Brake problems!!! ASAP

Posted: Sun Apr 27, 2008 9:13 pm Post subject: Brake problems!!! ASAP

I have got my wonderful 4age running Very Happy

Megasquirt RockS!! but i have a biggie problem .. i have bleeded the brakes so there is no air in the lines..

but i can not brake properly. it almost doesnt take at all and only at the bottom when i press the pedal... what can this be? help..

i have taken the boost vacuum thing.. apart from the brake master cylinder.. (i did not change the seal).. cud this be?

Posted: Sun Apr 27, 2008 9:46 pm Post subject:

yes it needs the vaccum

Posted: Sun Apr 27, 2008 9:57 pm Post subject:

You probably didnt bleed the brakes properly, or maybe destroyed the seals in your master cilinder during the bleeding (not very likely though).
If your master cilinder was empty of fluid, you'll need to bench-bleed it first to get all the air out.

Posted: Sun Apr 27, 2008 10:11 pm Post subject:

no air in system.. how do i bleed the master cylinder? Very Happy

Posted: Mon Apr 28, 2008 1:26 am Post subject:

Put it on the vice, same position as in car but the hole facing to you, put one some brake fluid on it, lets say 1/4 of the reservoir, make sure it wont run out while doing this.

1- Press the brake master cylinder (use some screw driver).

2- Put your free thumb on the holes in the upper side (F/R) as you release the the BMC. The idea is to dont let in any air as you release it.

3- Repeat the process a few times for both upper holes, till a big amount of fluid comes out fast like an eruption (if you´re working inside a building, it will probably hit the roof) when you press the MBC. Cover the hole again and release the MBC. When this appens, the bleed is done.

IMPORTANT: KEEP YOUR FACE AWAY of the upper side of the bmc IN ANY STEP OF THE PROCESS. In the last step dont even try to look at the holes too close. When the fluid is comming out its MANDATORY to stay away, and you dont know when its gonna be, happens when it needs too. Its a simple but bit dangerous process. If you can, use eye protection.

Posted: Mon Apr 28, 2008 6:47 pm Post subject:

If you want to do it properly, get some old bits of brakeline with fittings, screw the fittings onto the master cilinder and loop the lines back into the reservoir. Then you just keep gently pressing the piston in until you see absolutely zero bubbles zoming out of the lines. It takes quite some time for all the air to come out after the master cilinder has been empty of brake fluid.

Posted: Wed Apr 30, 2008 11:47 am Post subject:

My garage roof knows the taste of brake fluid... Cool

Ryousuke Joined: 30 Mar 2008 Posts: 125

Make sure you have enough vacuum for the booster.

Posted: Sat May 10, 2008 12:19 am Post subject:

An easy-bleed system that works on air pressure is also a good idea.. makes it easy to just stare at the fluid coming out of the bleed nipples untill you see absolutely no more air. You'd be surprised how long it can take some bubbles to show themselves.

Brake booster vacuum should not hinder braking force, it would only make it a lot more difficult to apply force to the brakes (you really have to stomp the pedal to get the car to brake decently, but you wont be pressing the pedal to the floor).

Posted: Sat May 10, 2008 7:24 pm Post subject:

Do you fit vacuum line to the booster properly, INCLUDING one-way plastic valve ?