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Brake Pedal Position Switch Replacement
 
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Pelican Technical Article:

Brake Pedal Position Switch Replacement

Nick Czerula

Time:

1.5 hours

Tab:

$35

Talent:

**

Tools:

Pick, DVOM

Applicable Models:

Volvo V70 (1998-01)
Volvo V70 2.4T (2001)
Volvo V70 AWD (1998-99)
Volvo V70 GLT (1998-00)
Volvo V70 GLT SE (2000)
Volvo V70 R (1998)
Volvo V70 R AWD (1999-00)
Volvo V70 T5 (1998-01)
Volvo V70 X/C (2001)
Volvo V70 X/C AWD (1998-00)
Volvo V70 X/C AWD SE (2000)

Parts Required:

Brake light switch

Hot Tip:

Clean around switch, pump brake pedal to reduce booster vacuum

Performance Gain:

Repair faulty brake position switch

Complementary Modification:

Replace brake light bulbs

Service brakes on the Volvo V70 consist of brake calipers and rotors at the wheels. The brake master cylinder activates the calipers hydraulically. A vacuum assisted brake booster multiplies the braking force exerted by the driver at the brake pedal.

When you step on your brake pedal you are compressing a piston in your brake master cylinder and forcing brake fluid under pressure to activate a brake caliper at each wheel. The brake booster is mounted between the brake pedal and the master cylinder. It is supplied with engine vacuum and assists the driver in applying the brakes. The vacuum powering the booster is generated by the engine intake manifold and delivered to the brake booster via a line with one-way check-valve(s).

The large hollow metal brake booster housing contains a rubber diaphragm. When the brake pedal is applied, an air valve opens allowing atmospheric-pressure air to enter the supply chamber of the brake booster. When this valve opens, the diaphragm moves toward the low pressure (engine vacuum) side. This movement along with the driver input on the brake pedal pushes on the master cylinder piston. When no vacuum is present or the valve does not open, the brake pedal may remain hard and difficult to push.

Volvo V70 models are equipped with a brake pedal position switch, mounted in the vacuum brake booster. This switch measures the amount of brake pedal travel and sends this information to the brake control module. The switch can fail causing the fault code ECM-9400. If you have this fault code, you will likely need to replace the brake pedal position switch.

Remember that your car may have been serviced before and had parts replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability.

Our vehicle may vary slightly from yours as models do change and evolve, as they grow older. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

The brake pedal position switch is mounted in the right side of the brake booster (red arrow).
Figure 1

The brake pedal position switch is mounted in the right side of the brake booster (red arrow). Before beginning, pump the brake pedal to remove the vacuum from the brake booster.

Start by disconnecting the electrical connector by squeezing the wire release and pulling the connector straight off the switch.
Figure 2

Start by disconnecting the electrical connector by squeezing the wire release and pulling the connector straight off the switch.

Clean the surrounding area (red arrow).
Figure 3

Clean the surrounding area (red arrow). This prevents debris from falling into the brake booster.

Use a small hook pick to pull the circlip (green arrow) out of the top groove.
Figure 4

Use a small hook pick to pull the circlip (green arrow) out of the top groove. Allow it to rest outside of the groove.

Move to the bottom of the switch.
Figure 5

Move to the bottom of the switch. Use a small hook pick to pull the circlip (green arrow) out of the bottom groove. Allow it to rest outside of the groove. The circlip should stay attached to the booster and not fall out thanks to the square mount (yellow arrow).

Pull the switch straight out of the brake booster to remove it (red arrow).
Figure 6

Pull the switch straight out of the brake booster to remove it (red arrow).

This photo shows the brake pedal position switch removed.
Figure 7

This photo shows the brake pedal position switch removed. To install the new switch, reverse the removal steps. Be sure that the circlip is properly engaged.

To test the switch, check the resistance with the plunger extended.
Figure 8

To test the switch, check the resistance with the plunger extended. It should be over 3000 Ohms.

Then, check the resistance with the plunger compressed.
Figure 9

Then, check the resistance with the plunger compressed. The reading should change to about 200 Ohms.

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Comments and Suggestions:
carrot Comments: Could you advise on how to remove the clevis pin from a c30 brake pedal please?
June 11, 2015
  Followup from the Pelican Staff: The lock for the pin has to be release first. Inside the bracket for the pedal is a retainer, squeeze it inward then fold it up and remove it. Then slide the pin out. - Nick at Pelican Parts  

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