Mushy brakes?

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Kraze

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Alright so my brakes are pretty much useless. It's not the pad or the rotors, I've had those checked out already. But basically what happens is I don't have any more braking power from just lightly pushing the pedal to pushing it to the floor. It also seems like the brakes don't want to work at all if you go from being pretty heavy on the gas to trying to brake right away. I've had to run many a red light just because I know I can't stop in time.

What could this be? Air in the brake lines? Bad brake booster? I'm clueless here :confused:
 
Yes it is. I need to get if fixed asap, I've already almost rear ended other cars because of it.
 
Your description of the problem still leaves me mystified. Have you glazed over your brake pads with all your RED LIGHT MADNESS ?
 
If a brake boost was bad it would be very firm
Does this happen when the car is cold if so sounds like air in the system
 
I guess the problem is kind of hard to describe. There's just no braking power anymore. It feels like the brakes are clamping just as hard at light braking as they are when you have the peddle mashed to the floor.

And say if you were accelerating quickly up an on-ramp or something, and you had to go right from accelerating to stopping suddenly, say because of traffic backed up, it takes a while for the brakes to even work at all. The brake pedal is stiff and it feels like it just doesn't want to be pushed in that situation.

Lol and by running red lights, I mean the light turns yellow as I'm approaching it and I already know I can't stop in time so I have to just keep going.

It's pretty bad when my 98 F-150 with crappy brakes still stops better than my Mark.

Edit: It happens all the time, whether it's cold or warmed up. And the pedal is firm, especially in the accelerating to sudden stop scenario I mentioned above.
 
check fluid level, add fluid, bleed the system... check for leaks... sounds like you have a leak.
 
I'd second that, bleed the system really good and look for any lil leaks anywhere.
The manual suggests to also check the big nut that hold the hub/axles on.
 
Well you may have a leak. When you say mushy to me that sounds like spongy if so that means you have air in your lines. Also if you flush out the system do not reuse brake fluid once you break the seal on the bottle. because with the brake fluid moisture will get into the bottle when its stored. But also it can be your caliper pins, if they cannot move your breaks will lock up.
 
One other thing other than a posb leak could be seazed caliper's or the slid pin's need some good grease. Check the fluid level, flush and bleed the system and check the movement of the piston and slid pins, grease as needed.

If it is still easy to push the pedal, you booster is still working but your master cyl might have an internal leak or is seized also.
 
im wondering if your rotors are too thin (when machined close to the specs, the caliper cant clamp down enough) thats what it sounds like to me, sounds like you can stop fine normally but in a panic stop it just gradually slows down
 
I'm wondering why your driving with a car that can't be safely stopped.

Id start with a complete fluid flush at the stealership so they can get the abs and everything flushed and bled properly. Then I would look at all four corner and verify that the pads/rotors/calipers/slides are all functioning.
 
I have the same exact problem on my 96. I have a new master cylender, pads, rotors, and had the lines properly flushed. Doesnt stop. Im ready to junk both of my pieces of crap....
 
Well I'm going to make an appointment to have the brakes flushed and I'll have them check for leaks while they're at it.

It doesn't seem like it would be a pad/rotor/caliper problem just because of the symptoms though. Why would it be worse when you go from accelerating straight to braking if it was something like that? However, I'm not an expert so I could be wrong.

I think it's interesting that two other people have the same problem though. It's kind of a unique problem, maybe it's something with the mark's that commonly goes bad.
 
Kraze said:
Well I'm going to make an appointment to have the brakes flushed and I'll have them check for leaks while they're at it.

It doesn't seem like it would be a pad/rotor/caliper problem just because of the symptoms though. Why would it be worse when you go from accelerating straight to braking if it was something like that? However, I'm not an expert so I could be wrong.

I think it's interesting that two other people have the same problem though. It's kind of a unique problem, maybe it's something with the mark's that commonly goes bad.
Click to expand...
Yeah its weird. is yours a gen 1?
 
Completely flush the brake system with fresh fluid. If fluid level was low to start with look for leaks or worn pads. Also check engine vacuum and brake booster check valve.

The brake pedal was a little soft in my Mark, after flushing out all the old nasty dark fluid with fresh the pedal is rock solid.
Use DOT 3 or 4.
 
Nope, it's a 97.

And the problem with mine isn't the pedal being soft, but I'm going to have it flushed anyways.
 
Have you checked to see if your booster is maintaining vacuum? (hard pedal + poor brakes usually = vacuum leak)

Leave car for a while, then pull the vacuum hose off the check valve on the booster - should be a loud hiss if vacuum is maintained. If nothing, you have found a problem!
 
93' Blue on blue said:
Have you checked to see if your booster is maintaining vacuum? (hard pedal + poor brakes usually = vacuum leak)

Leave car for a while, then pull the vacuum hose off the check valve on the booster - should be a loud hiss if vacuum is maintained. If nothing, you have found a problem!
Click to expand...

Well I just checked for vacuum leaks by letting it idle and spraying some starter fluid around the hoses and turned up nothing, but I'll try this too.

When you say leave the car for a while, do you mean after driving it, come back, turn it off, give it a good 5-10 minutes, then pull the hose? Or do you mean something else?
 
Kraze said:
When you say leave the car for a while, do you mean after driving it, come back, turn it off, give it a good 5-10 minutes, then pull the hose? Or do you mean something else?
Click to expand...

Yeah, thats right. Let it run for a while, turn off, leave a few mins and check. (i had a similar problem last year - no vacuum - disconnecting the hose after a few mins did nothing, but now, after fixing the leak, i can leave it for hours and it will 'hiss' when i pull that hose off - so i know my vacuum is good)

Do that first, tell us what you find.
 
Well.. it has vacuum.

So should I just replace the master cylinder? Or is it the brake booster, or both? Or can I take it somewhere and have them look to see if that's what the problem is?
 
Ok, heres another 'long shot'

The check valve that you disconnected the hose from. Is that functioning ok? (the check valve is a one way valve, allows vacuum to be drawn out from the booster, but shouldn't let anything back in)

Pull that valve out carefully and do a 'suck n blow' test. You should be able to consistently suck air through, at the end where the hose connects, but should NOT be able to blow back through it. (valve should keep clicking closed)

Any doubts with its operation - change it. Its a 5 dollar part from the 'help' section of any good auto store.

Once you have absolutely confirmed that vacuum is being maintained, do what others suggest - fluid flush and bleed etc. Also, check as much of your brake lines as possible, look for any crushes or kinks.
 
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