Vacuum Switching Valve Question

[mzdafrk]

I am loosing brake pressure, and I am getting a CLicking sound when I press on the brakes. The sound is coming fromt he Vacuum Switching Valve located by the VAF Sensor.

Any Ideas why, and while I am at it, what does the Valve do exactly?

[assassin10000]

mzdafrk Wrote:I am loosing brake pressure, and I am getting a CLicking sound when I press on the brakes. The sound is coming fromt he Vacuum Switching Valve located by the VAF Sensor.

Any Ideas why, and while I am at it, what does the Valve do exactly?

That valve near the MAF sensor is the IDLE up VSV. When you activiate ANY electrical load (IE: brake lights) it will click on. This is completely normal. Ignore it.

The brake pressure loss is a problem.
Is it a soft/spongy pedal that is the problem?
Are you loosing fluid?
Does it drop towards to floor?

Andrew

[mzdafrk]

thanks for the explanation.

It was just the master cylinder, replaced it this morning, and all is better, just took some time and bleed all the brakes really well, and I have better brakes than I ever had before.

It was weird, it didn't act like a blown master cylinder, but I was loosing brake fluid, so It had to be the master or a leak. But couldn't find fluid anywhere on or under the car. So went for the $25 shot in the dark and it worked, I was leaning more towards the Booster. At least it is fixed, and I can stop again.

[assassin10000]

mzdafrk Wrote:thanks for the explanation.

It was just the master cylinder, replaced it this morning, and all is better, just took some time and bleed all the brakes really well, and I have better brakes than I ever had before.

It was weird, it didn't act like a blown master cylinder, but I was loosing brake fluid, so It had to be the master or a leak. But couldn't find fluid anywhere on or under the car. So went for the $25 shot in the dark and it worked, I was leaning more towards the Booster. At least it is fixed, and I can stop again.

If it was loosing fluid you should have been able to find the leak. Or it was leaking out the rear of the M/C into the brake booster... was it wet there?

Andrew

[mzdafrk]

I couldn't find the fluid anywhere., but I am assuming that it was leaking into the Booster, the floor board and firewall were not wet. That is why it had me so confused, but I think maybe I was over analyzing the situation...lol.

[evfan42]

I had a simillar problem but with the clutch master cyldiner... replaced the master cylinder and it worked fine

[mzdafrk]

Yeah same here, when we replaced the Master, and did a very thorough Bleed job, I have brakes better than when I got the car. It is nice, And when I talked with my buddy he said that there was a little fluid in the master.