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Technical Brake Bleeding!?

Discussion in 'The Hokey Ass Message Board' started by jaw22w, Jan 2, 2022.

  1. alchemy
    Joined: Sep 27, 2002
    Posts: 17,912

    alchemy
    Member

    As was mentioned way back, Speedbleeders are worth their weight in gold.

    Here's how I bleed brakes, just in case you do things differently, or somebody else doesn't know the process: First, I never have "bench bled" a master cylinder. I assemble everything tightly, then using a small glass jar (so you can see the bubbles) and a two foot piece of rubber vac hose that fits firmly on the bleeder, I do the caliper/cylinder farthest from the master, usually the right rear. Set the jar on the ground with a half inch of fresh fluid in it, and put the hose on the bleeder and into the jar. You might want to put the closed end wrench on the bleeder first before the hose. And maybe you should see if you can fully rotate the bleeder from tight to loose WITHOUT REMOVING THE HOSE OR WRENCH.

    Have your assistant ready to depress the pedal, and make sure the fluid is high in the master. Set the lid on the master (it will probably squirt and make a mess). Loosen the bleeder and tell the asst "down slow". Have them say "down" when they are there. Tighten the bleeder. Tell them "up", and have them say "up" when they are there. Then go through the "down slow", and "up" as many times as needed til there are no more bubbles. Never remove the hose from the bleeder or bottle. If the bottle gets too full and you need to dump it, make sure to restart with a bit of fluid in the bottom and do another cycle to make sure no bubbles. Periodically check the master so it doesn't get empty or you will need to begin from the very beginning.

    Next do the other cylinder on that axle. Then the other farthest cylinder, then the last one.

    If you have Speedbleeders you don't need to tighten the bleeder after each pedal press. The internal ball and spring do it for you. Only tighten at the end of that wheel's bleeding.

    Some of the keys to my success are, I believe, never removing the hose from the bleeder, doing the strokes slowly and evenly, and tightening after each downward stroke.
     
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  2. squirrel
    Joined: Sep 23, 2004
    Posts: 50,921

    squirrel
    Member

    Interesting to read all the different techniques folks use. I've tried a bunch of them, and haven't noticed much difference....once a system is working well enough that it will bleed, it doesn't matter what I do, I get a good pedal out of it as long as I don't run the master cylinder dry accidentally.

    But some of them are a bitch...I guess this either is one of them, or it's already bled and there's another problem.
     
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  3. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    I have experienced a bypassing MC once before. With the bypassing MC it seems like there is a feeling like the pedal hits a bottom and then slowly releases. This feeling is more like stepping on a balloon (that doesn't burst). I'm not ready yet to call the new MC bad. I have a few more things to try before that.
     
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  4. Anxious to see what this turns out to be.
     
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  5. saltflats
    Joined: Aug 14, 2007
    Posts: 11,252

    saltflats
    Member
    from Missouri

    Are the seals in the calipers the high back off style?
     
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  6. 1971BB427
    Joined: Mar 6, 2010
    Posts: 7,261

    1971BB427
    Member
    from Oregon

    It doesn't matter much about brake pedal height, or piston sizing, etc. IF you still have air in the lines! You wont ever get a good pedal until you've gotten all the air out. And I've still seen no mention if you ever broke the fittings loose right at the master while someone held the pedal down?
    I just had this happen again a few weeks ago. I was putting a friend's old car back on the road for him, and the car needed a new master, front calipers, and rebuilt rear drum wheel cylinders. I used my power bleeder to do all the wheels, but still didn't get a great hard pedal feel. I finally gave up and had him hold the pedal down as I opened each of the outlet fittings from the master, and got a little spurt of air. After that I bled the brakes again, just to be sure it was OK, and the pedal was great. No more spongy feel at all.
     
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  7. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    I have tried that exact method. I have also tried pumping the brakes up before releasing the bleeder. I have tried vacuum bleeding.
    Right now I have the rear calipers off, and the pistons pushed all the way to the bottom after pumping the pistons out to a 3/4" shim. I am going to put my plug in the front brake outlet at the MC to isolate the rear system, then bleed the rear brakes. See where that gets me.
    I'll have to look into the speedbleeders. They would be a big help right now.
     
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  8. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    I did mention somewhere above that I did this last night. Wife on the pedal and no air at release, only fluid. I have to put a plug in the MC front outlet next. I will do it again then.
     
  9. littlemann
    Joined: Dec 23, 2013
    Posts: 10

    littlemann
    Member
    from colorado

    Mr Jaw, I am/was in your shoes with a 4 wheel disc brake set up and used 3 different size(s) of Wilwood MC along with the trusty (2 separate) GM MC that come in every damn "off the shelf kit" sold. I even went between frame mounted to firewall mounted...and...vacuum assisted vs not vacuum assisted...and even tried an electric vacuum pump to help reach 18" of pressure as my SBC has a little blower and was only pulling about 11"..... and then purchased a Wilwood pedal assembly when I went to firewall mounted. Just like you I've probably vacuumed and/or pumped 4 gallons of fluid through each caliper and kept getting the "stepping on a balloon" feeling.

    My Dad came out to visit and help around the house and I asked him (again) what it could be and to see if he could help. We walked out there after my truck was on jack stands ( for an F -ing year) in the front so air could travel up and I had a rock hard pedal and my front tires wouldn't spin! Its sat for a year on those jack stands.............................he believes the MC rod attached to my pedal was extended too much and wasn't allowing the pressure to release back into the MC. We disconnected it, turned it back a couple turns and started to get a good pedal and I couldn't spin the front wheels by hand anymore. Before I could have my wife or son hold the pedal down to the floor and I could physically spin the wheels. I even took it to a shop and had someone "power bleed" it - no luck.

    Here are my big lessons learned:
    1. Make sure your rear calipers are adjusted correctly - emergency brakes sometime do that when they're set but I don't have one. So I would manually push the lever with a screw driver until the pads were riding on the rotors.
    2. Tilt the front end or maybe in your case the whole drivers side to push the MC above the calipers if possible
    3. Bleed the furthest caliper and work towards the closest to the MC
    4. My pedal was a little loose when I dialed it out but it would appear it wasn't enough and needed to be backed off more to allow the fluid to return.
    5. WAIT A YEAR FOR THE DAMN AIR TO TRAVEL UP TO THE MC....I'm kidding but fingers crossed it worked for me!
    I need to fix the exhaust and then truly see if all that crap worked. Good luck brother - Lord knows I need it to!
     
  10. Texas57
    Joined: Oct 21, 2012
    Posts: 3,450

    Texas57
    ALLIANCE MEMBER
    1. 1952-59 Ford Social Group

    probably irrelevant, but years ago, I had the same issue of spending days trying to bleed my new 4 wheel disc system. My master (Mustang hydroboost system) had two bleeder valves that I was trying to bleed individually. I finally got an acceptable bleed on the system by using the glass jar with TWO rubber tubes bleeding both the master bleeders at the same time. I was hoping to see a pic of your master to see if it even had bleeders before posting this. Also, I am using the Wildwood proportioning valve.
     
  11. Boneyard51
    Joined: Dec 10, 2017
    Posts: 5,572

    Boneyard51
    Member

    I never “ pump up” the brakes , to bleed a system! Just a gentle “ pushing” of the fluid!
    Somewhere in my past I saw a demonstration of what happens to brake fluid under pressure with air in the lines. It can shoot air rapidly all through the system!
    That stuck in my mind forever!
    Many times on the line I would do a brake job and not even have to bleed the brakes per se.

    I know this does not help you, but I had to mention the air bubbles thing while under pressure!




    Bones
     
  12. milosmith
    Joined: Aug 27, 2020
    Posts: 89

    milosmith
    Member

    I have used this same method many times. The only difference is that I insert a one-way fish tank check valve in-line in the length of clear tubing that goes into the container than I use to collect the output. These are cheap check valves that you can buy on-line. The beauty of these is that it turns the bleeding process into a one person job. You can crack the bleeder valve, and pump away from inside the car (watching the fluid level in the MC, of course). The check valve prevents air from being pulled back into the lines during the pedal return stroke. No need to pull a reluctant helper into the process!

    They are available with many hose barb sizes. Just buy one with a similar barb size as the bleeder valve, and is a liquid tight fit with the clear tubing that goes on the bleeder valve check valves.jpg :

    Another tip - I always use clear tubing so you can see the fluid movement from the bleeder valve. Any cheap neoprene tube from the hardware store works. It lets you readily looks for bubbles too. You can buy it from the aquarium people!
     
    Last edited: Jan 6, 2022
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  13. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    I tried reverse bleeding by pushing the caliper piston to the bottom of the bore at each caliper and clamping it there, forcing all the fluid back to the MC. No love there.
    Then my new power bleeder arrived yesterday afternoon. So I thought I would try it next. I got a little bit of air at 3 calipers, but it really didn't improve the pedal feel.
    Then I plugged the front system off at the MC and bled the rears with the power bleeder. I now have a high hard pedal with the rear system only hooked up. That's how a pedal is supposed to feel. That's where I am now. Taking a break! (I used to tell my guys at work... If you see me not doing anything, I'm thinking)
    Ok. So it seems that the rear system is good. It appears that the problem is in the front system. I guess the next step is to block the rears off at the MC and bleed the front.
    It's looking better. I'll get back to ya.

    ...18 minutes later.
    Ha! I have a high hard pedal with only the fronts hooked up. I should be able to pull the plug on the rear and put the rear line back into the MC and have good brakes. I'm about half scared to take the plug out for fear of it not working.
     
    Last edited: Jan 6, 2022
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  14. alchemy
    Joined: Sep 27, 2002
    Posts: 17,912

    alchemy
    Member

    How does plugging one port allow fluid from that half of the master to exit the cylinder? Once the plunger has traveled past the small filler hole, it will be pushing a full supply right against that plug you installed. No wonder the pedal is high and tight.
     
  15. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    If I plug the rear and open a front bleeder, I can stroke the MC cylinder full stroke. With the bleeder shut and the plug still in the rear port it operates the front brakes normally.
    With the front port plugged and a bleeder open I can only stroke the MC about half pedal, then it hits the front brake system and won't stroke any further. There must be some timing system in there with port alignment. I'm really not that familiar with what goes on inside a Wilwood MC. I think it does tell me there is no air in there. Hell, I don't know. Apparently I dont know anything about brakes.
     
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  16. gimpyshotrods
    Joined: May 20, 2009
    Posts: 19,890

    gimpyshotrods
    ALLIANCE MEMBER

    Wilwood does not use those.
     
  17. gimpyshotrods
    Joined: May 20, 2009
    Posts: 19,890

    gimpyshotrods
    ALLIANCE MEMBER

    I have been doing just fine with solo bleeding, and without speed bleeders. There is not always someone around to help.

    I put a boxed-end wrench on the bleeder, and then a hose on the nipple. I run the hose up to a bottle taped to the top of my 4-foot step ladder (unless I am working on a megatruck, in which case I use a taller ladder). The hose goes through the cap, and is submerged in brake fluid.

    This creates a new, temporary highest-point in the system for the air to rise to.

    I keep pumping slowly until no more air comes out, and then close the bleeder. I only open the bleeder just enough to get fluid out. I do not pump to create pressure, just flow. Yes, this "wastes" a bunch of brake fluid, but that's ok.

    Before I take the hose off, I put hose pinch pliers on it, to avoid a mess.

    Of course, every 5 or so full cycles of the pedal I top off the master cylinder.

    My theory here is that since the master cylinder does not move all that much fluid with one push, if there are bubbles in the system, each time you push the pedal, you only move them a little closer to the bleeder. I try to move quite a bit of fluid through the system to make sure.

    Now, if it is a new system, I will do the bleeding procedure twice, a-day-apart. My goal there is to get any large bubbles to coalesce into bigger ones, and then get them out.

    This has worked for me for disc, drum, and even clutch systems. It's worth a shot.
     
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  18. squirrel
    Joined: Sep 23, 2004
    Posts: 50,921

    squirrel
    Member

    What type of hose do you use for your bleeder?
     
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  19. gimpyshotrods
    Joined: May 20, 2009
    Posts: 19,890

    gimpyshotrods
    ALLIANCE MEMBER

    Try my method described above, but with a twist.

    From your description is sounds like your front circuit is properly bled, and that is actually stopping you from bleeding the rear circuit, because it stops the pedal travel.

    Put together a rig like I described above. Attach it to the front circuit. Open the bleeder. This will temporarily remove the "stop" of the properly bled front circuit.

    Do the same to the rear, and then bleed both sides there, starting with the one that has the most line run from the master cylinder.

    Once the rear shows no bubbles, close it all up.
     
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  20. oldtom69
    Joined: Dec 6, 2009
    Posts: 578

    oldtom69
    Member
    from grandin nd

    another vote for the Speedbleeders!! I work alone and have to bleed brakes myself all the time.Also use a short length of cheap clear tubing over the end of the bleeder,so no mess on floor. A few other tips-NEVER re-use the fluid you've pumped through the system,also if your brake fluid container has been on the shelf,unsealed,not just capped for more than 30 days or so ,get rid of it!I always buy the smallest containers of brake fluid-the price per volume insnt worth the risk of large containers
     
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  21. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    Right now I have been using about 1/8" clear tubing from a breathing machine! I tried several different sizes. This stuff slips nicely onto the bleeder nipple and stays there.
     
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  22. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    I have been using this method for the last number of years since the shop is no longer full of buddies to assist. It works great and is the first method I tried when I started bleeding these brakes. Since the calipers are off and mounted on flex lines, I have even been holding the caliper elevated above the MC along with the elevated bottle. By this time I have run at least a gallon of fluid through each caliper.
    That Wilwood MC has a large reservoir. I have it figured where I can get 20 strokes on an open caliper before I have to refill it. I have moved a lot of fluid through the system with your method.
     
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  23. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    I thought about that the other day, to get around the "stop", but forgot about it. I was thinking to try bleeding all 4 at the same time with this method. My empty Gatorade G Zero bottles make a great bleed bottle. I drill a hole so the tubing slides in tight then a very small vent hole in the screw on top and run the tubing to about 1/4" off the bottom and put about 1/2" fluid in it. One other thing I found very handy. I have 2-1/2" x 2# lead discs. I tape one to the bottom of the bottle. Makes the bottle very stable.
     
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  24. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    I have removed the plug in the rear port of the MC and re-connected the rear system to the MC and re-bled the rears. I wish I could say I now have good pedal, but that is not the case. It seems to be a little better but nowhere near where it should be. After dinner I'm going to try a 4 wheel bleed all at once using the method gimpy described above. Or maybe just RR and RF at the same time. Then LR and LF.

    If all this fails I am starting to wonder about the volume of the MC, as many of you guys have mentioned. I know that Wilwood recommends this combination of components and have the numbers all worked out. I worked for a really good old engineer for a while. If he said it once he said it a hundred times. "The numbers don't lie". So I really have a hard time doubting the 7/8" MC 's ability to provide a hard pedal.
    I still have the Corvette 1" MC that was replaced by the Wilwood. I am thinking about swapping it back in, just for grins and giggles.
    Hell, I am actually getting to like brake fluid running down my arms all the way to my arm pits!
     
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  25. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    Residual Pressure Valve not holding pressure? How could this be checked?
     
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  26. saltflats
    Joined: Aug 14, 2007
    Posts: 11,252

    saltflats
    Member
    from Missouri

    Did you say the master acts different from when you block one end or the other during the bleeding proses?
     
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  27. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    Yes.
    Rear port blocked. Front caliper bleeder open. Can get full pedal stroke.
    Front port blocked. Rear caliper bleeder open. Can get only 1/2 stroke.
    I get the same thing when trying to bleed the rears without the front port being blocked. The pedal won't push any further than about 1/2. I figure it is running into the front brake system some how.

    I know. This seemed strange to me. I don't believe I have ever noticed this before.
     
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  28. Boneyard51
    Joined: Dec 10, 2017
    Posts: 5,572

    Boneyard51
    Member

    Are you getting any air bubbles when you are bleeding the brakes?






    Bones
     
  29. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,458

    jaw22w
    Member
    from Indiana

    I just did a RR and RF simultaneous bleed. then a LR and LF bleed pumping a full reservoir of fluid through. The pedal now doesn't seem to have any "pump up" to it now, but it sure is not a firm pedal. I think I have to test drive it. So I have to get all the calipers back on, all the wheels back on. I had to lower the left side exhaust to get to the MC. Got to get that back together and get it back down off the lift. I hope to hell I at least I have better brakes, but I don't have a lot of confidence. It's a PITA to get it back to where I can work on it.
    I'm hoping some of the problem is me not used to the 7/8" MC.
     
  30. saltflats
    Joined: Aug 14, 2007
    Posts: 11,252

    saltflats
    Member
    from Missouri

    That sounds one half of the master is not holding.
     
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