bleeding brakes sucks - no pedal

Discussion in 'The whoa and the sway.' started by BuicksRock, Nov 5, 2005.

  1. Ken Warner

    Ken Warner Stand-up Philosopher

    rod replacement.

    With the master cylinder off the booster you can see the end of the rod. Just grab it with some needle nose pliars, there is probably a bit of grease on it but it should pull out pretty easily. It seems like someone posted a picture of the 2 different lengths used on these but I'm not having any luck. Besided the only longer style rod I had was given away a few months ago. You situation sounds a LOT like my buddies Chevelle though... You would need a LOT of air for the pedal to sink to the floor as you are describing.

    sorry for the bad luck.
     
  2. tlivingd

    tlivingd BIG BLOCK, THE ANTI PRIUS

    I think ken is on to something. you can try to remove the master (w/0 disconnecting the lines and have a friend push the pedal to make sure the pin moves out of the booster. your pin may also be too short.
     
  3. BuicksRock

    BuicksRock Well-Known Member

    Well, after a couple more hours of work and a master cylinder change ($20 Autozone unit) I still don't have much of a brake pedal. But I have just enough to stop the car right at the bottom of the pedal travel.

    I am taking the car to Midas tomorrow and we'll see what they can do.

    -Chris
     
  4. BuicksRock

    BuicksRock Well-Known Member

    Nate,

    It defies logic to think that the pin is not contacting the master cylinder when I am getting a good stream of fluid out of the bleeders every time my buddy pushes the pedal. Obviously, the pushing of the brake pedal equates to movement of brake fluid. I measured the rods from both disc and drum systems and I swear they are the same. Does anyone have a picture of the different lengths? Is it a big difference?

    -Chris
     
  5. Ken Warner

    Ken Warner Stand-up Philosopher

    last comment I'll make on this....

    The guy I helped with the chevelle swapped a power drum for power disc setup (spindles, calipers etc). He bought a used vac. booster from another mutual friend and a Napa master cylinder. He re-used the pin/rod from the old booster figuring it would be the same...

    I think I found another pin here in my tool box from a bad booster I tossed from my donor car oh-so-many years ago... it measures 2 and 9/16'ths of an inch long. I'm about 99% sure this is the longer style pin. In fact if your pin is shorter I'll drop this in an envelope and sent it to you for free...

    My buddy with the chevelle is a capable mechanic type and his symptoms sound just like yours. His pedal went all the way to the floor and the car would just barely slow down. He was planning on driving it anyway and giving people a lot of following distance! :Dou: For the master cylinder to be bad enough to have the total lack of pedal you describe you would have to have brake fluid shooting from between it and the power booster. If you had nothing but air in either the front or rear lines you would still have a pedal that didn't go to the floor...

    I'm just trying to help. I used to be an ASE master tech. I worked at a Chevy dealership for about 5 years as a full time mechanic. I've been to several GM training classes on brake systems. I've got a 2 year (whoopie) degree in auto mechanics. Please, do yourself and your bank account a favor and pull the 2 9/16 nuts off of the master cylinder, pull it away from the booster a bit and pull that pin out... If the pin is too far back to get with pliars it is probably the wrong pin. Have someone push the brake pedal and you should then be able to reach it. Compare the length to the one I listed above.

    Good luck!!!
     
  6. BuicksRock

    BuicksRock Well-Known Member

    Ken,

    Don't give up on me yet. I appreciate your advice and the generous offer. Midas now has my car. They tried to fix the brakes today and had no luck either. They blamed the master cylinder (the second one I tried - the one I bought from Autozone), he said they went through a half gallon of fluid trying to bleed it. So, they are going to try one of their masters tomorrow. I went by and talked to the guy who is an older, very knowledgable mechanic that runs the place and asked if the rod was too short. He said he didn't think it was too short for the master from Autozone or theirs. He did say that the piston in the Year One master was recessed quite a bit when compared to the other two and that was probably the problem with it. I know he understood what I was talking about because he talked about compensating by adjusting the brake pedal linkage. I informed him that I had already adjusted it out about as far as I felt comfortable adjusting it.

    Anyway, I will see how they fair tomorrow and if they have no luck I will measure the rod in my booster. I have two extra boosters in my garage that have pins in them. But I could not get them out by pulling to measure. Do I just need to pull harder?

    I measured by placing the end with the brake pedal linkage on the ground after removing the linkage and pushed down on the booster body until it was at full travel, then I measured from the ground to the end of the pin coming out of the front of the booster. The ones I have are the same when measured that way. All three boosters I have also look the same when looking at the front of them with no master attached. None of the pins stick out very far.

    I will let you know as soon as I hear something from Midas.

    Thanks again,

    Chris
     
  7. BuicksRock

    BuicksRock Well-Known Member

    I think I just had a breakthrough... I took off work today and decided to take another look at the boosters I have in my garage. As I was looking into the front of the booster I decided to try to pull the "pin" out. And by pin or rod I though we were talking about the black cylinder coming out of the booster, but it looks to be firmly attached to the diaphragm inside the booster and it of course will not come out. Then I thought about Ken's post when he said the pin he had on hand was 2 and 9/16" long and thought that is funny, this black "pin" that I am talking about looks longer than that.

    Then Midas called and said they could not get my car's brakes figured out. I decided Ken must be right and the pin he is talking about is not the pin I am talking about. He must be talking about a smaller (girthwise) pin that fits into the black rod coming out of the booster. In all of my boosters, the rod coming out is hollow.

    So, I started digging through some parts I have and came across this:
     

    Attached Files:

  8. BuicksRock

    BuicksRock Well-Known Member

    The pin pictured above measures to the exact length of Ken's and it fits right inside of the black rod.

    I am attaching pictures of the two extra boosters in my garage that don't have the pin.

    Hopefully, this will clear up future confusion about this pin. But, it only sticks out from the black rod a small amount, < 1/2", so I think this might be the drum brake pin. Why none of my boosters had this I will never know, but at least I understand now.

    Now, what I need to know is how far the disc brake pin supposed to stick out from the black rod? :Do No: Anyone want to measure?

    I think I will start a new thread on this.

    -Chris
     

    Attached Files:

  9. GStage1

    GStage1 Always looking for parts!

    Chris,
    In the booster pics, you are missing the seal that goes around the input rod. I will take a pic of the one I have for a car being painted so you know what you need and how far the pin is supposed to be out.
     
  10. BuicksRock

    BuicksRock Well-Known Member

    Hey George,

    Thanks for the reply! I know I'm missing the seals, they are actually sitting on the ground beside each booster just outside the pictures. I removed them on purpose.

    Thanks,

    Chris
     
  11. tlivingd

    tlivingd BIG BLOCK, THE ANTI PRIUS

    Chris that's your problem. you NEED that pin installed. and it will fit really nicely inside that black plastic hole. and mine only stuck out about 3/8" inch from the plastic. I did a conversion from drum non power to disc so i did have a booster added and may have gotten lucky with the correct combo of parts.
    DOH. :Dou:

    -nate
     
  12. RogerZ

    RogerZ Well-Known Member

    I helped a friend of mine service his brakes on his one ton van and we had to "Run the engine" to get them to bleed, otherwise you could stand on the pedal and no fluid would come out.
     
  13. BuicksRock

    BuicksRock Well-Known Member

    UPDATE: I have brakes :TU:

    I took the pin up to the guys at Midas, they installed it and with the right combo of master and pin the brakes work great.

    Thanks to all who offered their advice :beer

    -Chris
     

Share This Page