should i bleed brakes with 340k miles?

[warrior86]

hey guys. I have a 94 s-10 blazer 4.3 vortech that was originally my uncles and now i use it as a commuter/dirbike tower. THe engine is all original and doesnt even burn oil. the brake fluid is black. It is the original brake fluid that came with teh car. My uncle never changed it. The brake feel is pretty crappy at the moment. Do you think i should leave the original fluid in or flush it all out?

also, is there some kind of adjustment for the rear brakes? like a proportion valve? i remember messing around with the truck in 2wd in the snow and no matter how hard i pushed the brakes the rear wheels would not lock up...even on ice. Its almost as if there not even doing anything at all. I mean, i hit ice and the front wheels lock up fast and i keep pushing the pedal down more and more but the rears never lock up. Whats the deal with that? (i dont have ABS) You would think they should atleast be able to lock up on ice considering ice gives very little resistance to sliding. thanks for any help. And yeah, the shoes are fine.

[Sparky2263]

I would definitely drain/flush the old fluid out.

As far as the rear brakes, the adjustment is the threaded wheel anchoring the bottom of the shoes. Adjust it to the point of minimal contact (drag) to the drum.

Rear hose may be shot not allowing fluid flow to the rear. Hose will collapse internally restricting flow.

[warrior86]

well my friend has a brake flush machine at his dealership. Do u think the fact thats its pressurized and everything is old and probably crudded up might cause a leak or eat my master cylinder?

[Sparky2263]

I make it a point NOT to use pressurized bleeding equipment. Open a bleeder, let it drain. If it needs a little help to get started, give it a push.

Brake fluid is cheap. Heck, I think a gallon of DOT4 is about 20 bucks.

Note I said DOT4, not 3 or 5.

[xacy0303]

Man, I know this thread is really old but my 89 s10 is doing the same thing. I replaced rear shoes, and one leaking wheel cylinder. I still cannot get the rear brakes to function properly. I adjusted them properly and bleed them too. I raised the truck to see if they are working at all, I put it in drive and let the wheels spin, hit the brakes and only the drivers side rear wheel stops. Note the passenger is the one that had the leaking wheel cylinder and the one that will not stop. Here is the catch, when I set the parking brake both rear wheels lock like they should. So, I am confused where to start on this problem? Could this be a collapsing line, proportioning valve? I am stumped, please help me!!!!!!!

[T Man]

Man, I know this thread is really old but my 89 s10 is doing the same thing. I replaced rear shoes, and one leaking wheel cylinder. I still cannot get the rear brakes to function properly. I adjusted them properly and bleed them too. I raised the truck to see if they are working at all, I put it in drive and let the wheels spin, hit the brakes and only the drivers side rear wheel stops. Note the passenger is the one that had the leaking wheel cylinder and the one that will not stop. Here is the catch, when I set the parking brake both rear wheels lock like they should. So, I am confused where to start on this problem? Could this be a collapsing line, proportioning valve? I am stumped, please help me!!!!!!!

Neither. Proportioning valve affects flow to both rears evenly. Same with the line, there is only 1 hose that leads to the rear, from there its all steel line. Did you replace the leaking wheel cylinder? If so, did you replace the shoes at the same time? What is the measurement of the drum? May have been turned too much. What is the adjustment like on the rear that wont stop the wheel? Lots of questions.

[xacy0303]

I replaced the passenger wheel cylinder, and replaced both sides with new shoes. I adjusted the shoes on both sides so that they barely touch the drum. I havnt measured the drum, but if the shoes can be adjusted to touch the drum it should be alright, shouldn't? what should my drum measure?

[Mikz86TA]

Around the outside edge of the drums is the minimum thickness they can be turned down too.
Be sure to doublecheck that the side you disassembled wnet back exactly as it was. There is a spring that crosses the bottom of some drum setups. If its installed backwards (and its real easy to go in either way), then it interferes with the star-adjuster behind it and binds the self-adjustment.
If you can, post a clear picture without the drum on (the inside crap) and Im sure one of us can tell if its all in right.

[xacy0303]

Alrighty, I'll try to get some pictures up. I forgot to mention that the emergency brake works great, i dont know if that helps the diagnoses but its kind of weird when the e-brake works and the regular brakes dont,lol. thanks a bunch.

[Mikz86TA]

If I remember right, the E-brake has a seperate lever it pulls to engage one shoe to the drum.