Brakes sticking, but only if I dont use a helper spring

[SLEEPYDUB]

When I apply my brakes, they stick and continue to stop the car UNTIL I put my foot under the brake and pull it back up. I installed a helper spring to pull the brake pedal back on its own and it has helped out a lot.

Does this sound right? Should it require a spring to pull the brake pedal back?
Or does this sound like I have something failing that needs replacing?

[jlevie]

A helper spring should not be necessary. There is a threaded clevis between the pedal and booster that can be adjusted to provide a small amount of free play. If there is no free play there the booster will not release. If there is free play the booster is bad.

[SLEEPYDUB]

A helper spring should not be necessary. There is a threaded clevis between the pedal and booster that can be adjusted to provide a small amount of free play. If there is no free play there the booster will not release. If there is free play the booster is bad.

Thanks. I will check this out this weekend.

[Earendil]

A helper spring should not be necessary. There is a threaded clevis between the pedal and booster that can be adjusted to provide a small amount of free play. If there is no free play there the booster will not release. If there is free play the booster is bad.

Wait, so Free play is both good and bad? Could you perhaps quantify that a little better? Are we measuring free play in mm, cm, or inches?

[LJ851]

Wait, so Free play is both good and bad? Could you perhaps quantify that a little better? Are we measuring free play in mm, cm, or inches?

Free play is good and necessary. I think you misread Jim's post.

[Earendil]

Free play is good and necessary. I think you misread Jim's post.

Or he miss typed it? I'm unsure how else to interpret this:
"If there is free play the booster is bad."
If-Condition-Result
Condition = There is free play.
Result = The booster is bad.

Perhaps he meant to say "If there is no free play" or "If there is massive free play", but I'm not sure which one, and it maters. I have "Free play" in my brake pedal, and it sounds like that's expected, but Jim's always accurate and informative post has left me confused :)

[LJ851]

Or he miss typed it? I'm unsure how else to interpret this:
"If there is free play the booster is bad."
If-Condition-Result
Condition = There is free play.
Result = The booster is bad.

Perhaps he meant to say "If there is no free play" or "If there is massive free play", but I'm not sure which one, and it maters. I have "Free play" in my brake pedal, and it sounds like that's expected, but Jim's always accurate and informative post has left me confused :)

What you are leaving out is the context of Jim's answer: OP's brake pedal does not return.

If your brake does not return and you have free play at the pedal then the booster is bad.

[Earendil]

What you are leaving out is the context of Jim's answer: OP's brake pedal does not return.

If your brake does not return and you have free play at the pedal then the booster is bad.

A brake booster is supposed to have free play regardless of whether it's bad or not? If that's true, I'm still confused how it can be used as an indication...

The only thing I can think is that it could have free play while depressed. If that's the case it all makes sense to me, but no one has said that. Is that the misunderstanding?

[LJ851]

A brake booster is supposed to have free play regardless of whether it's bad or not? If that's true, I'm still confused how it can be used as an indication...

The only thing I can think is that it could have free play while depressed. If that's the case it all makes sense to me, but no one has said that. Is that the misunderstanding?

Seriously?

Dude, you are thinking too hard. Pedal free play is not the indicator!

Explain how you could have free play while at the same time pressurizing your brakes (pedal depressed) and how that makes sense.



Jim's post makes perfect sense, not sure how else to explain it so you understand.

[Danny]

College kids ITT

[Earendil]

Seriously?

Dude, you are thinking too hard. Pedal free play is not the indicator!

Well, it sounds like it is, it just depends on the state of the brake pedal's travel whether it is valid or not :)

Explain how you could have free play while at the same time pressurizing your brakes (pedal depressed) and how that makes sense.

It makes zero sense, because this time I mistyped. When I said "depressed" I meant "compressed", which are obviously opposites. Sorry about that :)

Jim's post makes perfect sense, not sure how else to explain it so you understand.

There is no doubt that Jim is the man, but in this case he doesn't say anything about the compression state of the pedal when testing the booster for freeplay.

Gotta love that we're rapid firing responses, when my initial question was just meant to get a little clarification out of Jim when he returns :)

So let me see if I have this straight (and if it's too much for you to respond again that's A-Okay).

If there is free play while the pedal is pressed down, the booster is bad.
Is that accurate?

[Earendil]

College kids ITT

Or engineers. We like clarifications and as few assumptions as possible :up:

[LJ851]

If there is free play while the pedal is pressed down, the booster is bad.
Is that accurate?

No. That is not possible.

If your brake pedal does not return by itself thus keeping the brakes applied, and there is free play at the pedal (between the booster and the pedal) when the pedal is fully returned, then the booster is bad (causing the pedal to not return).

All of this is in relation to the pedal not returning, nothing else.

This was Jim's answer, i would add a sticky brake pedal pivot to the list of possible causes as well.

[Farbin Kaiber]

I was so gonna edit Danny's post to engineers. There are some things in life that don't quantify to an absolute. What's worse is running an auto repair shop in a bedroom community filled with residents from JPL and CalTech.

I once spent an more than an hour trying to describe how a Honda needed new brakes and rotors and the owner wanted to argue with weird fractions, mathematical calculations, and at the end of the day, he decided to request all the used parts we could find in the shop so he could stay late at work and do FEA calculations.

FML.

AND, no, not free play when the pedal is depressed.

[LJ851]

Or engineers. We like clarifications and as few assumptions as possible :up:

Not sure how i missed this post, clears things up considerably! :p