Help! My brake booster is not working correctly (or at all)

[ColdFlame53]

Hello everyone! So I just purchased a Festiva91GL about a week ago and at first I thought it just did not have power brakes but it does have a brake booster and all that good stuff but for some reason it is not working, theres some plugs around that area of the engine bay that are not plugged in but I'm not sure if thats the problem or not, does anyone have any experience or knowledge on this subject ?

[TorqueEffect]

There are three connectors by the coil that are supposed to be unhooked, they are test connectors.

Not a very intelligent design in my eyes because it looks sloppy.

[ColdFlame53]

Thanks you! Any advice on how to go about diagnosing the booster problem? my car has new brake pads and rotors

[jbibb1]

I had a festy once that was a bear to bring to a stop even though it had power brakes, after much investigation and new pads, which made no improvement, I found out that there was a wasps nest in the vacuum line to the brake booster. apparently some time before I got the car (it wasn't running when I got it) someone left the vac line off and the wasps made a home. After I took a wire and broke it all out and brakes worked great.

[bravekozak]

jb is correct First start by verifying that you have vacuum to the brake booster. That involves removing the hose at the manifold first. If it sucks there, put it back on and pull the other end of the hose off the booster and see if it sucks there as well. If it does, then use the search engine to see what great replacement boosters you can put on from other vehicles.

[Festy46]

The brake booster hose should have some preformed bends in it. If it is just an ordinary straight piece of hose, then you don't have a check valve in the hose and your brakes won't work correctly. Run the car at a fast idle for a minute and then shut it off. Remove the brake hose from the brake booster and you should hear the sound of air "hissing". If you don't hear air hissing (and have done bravekozak's check above), then you either have a hose with no check valve, a leaking check valve, or a leaking brake booster. You can verify if your hose has a check valve by squeezing the hose. There will be a hard lump in it about 3/4" long.

[jawbraeka]

if i can make a mention of a brake booster and cylinder upgrade if you are going to do some work to the beast in the future.. may i make the following suggestion:

moz came up with a great confirmed RHD combination which i'm sure will be a hit on the LHD's as well.

Protege Booster and Kia Rio cylinder. There is a thread for it in the forums somewhere.. just have a search.. also shortens the booster/cylinder length from the firewall and actually allows more brake pressure via the cylinder so i've been told..

[ColdFlame53]

Thank you soo much everybody! I just wired and got my Sunpro Tachometer working today! So tommorow I will have to do the tests you said to perform, bravekozak do i take the hose off while the car is running? Is that safe ?

[ColdFlame53]

Jawbraeka does that mean I must also replace the brake lines?

[bravekozak]

bravekozak do i take the hose off while the car is running? Is that safe ?

Yes. As long as the car is standing still, you do not need any vacuum for the brake booster to stop the car. I do a suck test to make sure the check valve is installed in the right direction. If you suck on the brake booster end of the hose, the check valve should be wide open. If you suck on the intake side of the hose, the check valve should be closed. The idea is that the vacuum builds up in the brake booster and remains there until you press on the brake pedal. If the engine vacuum drops when you step on the gas, the check valve closes and prevents vacuum from escaping the brake booster chamber.

[jawbraeka]

Jawbraeka does that mean I must also replace the brake lines?

Nope. the brake lines will be fine..

[defprun]

Someone screwed this up in my Festiva at some point! The hose was on right but the valve was the wrong way! Flipped the hose around and BOOM instant brakes.

Thanks Brave!

[jawbraeka]

In fact, using this setup will allow for better braking with less effort due to the different booster/cylinder combination. I hear the old one is 3/8" and the newer one allows more fluid into the lines quicker cause of the diameter of the cylinder.. The original lines will fit the new cylinder.

sent from the depths of hell.