1981 chevy truck brake problem

[jimmy4493]

I have a 1981 chevy scottsdale. 350 no 4+4.
I can start my truck. When i put into gear in either reverse or drive. my back wheels spin. It's like my front wheels are locked. i am digging a hole where the back wheels are.What do i need to do to get it moving again. What parts do i need I have asked and failed in trying to get help. I though it was the proportioning valve .I went to the chevy dealership and they told me that was not the problem. Then i was told that it might be the master cylinder or the sensor on the bottom of the mater cylinder.The truck moved to it's current place and then stopped. I had this problem where i could not move. i was told to clear the battery and sensor for 20 seconds. I did that and it moved to where it is stuck now. i have been told so many things that i can't figure it out. The truck was running fine until this winter. I had the truck overloaded with scrape so that might have caused some type of damage. i have not as of yet jacked it up yet. the weather has been cold and crappy.

[mrjohnwayne]

Do you mean that while the brake pedal is pressed in gear the rear tires are spinning, or the front are locked up and wont spin with the brake pedal not pressed?

[75K30]

Stuck proportioning valve? Are both front calipers stuck? Are both front wheels having a problem? Have you jacked up the truck to determine any of the above?

[dstrick32]

Also the rubber hoses that connect to the calipers are known to deteriorate with age causing the inner linning to collapse and lock front brake from releasing pressure.

[436'd skylark]

well is the truck in the slop? is it a 4x4? if so are the hubs locked? have you ever driven the vehicle before? any know front diff problems? have you pulled a wheel and inspected anything? do you have anything more specific? ya know, maybe I'm crabby, but d@mn, ya could look into it a bit before asking for help. geez. This is what i would do:
pull it in 4x4, if equipped, and then try to move it.
verify its not just stuck in mud..
think to myself how long its been sitting, and wonder if its possible that a lot of rust built up on the rotors. take a sledge hammer and give each front wheel a good smack, the shock is ussually enough to break stuck brake components apart. if that doesn't work
jack it up, pull a front wheel, make sure knuckle head friends didn't jimmy rig something to mess with me. inspect brakes for heavy rust. pry on the caliper, it should move around a bit if not, either the pins or piston are stuck. give it a few good whacks with a hammer, not crazy hard, just a few wake up calls. see if it frees up.
pull a caliper, and inspect it. see if rotor spins.. if not assuming its a 4x4,
unlock hubs, try again. if it spins, pull front diff cover, inspect gears for wrench friends jimmy rigged in just to mess with you.. remove wrench, and be on your way.
if looks good, pull front driveshaft, try again.


in the future, try to be more specific in your question, truck year make and model, 4x4 or not, any important info. what you have tried, how long it has been sitting, any recent work done. etc. etc. I enjoy being a tech, but it can be very frustrating.

[mudseeker]

[quote=436'd skylark;29224]

jack it up, pull a front wheel, make sure knuckle head friends didn't jimmy rig something to mess with me.
inspect gears for wrench friends jimmy rigged in just to mess with you.. remove wrench, and be on your way.
quote]
i think you need to find some new friends skylark!

[jimmy4493]

I have a 1981 chevy scottsdale. 350 no 4+4.
I can start my truck. When i put into gear in either reverse or drive. my back wheels spin. It's like my front wheels are locked. i am digging a hole where the back wheels are.What do i need to do to get it moving again. What parts do i need I have asked and failed in trying to get help. I though it was the proportioning valve .I went to the chevy dealership and they told me that was not the problem. Then i was told that it might be the master cylinder or the sensor on the bottom of the mater cylinder.The truck moved to it's current place and then stopped. I had this problem where i could not move. i was told to clear the battery and sensor for 20 seconds. I did that and it moved to where it is stuck now. i have been told so many things that i can't figure it out. The truck was running fine until this winter. I had the truck overloaded with scrape so that might have caused some type of damage. i have not as of yet jacked it up yet. the weather has been cold and crappy.

[chevyguy]

Very simple to determine. Jack it up, take the tire off. Try to spin the rotor, Remove the brake caliper (2 bolts ) and try again. If you cannot get the caliper to release,Loosen the bleeder and see if it releases the pressure. If it is holding pressure then its probally the master cylinder, If its not the caliper, then your front end is locked up or bound up. Jack it up and try the above and get back to us. We just need to determine if its brake, ir drivetrain.

[taz012]

i have a 1981 chevy truck 6 cylinder i have no brakes i put brake calippers and shoes on it we thank it is the master cylinder but cant get it off ne one know how to get it off theres a gold thing hoding the rod on but cant get the master cylinder off

[shortcut]

did you bleed the brakes?