caliper 51. The

pistons

52 and 53 comprise a first pair of oppositely facing pistons, and the

pistons

54 and 55 comprise a second pair of oppositely facing pistons.

The caliper 51 has liquid passages therein to provide liquid communication between the four cylinders within which the pistons 52-55 are slidably mounted. One of the liquid passages is shown at 56 and communicates through a passage 57 with the interior of the cylinder within which the piston 52 is slidably mounted.

The pistons 52-55 extend into an enlarged recess 58 within the caliper 51. The lower end of the recess 50 communicates with the upper end of the space through which the upper end of the space through which the rotary disk rotates so that a portion of the rotary disk rotates through the bottom of the recess 58.

Accordingly, when liquid is supplied to the caliper 51 through a fitting when the caliper 51 is mounted on the motor vehicle, the

pistons

52 and 53 are moved simultaneously toward each other, and the

pistons

54 and 55 are moved simultaneously toward each other. Since each of the pistons 52-55 moves a friction pad (not shown), which is mounted within the recess 58, into engagement with the rotary disk, ap-

plication of liquid through the fitting results in the rotary disk being engaged by the friction pads. The caliper 51 has a bleed valve (not shown) mounted thereon to permit removal of any air from the liquid system of the caliper 51.

When the caliper 51 is to have the pistons 52-55 removed therefrom for overhaul, the method of the present invention contemplates disposing the caliper 51 within a collection or drain pan 60. The pan 60 collects liquid when one of the pistons 52-55 is removed from the caliper 51.

The caliper 51 is connected to the hose 36, which has liquid supplied thereto under pressure from the reservoir 24 in the manner previously described. The hose 36 is connected to the caliper 51 through a connector, which has one end communicating with the fitting of the caliper 51 and its other end communicating with the hose 36.

Referring to FIGS. 12 and 13, there are shown two forms of connectors. As shown in FIG. 12, a connector 61 has one end clamped over the end of the hose 36 while its other end is adapted to be disposed within the fitting in the caliper 51 for connection thereto.

A second form of connector 62 is shown in FIG. 13 and is utilized when the caliper 51 has a fitting that is much larger in diameter than the fitting with which the connector 61 is utilized. Either of the

connectors

61 and 62 provides a liquid connection between the hose 36 and the liquid passages within the caliper 51.

In order to retain all but one of the pistons 52-55 so that they cannot respond to the liquid pressure supplied to the liquid passages (one shown at 56) in the caliper 51 from the reservoir 24, large clamp or fork 68 (see FIG. and a small clamp or fork 69 (see FIG. 11) are utilized. As shown in FIG. 9, the clamp 68 cooperates with two of the pistons on the same longitudinal side of the recess 58 while the clamp 69 cooperates with one of the two pistons on the other longitudinal side of the recess 58 so as to leave one of the four pistons 52-55 free to move in response to the liquid pressure.

The clamp 68 includes a U-shaped portion 70 (see FIG. 10) on one end thereof. The U-shaped portion 70 has

legs

71 and 72 with pointed ends thereon. The U-shaped portion 70 is adapted to be disposed within the enlarged recess 58 in the caliper 51.

When the U-shaped portion 70 of the clamp or fork 68 is disposed within the recess 58 in the manner shown in FIG. 9, the U-shaped portion 70 has its surface 73 hearing against the

pistons

53 and 55. Since the castings, which form the caliper 51. may be rough, the pointed ends of the

legs

71 and 72 permit the U-shaped portion 711 of the clamp 68 to be forced into the recess 58 is necessary.

As shown in FIG. 10, the U-shaped portion 70 has an upwardly extending portion 74 connected at its upper end to a support portion 75, which rests on a portion of the caliper 51. The support portion 75 has a connecting portion 76, which is substantially parallel to the upwardly extending portion 74, attached thereto.

The clamp 68 also includes a handle portion 77, which is parallel to the support portion 75 and connected to the lower end of the connecting portion 76. Thus, the clamp 68 may be easily handled for insertion and removal from the recess 58.

The clamp 68 is substantially similar to the clamp 41 shown in FIG. 6. The primary distinction is that the base of the U- shaped portion 70 of the clamp 68 is much longer than the base of the U-shaped portion 42 of the clamp 41. This is to cooperate with two pistons rather than a single piston.

The clamp 69 includes a rectangular shaped portion 78, which is adapted to engage one of the pistons to retain it within the caliper 51 when liquid pressure is supplied to the caliper 51 from the reservoir 24. As shown in FIG. 9, the rectangular shaped portion 78 of the clamp 69 is engaging the piston 54. Thus, the piston 52 is free to respond to the liquid pressure supplied to the caliper 51.

The clamp 69 also includes a base portion 79, which carries the rectangular shaped portion 78 thereon. As shown in FIG. 9, the base portion 79 is disposed between the base of the U- shaped portion 70 of the clamp 68 and the rectangular shaped portion 78. A finger 80 extends from the base portion 79 over the top of the rectangular shaped portion 78 and over the top of the caliper 51 so that the finger portion 80 rests on the caliper 51.

In carrying out the method of the present invention, the caliper 51 is first removed from the vehicle and is cleaned. Next, the hose 36 is connected to the fitting of the caliper 51 through one of the

connectors

61 and 62 depending upon the type of fitting on the caliper 51. At this time, the caliper 51 is disposed within the collection pan 60.

The clamp 68 is then installed within the recess 58 in the caliper 51 so as to retain the pistons 53 .and 55 in the retracted position of FIG. 9. The clamp 69 is next disposed within the recess 58 in the caliper 51 to retain the piston 54 in the retracted position of FIG. 9.

The reservoir 24 is next filled with liquid. The lever 33 is then actuated to pump liquid from the reservoir 24 to the liquid passages (one shown at 56) in the caliper 51. If there is any air within the liquid passages in the caliper 51, the bleed valve (not shown) on the caliper 51 is opened to bleed the air therefrom.

Liquid is pumped from the reservoir 24 to the caliper 51 by means of the piston 30 due to actuation ofthe lever 33. As the pressure in the liquid passages in the caliper 51 increases, the piston 52 is eventually removed from the caliper 51 even if the piston 52 is frozen within the cylinder in the caliper 51. Through the lever 33, the pressure acting on the piston 52 may be increased to 500 or more pounds pressure. With only the piston 52 being movable, the effective pressure on the piston 52 is greater than during braking when all the pistons 52-55 are movable.

When the piston 52 is pushed out of the cylinder within the caliper 51, the liquid within the liquid passages in the caliper 51 and in the hose 36 escapes through the removed piston 52 and is caught in the pan 60. The caliper 51 is removed from the pan 60 to allow the liquid to be discarded.

With the piston 52 removed, the caliper 51 is cleaned, and the piston 52 is inspected. If necessary, the piston is replaced. Then, the old or new piston is installed within the cylinder in the caliper 51 with a new seal.

With the piston 52 installed within the cylinder in the caliper 51, the clamp 69 is removed from retaining the piston 54 in its retracted position. The clamp 69 is now positioned to retain the piston 52, either new or reconditioned, in its retracted position. Then, the method is repeated to remove the piston 54 from the caliper 51.

After the piston 54, either new or reconditioned, has been installed within the cylinder in the caliper 51, the

clamps

68 and 69 are removed from the recess 58. Then, the clamp 68 is disposed so that the

pistons

52 and 54 are retained in the retracted position by the clamp 68. The clamp 69 is then positioned to retain one of the

pistons

53 and 55 in its retracted position. If it be assumed that the clamp 69 is retaining the piston 55, then the method is repeated to remove the piston 53 from the caliper 51.

With the piston 53 installed within the cylinder in the caliper 51, the clamp 69 is removed from retaining the piston 55 in its retracted position. The clamp 69 is now positioned to retain the piston 53, either new or reconditioned, in its retracted position. Then, the method is repeated to remove the piston 55 from the caliper 51. Thereafter, the caliper 51 is installed on the motor vehicle.

Referring to FIG/ 14, there is shown a caliper 81, which has a single piston 82 movable therein for cooperation with a rotary disk. The single piston 82 is movable into a recess 83 in the caliper 81 to engage the rotary disk. The piston 82 has a friction pad thereon that cooperates with the rotary disk. Only the single piston 82 is employed to stop rotation of the rotary disk.

IN carrying out the method of the present invention with the caliper 81, the caliper 81 is first removed from the vehicle and is then cleaned. Next, the hose 36 is connected to the fitting of the caliper 81 through one of the

connectors

61 or 62. The caliper 81 is then disposed within the collection or drain pan 60.

The reservoir 24 is next filled with liquid. The lever 33 is then actuated to pump liquid from the reservoir 24 to the liquid passages in the caliper 81. If there is any air within the fluid passages in the caliper 81, a bleed valve (not shown) on the caliper 81 is opened to bleed the air therefrom.

With the collection or drain pan 60 having the caliper 81 positioned therein, the lever 33 pumps liquid from the reservoir 24 to the caliper 81 by means of the piston 30. As the pressure in the liquid passages in the caliper 81 increases, the piston 82 is eventually removed from the caliper 81 even if the piston 82 is frozen within the cylinder in the caliper 81.

In order to obtain a more effective pressure on the piston 82 than is available during the braking action, it is necessary that the pressure acting on the piston 82 be greater than the pres sure applied during braking action since there is only the single piston. Thus, it is desirable that the pressure supplied to the piston 82 by the lever 33 be greater than in the prior embodiments.

When the piston 82 is pushed out of the cylinder within the caliper 81, the liquid within the liquid passages in the caliper 81 and in the hose 36 escapes through the removed piston 82 and is caught by the pan 60. After the caliper 81 is removed from the pan 60, the liquid is removed from the pan 60.

With the piston 82 removed, the caliper 81 is cleaned, and the piston 82 is inspected. if necessary, the piston is replaced. Then, the old or new piston is installed within the cylinder in the caliper 81 with a new seal. The caliper 81 is then mounted on the vehicle.

Referring to FIG. 15, there is shown a caliper 84 having a single piston 85 slidably mounted therein. The piston 85 carries a friction pad thereon. The friction pad is mounted on the piston 85 by means of a mounting hook 86.

When using the caliper 84 with a rotary disk, two of the calipers 84 are required with one disposed on each side of the rotary disk. Thus, by simultaneously applying liquid to both of the calipers 84, the pistons 85, which are oppositely disposed, are moved toward each other to clamp the rotary disk therebetween. However, each of the calipers 84 is separate so that each of the pistons 85 must be removed from its caliper 84 separately.

In carrying out the method of the present invention with each of the calipers 84, the caliper 84 is first removed from the vehicle and is cleaned. Next, the hose 36 is connected to the fitting of the caliper 84 through one of the

connectors

61 or 62. The caliper 84 is then placed within the collection or drain pan 60.

Thereafter, the method is the same as that described for the caliper 81. This results in the piston 85 being removed from the caliper 84.

An advantage of this invention is that it reduces the time to remove the pistons ofa power disk brake from the caliper for overhaul. Another advantage of this invention is that it decreases the cost of overhauling a power disk brake.

For purposes of exemplification, particular embodiments of the invention has been shown and described according to the best present understanding thereof. However, it will be apparent that changes and modifications in the arrangement and construction of the parts thereof may be resorted to without departing from the spirit and scope of the invention.

What is claimed is:

l. The method of removing a piston from within a disk brake caliper of a vehicle, the method including first removing the caliper from the vehicle, supplying liquid under pressure from an external source to the caliper to act, directly upon said piston, so that said piston can respond to said pressure and increasing the pressure of the liquid on the piston until the piston is removed from the caliper.

2. The method according to claim 1 in which any air is bled from the liquid lines in the caliper when liquid is initially supplied thereto.

3. A method for removing each of a plurality of liquid connected pistons from a caliper in which the pistons are slidably mounted, the method including supplying liquid under pressure to the caliper to act on all of the pistons, holding all of the pistons but one of the pistons so that only the one piston can respond to the liquid pressure applied to all of the pistons, and increasing the pressure of the liquid acting on the pistons until the one piston is removed from the caliper.

4. The method according to claim 3 in which any air is bled from the liquid lines in the caliper when liquid is initially supplied thereto.

5. The method according to claim 3 in which the caliper has a pair of oppositely disposed pistons slidably mounted therein.

6. The method according to claim 3 in which the caliper has two pairs of oppositely disposed pistons slidably mounted therein.

7. A including for removing from a caliper at least one pair of oppositely facing pistons that are liquid connected to each other comprisingv means to lock all but one of the pistons within the caliper in a retracted position, means to supply liquid pressure to all of the pistons, and said supply means including means to increase the liquid pressure until the one piston is forced from the caliper.

8. The device according to claim 7 in which the caliper has two pairs of oppositely disposed pistons slidably mounted therein.

9. The device according to claim 7 including means to support the caliper.

10. The device according to claim 7 in which said supply means includes a liquid reservoir, means connecting said liquid reservoir to the caliper, and means to pump the liquid from said reservoir through said connecting means to the caliper.

11. The device according to claim 10in which said connecting means includes a check valve to prevent reverse flow of liquid to said reservoir.

12. The device according to claim 10 including means to support said liquid reservoir and the caliper thereon.

13. The device according to claim 12 including means mounted on said support means beneath the caliper to collect any liquid from the caliper.

14. The device according to claim 11 in which said pumping means includes a piston slidably mounted in said reservoir and means to actuate said piston.

15. The device according to claim 12 in which said pumping means includes a piston slidably mounted in said reservoir and means pivotally mounted on said support means to actuate said piston.

Claims

1. The method of removing a piston from within a disk brake caliper of a vehicle, the method including first removing the caliper from the vehicle, supplying liquid under pressure from an external source to the caliper to act, directly upon said piston, so that said piston can respond to said pressure and increasing the pressure of the liquid on the piston until the piston is removed from the caliper.

7. A device for removing from a caliper at least one pair of oppositely facing pistons that are liquid connected to each other comprising means to lock all but one of the pistons within the caliper in a retracted position, means to supply liquid pressure to all of the pistons, and said supply means including means to increase the liquid pressure until the one piston is forced from the caliper.

9. The device according to claim 7 including means to support the caliper.

11. The device according to claim 10 in which said connecting means includes a check valve to prevent reverse flow of liquid to said reservoir.