help quick! new brake system wont firm up! - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

Reply
 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 07-04-2002, 01:56 PM Thread Starter
 
Join Date: Oct 2000
Posts: 609
Thanks: 0
Thanked 0 Times in 0 Posts
 
help quick! new brake system wont firm up!

I am having a fit with my brakes today. I put in all new premade lines from autozone. New stainless flex lines. Everything new as far as drums and discs. New adjustible proportioning valve. Used power booster and master from a junkyard.

The rear brakes seem like they blead ok. The fronts are giving me fits. I am getting way to many air bubbles. I have tried both the pumping and the gavity bleeding techinics. Nothing seems to be leaking. So i have a few questions:
1) Why is this happening?
2) How do i tell if the master is bad?
3) I have a washer between the flex hose and the caliper where the banjo bolt is. Should that be there?

Whats the deal any help is greatly appreciated. Happy forth- Tim
3)
timCsjeep is offline  
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 07-04-2002, 02:01 PM
Mud in my Veins
 
Caver Dave's Avatar
 
Join Date: Apr 2000
Location: Winston-Salem, NC
Posts: 5,512
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: help quick! new brake system wont firm up!

Did you "bench bleed" the MC? If it was a junkyard item and had been drained, you'll likely have to get all the air out of the MC before it'll do anything.
Caver Dave is offline  
post #3 of (permalink) Old 07-04-2002, 04:25 PM Thread Starter
 
Join Date: Oct 2000
Posts: 609
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: help quick! new brake system wont firm up!

yeah i bench bleed the master.

I have been working on them all afternoon and i think i finally have it. Is it possible to get air in the system through the bleeder screw? I only opened them up about half a turn but it looks like i was getting air through them. I am i making this up? [img]images/icons/smile.gif[/img]- Tim
timCsjeep is offline  
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 07-04-2002, 05:02 PM
Way Outta Control
 
Join Date: Sep 1999
Location: The Palouse
Posts: 13,432
Thanks: 1
Thanked 3 Times in 3 Posts
 
Re: help quick! new brake system wont firm up!

Tim, yes it is possible to get air back through the bleeder screw if it's not tightened down correctly.

Every time you attempt to evacuate the line the siphon effect will draw air back into the line if the screw's not tightened back down. It doesn't take much to have that air sucked into the line.

The screw should be tight each time before you let up on the pedal, if you're using the pedal to pressurize the line. Then repeat the process.

Let's go over some basics for whoo ever may be reading this post:

Bench bleeding is nothing more than creating a hydraulic system on your bench and gettin' the air out before the master cylinder is put in the Jeep. Here's the steps:

1. Mount the master cylinder in a vise
2. Install sections of brake line on the MC.
3. Bend the lines back into each respective reservoir.
4. Fill the reservoir with brake fluid so it covers the lines in step 2.
5. Pump the piston until air bubbles no longer form in the fluid.
6. You're done...

Now for the rest of the system... Here's how I bled my CJ brakes before I bought a wonder tool called a "Mighty Vac" pump and gauge.

Do the breaks in the following order:

1. Passenger side Rear Wheel.
2. Driver side Rear Wheel.
3. Passenger side Front Wheel.
4. Drivers Side Front Wheel.

Steps to be taken on each of the above steps:

1. Open the bleeder screw and attach a clear line from the bleeder screw into a jar. You want to see what's coming out!
2. Top off the master cylinder.
3. Have a buddy slowly depress the brake pedal.
4. When the pedal reaches the floor close the bleeder screw.
5. Release the pedal.
6. Reopen the bleeder screw.
7. Reapply pressure to the brake pedal.
8. Continue steps 1-7 untill you see a constant flow of fluid with no air coming out of the bleeder screw.

When the Passenger Side Rear wheel line has been bled, do each of the other lines in turn. When no air is trapped in the lines you're done and the brakes should NOT be spongy, but firm when the pedal is depressed.
LEVE is offline  
post #5 of (permalink) Old 07-05-2002, 09:53 AM Thread Starter
 
Join Date: Oct 2000
Posts: 609
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: help quick! new brake system wont firm up!

leve- I was doing exactly what your directions said to do yesterday. And here is where i am at now: I no longer get air out of the bleeder screws (I gave it 10-15 pumps after i saw the last air bubble) But my pedal still refuses to firm up. I guess that means i still have air in the system right?
timCsjeep is offline  
post #6 of (permalink) Old 07-05-2002, 09:58 AM
Way Outta Control
 
Join Date: Sep 1999
Location: The Palouse
Posts: 13,432
Thanks: 1
Thanked 3 Times in 3 Posts
 
Re: help quick! new brake system wont firm up!

Yep... it's time for a MightyVac pump. Pardon the pun.. but let that little sucker do the work for you!
LEVE is offline  
post #7 of (permalink) Old 07-05-2002, 10:49 AM
 
Join Date: May 2001
Posts: 1,271
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: help quick! new brake system wont firm up!

While Leve's information is concise and correct, as usual, I might also suggest trying a gravity bleed for about 20 minutes. While you're at it pull the calipers and "burp" them (i.e. take caliper off mount, make sure the open bleeders are at the top most part of the caliper and let them drain, may need to roll it around as you open bleeder).

Do a search on gravity bleed, been talked about lots o times.
bluseman2a is offline  
post #8 of (permalink) Old 07-05-2002, 01:56 PM
 
Join Date: Oct 2000
Posts: 2,001
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: help quick! new brake system wont firm up!

did you adjust the rear adjusters?
that would make a bit of difference [img]images/icons/smile.gif[/img]
glad to hear you have a new jeep going for you.
JoeyCJ55 is offline  
post #9 of (permalink) Old 07-05-2002, 04:08 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: help quick! new brake system wont firm up!

Good point Joey, I would also like to point out that the rear drivers side should be done before the passenger's cause it is actually further from the M/C. Not as the crow fly's but by the lenghth of brake lines.
post #10 of (permalink) Old 07-05-2002, 06:53 PM Thread Starter
 
Join Date: Oct 2000
Posts: 609
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: help quick! new brake system wont firm up!

just so i get this straight: NOBODY THINKS MY MC IS BAD???[img]images/icons/smile.gif[/img]

joey- no i havent touched the rear adjusters. I was under the impression they were self adjusting. What will adjusting them do for me?

blues- I already tried the gravity bleed for about 20 min on each caliper. Thanks- Tim
timCsjeep is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome