hard pedal feel? - Suspension and Brake Forum

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hard pedal feel?
Tuesday, March 11, 2008 10:10 AM
hey guys just trying to figure out what is going on with my brakes. when i try to push them down initially i have a very hard pedal and it wont depress more than an inch and a half. I did put brake fluid in a few months ago because it was low . could i have a bubble in the lines and just need to flush them out . it feels as though the calipers are not clamping all that well like they are starting to go. help me out thankyou.

Re: hard pedal feel?
Tuesday, March 11, 2008 3:22 PM
Brake booster leak, not getting vacuum assist.




14.330 @ 96.37mph
Re: hard pedal feel?
Tuesday, March 11, 2008 6:37 PM
are you positive that is the problem?
Re: hard pedal feel?
Tuesday, March 11, 2008 7:34 PM
A good rule of thumb for Internet advice is to take it as a suggestion. For all we know, you could have a grapefruit jammed under the pedal. Frankly, I'd love to have a firmer brake pedal. Mine has been inexplicably spongy for quite a while.



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Re: hard pedal feel?
Tuesday, March 11, 2008 8:08 PM
How low was the fluid?

Did you bleed the brakes?

Could also be a booster problem as Bill mentioned



Re: hard pedal feel?
Tuesday, March 11, 2008 8:29 PM
i do hear a hissing sound like a vacum leak at idle but not when im under power. could this have something to do with the brake booster. ill look at all the vacum lines to it tomorrow but i also heard it could be the diaphram inside the booster if that makes any sense.
Re: hard pedal feel?
Tuesday, March 11, 2008 8:36 PM
Sounds exactly like thats your problem. No power assist will cause a high hard pedal 100% of the time and its one of the few things it could be. Fluid is not compressable, Air is so any air in the lines would result in a soft pedal or in extreme cases no pedal resistance at all.

Check the vaccum hose running from behind the throttle body (Its the biggest one) to the brake booster. Pull the 90* check valve out of the booster and shine a light in there and see if you can see any cracks or deterioration.


What type of fluid did you put in? As long as its dot 3 your ok

Anything else and I hope you like pulling every brake componant out and replacing all the seals and the ABS unit. Its possible with anything petroleum based to have the rear master cyl. seal expand and stop sealing allowing for fluid to leak into the booster and eat at the diaphragm.



Buildin' n' Boostin for 08' - Alex Richards
Re: hard pedal feel?
Wednesday, March 12, 2008 3:04 PM
Matt Macomber wrote:are you positive that is the problem?


How can I be positive when I've never SEEN the car, let alone got my hands on it to properly diagnose it?

To correct Alex, Dot 4 would be fine as well.




14.330 @ 96.37mph
Re: hard pedal feel?
Wednesday, March 12, 2008 3:35 PM
When I said "anything else" I meant any petroleum based fluids.

Dot 4 is borderline. As far as I'm concerned nothing but DOT 3 should go in. Especially if you dont flush the entire system out first.



Buildin' n' Boostin for 08' - Alex Richards
Re: hard pedal feel?
Wednesday, March 12, 2008 6:22 PM
i dont put anything but dot 3 , im going to pull the vacum off the check valve on the booster tomorrow to check for vacum , the check valve might have gone to . the car doesnt get driven to often so that might have something to do with it.
Re: hard pedal feel?
Saturday, March 15, 2008 4:29 PM
how old are your brake calipers? you could have a seized caliper that would cause i stiff pedal. Hard to push something that won't move :S the other suggestions are possibilities too!! happy braking =)

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