Brake Tapping

cherrington17 · 05-15-2009, 04:24 PM

As far back as i can remember, my brakes make a groaning/tapping noise when i lightly step on the pedal. u can sometimes feel it in the pedal itself. (no abs on my car)

It sounds like something needs grease, and its not the brakes themselves. It sounds like its coming from just on the other side of the firewall.

suggestions?

CactusWill · 05-15-2009, 04:28 PM

Hmm, I don't know about the groaning, but I can feel when the brake light switch is activated on mine. Just a gentle click and the brake lights come on.

cherrington17 · 05-15-2009, 04:35 PM

nah. thats not it. it does it several times repeatedly. if i let off the brake a little then push down hard, it doesn't. only when i brake really lightly. Also.. only in the first... 1/3 of the way. if i push it to the floor, it doesn't "tap" all the way.

the groan just sounds like two things rubbing that aren't greased. nothing like my brakes are bad, wheel bearing groans.

cherrington17 · 05-22-2009, 07:31 PM

whelp... come to find out.. my passanger caliper pins are completely rusted in place. That would explain the odd noises. (driver's side is fine)

the even more odd thing is, i tore apart the driver's side, thinking thats where i heard the noise. Found nothing, reassembled, bled the brakes. and still have 0 brake pressure.

Is this because i haven't bled the other side yet? or is something fubar'd? i did manage to have the caliper piston push out most of the way, so i had to re-seat that. but its back in and seems to be working. I can bleed them, and get pressure, but as soon as i start the car, its gone... completely. Not leaking anywhere, either.

clutch1 · 05-22-2009, 08:56 PM

Check the rear passenger side... see if you have pressure in that one.

If not, you need a new master cylinder.

cherrington17 · 05-22-2009, 09:05 PM

ok.. i was originally working on the front drivers. come to find out the front passanger caliper pins are shot.

why would i check the rear passanger?

... and i can't say i've ever checked pressure on my rear drums... no clue what i'm doing there.

Afugy · 05-22-2009, 09:15 PM

Did your reservoir ever get to low?

Your reservoir is full?

Non the less it sounds like you need to rebleed both sides and make sure you clear it to new fluid. Clearing it to new fluid is just something that I got in the habit of doing and will not hurt to do every time you need to bleed your brakes. And how are you bleeding your brakes?

Before you started working on the brakes every thing was working ok besides the sounds?

cherrington17 · 05-22-2009, 09:18 PM

yes, everything was fine. Resevoir got low.. a little below "minimum" never emptied.
i'm using a 1-man bleeder.

i have fluid straight through to the resevoir (both the master cylinder and the bleeder) driver's side. I definitely don't have any air on the driver's side.

Due to the bad pins on the passanger, i haven't bled that yet. Not going to bother for a while... since its a moot point.

clutch1 · 05-23-2009, 02:50 AM

Quote:

Originally Posted by cherrington17

why would i check the rear passanger?

... and i can't say i've ever checked pressure on my rear drums... no clue what i'm doing there.

Most new cars have 2 hydraulics circuits, and they are diagonally split (FR/RL, and FL,RR are both connected hydraulically). The master cyl has 2 seperate seals to pressurize these.

If both the front driver and rear passenger don't have pressure, I would suspect the seal in the master cylinder that pressurizes them is shot.

Merlyn · 05-23-2009, 03:22 AM

Quote:

Originally Posted by cherrington17

...the even more odd thing is, i tore apart the driver's side, thinking thats where i heard the noise. Found nothing, reassembled, bled the brakes. and still have 0 brake pressure.[/i]

If the brakes aren't bled completely as well, air bubbles inside the lines can make it feel mushy or not there when you press the pedal.
The drums are auto-adjusting, and so shoudl the calipers in the front. So test with the car on, press the pedal a few times..( don't ram it through the floor ).

bdyman · 05-23-2009, 09:38 AM

Quote:

Originally Posted by clutch1

Most new cars have 2 hydraulics circuits, and they are diagonally split (FR/RL, and FL,RR are both connected hydraulically). The master cyl has 2 seperate seals to pressurize these.

If both the front driver and rear passenger don't have pressure, I would suspect the seal in the master cylinder that pressurizes them is shot.

he`s right
when you bleed brakes its always the farthest side first, so it would go right front, left rear, left front, right rear, like that,

this is what i would and i make it a ahbit when i do brakes

when you have the caliper off the bracket, i always clean the mount points, on the bracket, clean the mount point on the caliper, then i put just alittle bit of anti seize on all the mounting points, and i always have the rotors cut, always

so when you put the new cliips in the bracket, put alittle anti sieze on those too it wont hurt, i do a mounting kit too should come with new caliper bolts, habit of mine too, same thing with the x-pattern brake system, push the farthest piston back in, and leave the master cylinder closed

the rear shoes, very easy to do espicialy on a gm, remove the drum get a couple can of brake cleaner and clean the crap out of the rear brake system, if you look at the bottom of the backing plate you will see the star adjuster, spin it out to make the shoes go wider spin it back it to make the shoes adjust in, as your doing this put the drum back on and you want the drum to have just enough drag to stop it on its own

oh ya i also put alittle anti sieze on the backing plate where the shoes sit
you could also have a bad wheel clyinder in the rear, you will see it too and the shoes should slide if you push on the top of them back and forth

real simple so simple i taught mrs.bdyman gm brakes so you can too

clutch1 · 05-23-2009, 01:29 PM

D'oh, didn't think of air in the lines. That sounds like a chance, too.. without the power assist of the running engine you might not feel the mushy pedal.

Bleed the back opposite side, then front Dside, thennn see if the problem persists before you throw a new master on :P

cherrington17 · 05-23-2009, 01:41 PM

ok... all the pads/shoes and rotors are ok. how do i bleed the back? i know they have a self adjustment screw, but i've never looked close enough to know anything about drums.

does it have a bleeder valve like the fronts do?

bdyman · 05-23-2009, 02:07 PM

yes look in back of the backing plate where the wheel cylinder is you will see the screw

clutch1 · 05-24-2009, 02:36 AM

If it's super risty you may want to make sure you've got enough cash for a new pistol assembly... not expensize but certainly something to be aware of should you twist off the bleeder nut.

While your back there, pull back the boots where the pistons come out of the bore, and check for fluid leaking/seeping out. (fig A) If you see any, that's bad, and I'd suppose could cause low pressure on that circuit as well.

fig A

cherrington17 · 05-24-2009, 08:05 AM

no image clutch.... try again.