vacuum connection for brake booster

[Eugene at Pelican Parts]

My booster isn't working correctly and I believe the vacuum line is not connected properly. Can somebody please tell or show me where the line should be connected in the engine compartment? The first half of the pedal travel feels like a wet sponge while the rest is hard as a brick. Please help! Thanks.

[ChrisBennet]

Let me guess, you just did something with your brake pads? I've seen this before on 2 piston calipers. It happens if you push the pistons all the way back in their bores to put pads in.
-Chris

[BGCarrera32]

To test your booster, step hard on the brake pedal with the engine off. Now crank engine and start car. Pedal should sink slightly after engine vacuum comes on.

[Eugene at Pelican Parts]

Originally posted by ChrisBennet
Let me guess, you just did something with your brake pads? I've seen this before on 2 piston calipers. It happens if you push the pistons all the way back in their bores to put pads in.
-Chris

Actually no. All I did was bleed the brakes and change to steel braided hoses while the motor was out. I only went through about half a can of ATE blue. Although I thought I reconnected the engine bay vacuum hose correctly, that is my only suspect since I didn't touch anything else. Could I have somehow damaged the booster?

[BGCarrera32]

Could I have somehow damaged the booster?

Highly unlikely...

Sorry I can't be of more help on the connection...I'm a Carrera guy...

[Eugene at Pelican Parts]

burp (excuse me)

[Al S]

To answer your question, the brake booster vacuum line connects to a black plastic "Y" shaped device (vacuum amplifier) approx 75mm long, which is in turn connected to a ~10mm dia. metallic "U" tube, on the left side of the throttle body. The brake booster line should be connected to the "branch" of the "Y" that is off to the side. Confused yet? Hope this helps.

[Eugene at Pelican Parts]

Thanks Al. Unfortunately, that's exactly where it is connected. Perhaps I have a leak and I will check for that tonight, but if those connections are solid, what could be the culprit? Where are the common points for brake booster failure?

[ruf-porsche]

Originally posted by AlwaysWong
The first half of the pedal travel feels like a wet sponge while the rest is hard as a brick. Please help! Thanks.

It sound as though you still have air in the lines. Try bleeding all the lines again, starting with the right rear brake, left rear brake, right front brake and finally left front brake.

[Eugene at Pelican Parts]

New question to bump. Where is the brake booster check valve?

According to Bentley, it is located within the engine compartment. I was just in there last night and I see no valve at all in my vacuum line. The description by Al below is dead on, and no mention of the check valve.

Originally posted by Al S
To answer your question, the brake booster vacuum line connects to a black plastic "Y" shaped device (vacuum amplifier) approx 75mm long, which is in turn connected to a ~10mm dia. metallic "U" tube, on the left side of the throttle body. The brake booster line should be connected to the "branch" of the "Y" that is off to the side. Confused yet? Hope this helps.

[Eugene at Pelican Parts]

Can I get a bump bump? Still can't find the check valve!

[RoninLB]

Originally posted by AlwaysWong
Still can't find the check valve!

the routine is for a check valve to be between the power booster and the vac line.. there is a rubber grommet that attaches the check valve to the booster.. check it out.. but I'm not AlwaysRight

[TurboBert]

Like Ronin says, the check valve plugs into the vacuum booster in line with the vacuum hose. It's number 29 in the picture.

[TurboBert]

Ronin,
There are lot of different ways to skin a cat(bert), but here are the steps I used:

1. In the application, hit the Print Screen Key. (this copies the screen image)

2. Open Microsoft Paint, and paste the image (click Edit and then Paste or use Ctrl+v keys).

3. The image will probably be much bigger than you want (you can't have an image greater than 100Kb - this is where most people probably have problems). I used the Paint Crop command to select the area to cut it from the image and then I paste it into a new session before saving it. [refer to Paint Help to learn how to crop if you aren't familiar with this]

4. Save the file as a .jpg format (click on Save As box and choose .jpg format, as shown below)

5. Next, click on the Attach Multiple text.

6. Use the Browse button to locate the .jpg file that you created in step 4, then press the Upload button.

7. If the upload is completed successfully, you will see some text (script) get written in your reply. Don't change the text (but it's OK to move it so long as you change none of the letters).

I know this is probably overkill with the explanation, but maybe it will help others on the board. Good luck.

[maxnine11]

thanks TurboBert !! ( and my girlfriend for showing me the "print screen" button is on the keyboard) i have been printing out the illustrations, then scanning them. DOOHH!! i now have seen the light. Sometimes being self-taught means you have a dumb teacher
max