proportioning valve

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I replaced all brake lines on my CJ

how does one bleed the proportioning valve ('79 CJ5)?
(it pretty much drained when I cut the old lines off)

thanks,
Ron


Re: proportioning valve
Very carefully....

There is a special tool made for holding the pin in the end of the valve
from moving when you are bleeding.  If this pin pops out (or in
depending on the version), it can block off the flow to one set of
brakes (rears usually) so no fluid will come out.

Sometimes starting with a plain gravity bleed does the trick, just open
all 4 bleeders and keep the master full until you have fluid coming from
all 4 corners.

You can then try a conventional bleed starting at the back corner and if
you are real lucky it will work.

I just replaced all my lines and bleeding didn't work, my valve popped
and the rears shut down, no fluid flow.

I had to have someone then pump up the brake pedal really hard and hold
it down while I opened a front bleeder.  This allowed the valve to pop
back the other way because it was then trying to shut off the front
fluid flow thinking ther was a leak.  After that I had no problems bleeding.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00
'New' frame and everything else in '09.  Some Canadian Bush Trip and
Build Photos: http://mikeromainjeeptrips.shutterfly.com

csdude wrote:
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Re: proportioning valve
I saw the tool online in a few places. (there must be something
terribly expensive hidden in the plastic end of that tool, to make it
that expensive ($30+)

ah, that's how the thing works. I thought the valve, when depressed,
bypasses the proportioning part, send the same pressure to all
outgoing ports and bleed the air out?

I try and hunt down the tool and try to gravity bleed the brakes

thanks,

Ron

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Re: proportioning valve
csdude wrote:
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Usually you bench bleed the proportioning valve, but you can do it
in the vehicle.  Just run two lines from the output back up to the
reservoir. Then bleed away, both sides will bleed so the valve
won't move.  That get most of the air out.

Then go after the lines (there will be a bit of air get back into
the proportioning valve, but it's insigificant.

http://www.thefind.com/cars/info-proportioning-valve-depressor
Sometimes it just takes a penny and a small clamp.

Start here then go to the "brake dancing" article.
http://www.gnttype.org/techarea/brakes/prop.html


--
DougW



Re: proportioning valve
Hi Doug,

I didn't replace the proportioning valve, I just took it out by
cutting the lines, cleaned it, attached the new lines that go to the
master cylinder and put it back in.
(It didn't look too bad at all, wiped it off with some brak cleaner
and it looks as good as new.)

I have actually been thinking that if the tool is that expensive or
hard to find, that I can probably keep the little pin depressed with a
c-clamp or so. (the tool looks much easier though)

I read somewhere that when bleeding brakes you always need to depress
that proportioning valve ?


Uhm, btw...   a "little air" in the brake system would me make me "a
little" nervous

thanks,

Ron



wrote:
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Re: proportioning valve
Does the  pop in or out depend on the type ?   I read there's a 'W"
and a 'D' type used in those years.  Does the W type pop out and the D
type in ?  Or the other way around ?

thanks,

Ron



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Re: proportioning valve
I would Highly recommend you get yourself the Haynes CJ manual, it isn't
expensive and it covers most repairs really well including the brake
bleeding sequence.

I have only seen the prop valves that pop out and the one that has 'no'
pin, I haven't seen the one that pops in yet and do not know which types
they are called.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00
'New' frame and everything else in '09.  Some Canadian Bush Trip and
Build Photos: http://mikeromainjeeptrips.shutterfly.com

csdude wrote:
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