boggy brake pedal

[tazdevl35]

That would be after bleeding and you would be clamping the brake hoses. Here is the tool from Lisle...Sears carrys Lisle as do other tool stores. You will need 4 of these one for each brake hose- http://www.lislecorp.com/tools/clipart/index.htm. Hope this helps



Taz

 

[Ludigdrums]

Thanks Taz, but the link unfortunately brought me to a page with clipart and didn't show me any specific tool. Don't mean to be a pain, but could you try again, or give the the part number or name. Thanks bud!

- Jeremy

 

[Chesh]

Jeremy -

Let me know what you find out. I have the EXACT same problem on my 76!

Frustrated!!!

Brent:confused

 

[Ludigdrums]

Will do Brent. Haven't been able to work recently as I've been too busy and it's been too cold! I need to get a good heater or something. I see that you're from NJ...let it snow...

- Jeremy

 

[KANE]

I had the same problem with my rear brakes. Run out was the problem. Once I ha the rear spec'd, bearings replaced, etc. it cleared up.

 

[Robin7TFour]

HELLO ALL, okay he're a different turn. i have a good firm pedal. no fade ,no pulsing,no loss of braking. however, the pedal goes about 3 inches before it gets firm. same travel without the p/b booster working. is this normal amout of pedal movement?
if not , how much movement is correct? and what is the solution to the issue?

another poser for the great minds.

ROBIN

 

[jbonifas]

I am very interested in this issue now. I have read this post and am still confused. My brakes were working fine then all of a sudden they got mushy and the light came on. I bled all the brakes, no air was evident. The pedal is rock hard until I crank up the car, then it gets soft again. Is this due to the power assist and Master cylinder? Or why is this happening?

 

[Ludigdrums]

I'm still working on this myself. I even got a professional pressure bleeder and bled the brakes. Which did work better than any other methods, but I think I messed up a little and need to do it again. This time when the pedal became mushy I was able to pump it up whereas the other times I wasn't. Still confused, still cold to work!

- Jeremy

 

[Tomcatt]

Hey,Just thought I'd tell you that I had the same brake problem on my 74----It was air,air ,air,in the line! Bled the lines myself,had professionals do it----- got on my knees and prayed over it-- then cursed it-nothin helped, so how did it get solved? Well it was air- after I replaced everything you did- I jacked the car up higher in the back than in the front let it sit for 30 min then bled the brakes in the right order. It seemed logical to me that air rises and it worked for me that any air in the lines trapped between front and back would rise to the back calipers. Oh ya I used up at least 5 gal of brake fluid before this solution.

 

[Tomcatt]

one other thing the air was comming from the front brake calipers,they both were out of specs bad. as much as 1/8 under,had to machine them apart to knock the rivets out and replace them with new ones--- Tom

 

[cwerve74]

I think this is the answer to the question robin74 posted. This is from the GM assembly manual. In a NO power brake car the brake pedal must move no more than 3.125 inches when 80 lbs of pressure is applied. If at 80 lbs you travel more than 3.5 inches check for air. Not sure what happens between 3.125 & 3.5 I guess that is not good and not bad. At the top when no pressure is applied you can have up to .25 inches of free travel. All of these measurements are taken in the middle of the pedal. I used a line of stitching in the seat as a reference point.

For a car WITH power brakes the spec is 1.80 inches with 80 lbs of force. This check is made with the motor OFF & no vacuum assist active.

For the 80 lbs part I didn't have anyway to measure that so I just tried pushing on a bathroom scale to get a feel for it. Then went to the car. When I had air in the system the barke pedal went past the 3 inch mark with 2 fingers & a thumb pushing , no air I couldn't get it to 3 inches.