Can't Get My Brakes Right!

[ashley_j]

Thanks for all the tips. I am using regular DOT 3 fluid and I did not use a gasket between the M/C and Booster so the rod is probably maxed out. If there is an adjustment I do not see it. I am going to do the M/C bleed tomorrow if the weather can give us a break.

Everyone keep the people in AL in their thoughts. We dodged the tornado bullit today in my area but tomorrow may be different.

 

[ashley_j]

Well, I bench bled the M/C and found out that the pushrod is adjustable. I had not noticed the striations for a grip and the hex at the bottom of the ball/swivel end. I measured from the swivel seat on the M/C to the mounting face and got 13/16"  I adjusted the rod to just over that and had a slight tension as I torqued down the the M/C. So far so good.     I re-bled the brakes and had a firmer pedal without power but with power added.... no change. The spongy pedal remains.    Is there a recommended rod length or a way to know if you have the right length?   

Any suggestions? More Rod Length, better bleed......   

Also, does anyone have their own method for bleeding thru the proportioning valve? I have used the In-Line method (below) but I don't know if it is effective as my results have not changed.

(Pump, crack both front at least 5 times to equalize pressure. Then acquire a good flow to both rear by opening both rears and pump, slowly, until good flow, close both and bleed as usual)

 

[ashley_j]

Any Suggestions? I need a direction. 

 

[Bullitt-]

Any Suggestions? I need a direction. 

 

All I've been able to find is that it is adjustable, in my minds eye it seems there is something on the very end of the rod that goes into the M/C that is threaded. It's been a while since I had mine apart & that was not a concern at the time....Guess I need some how-to info as well

[ashley_j]

Yes, that is what I found. The rod that is in the booster now has a half-ball threaded rod with a hex that can be adjusted in or out. I did not get a pic (sorry). I just don't know what the correct adjustment and how it affects the pedal feel. I ran it out just enough to feel tension when I torqued down the M/C. Is that enough, not enough or too much and will that affect the pedal issue?

Gee..what happened to just being able to bleed the brakes and go? 

I keep thinking that the proportioning valve is part of the issue. I may have misunderstood the bleed method I was given by In-Line. Is there a better way? 

Thanks Bullit for the attention!


 

[72cudamaan]

If you get good fluid flow out of the wheel cylinders, and you can't turn the drums with the brakes applied, then I would think that the prop. valve is O.K.
Do you have spongy flex hoses somewhere?

[Bullitt-]

Yes, that is what I found. The rod that is in the booster now has a half-ball threaded rod with a hex that can be adjusted in or out. I did not get a pic (sorry). I just don't know what the correct adjustment and how it affects the pedal feel. I ran it out just enough to feel tension when I torqued down the M/C. Is that enough, not enough or too much and will that affect the pedal issue?

Everything I've read says it should just touch, if there is resistance you can create a whole other problem of holding the brakes on all the time...  Could you tell any difference after the adjustment?

[burdar]

Inline Tubes prop valve have known issues.  At this point, it isn't going to hurt anything by trying another "used" valve.  Is your origonal one long gone or do you still have it?

[ShelbyDogg]

Had a friend with a new valve that also had a problem. He cleaned one up out of a used challenger and it woked as it should.  As far as the push rod length, I adjust it so it barely touches like burdar said.  The recent one I did on my resto, I had some left over plastic gauge. I stuck a piece to the end and cranked down the 4 bolts to check the "squeeze"

[ashley_j]

All the flex hoses are new. I do have the original valve or lets say the one that was in the car when I got it. I changed it because nothing was helping with the spongy feel of the barkes or having to pump up the brakes. After all the replacement of parts (mostly during the restoration phase) the brakes are basically the same as when I first tried the brakes after the initial startup. I never drove the car when I bougth it as it had been sitting for 2 years. I tore her down and started the restoration. As I stated in a earlier post. Everything is new except for some lines but I do have flow to all foir corners. This makes me think I have doing something wrong somewhere with an adjustment or a bleeding procedure thru the prop valve.

The original valve looks OK from the outside but that does little for what's inside. I do not know of a way to test a valve off the car. I was hoping for a better method from an experianced hand.

I did try to use a vacuum pump (hand) to get the fluid thru the lines and get the air as well but it does not seem to work well on the rears thru the prop valve. (?) I can't get a continuous flow.

Thanks guys for the input!   

 

[72rtchallenger]

late to this post,,so i will ask is someone helping you bleed the brakes,,pumping them up and holding pressure on the pedal while you crack the bleeder fitting opening and continue to hold pressure on the pedal until it goes all the way to the floor and continue to hold it down until you tighten the bleeder fitting back down,and do all four wheels this way .you may be doing this i just thought i would throw it out there as you seem to be having a lot  of trouble 

[Strawdawg]

If you got the air out with the MC bench bleed, then it sounds like the problem is down the line.

When you are bleeding by pumping the brakes, I understand that you need to hold the plunger up on the valve while doing the rears.  You may accomplish the same thing by cracking a front bleeder and stepping on the brake to move the piston off center to simulate a fault situation as I understand it....then the rears get full flow.

I think this was discussed somewhere up the thread.

  Given the reported problems with the new valves, you might want to try the old valve and go thru the process one more time, if you have not already tried this.

I am pretty leery of rebuilt MC's working properly, myself.  Seems like a crap shoot sometimes.

[Bullitt-]

Everything I read on-line says it's air in the lines if the M/C is good, no leaks & rear shoes adjusted. 
Low vacuum, bad Booster or proportioning valve would not cause the low pedal.
One thing I've heard of a few times was the front calipers being installed on the wrong sides leaving the bleeders on the bottom. I have used a one-man bleeder & caught myself loosening the bleeders to much so that air could be sucked back in around the threads, best method is the one 72rtchallenger described.

[ashley_j]

That is the method was using, 72rtchallenger, the last time with my sons assistance, which is usually the method I use. I only tried the vacuum pump because of the issues this time around.  Maybe I just need to keep bleeding a few more times after I switch back to the old prop valve and go thru the bleed again. 

Thanks for all the advice. I hope to give a different result soon. 

Jeff
 

[Strawdawg]

Have to hold the plunger on the valve up when doing it by the pedal on the rears unless the piston in the valve was offset by first cracking a front bleeder and mashing the pedal down to simulate a failure.  Brake lite should come on if that circuit is functional.

If gravity bleeding, or vacuum bleeding, then the plunger does not need to be held up....at least that is what the manual says

I use a Phoenix tool and bleed backwards from the cylinders/calipers...that way no air is sucked in around the bleeders as the threads are under pressure