FireDemonSiC

Guys, I've done alot of research on here and it seems quite a few people have this issue, but I have not yet found an answer as to what causes it.

There is one final problem with my braking system that still has me perplexed. It seems at the beginning of pedal stroke when you step on the brakes, there is a large period where simply nothing happens. Then as you get more into the stroke, the brakes start to grab and operate normally.

Something of interest here is that after rebuilding my rearend, both axle seals initially leaked coating all of the rear brake shoes and drums in grease effectively reducing me to only my front brakes. During this period before replacing the shoes and axle seals I had to make a near emergency stop and was actually able to push the pedal all the way to the floor without locking the front wheels. I actually thought I was going to rearend the car in front of me but managed to stop in time.

To someone who had never driven the car before this would more than likely freak them out as they would think the brakes did not work very well. Even for me who knows this vehicle like the back of my hand it is a bit disconcerting every time I step on the pedal during the initial "deadzone".

I have replaced the front pads, rotors and calipers. I changed out the rear brake shoes and had the drums turned in addition to replacing the wheel cylinders and installing a new drum hardware kit. The brakes have been bled at all 4 points until new clear fluid was coming out. All of the brake hoses have been replaced as well. All performance parts. I know there is no air in the lines because if you pump the pedal with the car off until there is no vacuum left in the reservoir the pedal becomes rock hard with no sponge effect.

TBH, I have a love hate relationship with this problem because when you're going for a "spirited" drive it minimizes the chance that you will hit the brakes too hard and lock the wheels but at the same time I know that having difficulty locking the brakes on a non ABS car is a red flag.

I have no disappearing fluid and to the best of my knowledge the booster is not leaking. What exactly causes this?

MAC_87

iTrader: (3)

With the exception of the above, i have had the EXACT same
issue, down to the T. no joke.

Had this happen as well.

MAC_87

iTrader: (3)

Occasionally, when i depress my brakes, they work fine. 2 times out of 10.
I wish i knew how brakes worked better, but my theory is that it has to do with the brake booster hose...

I also have literally replaced EVERYTHING having to do with my brakes.
Rotors, calipers, pads, hoses, master, booster, prop v, bled them several times...
it STILL feels like theres tons of air in the lines 8 times out of 10.
I CAN stop, but it takes a lot of leg strength to do so at times. I almost feel as though theyre manual brakes as opposed to the power brakes theyre supposed to be.

I have 4 wheel disc btw. and its felt like this BEFORE and AFTER everything was replaced. Yes, the braking power got a LITTLE better after replacing everything, but not enough to take a match to..

MAC_87

iTrader: (3)

Fire, does your car stop better in reverse than it does going forward as well?
i reversed down my street and stomped the brake and it stopped pretty well, going forward at the same speed - it didnt stop as well. This may not be of any relevance, but im
just curious.

FireDemonSiC

Hmmm. I haven't really tried any hard stops in reverse at anything other than 10MPH (To set the starwheels), but it did lock the wheels.

Another thing I've noticed is that pumping the pedal while stopping seems to wake the brakes up.

I've put alot of effort into beefing up the stock brake system as much as possible.

- DOT4 fluid
- SSBC slotted rotors and pads
- Carbon metallic shoes
- Aluminum drums
- Braided steel hoses

only two things I haven't done is the SSBC dual piston calipers (Too much $$$ IMO) and adj. proportioning valve, but I don't anticipate either of those helping much.

sailtexas186548

iTrader: (2)

I had the SAME issue, occasionally the pedal would just go to the floor for no reason, sometimes it was fine. I replaced the fluid, bled everything, booster was good etc etc, the master was all it could be... I have put a new master on and will know in a couple of days if it fixed the problem, it should i have done a bunch of research on the issue

a couple things you can check:

- if you can turn the car off at night, and in the morning you can get a press of two on the pedal before it gets hard it means your booster is holding vacuum and is most likely fine.

- is your fluid dark? when the master starts going bad the seals deteriorate and the fluid gets dirty/dark, if you put new fluid in and it gets dark quickly it's very likely the master.

- have you bench bled your master? to do this you have to have the body of the master level (horizontally, take it out of the car and hold it in a vice by the mounting flange, or jack the rear of the car up until it's level), fill the reservoir, take two clear hoses and attach them to the two outlets on the master and the lose ends into the fluid in the reservoir. Then take a wood dowel or other wood rod (wire brush handle is what I use) and SLOWLY press the cylinder in the master in one inch (NO more or you could damage the seals), then slowly release. Make sure to keep the clear lines submerged in the reservoir, and keep pumping the master until there are no more air bubbles in the clear lines or coming up from the bottom of the reservoir. put it back in the car, bleed your lines to at the calipers (in order: pass rear, then drivers rear, pass front, drivers front)

FireDemonSiC

BTW, our problem is def not related to the booster. If you think the booster is not boosting as it should, try driving around the block without it hooked up.

This happened after I installed my hooker 2055 headers and Y-Pipe. When I started the engine, it ran HORRIBLE and almost stalled. Perplexed I put the car in drive and began driving around the block. Worried something had gone seriously wrong during the install due to the way the engine was running, I realized I had forgotten to hook the vacuum hose back up to the booster when I stepped on the brakes and it felt like I was pushing my foot against the floor.

Without the booster hooked up, it was extremely difficult to get the pedal past the beginning of the stroke, but it felt about the same otherwise: no real braking effect until you start to get on the pedal. Pedal had ZERO "sponge" without the booster working. From the very beginning of the stroke it felt like I was stepping on a rock.

Ever worked out on a leg press before? Yeah, no joke.

MAC_87

iTrader: (3)

Is Dot4 safe to use?...Ive always been told not to switch/mix, nor even use it
in our cars for that matter. i'd love more than anything to get this issue resolved.

FireDemonSiC

There's really no reason you shouldn't be able to use it. I was going to go with the DOT 5 fluid but the price on that stuff is ludacrous, so I went with valvoline Dot3/4 synthetic instead.

MAC_87

iTrader: (3)

i'm glad im not the only one with this issue, I was literally going to create a thread about this before I read yours...I couldnt have stated it better though...
Hope a solution can be found.

FireDemonSiC

I am beginning to wonder if a rather large amount of build-up has not accumulated in the body hardlines over the years (Kinda like someone who has high cholesterol and clogged arteries) reducing the effective pressure to the brakes. I know that when I cleaned out the MC reservoir after draining out all the fluid (Made sure to leave small puddles of fluid at the MC entries so the MC didn't run dry), I had to take a couple shop towels and wipe out the reservoir due to an accumulation of crud.

I've read of people replacing their ENTIRE brake system including the MC and booster without clearing this problem up, but not once have I seen anyone go to the trouble of replacing the bodylines. Then again, I can't imagine that would be a fun venture what-so-ever.

I just can't see the brakes working like this when my car rolled off the assembly line 27 years ago (WOW! You never really think that your car is older than you until you actually say it!).

I did replace the bodyline going from the rear T-fitting to the driver side rear brake when I discovered it had been flattened against the axle tube, but didn't think to cut it open and look before throwing it away.

MAC_87

iTrader: (3)

does your "BRAKE" light stay illuminated while driving?...maybe flash intermittently?

naf

iTrader: (7)

A reman master runs less than $30 and will come with the fittings required to bench bleed it. I'd swap it out, get all of the remaining crud out of your system and be done with it.

If you're worried about your metal lines, you can disconnect them and blow them out with some cleaner. If they appear clogged or constricted a replacement set is less than $80, from Finelines or one of those sites.

FireDemonSiC

No. If yours does, this is a serious problem that needs correcting ASAP. One of your circuits isn't getting any line pressure.

Sick92

You can buy some "line locks" from napa, they look like a mini-plastic c-clamp, with a rounded edge on the bottom, and a metal wing nut so you can safely "crimp" the rubber lines on your brake system. Clamp all 4 wheels, and see if your pressure is WAYY better. If not, then you have a leak somewhere (either master, or a line).

The only times I've ever had this issue is when I reused copper washers, or didn't tighten banjo nuts enough (to torque spec). Because AIR can get into the system, without brake fluid leaking. It's strange but true.

The torque spec for a 92 camaro - brake hose to cliper - 30ft lbs

MAC_87

iTrader: (3)

what do you mean by this?

FireDemonSiC

The next time you are under the hood, take a look at the distribution block (The smaller master cylinder looking part under the actual master cylinder). You will notice on the top of it in the middle there is a sensor with a single wire attached to it.

This sensor monitors the pressure difference between the front and rear brake lines. If there is a LARGE difference (Read Leak, air in lines or bad distribution block), it will illuminate the brake light as a warning. So far, mine has not come on other than when I pull the parking brake.

MAC_87

iTrader: (3)

mine doesnt even come on when i engage the ebrake. but my ebrake works 100% fine.

MAC_87

iTrader: (3)

are you saying my master cylinder is bad?..0_o
i just had it replaced with a brand new
one from oreilly's maybe 3 or 4 mo. ago..

FireDemonSiC

If your brake light does not come on with the E-Brake, try pulling the console lid and make sure the grounding wire is properly attached to the E-Brale.

Not saying your master is bad. Could be a leak in one of the lines or a bad distribution block.

BTW, love the "bandit" paint job on the front nose. Never seen that before.

MAC_87

iTrader: (3)

by "bad distribution block" you mean the proportioning valve? correct?.. it was replaced at one point..
I suppose i can see that being the light problem (sensor being bad), but- would this not also pertain to the other issues we're having? if it's indeed malfunctioning beyond the sensor?...perhaps mine is a greater case than yours (a step further progressed?) - maybe your *distribution block* is also messed up? and has yet to have the sensor mess up?

MAC_87

iTrader: (3)

and thanks for the compliment i saw it on a third gen from
dubai that had a custom white paint job and fell in love with that part of it

FireDemonSiC

It very well could be. I'm going to try replacing my master cylinder first and see if that helps.

Now that I think about it, I seriously doubt it could be related to the body lines. I remember 4 years when I first bought the car, I could lock the brakes on command. I used to do this with my ex in the car when ever she'd try to get on my nerves about something. Shut her up real quick, LOL!

Something somewhere has rapidly gone downhill over the past couple of years.

MAC_87

iTrader: (3)

i've only had the car since JAN of last year, but its been like this the entire time. never been able to lock the brakes. Only time ive ever been able to even stop hard enough to squeal the tires was when i was going in reverse and slammed the brakes hella hard. (thats why i asked that question before about reverse braking)

FireDemonSiC

Here's something else I noticed. Our cars are supposed to have a one way check valve in the line that goes from the intake to the booster. I discovered it today at work while browsing through the brake section on the computer.

Is your missing as well?

MAC_87

iTrader: (3)

mines just a straight hose, booster to intake. nothing in between except the odd connector to the booster.

FireDemonSiC

There is supposed to be a check valve there. Mine is missing too.

Some of the things these PO's of our cars do boggles my mind. It's no wonder the 2nd and 3rd gen F-Body line are considered red-neck trash. Even the 4th gens are beginning to fall victim now.

MAC_87

iTrader: (3)

sooo, theres supposed to be (for example) Booster -> Vac hose -> check valve -> vac hose -> intake?....

MAC_87

iTrader: (3)

im honestly saddened on how people are trashing the 4th gens. they arent even that old, and i rarely see a mint early or late 4th gen.
As for 3rd gens possessing the red neck trash reputation, i put that to shame.
i'm Indian, yes - From India. (no, no accent lol) and absolutely LOVE the third gen. im gonna be buried in this car >.<
Idc how many weird looks i get when i step out of the car, i Love my car.

sailtexas186548

iTrader: (2)

yes

the newest 4th gen is 10 years old, the oldest is 19... they are quickly approaching third gen status

MAC_87

iTrader: (3)

Sail, can you point me in the direction of a photo of the check valve? i'll have to try and snag one up from the scrap yard or something..

FireDemonSiC

http://shop.advanceautoparts.com/web...zoneAssigned=1

$7.39. I would highly recommend skipping the junkyard approach.

MAC_87

iTrader: (3)

they still shouldnt be looking like the majority of them do.

sailtexas186548

iTrader: (2)

http://auto.howstuffworks.com/auto-p...wer-brake1.htm

that shows you where the check valve is located just scroll down a bit

and MAC do you have more pics of your car? I like the black between the headlights I'd like to see more angles of it

MAC_87

iTrader: (3)

oh, thats the check valve...i have that on there, my mechanic even gave me another one to try. it didnt help...

MAC_87

iTrader: (3)

Here ya go Sail, I just posted an *about me* (including pics of car)
https://www.thirdgen.org/forums/nort...-thread-2.html

MAC_87

iTrader: (3)

I had a theory to test!

I disconnected the distribution block/proportioning valve sensor before my drive home to see if it made ANY difference at all, (i of course tested to make sure i still had brakes before i went anywhere) The brake light stayed off for about 3mi, during which i felt NO difference in braking power, then it blinked a few times and stayed on..after which i noticed i didnt have to press quite so far down on the pedal before i had resistance...however the braking power didnt really change, i just didnt have to press down so far before feeling something.

This may have nothing to do with it, but then again it may. It was just a theory i wanted to test perhaps this will help us pinpoint the real problem.

t-top havoc

iTrader: (3)

.

MAC_87

iTrader: (3)

you're a dot!, havoc! lol

cjh1505

hey guys i had the same problem with my 86 roc also. i put in the check and it made a small difference.i am now in the process of replacing my rear drums to disc.first i replacesd the tiny 10 inch rotors to 12 inch with corvette(pbr) dual piston calipers. this made a hugh difference. i can actully lock up the fronts.


i am starting to think that there maybe play in the system going from the pedal to the booster. maybe something is flexing as i push down the pedal?or there is something out of adjustment going to the booster.

MAC_87

iTrader: (3)

i messed around with the check valve a bit more today. didn't help any. Fire - if your hose from intake isnt connected to the check valve then to the booster, how exactly is it connected to ur booster?..

FireDemonSiC

Hmmm. I thought that connection was simply just that. I didn't know that was the actual check valve. Maybe I've been mistaken.

MAC_87

iTrader: (3)

same here, i expected something a little more impressive looking..

MAC_87

iTrader: (3)

how many miles on your car fire?

FireDemonSiC

Don't have an exact number since the speedometer was swapped out by a PO around 140k, then I reset it to 0 when we installed the new longblock AND ran it for awhile with 28" tires in the back without changing the speedo gear, but it should be around 170k original miles.

MAC_87

iTrader: (3)

ah mk. 156k here.

FireDemonSiC

Today while out on a delivery, a fab shop who I've buddied up with flagged me down and said he had some Camaro parts that he just got in.

For $20, I got a master cylinder and a rearview mirror with map lights that came off a totaled 92 RS with a little over 30k original miles before being rear ended

Tore the master cylinder apart and found a small amount of gunk, about what I'd expect for a 30k car. The pistons, springs and seals looked to be in top notch shape however. I wiped everything down and swirled the pistons in fresh brake fluid and put it back together. I'm gonna be installing it on the car soon and post back with the results.

sailtexas186548

iTrader: (2)

a remanufactured master is only $29 minus a $9 dollar core charge and has a year warrantee

FireDemonSiC

I would have offered the guy $10 if it hadn't been for the map light mirror. Don't think I did too bad.

Sick92

DOT5 will destroy your system, fyi. You can interchange dot4/dot3, but not dot5.