Brake pedal travel

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Old May 21, 2023 | 02:25 PM
  #1  
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Brake pedal travel

So I replaced the diverter valve on my '72 Supreme and all 4 corners bled good. Now it takes more pedal travel before the brakes engage. Before I would barely have to press the pedal to whoa it down, whereas now I have about 3/4 of the distance to the floor before I can feel the brakes. She stops good and when I'm in reverse and hit the brakes, I can feel the car rock backwards.

Before I replaced the valve I'm pretty sure the rears weren't engaging because my wheel cylinders were shot and the diverter valve had shifted. Is it possible that because no fluid was moving to the rear and only to the front it took less pedal travel, or do I need to adjust the rears more, or am I good?

Last edited by 72455; May 21, 2023 at 02:31 PM.
Old May 21, 2023 | 03:31 PM
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I'd try adjusting them first. When you changed the valve did the MC run dry?
Old May 21, 2023 | 03:59 PM
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Originally Posted by oldcutlass
I'd try adjusting them first. When you changed the valve did the MC run dry?
Nope...we made sure we always had fluid through the whole process. Do I need to adjust them manually or can I use the self adjust process?
Old May 21, 2023 | 04:22 PM
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FWIW
I'm not 100% certain if you changed anything on the rears? None-the-less, it may not be too far-fetched if those rear brakes haven't been used in a long, long time (since you admittedly haven't had any pressure going to the rears - right?) the arc of the rear shoes might not be matching the drum radius, deflecting the shoes somewhat. This gets better as the linings wear in to the drums. I'd probably drive it for a week or two before making further adjustments.

Dave - Diverter valve? You have a combination valve, buddy.

EDIT: I hit the Post button too quickly. I agree w/ Eric an adjustment might be needed; however, I (personally) would drive it a week or two, and (this is just me) would bleed the brakes again once or twice. That would be my first choice before adjusting since it's really, really easy to suspect air remains "somewhere".

Last edited by Vintage Chief; May 21, 2023 at 04:26 PM.
Old May 21, 2023 | 04:26 PM
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Originally Posted by Vintage Chief
FWIW
I'm not 100% certain if you changed anything on the rears? None-the-less, it may not be too far-fetched if those rear brakes haven't been used in a long, long time (since you admittedly haven't had any pressure going to the rears - right?) the arc of the rear shoes might not be matching the drum radius, deflecting the shoes somewhat. This gets better as the linings wear in to the drums. I'd probably drive it for a week or two before making further adjustments.

Dave - Diverter valve? You have a combination valve, buddy.
That makes sense Norm...I'll see how that goes. Once the shoes wear to the drums, will I have less pedal travel?

Oh, and thanks for the clarification on the valve nomenclature
Old May 21, 2023 | 04:30 PM
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Originally Posted by 72455
That makes sense Norm...I'll see how that goes. Once the shoes wear to the drums, will I have less pedal travel?
Dave - I can't say w/ any degree of certainty if you'd have less pedal travel to be honest & I'd hate to speculate just to suggest I think it would be more or less pedal travel. I'd be patient with it - you haven't had rear brakes in some time. Increase the patience level a couple notches and drive it awhile before getting wrench-happy on it. Again, personally, I'd drive it then my first approach would be to bleed the brakes one more time before making adjustments. Your call. Glad you got the combo valve installed.
Old May 21, 2023 | 04:45 PM
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Originally Posted by Vintage Chief
Dave - I can't say w/ any degree of certainty if you'd have less pedal travel to be honest & I'd hate to speculate just to suggest I think it would be more or less pedal travel. I'd be patient with it - you haven't had rear brakes in some time. Increase the patience level a couple notches and drive it awhile before getting wrench-happy on it. Again, personally, I'd drive it then my first approach would be to bleed the brakes one more time before making adjustments. Your call. Glad you got the combo valve installed.
Thanks again...and I do know that the rear shoes have the same amount of lining as a new set. I know this because I put a new set on while I was replacing the wheel cylinders. Oh, and btw it may take more than a couple weeks to seat the shoes to the drums....I usually only drive it once a week

Last edited by 72455; May 21, 2023 at 04:49 PM.
Old May 21, 2023 | 05:22 PM
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I always tighten the shoes using a tool through the access hole in the backing plate. Turn the star adjuster until the shoes just contact the drums.
Old May 21, 2023 | 05:29 PM
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Originally Posted by Fun71
I always tighten the shoes using a tool through the access hole in the backing plate. Turn the star adjuster until the shoes just contact the drums.
How would you know when the shoes contact the drums?
Old May 21, 2023 | 05:43 PM
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I can feel the star adjuster tension increasing.

You can also lift the car and remove the wheel you are working on so that you can manually rotate the drum/axle shaft. Adjust the shoes until you can feel the drum dragging when you rotate it.
Old May 21, 2023 | 06:03 PM
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Originally Posted by Fun71
You can also lift the car and remove the wheel you are working on so that you can manually rotate the drum/axle shaft. Adjust the shoes until you can feel the drum dragging when you rotate it.
Best method, IMO.
Old May 21, 2023 | 06:08 PM
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Realized after re-reading that you don’t need to remove the wheel. Just lift it off the ground.
Old May 21, 2023 | 07:27 PM
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Or...do I need to adjust them? As asked in my first post, is the pedal travel I described normal/acceptable?
Old May 21, 2023 | 07:59 PM
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You do realize you MUST have SOME drag when installing right? The rear wheels should NOT be able to free-wheel (spin). That's where to begin. If the rear wheels are freely spinning they need further adjustment. It should take just a little bit of strength for you to turn the wheels and they should NOT be able to spin. The only way they should spin is if you have to apply some force to make them spin.
Old May 21, 2023 | 08:02 PM
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You don't need this tool....you already did the work; but, look at the amount of drag after this install...that's what you want.

Old May 27, 2023 | 12:50 PM
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UPDATE: I haven't done any adjustments since I started this thread because I wanted my buddy Mike to drive it and get his input. He came over today and in his opinion, all is good. He has a '69 Cutlass so I trust his judgment, so I'm calling it a wrap on the brake work.
Old May 27, 2023 | 01:07 PM
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That's great, Dave!
Good time to consider changing the fuel sending unit sock filter in the fuel tank w/ your added free time.
Old May 27, 2023 | 01:45 PM
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Originally Posted by 72455
So I replaced the diverter valve on my '72 Supreme and all 4 corners bled good. Now it takes more pedal travel before the brakes engage. Before I would barely have to press the pedal to whoa it down, whereas now I have about 3/4 of the distance to the floor before I can feel the brakes. She stops good and when I'm in reverse and hit the brakes, I can feel the car rock backwards.

Before I replaced the valve I'm pretty sure the rears weren't engaging because my wheel cylinders were shot and the diverter valve had shifted. Is it possible that because no fluid was moving to the rear and only to the front it took less pedal travel, or do I need to adjust the rears more, or am I good?
Originally Posted by 72455
UPDATE: I haven't done any adjustments since I started this thread because I wanted my buddy Mike to drive it and get his input. He came over today and in his opinion, all is good. He has a '69 Cutlass so I trust his judgment, so I'm calling it a wrap on the brake work.
2 wrongs don't make a right. If it takes 3/4 of pedal travel to the floor to stop the car, the brakes need adjusting. It takes less than an hour to perform an adjustment even taking a coffee or beer break.
Old May 27, 2023 | 01:50 PM
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Originally Posted by oldcutlass
2 wrongs don't make a right. If it takes 3/4 of pedal travel to the floor to stop the car, the brakes need adjusting. It takes less than an hour to perform an adjustment even taking a coffee or beer break.
I forgot to mention that I was wrong about the pedal travel. The pedal actually stops when it's about even with the gas pedal.
Old May 27, 2023 | 01:51 PM
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Originally Posted by oldcutlass
2 wrongs don't make a right. If it takes 3/4 of pedal travel to the floor to stop the car, the brakes need adjusting. It takes less than an hour to perform an adjustment even taking a coffee or beer break.
That's really good advice. It may take longer if he eats a cheese Danish w/ his coffee.
Old May 27, 2023 | 01:52 PM
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Change your fuel sending unit sock filter and call it a day, Dave.
Old Jun 4, 2023 | 03:43 PM
  #22  
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Originally Posted by Vintage Chief
FWIW
I'm not 100% certain if you changed anything on the rears? None-the-less, it may not be too far-fetched if those rear brakes haven't been used in a long, long time (since you admittedly haven't had any pressure going to the rears - right?) the arc of the rear shoes might not be matching the drum radius, deflecting the shoes somewhat. This gets better as the linings wear in to the drums. I'd probably drive it for a week or two before making further adjustments.
Norm, out of curiosity, today I checked for wear on the new rear shoes and saw rubbing on the outside edges of the shoes, which means they are making contact with the drums. This would support your suggestion that they need to "wear in" to the drums. I've only driven it a couple times since I replaced the shoes, so I'm guessing more time behind the wheel is needed. After doing some research, I came across this, and wanted to ask if you've ever heard of doing this?

https://itstillruns.com/properly-bre...s-7571495.html
Old Jun 4, 2023 | 04:05 PM
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Originally Posted by 72455
Norm, out of curiosity, today I checked for wear on the new rear shoes and saw rubbing on the outside edges of the shoes, which means they are making contact with the drums. This would support your suggestion that they need to "wear in" to the drums. I've only driven it a couple times since I replaced the shoes, so I'm guessing more time behind the wheel is needed. After doing some research, I came across this, and wanted to ask if you've ever heard of doing this?
Dave - That's pretty much how I've always broken in drums from the first time I worked on drums (1969). The only thing missing is going in reverse 6 or 7 times and locking them up each time in reverse.

EDIT: I don't mean head in reverse at 30 miles per hour or pull a hole shot and slam on the brakes. Just rapidly go into reverse 6 - 7 times maybe 20' - 25'.

Last edited by Vintage Chief; Jun 4, 2023 at 04:15 PM.
Old Jun 4, 2023 | 05:07 PM
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Originally Posted by Vintage Chief
Dave - That's pretty much how I've always broken in drums from the first time I worked on drums (1969). The only thing missing is going in reverse 6 or 7 times and locking them up each time in reverse.

EDIT: I don't mean head in reverse at 30 miles per hour or pull a hole shot and slam on the brakes. Just rapidly go into reverse 6 - 7 times maybe 20' - 25'.
And "lock them up?:...as in locking up the tires and skidding in reverse? Should I do a "police turnaround" while I'm at it?
Old Jun 4, 2023 | 10:49 PM
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I just brake hard. If the tires lock up, don’t brake as hard the next time.

You can skip this process by using a tool to tighten the star adjuster as I posted earlier.

Last edited by Fun71; Jun 4, 2023 at 10:51 PM.
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