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Author Topic: Poor Brake Pedal  (Read 3896 times)

Gary Buckley

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Poor Brake Pedal
« Reply #30 on: March 19, 2012, 06:34:28 PM »

Yes When I pushed the pedal down the fluid in the section farthest away from the push rod erupts.The section at the push rod end really does nothing noticeable other than a slight movement in the fluid.I really didnt know what to expect with the cover off  while pushing in on the pedal slowly.So when you push on the pedal should the fluid level go down and when you let off should the fluid return as he did when erupting ?Does having he cover off effect how the brake MC works?


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Gary Buckley

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Poor Brake Pedal
« Reply #31 on: March 19, 2012, 06:36:15 PM »

My shoes have one cylinder  at the top.


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Poor Brake Pedal
« Reply #32 on: March 19, 2012, 06:56:41 PM »

There is a small hole located at the bottom of each of the reservoirs. When the pedal is pushed, there is a rubber piston that pushes and closes this hole after less than quarter inch of movement and is able to pressurize the fluid to the brake cylinders. Since it is full of fluid, along with the wheel cyinders and lines, That piston is compressing about 3/4 an ounce of fluid (thus pumping the brakes for low pedal is able to pull more fluid back into the plunger piston faster than the brakes can allow it to bleed out, thus more pedal power, which bleeds off when the brake is not pushed after a few seconds naturally). OK, now, when you back off the pedal (under normal conditions), there is fluid that fills in behind the piston through this hole, and when you back off the brakes, that fluid is forced out the hole because of the 1200-1500psi pressure from the brake pedal fluid, thus is squirts, but slows down the pedal speed because the hole restricts the brake fluid speed and keeps things from breaking after a few months of this, but it should squirt when the brake is released, not when it is pressed. This indicates something is WRONGGGGGGGG. In thinking about this and rereading what you are saying, the front piston has some kind of damage, backwards, part missing, because the rear pressurizing plunger is somehow putting pressure against the front cylinder and I bet if you did it often enugh you could actually transfer fluid from the one non-squirt reservoir to the other reservoir. Look at a blow-up assembly in your link of the master cylinder and you will see two sets of plungers, some separators and springs that work together (sometimes different diameters) and how they both push fluid with equal pressure but can do different volume (disc take larger volume, so being located on the front it would be a bigger piston/cup and the rear would be smaller so they work correctly to brake evenly), but yours for some reason isn't doing that, it is pushing fluid from the rear to the front and it shouldn't.
 
Does that help?
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Gary Buckley

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Poor Brake Pedal
« Reply #33 on: March 20, 2012, 04:42:33 AM »

Thanks for the info.When I bench bled the MC it seemed to be fine so I guess something has gone wrong.I will pull it off and take it apart.


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Steve

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Poor Brake Pedal
« Reply #34 on: March 20, 2012, 04:51:06 AM »



Single.  Yeah I forget some of the incidentals
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Gary Buckley

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Poor Brake Pedal
« Reply #35 on: March 21, 2012, 06:51:58 PM »

Ok people I am back.Today I think I gained some ground with the beast. First thing I did was block off the 2 lines on my MC and it passed  with flying colours.Pedal was at the top and never dropped any amount so I am now ruling out the master.I removed the right front wheel to inspect the brake lining and check to see if I was running out of travel on my shoes.The lining is defenitely down over half way so I will be ordering new shoes .I noticed one of the rubbers on the wheel cylinder was damp so I released the one spring and the pins that hold the shoes on and let them swing away from the cylinder .When I did this I noticed another set of adjusting cams hidden behind the shoes.Which was great to find.I removed both rubber boots from the cylinder and found both ends were leaking.I removed all the rubbers and spring .Checked them thoroughly ,cleaned everything up and reassembled everything .I then removed the drivers front and checked it out .No leaks and the shoes are getting close to the rivets towards the top as the passengers side were.Once I had the wheels back on I adjusted the front shoes more than I did the previous day using the top adjusters this time.I proceeded to get my wife out and do some bleeding.Using the one pump method that was suggested I bled all wheels.I bled the rear 10 times per wheel and the pedal stayed very low but you could hear it drop when I opened the bleeder.I next bled the left front ,the same amount of 1 pump per bleed.Some air cam out but not alot.At this point we still didnt have any pedal.I then proceeded to the right hand front.After 2 bleeds fluid finally came out.Instantly my wife yelled out that she had a good pedal.I continued to bleed until all air seemed gone and then topped off both sections in the MN again.Now when I hit the pedal  I have quit a bit and with the second and third pump it just gets better.1 pump I can hear front and back shoes moving so I think I may have this beast whipped .Pedal feels spongy as it did last summer driving with the original running gear and rear housing .I am going to order a kit for the 2 wheels cylinders and some brake lining just the same.I want to thank everyone for their input it was greatly appreciated.
.




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Gary Buckley

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Poor Brake Pedal
« Reply #36 on: March 21, 2012, 06:55:24 PM »





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Gary Buckley

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Poor Brake Pedal
« Reply #37 on: March 21, 2012, 06:58:36 PM »

By the way regarding the brake hoses.Yes I replaced every hoe and line on the car this winter.The only used parts are the front brake shoes and the 2 front wheel cylinders.When I installed the 9" ford housing I replaced everything on the housing except the backing plates which were in great condition.I will try and download some pics to give you guys some idea of the work I did in the last 4 months


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Poor Brake Pedal
« Reply #38 on: March 21, 2012, 06:59:04 PM »

We ain't done yet, but at least going through procedures you learned a lot, learned how to adjust brakes (and check a master cylinder, which I am glad to hear it is OK), and know what needs fixed on top of everything else. Keep us informed, you have a good start to being able to cruise in a week or so!
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Gary Buckley

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Poor Brake Pedal
« Reply #39 on: March 21, 2012, 08:08:41 PM »

Ok I posted some picks of the last 4 months .I was a busy beaver this winter.I uploaded the pics to my profile I am not sure if everyone can see them or not .let me know if you cannot and I will move them to whatever the moderator tells me to i guess thanks again


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