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Discussion Starter · #1 ·
Hi I have a 1980 Chevy Scottsdale K20 4x4 that has a brake issue. The brakes will take effect at about the 9th pump of the pedal but once I take my foot off the pedal it loses pressure; I have to pump about 9 times before they come back. No leaks anywhere that I can see. I am 14 and WILL NOT sell this truck. (Back brakes leaked severely, clamped lines shut no pressure or fluid leaks from that area.)
 

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First try bleeding. When you replace a wheel or master cylinder, you should replace them all. Also, brake fluid should be changed every 5 years with the correct type.
 

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Discussion Starter · #3 ·
Hi Corday I have bled the brakes at least four times and no difference. As far as I know, no wheel cylinders or master cylinder replaced. Was my grandpa's truck and he gave it to me for free. Brakes worked great after I got it running two years ago. This issue started about a year ago.
 

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I hope you've changed fluid with each bleed. The correct way to bleed is to start with the rear passenger one, then driver rear, then passenger front and finally driver front. You're actually working back to the master cylinder. Each wheel should be bled 3 times.
 

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Discussion Starter · #5 ·
Hi Corday I have done that with the fronts but, as stated before, I have the back brake lines clamped off so I have no fluid to the back brakes, as they leaked severely. Fluid was changed.
 

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I thought you had fixed that. Clamping off is an emergency procedure, not a fix. Because of liability law, the only advice I can give is get thee to a brake specialist.
 

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I am a brake specialist on older non abs vehicles, corday's bleeding procedure is CORRECT, clamping off a line is illegal in most states to the best of my knowledge,I would also check the brake master cylinder after you have removed all fluid from the lines, that is easy, once everything is bled and the fluid is all changed out hold pressure on the pedal after pumping it hard three times, if I moves toward the floorboard the master cylinder is leaking internally, also remove the master cylinder from the vac booster, with out loosening the lines and look inside the booster with a flashlight, if you see fluid, the booster will need to be replaced also,
Once I replaced a master cylinder on a Jeep and pumped a entire bottle of brake fluid into the vac booster because of a defective seal
Brakes are my pet peeve, when a car leaves my yard I couldn't care less if it moves forward as long as when that ball comes between two cars and a child follows it you can stop
 

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Discussion Starter · #10 ·
Hi I have changed the brake fluid and have done as suggested. It takes about 6 hard pumps before it holds pressure IF I keep my foot on the pedal. When my foot is on the pedal, it does not move. When I let off, pressure is gone in about 3 seconds. It holds a little pressure but not enough to operate the brakes. I pump the pedal about 6 times, they "take hold" (for lack of a better term).
 

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Please, please, please do what your grandfather would have done. Get to a brake shop immediately.
 
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Are you the original owner?or maybe your father or grandfather, I know this might seem far fetched, but are the bleed screws at the top of the caliper or the bottom?
I've never seen a private person do that, but I have seen brake shops do that

jk4229, I wish you lived here in Northampton county NC or near, I do not charge to look, only to fix, and I charge 30 a wheel for brakes,plus parts
and I PROMISE you it'll stop on a dime and give you 9 cents change and a 1 cent govt kickback when I'm done
 

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I've seen someone put the bleeders on the bottom.....my son!! He won't do that again....:ROFLMAO: He was doing the 'bleeding' and I was in charge of the brake pedal. My leg was getting tired from pumping the brakes up....we were almost out of brake fluid, too. We traded places.... as soon as I looked at the calipers I told him to put them on the correct sides. After that we had to bleed each side.....only one time...:whistle:
 

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Discussion Starter · #14 ·
Hi My grandfather owned it and he gave it to me. The bleed screws are on the top. I plan to get it to a shop near home at some point, but it is not too important. It is only used around the farm and it isn't licensed. Wolfen1086, I live very near Flandreau, SD. Small town.
 

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Hi My grandfather owned it and he gave it to me. The bleed screws are on the top. I plan to get it to a shop near home at some point, but it is not too important. It is only used around the farm and it isn't licensed. Wolfen1086, I live very near Flandreau, SD. Small town.
Question, if at idle, engine warm and you press the brake, is there ANY change in indicated RPM, or eng sound?
 

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Vacuum leak in brake booster. Check with a gauge if you have one.
 

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Corday is correct, there is a possible vacuum leak in either the line to the booster or the booster itself
Test it with a soapy water mixture, in a spray bottle, spray everything down with it with the eng running and see if theres any change, believe it or not THAT will save you about three hundred dollars because the mechanics is gonna do the same thing.
Spray the booster, the line where it goes into the booster and the line where it hooks up on the intake manifold first, then spray the line itself, I'm not saying this is your problem, but back in 84 I have a 76 C10 4x4 and no power brakes at all, and it was the rotted grommet that little plastic fitting was in
 
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