Brake Problem

[GOTROCKS]

I have an 87' Zuk that I am having problems with bleeding the brakes on.  I have read a bunch of other posts on this but none of them seem to answer my questions.

I had to pull my rear axle apart to replace my axle housing so I removed the brake lines and strung them up on the right side to hopefully keep from draining all the brake fluid on the ground.

So when I put it all back together I bleed the brakes and the Left Rear and Right front go fine and when you push on the pedal those 2 brakes seem to work. (cant turn the wheel)  The Left Front and the Right Rear will not bleed though.  I have speed bleeders on all four wheels but cannot get any fluid or air out of those 2 brakes.  I tried gravity bleeding and I can get fluid out of both of them that way but still will not pressure bleed. 

I read some stuff about bleeding the P-valve.  How do you do that?

Should I try gravity bleeding for longer to see if I can get the air out that way?

By the way.... My brakes worked great before taking everything apart.

Thanks for any help.

[Scott410]

I would try to gravity bleeding again, if you can get your hands on a vacuum bleeder it would really help you out, also make sure that you are doing it in order. I had a similar problem, I just keep bleeding and it finally got whatever air was trapped out. Good luck.

[Reaney in NH]

I have an 87' Zuk that I am having problems with bleeding the brakes on.  I have read a bunch of other posts on this but none of them seem to answer my questions.

I had to pull my rear axle apart to replace my axle housing so I removed the brake lines and strung them up on the right side to hopefully keep from draining all the brake fluid on the ground.

So when I put it all back together I bleed the brakes and the Left Rear and Right front go fine and when you push on the pedal those 2 brakes seem to work. (cant turn the wheel)  The Left Front and the Right Rear will not bleed though.  I have speed bleeders on all four wheels but cannot get any fluid or air out of those 2 brakes.  I tried gravity bleeding and I can get fluid out of both of them that way but still will not pressure bleed. 

I read some stuff about bleeding the P-valve.  How do you do that?

Should I try gravity bleeding for longer to see if I can get the air out that way?

By the way.... My brakes worked great before taking everything apart.

Thanks for any help.

    Sounds like your propertioning valve is stuck... Sammies have a criss cross braking system. Try tapping the prop valve with a hammer and hopefully it will pop back to center.
     A Vacuem bleeder would help too.
     Good Luck
     Reaney in NH

[Surly]

I read some stuff about bleeding the P-valve.  How do you do that?

Only the pre-88.5 Zuks had the P-valve with the bleeder. You just bleed it like it were another wheel cylinder. HTH

[GOTROCKS]

Only the pre-88.5 Zuks had the P-valve with the bleeder. You just bleed it like it were another wheel cylinder. HTH

My wheel cylinders have bleeders on them.  The proportioning valve does not.  How do you bleed it without having a bleeder valve on it?

[Biggerhammer]

I believe the 87's prop valve had a check valve in it. incase one of the wheel cylinders failed it wouldn't let fluid past it. A vacumn bleeder will help in the long run. You will just have to keep bleeding them till the prop vale's check valve get's fluid past it. HTH


Try tapping it lightly with a hammer while someone is pressing the brake pedal.

[phoenix827]

Not to hijack, but it's related. Anyone know why sometimes when I hit the brake pedal I have almost nothing there? If a get off it and right back on, (one pump) it stops fine, just that first pump is almost no pedal. Most times they are fine, but every once in a while,,, M/C going?

[86badboy]

probably needs a rebuuild, does it lose fluid?

[GOTROCKS]

OK..... Can I have my thread back now  

Does anyone know how to rebuild and/or bleed the fluid from a P-valve?

Thank You

[86badboy]

yours is an 87, so it should have a bleeder valve on it... then u bleed it like it normaly

u may need to take a wire brush up there to find it, mine was kinda a pita to find with all the mud

[phoenix827]

probably needs a rebuuild, does it lose fluid?

no, and I will be quiet now.

[GOTROCKS]

yours is an 87, so it should have a bleeder valve on it... then u bleed it like it normaly

u may need to take a wire brush up there to find it, mine was kinda a pita to find with all the mud

I dont go muddin so I can actually see mine without using a wire brush.   I'll look again but I am almost positive that there is not a bleeder valve on the P-valve.

[samilitant]

I have an 88 1/2--here's my prop. valve, or so I think.  Just took the pic for my thread so I had it handy;

[86badboy]

maybe this will help, should be in the same spot for you according to fsm for an 87

[Agent K]

Proportioning valve on an '87...








I don't see a bleeder valve 

[86badboy]

i have an 86 an it looks the same...but when i did my brakes i asked my dad if he bled the prop valve and he said yes

the fsm shows one for my 86 in the same spot as my last post is the fsm wrong and there isnt one on the86 and 87

we need a pro. to step forward

im really confused now

[GOTROCKS]

Mine is definatly the one in the second set of pics.  The one without the bleeder valve.  Can anyone give any info on how to bleed one of those.

[wheresmyhat]

bleed it like a master cylinder. just crack one line at a time.   Pump the peddle and hold it down.  crack the line, close the line and repeat

[86badboy]

that makes more sense

[GOTROCKS]

AAAAAHHHHHHHH..... Thank you.  I'll try that tommorrow.  I'm also gonna take off the lines from the P-valve back and blow them out with air to make sure they are not clogged.

[Bad Zuk]

As for a vacuum bleeder I made my own redneck style.  I took an old bucket with a lid and cut 2 holes in it, one for the shop vac hose and one for a 3' section of vacuum line.  Slide the vacuum line over the bleeder and turn on the vacuum, and make sure the reservoir is full.  You can assist things by pumping the brakes while they are under vacuum.

[GOTROCKS]

OK.... Finally found the problem.  One of the two springs inside the master cylinder were stuck in the compressed position.  This was preventing the actuating rod from being pushed all the way back out so one of the chambers of the master cylinder was doing nothing.  This was actually really weird cause on the last trip I went on, I didnt have any problems with my brakes.

When I pulled the master cylinder apart I discovered that the screw that secures the spring that was stuck compressed was backed out some and the spring flange was stuck on the threads of the screw.  When I pulled the screw out I found that about half of the threads looked as if they had at some time been cross threaded. (I have never had my master cylinder apart, must have been the previous owner).  So instead of testing fate as to whether or not it would happen again, I just replaced the master cylinder with a remanufauctured unit. (Reman Master Cylinder was $40.00, Rebuild kit for master cylinder was almost $400.00, Can you say RETARDED).

Well its all good now.  Thanks to everyone that helped with info.