I have searched for a while and found that the proportioning valve will lock off the back or front brakes depending on if the system is fully functional or not (correct me if i am wrong), and i have had some problems draining the rear drum brakes of my Camino.

The front brakes we've flushed and bled them without a hitch, simple. and when it came to doing the same to the rear we were not getting any pressure at all out of them, i read about the valve, we played around with it some pulling the pin out and such, but with no luck.

Anyone have any suggestions on what could be causing this, could that valve have gone bad? If so what's an easy way to check it for sure? (My brakes are Disc/Drum)

thanks guys !
-jake.

sounds like a bad valve--or has crud in it?/ Your using new fluid right?/ single or double master ?? check to see if there are any kinks or flattened places in the line--try disconnecting the line out the back to the rear brakes and see if fluid comes out first--Glenn:dontknow: your suppose to do the rears first--starting with the one farthest from the resorvoie Right rear??--but that is not the problem

I've inspected the hardlines, and they appear fine. I'll get under it tomorrow, and disconnect it from the valve. I am using new fluid, it's a double master cylinder.

My Wheel Cylinders in the rear are brand new as well. Mechanic friend of ours i relayed the problem to said the rubber hose from the single hard line to the T-Split on the rear lines swelled up on one of his previous project cars, it swelled so much that they barely got any fluid out the back, i figure i'll check there too, but any suggestions are welcome. :)

Thanks Viet Vet:beer:

All I can say is whats already been said. Brake lines are relatively simple but for some reason can cause the most complications. So just check for leaks check the valve for crud and you can try taking the lines off from both ends and running some air threw with a blower to maybe try and get anything that's stuck in the lines themselves out. Good luck and be careful its fun and games till you cant stop.:nanawrench:

What type of Brake Fluid are you useing , Dot 3, or Dot 5 ? Check your specs. DO NOT use a silicone type of fluid. It will destroy all your seals, and brake components (they are a different type for silicone) + they don't mix.
But Hay - you knew that.:poke: I'm leaning towards a bad valve.:dontknow:

It's DOT3, and it Master Cylinder says so as well, i'm thinking right inline with you 74elco, this morning i woke up and thought "i could air flush the system?" i'll disconnect the rear lines from the valve today and see if brake fluid wants to even flow out of there, i figure if it aint coming out of the valve it aint clogged it's just a bad valve :/

thanks for the heads up guys & ideas, i'll get back to ya and let you know what i find.

You'll find you can get more PSI with a power brake setup(with engine running) and brake fluid than a compressor and air thru the system--Let us know what you find out is wrong--glenn:dontknow:

Alright so i removed the hardline from the valve, and it seems to flow with ease, so that tells me the valve is good but something between there and the Wheel Cylinders is not.

I removed the two hardlines from the wheel cylinders to the T Join/Rubber Hose, and i still got nothing so my guess is now that either there is a major kink im missing in the hardline (which i didnt see the two times i inspected it) or the rubber hose from the main hardline to the T Joint.

My guess is from what i've heard and read is that that rubber hose has broken down over time and is in need of replacing (as well i can see mild cracks on the exterior of the rubber line). Does this sound like a legit reason i would get absolutely no pressure to the back wheel cylinders from the master cylinder?

Does this sound like a legit reason i would get absolutely no pressure to the back wheel cylinders from the master cylinder?


Yes Sir, THAT would be the Next place of inspection / repair.
If, (and I think you should) you replace that line, this would be a great time to think about using a Steel Braided Line at that location.
If you were to change ALL your rubber lines to the Braided type, you will end up with a more Positive Brake system, due to less to no line expansion from the pressure of the Hyd. Fluid. (Just something to think about if up grading the system is in your future):dontknow:

lol wish i would've known before i bought the front but that's okay, live n' learn, yeah i'll definately replace this rear rubber line, it seems pretty far gone, and 15-20 bucks aint nothing compared to a wreck from the lack of brakes!:poke:

TIP ::: While you have the rubber hose off, take the other two lines off ass well and flush the "T" with a can of Brake Kleen, just to be sure that any degraded rubber pieces are Not lodged in the "T". Luck to ya Bro.:beer:

Alrighty ya'll after a couple of weeks of some family issues and things and such i finally got up under there and pulled that rubber hose & t joint off. Turns out the Hardline compleatly RUSTED to the Connector on the rubber hose. So thus as i was turning it i failed to realize what was turning was the hardline, and thus it snapped off.

So i have a severed Hardline in the rear of my el camino, now first thoughts i assume are going to be to replace that whole hardline, however i'd like to steer clear of that if possible. If worse comes to worse i suppose i can.

My idea is; make a clean cut on the hardline that is remaining, take a flaring tool and a connector & push the connector on Flare it and put it back as was.

The hardline was not severed far enough to need a longer black hose ( i believe) but for sure that was my problem, it was 100% rusted together, and there's no way brake fluid was getting through the rubber hose.

Is my idea trial worthy or should i just scrap that hardline and invest in a new one? if so where should i start in replacing the whole hardline running from the Proportioning valve to the rear? (seems like a bit of a task)

thanks ya'll

Go with your FIRST IDEA. There is nothing wrong with a new fitting and flairing the line.:beer:

I hate to be the bearer of bad news, but here it comes. If you decide to replace the hard line all the way from the prop valve, be advised that there's a retaining clip on the TOP side of the frame, under the floorboard. It's the first one downstream from the valve. It is impossible (well, for me anyway) to access the 13mm bolthead without raising the body off the frame. That means all the drivers side body mounting hardware needs to at least loosen as much as possible. I just removed mine altogether. The e brake cable might limit the upward travel too, I disconnected mine from inside the car. I don't mean just disconnect it from the pedal, I mean that AND release the cable sheath from it's keeper. Then the body will lift enough to access that bolt head. It's a PITA. Much better to cut and flare it as close to the end as possible if you can. Good luck.

Thanks ya'll i'll cut n' flare, i didnt think my line ran on top of the frame at all, from the looks of mine it's running where it's all accessable, guess it dont matter much anyways lol, im going to go the other route, thanks ya'll i got the part ordered should be in tomorrow!

now only if the new O'Reilly's dipstick working the counter could sell me a proper fuel line, he gave me the wrong part even when i second guessed him today :poke: but he works there he knows it all.:neutral2:

Alright, well i got it all pieced back together, but now here's my other problem, bleeding the wheel cylinders, i guess it must be a GM thing but the Bleeder Valve is up in a tight counter bore. I dont quite understand why but since it is it's a tough valve to get to, Needless to say i need help in how to bleed the rear brakes, my dad and i both are fairly stumped and im just unsure of what to use, we did find a socket that will sit down in the counterbore and will turn it, however it's hard to use a socket and bleed it at the same time. Any suggestions, tools or anything at all we're overlooking?:dontknow:

Hit the tool shelf at the local parts store and grab a bleeder wrench of the proper size. They are boxed end wrenches with a real high offset.

The problem is i did, :/ the boxend wrench would have to be a thinwall as well, the bleeder valve is just that deep in the wheel cylinder i dont understand why.

we found a Socket and used that with a pair of vice grips to bleed it, along with a tube just small enough to fit in the socket but large enough to fit the bleeder valve, i believe we have it but it just seems like there should be an easier tool. I just have this feeling these guys at GM are laughing at noobs like me that cant figure out the right tool lol.:poke:

ah well after a long day the brakes are done.

Just think about all the experience you have on brakes now :nanawrench:

lol thanks bill, that's an upside :-P :nanawrench:

:dontknow:But how do you reset the prop valve. The reason I ask is mine is fully extended and I need to reset it.:nanawrench:

It's just a pin, grab it with a pair of (needle nose) pliers and push it in, or pull it out. it can only go one of two ways. It's not very hard to do either. so dont go godzilla on it! :P

gl!:nanawrench: