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Old 04-18-2004, 11:39 PM   #1
machinetodd
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Default Soft brake pedal

I just replaced the front calipers, hoses, rotors, pads and hoses and completely bled(2 quarts worth) the system on my 77 350(L)

This is my first Vette and I have only had her for a week. I have done about a million and one brake jobs in my life but never on a corvette

While I was bleeding the rear I noticed that the rear calipers are leaking from the seam in the middle. I am going to replace the rear calipers steel lines, pads and rotors as well. I am hoping that the brake pedal gets better.

Any suggestions on why my pedal is so low and soft,? and the lbrake light is always on.
The rear caliper that is leaking really isn't leaking all that much. I am aware that any leak at all in a hydraulic system is bad but I guess I am looking for
some one with simialr expierience to ease my mind.
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Old 04-18-2004, 11:53 PM   #2
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Default Re: Soft brake pedal (machinetodd)

Welcome to the Corvette world and to one of the most troublesome areas of concern. For the time being, bleed those rears, both upper bleeders on each side. You should be able to get much information on the archives on this problem. Use only stainless steel sleeved calipers and do not change those rotors unless you have to, especially if the rivets are still intact. You need to inspect the rotors to determine their condition and check the runnout. If you use SS calipers and get your runnout within specs, the brakes should stay hard and should be relatively trouble free, but you need to do it right the first time.
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Old 04-19-2004, 12:13 AM   #3
machinetodd
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Default Re: Soft brake pedal (wombvette)

the rotors on the front had to be changed, the guy that had the car before me let the brakes go metal to metal in the front, they had less than a1/4 inch of meat on them and what was there was scored horribly.

The calipers are definately s/s sleeved, as will be the rears I am buying tomorrow.

Should I be worried about a porportioning valve as well?

The master look brand new but I bled it anyway.
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Old 04-19-2004, 12:59 AM   #4
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Default Re: Soft brake pedal (machinetodd)

If I were you, I'd o-ring the calipers, or buy ones from Vette Brakes that are already o-ringed for you. This will eliminate the rears from pumping air when the runout gets out of whack.

I have a step by step on my website, if you have any questions.
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Old 04-19-2004, 07:07 AM   #5
ettev
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Default Re: Soft brake pedal (wombvette)

Does anybody know of a good source from which to purchase the one way/one person (check valve) bleeders?
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Old 04-19-2004, 08:49 AM   #6
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Default Re: Soft brake pedal (ettev)

Quote:
Does anybody know of a good source from which to purchase the one way/one person (check valve) bleeders?
I bought mine at my local autozone.. :seeya
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Old 04-19-2004, 02:57 PM   #7
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Default Re: Soft brake pedal (ettev)

Pep Boys, O'Reillys and Discount Auto Parts all sell them. They are called Speed Bleeders.

Words of warning though. Look at the taper on the Speed Bleeder versus a normal Bleeder. The angle is different. Also some Speed Beleders are stainless. I used Russell Speed Bleeders and could not get a good seal in 3 out of 4 calipers. I went back to the regular bleeders and had hardly any trouble. The Speed Bleeders do not like to push air. You really need some fluid at the ball bearing for them to work right.

Some of the Speed Bleeders are Stainless Steel. The calipers are cast iron. The stainless Speed Bleeders can "cut" the cast taper and even crack the cast as they are harder then the "soft" cast iron. If you must use Speed Bleeders get the cheaper soft metal kind in the HELP section at PEP Boys. At least if you screw up a bleeder it only costs you $3 instead of $100 for a new caliper.

I found the best way to bleed brakes was to gravity bleed first, then do vaccum/buddy bleeding after. Use the money from the Speed Bleeders to buy the friend that helps you a six-pack.

My brakes are finally great!
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Old 04-22-2004, 12:04 AM   #8
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Default Re: Soft brake pedal (stingry)

Tried the speed bleeders, and in my opinion they are junk.

I finally got a nice brake pedal after replacing all 4 calipers all four brake hoses the two rear hard lines, 1 and a half gallons of brake fluid two sets of pads in the front (the first were organic and they are in the garbage with the speed bleeders) and a set of rear pads and about three hours of bleeding time.
But I keep telling myself "I love my car, I love my car, ...ect

thanks for all the advice guys! :smash:
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Old 04-22-2004, 03:44 PM   #9
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Default Re: Soft brake pedal (machinetodd)

The key is the right bleeding sequence. I went through the same thing. Consult the GM shop manual (I don't have it handy right now) for the right sequence. It is different than most all cars, and you must do it the stated way. I could not get a hard pedal until I ran the proper sequence. The barke light is staying on because the pedal has bottomed out. To clear it, get the brakes bled properly first. Then you have to hold the pedal down HARD for about 5 sec. and then you will feel a kind of blip in the brakes and the light will clear. This is also per the GM manual. I have seen more people here in the forum buy every part in the system, and the porper beleeding sequence was the issue. While "O" ring calipers are godd, this probably isn;t the reason for a soft pedal, unless one of the calipers has a problem. Corvettes have had working brakes for years with the standard seal. Even if you get "O" ring calipers, you will still have a soft pedal in not bled properly. This bleeding question comes up about once every 3 weeks. Next time I am going get the exact instrcutions from my shop manual and post them here.
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Old 04-22-2004, 03:49 PM   #10
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Default Re: Soft brake pedal (machinetodd)

One more thing. I see notes about "hours" of bleeding time and gallons of fluid. If you do it per the GM procedure, you can do two full circuits of bleeding in about 20 minutes (with two people). I never went through more than a quart of fluid. Not long ago a mechanic on here gave a technical expalanation of what happens if the sequence is wrong. You're just basically shifting air bubbles one way and the back the other, so you never get bubbles all of the way out. I also have Speed Bleeders which help immensly, and I have found to work very well, but two people give a chance to really move fast. Every since I did this the right way the brakes are great, and I have the stock, orignal set up on 25 year old, rebuilt orignal numbers calipers. I would save you money and try the reccomended procedure first. If that doesn't work, then move on.
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Old 04-22-2004, 04:07 PM   #11
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Default Re: Soft brake pedal (machinetodd)

Leakage from the seam on my brakes came from fluid pushing around the lip seals and then out the dust boots. It then runs behind the pads and ends up at the split.
Even small fluid leaks of a teaspoon per outing made the brakes feel mushy.
The last leak was stopped by going to 0-ring type seals and new pistons from Vette Brakes and the pedal felt normal immediately.

I went through 4 quarts of brake fluid doing and re-doing the brakes.
At least 2 of the quarts ended up either on me or the garage floor!


[Modified by triadecho, 8:11 PM 4/22/2004]
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Old 04-22-2004, 04:16 PM   #12
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Default Re: Soft brake pedal (triadecho)

If the calipers were split at any time they may have pinched the little o-ring for the porting between the caliper halves. My 2 cents.

Steve
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Old 04-22-2004, 06:25 PM   #13
Nifty 71
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Default Re: Soft brake pedal (machinetodd)

Also check the rear caliper lines and make sure they are not leaking where attached to the calipers. I had to replace these lines to solve a similar problem due to leakage from the right rear.
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Old 04-22-2004, 06:30 PM   #14
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Default Re: Soft brake pedal (machinetodd)

i always gravity bleed my brakes. open the bleeders in this order. pass rear, driver rear, pass front, driver front. and close in the opposite order. just add fluid to the master cylinder as it drops.

chris
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Old 04-23-2004, 11:48 AM   #15
gliot1
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Default Re: Soft brake pedal (cmashark)

C3s are not done farthest to shortest. It you do it as noted above, fartheset to shortest you may never get it bled properly. Consult the GM manual. I was working this for a summer, until I read the book. I wanted to punch myself in the face.
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Old 04-23-2004, 12:10 PM   #16
wcsinx
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Default Re: Soft brake pedal (gliot1)

Quote:
C3s are not done farthest to shortest. It you do it as noted above, fartheset to shortest you may never get it bled properly. Consult the GM manual. I was working this for a summer, until I read the book. I wanted to punch myself in the face.
:iagree:

As I recall, the proper C3 bleed order is

Driver Rear Inner
Driver Rear Outer
Pass. Rear Inner
Pass. Rear Outer
Driver Front
Pass. Front

Someone correct me if I'm wrong.
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Old 04-23-2004, 03:19 PM   #17
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Default Re: Soft brake pedal (wcsinx)

hmmm, maybe i should get one of these gm manuals. must have just been lucky with the last few vettes. i should have played the lottery!!!! :banghead:
how much is that manual and where did you get it. i have the haynes manual, but it has always been useless.

chris
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Old 04-23-2004, 03:47 PM   #18
Garys '68
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Default Re: Soft brake pedal (cmashark)

I'm doing mine this weekend, thanks all for the info.
Question: On the rear inner/outer, the inner is only on the bottom. Aren't the fluid passages in the calipers at both the top and bottom? Wouldn't just the outer bleed it OK?
Gary
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Old 04-24-2004, 02:16 AM   #19
machinetodd
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Default Re: Soft brake pedal (Garys '68)

there should be two bleeders on the top of each rear caliper. On the re-mans I bought there was also a bleeder on the bottom outer of each caliper. I have no idea why. Air rises to the top, thats basic physics, maybe the bottom bleeder is so that people like us can just get more frustrated and keep these forums full.
:smash:
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Old 05-22-2012, 10:39 AM   #20
61toutrj
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Default Pedal still soft?

Hi all...have been following the post and have just completed my complete brake job on a 76 this past weekend. Have gravity bled the brake system 3 times in the order as posted but still experiencing a soft pedal when sitting at a stoplight or after 5-6 brake applications. The pedal feels hard and brakes are very responsive but as noted there is this soft feel. Is it possible the master cylinder could need rebuilding too? Anyone experienced this phenomenum?
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Old 05-22-2012, 10:39 AM
 
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