Need more help with brakes please

[wipeout]

Hi,

Ive been trying to bleed the brakes on my 77 vette, rears bleed fine but as soon as i get to the passenger side front caliper I must of had spent a good hour pumping the brakes, releasing the valve over and over again and still air is coming out. It seems to be getting less and less worse but I worry that maybe it will never end.

Has anybody ever encountered this sort of problem or is it common. Should there be something i should be looking at taht may be sucking air in.

Please help I wanna go for a ride.

 

[1BAD80]

Are you bleeding the rear with the tire's on? There are 2 bleeder's on the rear. It may help to put the front in the air to help the air move on it's own, and tap on the caliper to help move any traped air. Put the hose, (IM assuming your using one so it don't squirt all over) in a small can or bottle filled with a little brake fluid, so if it suck's back thru the fitting it will suck fluid in.
Don't let ther pedel go all the way down to the floor, since it never goes that far you can ruin the seal's in the master, I usually put my toe's from my other foot under the pedel to help stop it from going past the normal travel. You can get new bleeder screw's for a 1 man/woman job, they have check valve's in them.

 

[wipeout48]

I have also noticed that the brake fluid in front reservoir in the master cylinder is always becoming black no matter how much new brake fluid I ad to it.

Could the master cylinder possibly be shot.

What would the effects of a bad master cylinder be.

 

[1BAD80]

It sound's like the master is gone. The black is the dirt pass the normal working area of back and forth operation. The seal's are gone and bypassing passed the seal's allowing the dirt from over the year's of use, plus the "0" ring seal's are black. This will not give the pressure as the seal's are shot. It's just like the caliper's after a while when you do the brake's and push the puck's back in they stick or leak, condinsation play's a part in this also.
When you put on the new master pre-prime before putting it on.

 

[wipeout48]

I got myself a new master cylinder today gonna try to put it in tomorrow. Ill let you guys know what happens.

 

[JonM]

Bench bleed the new MC before you put it on.

 

[JohnZ]

Have you replaced the rubber flex hoses? When they deteriorate, they do so from the inside out; they swell up internally and start flaking bits of rubber. Take a look at the dates printed on them - if they're more than ten years old, they need replacing.

 

[wipeout48]

Another thing when im at the caliper and we push down on the brakes I can hear a squishing sound coming from that area. Almost like if its sucking in air back in when we release the brake pedal.

And with the constant air coming out of the caliper could it just be a pin hole in the line somewhere just just keeps sucking in air.

Maybe I should replace the lines first before I start swapping the master cylinder.

 

[wipeout48]

would the rubber flex hose deteriating cause this sort of effect.

 

[1BAD80]

I suggest doing both the line's and Master cyl. since you had particle's coming from the Master cyl. save some future time, and if you done the brake's it should be leaking fluid from the caliper and not just air sucking. Something don't sound correct, when pushing down it should leak fluid, could be the puck is sticking, and sucking air. Do you have the new type with the stainless sleeves? If not you will need to change them out instead of getting the one fixed, it seems if one goe's they all will follow.

 

[wipeout48]

Alright I think I figured it out. I took a really close look at the flex hose going to the caliper that was making that noise and one part of the hose doesnt have any rubber left on it you can actully see the inner threading.

Im guessing thats where all the air was coming from. HAHAHa its propably the original hose.

Gonna change it tomorrow dont have time today ill keep you posted on my slow but steady progress.

 

[wipeout48]

Ok i have replaced the flex hose and it made a huge difference. I now actually feel safe enough to drive the car around.

I still have to push the pedal pretty far down but all 4 wheels are have brake power.

 

[VRGSVET]

you're not done yet

I recently bled the brakes on my 80 vette. Boy, what a pain. If you still have to push that far on the pedal there is still air in the system, and you don' t want that. You definitely want to replace all your flex rubber hoses at each wheel. I would recommend installing the stainless steel braided ones. While your at it replace all your bleeders with the type that have check valves in them. Doing that saved me TONS of time. Another huge help was using clear tubing. That way when you pump the pedal, just keep pumping until you see solid fluid coming out - no more air bubbles. It doesn't have to be solid all the way through the tube, just past the bleeder. Also, pay close attention to the reservoir; fill it often to avoid depleting it and sucking air in the system that way. Assuming you still have the stock type calipers, on a 77 the bleed sequence shoud be: left rear, right rear, left front, right front. If you have newer rear calipers, they have two bleeders each. In which case, the sequence is: LR inner, LR outer, RR inner, RR outer, LF, RF. All in all, definitely get the check valve bleeders. They are available at almost any auto parts store. With mine, I just pumped away at the pedal; even all the way to the floor, until I saw solid fluid in the tube. Then filled the reservoir, and switched to the next one. I was actually able to do it myself, and my pedal is nice and firm. Oh, and don't worry, there will be some back material in the fluid, as long as it's not too thick it should be all right. Once your brakes are bled properly, most of the debris should be gone. Hope this helps.

Verge