Am I doing it wrong? (Bleeding brakes 81')

[Narnian]

Me and a buddy tried bleeding my brakes yesterday after hooking up the last tube
Ralph left for me. We got the brakes feeling mostly OK - just a hair mushy - BUT
the "BRAKES" light on the dashboard would not go out. So, we did the thing guys do
last - we pulled out the service manual and read the section on bleeding brakes. It said
that there is a button on the proportioning valve that must be held in while the
brakes get bled.

I found the button and pressed it, and viola! the light on the dashboard went out.
Unfortunately, the brakes got noticeably mushy after that. So we clamped the button
down, and went around all four and bled them again. Now the pedal is mushy
enough to go to the floor. We were wore out, so we turned in for the evening.

If I get through my chores I might try again tonight. Do I need to clamp this button
down like the book sez, or is that only under special cirumstances?

[ August 04, 2002, 07:59 AM: Message edited by: Narnian ]

[irbob]

Narnian...i've never heard of such a beast. (button on the proportioning valve) What vehicle are you doing this on. Usually you just start at the furthest wheel away from the resurvor and I like to let the fluid flow until I see the clean stuff coming out. I also use a Mitty-Vac pump to bleed the system instead of the "pump the pedal" method. I remove all the fluid from the resurvor first, clean it out and put fresh fluid in first. It may be a little over-kill but that's just how I do it. Wish I knew mor about that button. Have a pic of it or can you tell me exactly where it is?

[joe]

That button on the prop valve does need to be held in during bleeding(or extended out depending on what type of prop valve you have).
You've still got air in the system if the brakes are mushy. Are you bleeding each cyl(farthest from master first) till the fluid runs clear w/no air bubbles? Are you closing the bleed nipple while the pedal is still down? Are you making sure the fluid level stays high enough in the master so you don't suck more air in? If you're doing all of the above just keep at it... smile.gif

[Narnian]

I think my problem may be that I'm not closing the bleed nipple fast enough. I kept waiting till my buddy said "It's down!" to tighten it up. I probably should have been closing it when the stream began to slow.

I'll have to work harder at getting my chores done today, then try again. I have an 81 cherokee, and my manual is for the 84 wagoneer. I am assuming they both have the bitty button designed to go in, since the valve I have looks like the drawing in the book. So I'll put my clamp on it again joe.

Bob, I think you are on to something here. I called Autozone asking if they had a self bleeding system so I could do this without bugging my buddy. The girl thought I was nuts and claimed there was no such thing. But after reading your post, I just remembered the MityVac thingy I bought from them last fall to test the vacuum system on my intake manifold. I'm almost positive it had instructions with it for bleeding the brakes the way you describe. I shoulda been using it yesterday. I'll have to go dig it out of the shed.

[joe]

Narnian, I second the "get a MityVac" idea. Not only are they great for single handedly bleeding brakes, clucthe cyl's but are super handy for testing and trouble shooting all the vac stuff on these rigs. Shop around though. They sell anywhere from about $30-$60 depending on who's selling them.

[chrisnsarah]

the mityvac works great but you have to make sure it's not sucking air bubbles from around the bleeder screws. This will give you a false idea that the brakes still need bleeding and you'll be pumping forever. This happens mostly on large bleeder screws like the front calipers. I used to put vaseline around the screw and that helps a little while I'm bleeding (the brakes).
You have to hold the valve open the entire time you're bleeding. You can make a bracket like the one the manual shows.

[dnixon]

There is an article in the tech section on how to make the tool here is the link to it:

Brake Proportioning Valve Tool (http://www.ifsja.org/tech/brakes/brakevalvetool.shtml)

[billyrb]

Ok, guys, I'll shed a little light on a secret I have known for about two years now....used on many racing circuits:
www.speedbleeders.com (http://www.speedbleeders.com)

They have their own backflow preventers built in, and you can bleed the brakes all by your little lonesome self, and do a kick-tail job. The only thing you need to worry about it the button on the proportioning valve.....

Hope this helps.
~ryan

[Ralph]

Am I doing it wrong? (Bleeding brakes 81') I used to put vaseline around the screw and that helps a little while I'm bleeding (the brakes).
Um, I think Narnian knows that you meant by that. He reeeeeeealllly loves his Jeep!

[ August 04, 2002, 10:02 AM: Message edited by: Ralph ]

[dnixon]

that link wouldn't work but when i took out the "s" it worked just fine.. thanks for the good tip.

Speed Bleeder (http://www.speedbleeder.com/)

[dnixon]

Hey Billyrb,
For that speed bleeding system, which ones did you use. Did you use the Cherokee 77-97? I assume this is would be applicable to a 83 Wag? Thanks in advance!

[BIG BAD JON]

Well, I attempted to bleed the brakes on my '86 GW and, after I was done, I didnt notice any brake light come on, but I did notice that there was plenty of air still left in the line. :rolleyes: :D

[dnixon]

Not being able to stop just adds a little more excietment to your life.. Isn't it nice hitting the brakes and just not stopping. haha... good times...

[Thomas DeBusk]

Well, I've used my MityVac and I've done it the old-fashioned way with a tube in a jar. And I've never been able to get a nice, firm pedal like other people seem to get. Doesn't seem to matter how much I bleed, or when I shut off the screw.

Is this from air leaking back in around the screw? If so, how do I fix that? I've been through whole bottles of fluid and still have that spongy feel. Or does this have something to do with proportioning valves. I've never fooled with any proportioning valves when I've bled brakes. Is this a Jeep peculiarity, or do other vehicles have this thing that needs to be pressed while bleeding?

Thomas

[ August 04, 2002, 08:28 PM: Message edited by: Thomas DeBusk ]

[BostonWagoneer]

Make sure that the caliper bleeder screws are on the top. Sometimes the calipers can get mixed up and you put the wrong side on.

Does it take that much more effort to type out "says" instead of "sez"? tongue.gif

[Narnian]

OK, so now we sing the song that we sing when someone does something REEEEAAAALLLY boneheaded.

Basically, I had been loosening the front hoses from the calipers and trying to bleed from those big nuts. My bleeder valves were covered in mud and camo'd. I didn't find them till Ralph told me where to dig. Soon as I found them, it was easy to get good firm brakes by using the MityVac. Well, not easy - I had to replace both bleeder valves, but overall not so tough either.

Thanks for the help folks. Now you get to sing your song.

[joe]

Originally posted by Thomas DeBusk:
I've never fooled with any proportioning valves when I've bled brakes. Is this a Jeep peculiarity, or do other vehicles have this thing that needs to be pressed while bleeding?

ThomasSo far as I know any car with disc brakes/prop valves have the button. At least all mine have had them. One's an innie and ones an outtie depending on if it's a D or W type prop valve which I think are the only two types used on US rigs?.
Bob may have gotten away with not dealing with the button because of using the vac pump because just maybe since the fluid is being sucked through the valve rather than being bushed through conventionally the button doesn't need to be held in/out?
I know in the past bleeding brakes conventionally I had to operate the button. When using the vac pump I've also held the button in because of habit but maybe that's not needed if using the pump and drawing the juice through it? I'm gonna try it w/o operating the button next time I use the vac pump and see what happens.