In order to participate in the GunBroker Member forums, you must be logged in with your GunBroker.com account. Click the sign-in button at the top right of the forums page to get connected.

78 Vette Brake Problem

cbxjeffcbxjeff Member Posts: 17,568 ✭✭✭✭
edited May 2009 in General Discussion
My son has been helpng my sister-in-law get her Vette ready to sell. There has been a long going brake problem. Allan has found and replaced 3 leaking calipers. As of last weekend, there are no leaks. Unfortunately the pedal still is bad. He says that he can get a steady stream from each caliper when bleeding. I feel that elimates the master cyl.

I thought my working on cars ended 15 years ago but here I am. I hardly remember, but think I have read that the brakes should be blead w/ the engine running (P.B.). Also I think I remember that the caliper most far from the master cyl should be blead first.

Any ideas guys? She REALLY needs to sell this car as her truck is over 200K and needs a new one.

Thanks,
It's too late for me, save yourself.
· Share on FacebookShare on Twitter

Comments

  • savage170savage170 Member Posts: 37,504 ✭✭✭✭
    edited November -1
    It could be master cylinder leaking by with pressure. I use to have 77 vette along time ago found that alot of the chevy pickup brake parts were the same for 1/2 the price
    · Share on FacebookShare on Twitter
  • grumpygygrumpygy Member Posts: 48,464 ✭✭✭
    edited November -1
    Could be Vaccuum too. But if there was 3 bad calipers then would venture to say water had gotten into the system and the Master Cyl will also need replaced.

    Yes Fartherest 1st.
    · Share on FacebookShare on Twitter
  • savage170savage170 Member Posts: 37,504 ✭✭✭✭
    edited November -1
    Make certain rotors are thick enough if they are below min. that will make a soft pedal also
    · Share on FacebookShare on Twitter
  • select-fireselect-fire Member Posts: 69,446 ✭✭✭✭
    edited November -1
    Power brake booster is shot.
    · Share on FacebookShare on Twitter
  • A J ChristA J Christ Member Posts: 7,534 ✭
    edited November -1
    What do you mean by the pedal being bad?

    Soft? Travels to the floor?

    What year 'vette?
    · Share on FacebookShare on Twitter
  • SuwanneePirateSuwanneePirate Member Posts: 65 ✭✭
    edited November -1
    Select- fire is right on the money if the pedal is hard to push down . The booster is a duel diaphram type and if only one diaphram is bad the pedal will feel wrong if both are bad it really feels bad. If you get a strong stream while pushing on the pedal the master cylinder is most likely good unless it fails under pressure ,like pushing the pads against the disc ,then the master cylinder is bypassing internally.On an older high performance car I would replace all components and feel safe about it knowing that an old part is likely to fail as it won't take the pressure that the new componets will .Good luck
    · Share on FacebookShare on Twitter
  • turtles11756turtles11756 Member Posts: 1,118 ✭✭✭✭✭
    edited November -1
    the rubber hose connecting to calipers rot from the inside and need to be new are they original ? . replace the 4th caliper . master cylinder ? check all the steel lines from master cylinder back to calipers. are the rivets holding rear drum to spindles still there ? www.zipproducts.com. the new calipers are stainless steel sleeved. national corvette restorers society
    · Share on FacebookShare on Twitter
  • john wjohn w Member Posts: 4,104
    edited November -1
    Ok first thing you want to check is all the fittings for tightness. If you have a loose fitting it can suck air and you can still get a full stream out of ther bleeder but when you close the bleeder and pump the pedal you suck in air thru the not tight enough fitting again and most of the times they will not leak which is wierd!.
    · Share on FacebookShare on Twitter
  • givettegivette Member Posts: 10,886 ✭
    edited November -1
    Vintage 'Vettes have the "Bendix" style brakes, whereby there's piston cups that keep the fluid on the correct side of the piston, and a hairspring to keep the pistons against the pads.

    There are sixteen pistons on your 'Vette. If the car hasn't been driven regularly, and it has original calipers, the caliper interiors will develop rust spots due to condensation..so much so that rebuilds have upgraded to stainless steel inserts installed as part of the build.

    Above posts have solid info, but give the calipers a real careful check. Best, Joe
    · Share on FacebookShare on Twitter
  • Horse Plains DrifterHorse Plains Drifter Forums Admins, Member, Moderator Posts: 39,863 ***** Forums Admin
    edited November -1
    quote:Originally posted by A J Christ
    What do you mean by the pedal being bad?

    Soft? Travels to the floor?

    What year 'vette?


    Yep,need more info. Nothing here says the vaccuum booster is bad.
    · Share on FacebookShare on Twitter
  • dav1965dav1965 Member Posts: 26,540 ✭✭✭
    edited November -1
    I have had several vettes over the years i have a 90 vette now. When i first got this car i had the cruise fixed while at the shop they looked at the brakes for me. They found nothing wrong with them. I had a soft pedal, and sometimes it just did not feel like i was going to stop. Let your sister in law drive the car and see how much better it stops now. Older vettes never had good brakes. Its not like they had abs brakes like now. If anything is bad i would guess the brake booster. Good luck.
    · Share on FacebookShare on Twitter
  • dav1965dav1965 Member Posts: 26,540 ✭✭✭
    edited November -1
    By the way where do you live and how much for the car? I might be interested my car is about fixed up now and i need a new project.
    · Share on FacebookShare on Twitter
  • turtles11756turtles11756 Member Posts: 1,118 ✭✭✭✭✭
    edited November -1
    when the brakes are right in a corvette it will "stop on a dime"
    · Share on FacebookShare on Twitter
  • bartobarto Member Posts: 4,734 ✭✭
    edited November -1
    On my '76 the caliper seals were grabbing the pistons(for whatever reason) & actually retracting the pistons TOO far, creating a over-long travel.
    As stated earlier, with 16 pistons the master cylinder has to move a lotta fluid before the pads move.
    Solution was to replace all the calipers.
    Worked for me!
    [^]barto[^]
    · Share on FacebookShare on Twitter
  • Horse Plains DrifterHorse Plains Drifter Forums Admins, Member, Moderator Posts: 39,863 ***** Forums Admin
    edited November -1
    quote:Originally posted by Barzillia
    Brake fluid is not compressible, but water and air are.


    HUH???
    · Share on FacebookShare on Twitter
  • bamafanbamafan Member Posts: 4,011 ✭✭
    edited November -1
    quote:Originally posted by MT357
    quote:Originally posted by Barzillia
    Brake fluid is not compressible, but water and air are.


    HUH???



    Yeah. I wanna see some compressed water..
    · Share on FacebookShare on Twitter
  • 320090T320090T Member Posts: 2,715 ✭✭✭✭✭
    edited November -1
    Water will not compress until converted into steam. Both my Corvettes had excellent brakes. I'd replace the last caliper and the master cylinder. If it has rubber flex hoses, check them for bulging under pressure.
    · Share on FacebookShare on Twitter
  • givettegivette Member Posts: 10,886 ✭
    edited November -1
    There are six bleed fittings on a vintage 'Vette. The order of bleed is:
    RR inner. RR outer.
    LR iner. LR outer.
    RF
    LF.
    Bleed sequence is important.

    If the car was not going to be sold, I'd change out the calipers, and upgrade to braided steel brake lines. Combo of both makes for a "rock solid" brake pedal. Perhaps change the little rubber grommet that the vacuum hose fits into on the booster. It's an old car, and each item needs to be changed-out over time (if the car was to be kept).

    Perhaps after all the mods, she will decide to keep it? Could the brake problem be why she wants to sell? Hmmmmmmm..the plot thickens!

    Sidenote: before internet, I used to order from a catalog called MAD designs. That's Mid-America Corvette. Check and see if they are still online. Many parts otherwise unavailable are in the catalog. Best, Joe
    · Share on FacebookShare on Twitter
  • select-fireselect-fire Member Posts: 69,446 ✭✭✭✭
    edited November -1
    I've seen alot of Corvettes with bad brakes. Most times it is a simple solution or someone replacing the brake fluid with the wrong kind. Stainless steel calipers were the go to replacement for years. This is another alternative for C-3's

    http://corvettec3.ca/wilwood.htm
    · Share on FacebookShare on Twitter
  • cbxjeffcbxjeff Member Posts: 17,568 ✭✭✭✭
    edited November -1
    Thanks for the replies. The car is a '78 w/ P.B. We live in the Indy are but the car is at her lake cabin at Racoon Lake - west of Indy. She has to sell the car in order to replace her 200K Silverado! She isn't rich - her late husband bought her the Vette maybe 20 years ago. We will probably put it on eBay. I don't know what it's worth but all #s match, owned for maybe 20 years,and w/ about 60K miles - we don't want to give it away. The pedal goes almost but not quite to the floor. He has bled these brake so much that the fluid looks like is came right from the can!

    Yeah, Mid-American is a good place. I've had Vettes since '65. Had two for about 10 years but sold my '93 coupe and just have the '00 Conv't that we bought new. Going to sell that one & I hope my wife doesn't start talking about a new one!
    It's too late for me, save yourself.
    · Share on FacebookShare on Twitter
  • cbxjeffcbxjeff Member Posts: 17,568 ✭✭✭✭
    edited November -1
    WE GOT BRAKES!

    Just heard from my son. He bled them once again using the inside & longest run first routine. Fired it up and there they were. Thanks for all the suggestions guys. This has been a real hassle since the car is about 50 miles from us so it's been many weekend trips to work on it. Next is to get it on e-Bay.
    It's too late for me, save yourself.
    · Share on FacebookShare on Twitter
  • givettegivette Member Posts: 10,886 ✭
    edited November -1
    quote:Originally posted by cbxjeff
    WE GOT BRAKES!

    Just heard from my son. He blead them once again using the inside & longest run first routine. Fired it up and there they were. Thanks for all the suggestions guys. This has been a real hassle since the car is about 50 miles from us so it's been many weekend trips to work on it. Next is to get it on e-Bay.


    (Hee Hee)....glad to be of service. Glad someone listens to me out there in "posterland" Best, Joe
    · Share on FacebookShare on Twitter
  • select-fireselect-fire Member Posts: 69,446 ✭✭✭✭
    edited November -1
    Same exact thing the link I put up said

    GW.. the corvette guy.
    · Share on FacebookShare on Twitter
Sign In or Register to comment.