I have been having trouble lately with my brakes acting kind of funny.

sometimes when you go to stop , the instant your foot even begins to touch the pedal , the rear brakes lock up , and it slides , the front brakes are not applied at all at this point, let off and step on them again , same thing , drive a little farther , and it works fine.

another thing it did , was one day it was parked , and i got in , the brakes were locked on , i had to back up to get them to let go.

any idea's what is wrong here?

 

Well, I can't tell you exactly what is wrong, but, you will need to pull the drums no matter what it is. Check for an axle seal leaking and also check for a wheel cylinder leaking. You may also have some lining on the verge of disintegrating too.
Tom

 

Sounds like a broken spring. Pull the drums and you may get powder!

 

my work truck did this at one point too , did it one night the pedal went right to the floor. i got it to pump back up , abs lights came on , then went away.

the next day it would lock up one wheel with just a ligth touch of the pedal , i pulled the drum on that side , and it was all new in there , the brakes had just been done on it , i could find nothing wrong...

i will pull the drums on my truck this weekend and see what is goin on

 

Keep us informed

 

Well , i got today and tomorrow off of school , so i tore into it this morning , got the drum off after much persuasion , and found the axle seal had been leaking , so i pulled the axle then the hub , and now i am waiting for mom to come and take me into town so i can get some parts , and borrow some brake spring pliers , since i have none.

i will post when i am done. hope this fixes my problem.

 

I got a new seal , but found the bearings in the hub were going bad , so i had to order then for tomorrow , put new brake shoes on , got some other stuff all cleaned up , and tore into the other side , seal was goin bad but not leaking over there , so now i need another seal. and i have to put new brake shoes on that side too....


hope nothin else goes wrong tomorrow , had to leave my baby sittin on jackstands for the night

 

While you're at it would be a mistake not to replace the wheel cylinders with larger GMC 1 ton cylinders (Napa #4637337)
About $12 each, I guarantee you'll like the stopping difference.

 

I like ths stopping different now , when these wheel cylinders go bad i will be installing larger ones , but for now , the brakes suit me fine.


I do have another problem , i notice sometimes when i step on the brakes , the pedal is really hard , and if i let off , and step on them again it feels normal? any idea's? hydo boost going bad?

 

anyone?

 

I thought when it does the opposite the booster (or vacuum source) is going bad. Ie if you can only hit it once then it goes hard....

 

Sounds like you still have air in the system or if you bled by pumping the pedal may have damaged the master cylinder's seals causing an internal leak.
What happens if you bleed with the pedal is that the longer brake pedal stoke with no resistance takes the master cylinder into an area where it never gets used and may be rusty, tearing up the seals.

 

I never thought of that, very true though.

 

Hello, sorry I got into this late, but I'm gonna go with Infidel on all of the above.

When I first read about the wheel grabbing, I thought seal leaking. This is a classic sign of the wheel cylinder leaking or the axle seal.

Just out of curiosity, how much the did the bearings run you?

Also, sounds like air in the system. You should put a piece of wood like a 2x4 between the brake pedal and the floor boards so when you depress the pedal, you don't go past the "normal" travel. Like Infedel said, might have scuffed the seal (s) when you over travelled the pedal. But of course, bleed the system first starting with the right rear, then left rear. Then go to the right front and finally the left front. Hit em with some penetrating oil the day or two before.

Now is a golden opportunity to upgrade to the bigger wheel cylinders, replace the other side bearings (just to be done with em both), and to flush the entire brake system (should be done every two years).

Sorry about your misfortune, but take it as an opportunity to make some improvements and get some prev. maint. done.

Good luck, Kevin

 

I didn't have to bleed the brakes? so it cannot be that , and it has been doin this for quite a while now , i first noticed it this summer.

i will be upgrading the wheel cylinders sometime down the road , as i don't need them right now , this is my daily driver aside from hauling my quad and for about a month in the spring i deliver corn seed , around 4500 - 6000 lbs at a time. it stops great now imo , and i don't want to worry about it locking up in the winter on snowy roads.

i don't have the invoices on me right now , but the innner bearing was about 17 bucks , outter bearing was about 15 , and the races were about 12 bucks each , and the seals were 15 bucks each.


I only did bearings on one side because the passenger side was still in great shape , someone has replaced them shortly before i got the truck , and i would have had to wait 5 days for another inner bearing as no body in town has them in stock , not even the (big gulp) furd dealer , yes i even tried there.

also , how do i know what axle i have? there is a tag under my hood that states that it has a dana 80 , but i thought those only came in the 3500 series?