new cylynders...brake pedal to the floor after bleeding...WTH? (real time) (1 Viewer)

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new cylinders...brake pedal to the floor after bleeding...WTH? (real time)

Hey guys,

Spent two long grueling days replacing all the wheel cylinders in my 72 FJ40....the brakes worked "OK" before I started but I had two leaky cylinders that were getting real bad so I went for it and ordered a full set.

I did the full research before starting this project...Everything is done as per Coolermans amazing web site with all brake cylinders in proper order + bleeding brakes ( Thanks Coolerman!!!)

After doing the full adjustment with all shoes slightly dragging on all wheels and correct bleeding sequence.....now I get a pedal to the floor with nothing...worse than when I started with leaky cylinders and shoes in need of adjustment.....I am assuming either I need to continue bleeding the back (front is bubble free...back was done as far as I could take it with a few tiny bubbles and no improvement after going through 2 whole big bottles of brake fluid) or # 2 = the MC has gone bad in the process....I'm getting bubbles escaping from the rear filler on the MC now as well....any help to determine what is faulty would be greatly appreciated....do I need to bleed more or has the MC gone bad?

Thanks in advance!!!
Ben
 
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I just went through this. If you didn't replace the MC then you shouldn't have to bleed it. The rear cylinders(if they are aftermarket) on all four wheels will need to be "burped" to get the trapped air bubble out. You will need to take the shoes off and remove the piston and get the rubber seal out, top off the cylinder with clean fluid, insert the rubber seal vertically into the cylinder and rotate it onto the spring so it sits horizontal. Then reinstall the piston and outer boot, then reinstall the shoes.
This should solve your issue unless your MC went bad.
:beer:
 
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I just went through this. If you didn't replace the MC then you shouldn't have to bleed it. The rear cylinders(if they are aftermarket) on all four wheels will need to be "burped" to get the trapped air bubble out. You will need to take the shoes off and remove the piston and get the rubber seal out, top off the cylinder with clean fluid, insert the rubber seal vertically into the cylinder and rotate it onto the spring so it sits horizontal. Then reinstall the piston and outer boot, then reinstall the shoes.
This should solve your issue unless your MC went bad.
:beer:

oh man...never would have guessed this....yes they are all aftermarket...just finished bleeding the MC and still have the same issue... although it is slightly better but not drivable...this has to happen on all four wheels? What a PITA!! I may be fighting this + the MC...after bleeding the MC I am still getting bubbles back up through the "rear" reservoir when the pedal is released......but not the front res.....could these bubbles still be from the cylinders needing to be burped?

thanks again for everyone's input and help...I really appreciate it!!!

Ben
 
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Adjust shoes with rims on. Make sure the wheel cyl are adjusted equally. If you adjusted the shoes with just the drums that is the problem.
 
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yep...they were all adjusted correctly with wheels on...even after bleeding they all have a nice slight drag when jacked up and the wheel is spun....
 
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"A nice slight drag" might not be tight enough. If they aren't tight enough, you'll never get the pedal off the floor.
They should be tightened until you can't turn the wheel and then backed off 2-3 clicks.
I'm always surprised at how much drag is "normal".
 
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I just went through this. If you didn't replace the MC then you shouldn't have to bleed it. The rear cylinders(if they are aftermarket) on all four wheels will need to be "burped" to get the trapped air bubble out. You will need to take the shoes off and remove the piston and get the rubber seal out, top off the cylinder with clean fluid, insert the rubber seal vertically into the cylinder and rotate it onto the spring so it sits horizontal. Then reinstall the piston and outer boot, then reinstall the shoes.
This should solve your issue unless your MC went bad.
:beer:

went thru this last week. you'll need to burp all the wheel cylinders. i found about 2 cubic inches in the front passenger rear wheel cylinder.......
 
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went thru this last week. you'll need to burp all the wheel cylinders. i found about 2 cubic inches in the front passenger rear wheel cylinder.......

There you go...2 who have had the burping issue....so do I need to actuate the pedal and bleed each again while everything is apart to "burp" the cylinder? Or is it just the simple act relieving the pressure off the cylinders that allows the air to finally escape? Please advise.

Thanks!
Benjamin
 
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SEARCH FUNCTION...WHAT A CONCEPT:hmm: :)...sorry guys.

After reading this post below... I may just have my OEM's rebuilt or buy new ones...this process seems like it will take twice as long as just replacing these POS cylinders!!!!!!! AGAIN!!!:mad:....

for the record I have CCOT on the back (bought last year) and cruiser corp on the front......the Corp one def seem better quality....the backs are definitely the problem...hoping I can leave the fronts in place.....any thoughts?

Courtesy of FJROSS..Thanks!:

Once again I'd like to thank the members for all there help. I just got done going thru a few weeks of brake repair that started out with the front discs locking up. This lead into flushing of the lines and replacement of the master, booster and wheel cylinders and brake lines. I believe that the brake lock up was do to crude in the brake fluid and the residual valve not relieving the pressure. After replacing all the components mentioned, I tried for a couple weeks to get a hard pedal with no luck. After isolating one item at a time it ended up being the rear wheel cylinders. The wheel cylinders I purchased were the economy models from CCOT since I plan on restoring the truck in the future. After weeks of bleeding and adjusting brake shoes, the culprit was air that was trapped in the rear cylinders. This air trapped in the rear cylinder gave you a pedal that would pump up. I myself thought that air would make the pedal soft all the time and not pump up, but not so. Awhile back Mud member hamm made me aware of a problem with CCOT cylinders and bleeding the air out of them. The method that we used was to remove the caps off the rear cylinders and push down the piston with a large c clamp vise grip to bleed the air out the tapped holes that are located below the high point of the wheel cylinder. This was done while pressure bleeding and bleeding thru the bleeder screws. This method did not work. It wasn't till member 65swb45 offered the method of disassembling the cylinder, removing the rubber seal and inserting it into the cylinder in the vertical position and then rotating it horizontal while being submerged in the fluid. While performing this you must have the drum on the opposite side of the truck and a clamp on the other wheel cylinder that you are trying to bleed. This is for you don't push the piston out of the other wheel cylinder as your working on the current one. While assembling the cap you want to be bleeding thru the bleeder screw to displace the fluid while inserting the cap into the cylinder. The CCOT cylinders are definitely different from the stock ones that were removed off the truck , The stock ones have a metal cap that has the seal on top of it as the ccot basically has a spring with just a rubber seal that causes a larger area to catch air. The absence of this cap may be the reason why the CCOT cylinders were such a pita to bleed. If it wasn't for 65swb45 and my mechanic's thrive to not let the drum brakes get the better of him, I don't think this problem would have been solved. Some may say that normal bleeding should have taken care of this problem, but not so. This system was pump bled, vacuum bled and pressure bled several times. I hope this may help others with the same ongoing problem.
 
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"The CCOT cylinders are definitely different from the stock ones that were removed off the truck , The stock ones have a metal cap that has the seal on top of it as the ccot basically has a spring with just a rubber seal that causes a larger area to catch air. The absence of this cap may be the reason why the CCOT cylinders were such a pita to bleed."


Hmmm, yeah, what he said. Did you take the OEM parts out of the OEM wheel cylinders and install into the new CCOT cylinders? :banana:

I did, it worked just like I was using the OEM ones. No bleeding issues. That was in 2006 and they are still working fine...:clap:
 
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This is true. There was no mention of replacement or draining the fluid out of the MC.

I never let it go dry...but I did bleed it last night just for kicks...still all the same issue were talking about here...bubbles still escaping from the "rear" MC reservoir when the pedal is pumped...makes sense if the rear cylinders have those trapped air bubbles...

Thanks again for your initial post and thoughts on the aftermarket cylinder issues...

Ben
 
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oh man...never would have guessed this....yes they are all aftermarket...just finished bleeding the MC and still have the same issue... although it is slightly better but not drivable...this has to happen on all four wheels? What a PITA!! I may be fighting this + the MC...after bleeding the MC I am still getting bubbles back up through the "rear" reservoir when the pedal is released......but not the front res.....could these bubbles still be from the cylinders needing to be burped?

thanks again for everyone's input and help...I really appreciate it!!!

Ben
Your MC may need to either be bled again or rebuilt. Sounds like there's a leak within if you keep getting air bubbles in the rear resevoir.
Yes! You need to burp the air out of all 4 "rear" wheel cylinders.
 

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