Brake / MC problems

ok, so while bleeding, I have to press in the front valve on the Prop valve. Do I have to hold it in the whole time or will it press in and stay? Also is this all possible with out the little tool?

I will be stabbing at this tomorrow evening.

Brigrat--- I am not getting fluid to the cylinders yet, so I can't check anything of the nature you described.

I have to definitely check my pushrod and travel and play. Then I have to check my Prop valve.

Now to check that, I press in the valve in the front. Can I then unhook the lines and make sure I get fluid coming out of the front and back ports on the prop valve?

V8bob--- I recall bubbles coming up in the MC before, but no longer anymore. I honestly don't know what changed that, but there are no bubbles anymore. I was told I need to rebleed my MC and that it could potentially be bad, even though it is new.

 

"Brigrat--- I am not getting fluid to the cylinders yet, so I can't check anything of the nature you described"

I bled the brakes every way conceivable and quadruple times.
It was a real I opener when I bled the rear break line AT the M/C, even there I only get a dribble with no real squirt or pressure you would think it would have. I replaced the new M/C with another new M/C and got the same results, so I figure it has to be in the machanic's......................

 

brigrat-- maybe your pushrod isn't going in far enough into the MC, if you
tried it with two different MC's and still getting little fluid, that would be
my only guess. Is the pushrod hooked up to your brake pedal obviously?
I bet the problem might lay there. Or Proportioning valve if you are running one.

 

Is that a dual 7? booster? looks really small. My 2 cents is I'd go to pickapart for a core and then go buy a booster/MC from autobone.

Here's my story. I bought that universal dual 8" diaphram/MC combo from online. It was such a piece of junk the rod in the booster snapped while bleeding. I read later those chinese generic boosters don't give as much boost as they're supposed to, can't remember why.

I bought the autozone part for around $150, has a real metal pushrod, I think I bought a clevis from a hotrod shop to hook it up. The other great thing is they have a lifetime warranty, which I saved a few bucks buying stuff online but zero warranty means I was screwed.

I bleed the master cylinder by using a couple plastic syringes, one for feeding medicine to cattle and one for kids. Use the little one to fill the ports inside the resevoir and the big one to shoot fluid in the ports that go to the brakelines. Works perfectly every time its great and only cost like 10 bucks.

That prop valve sounds like a real PITA. I read they're supposed to only go on the car they're intended for but my wild *** guess is that they're probably fine for any car.

I put an adjustable one on the rear since I'm runnning rear discs and I've only run it wide open, so far it seems like a waste.

If you really want to diagnose this, get the $50 pressure tester with adaptors from ssbrakes. You just thread it into the wheel cyl or any fitting and it'll tell you how much brake pressure you're getting there. Keep going till the pressure drops and you know the obstruction is before that.

I think you need 1000+ pounds on the discs, I can't remember for drums

Oh I allso tried an air compressor driven power bleeder suction type thing. Wasn't worth the time it took to build it for me.

Even with all new lines it doesn't take all that damn long to pump the brakes.

I use speedbleeders, which I think are a god send, and some clear tubing into a plastic bottle.

Oh and that last 1/4" or so of push rod travel is where you get a lot of pressure from, so make sure you're bottoming out that MC.

Also when you're filling the disc/drum MC you can tell they look the same but one takes way more fluid than the other, use that for the front discs. I had the lines reversed and it made a big difference.

When I do this stuff I replace everything, lines, wheel cylinders, hoses, the whole deal. Saves time in the long run, but opinions and budgets vary.

I hope you didn't use that generic firewall mounted brake pedal that costs like $100 and is adjustable. That was the most worthless piece of **** I ever had the misfortune to lay eyes on.

Good luck man, keep at it and just be methodical and you'll get it figured out.

Oh and I'm just a backyard hack, so take my advice for what it's worth.

 

Johnny 1290

Yeah it is a dual MC with a 7" booster. Prolly made in china.
I am using an s-10 brake ***embly. I didn't buy theirs

Sounds like you put a valve on your rear lines, I believe you only need them for drum brakes, as it keeps about 10lbs of pressure on them at all times. Someone can correct me if I am wrong. But I don't believe you need them for disc brakes.

The proportioning valve is suppose to do all the for me I am suspecting.

I am confident I will get to the bottom of it and let you guys know. I am thinking I am
not maxing out my MC and or my proportioning valve got off centered, because I had some leaks while bleeding.

 

well, I ****ing hate this POS setup I got. First off, I am never buying something off ebay from some idiots that don't know anything about their product. That is what I did and learned the hard way, they seriously didn't know **** and recommended some websites. They also proceeded to tell me the reservoir's are the same size and will run both disc/disc or drum/disc etc. IF that is true I don't know, I am just learning this brake stuff.

Anyway, enough tears have been shed. My prop valve is getting such little fluid it is ridiculous. So I disconnected the lines that went into the Prop valve and pushed the pedal. Not too much fluid coming out. I would ***ume there should be quite a bit of fluid coming from there since that is the first line past the MC for fluid to come out. So if that is true, could I have a bad or poorly blead MC and or possibly my push rod is not engaging far enough? Those are my only thoughts.

I don't seem to have much fluid flowing at the first chain of command.

any ideas? Should I just sell the whole truck??

 

You probably have a Corvette M/C, both reservoirs look same size and probably are. If so it's a street rod version, outlets on both sides?
If so the closest to the push rod is for the rear.
When you first push....... both front and rear rods and seals inside the M/C will start moving, but at some point they will not move the same as the springs on the rod & seals are of different rates. Look at an exploded view of a dual master cyl.
I know this is like the blind leading the blind but I do believe your problem is in rod travel/ratio. Make sense? I may have the same problem but wont know till tomorrow...............

 

Have you checked the push rod yet?
Hell pull it out and slip a lil socket on the end and slide it back in and see if that helps..... no harm no foul.
I have came across this several times, if it works then...... =)

 

I am going to try that push rod today. I am working solo so it is hard to tell what is going on. but I'll manage thanks fellas

 

well, the push rod seem like it is traveling good about 1.5 inches or so.

I took the lines from the MC and put hoses on the end and bleed it back into the reservoir. I then hooked those lines back up to the prop valve.

I disconnected the line in the front p*** tire (before caliper) hooked up a line and bottle to it. I can see fluid coming up and down from the bottle but no fluid coming out of the brake line itself. Same with the rear.

Upon holding pedal down, releasing the hose (to let air out) putting the hose back into the bottle and letting pedal come back up, I can see bubbles in the bottle. But it seems to be the same pattern for the front and back lines. It just ****s up about five inches of line worth of fluid and pushes it back down, back and forth back and forth as I press the pedal.

It seem like I am getting pressure as it has good suction, but no fluid.

The valve in the front of the Proportioning valve still isn't making sense to me on what I do with it. I have tried pushing it in when the pedal is pressed down. If I keep it pushed in at all times while pumping pedal, it seems like it will **** air in.

Right now I have both front and back lines submerged in bottles. Will this let it gravity bleed? Or do I need the lines open to air?

Lastly, during pumping of the pedal. I see absolutely no bubble in the MC. When I hooked this up months ago and tried it a couple times, I saw bubbles.

 

"Right now I have both front and back lines submerged in bottles. Will this let it gravity bleed? Or do I need the lines open to air?"

With your M/C so high on the firewall you are good to go on the gravity thing...............
When your bleeding alone it really helps to get the speed bleeders as mentioned........................
Have you checked the distance/clearane from the power diaphram rod to M/C rod?

 

Fellows I'm just getting in on this, but one question I didn't see ask was: Is the MC for powerbrakes or manual. MC looks the same, but the distant inside the MC were the rod goes in is longer on the manual and short on the power, if memory severs me. I've seen them mixed up. I also always keep the valve centered in the prop valve with a home made piece. On the subject of prop valves I've also used a prop valve that matches the brake I'm installing. Camaro disc in front with drums, use a prop valve for a camaro or what ever the brakes are from. my 2 cents

 

"MC looks the same, but the distant inside the MC were the rod goes in is longer on the manual and short on the power, if memory severs me."
They make a spacer for that if you need to convert.................

 

Fwiw his booster/mc/prop valve came pre-***embled if I underrstand correctly.

Hey can you make a short video for us to see what's happening?

There's no subs***ute for an experienced eye taking a look at this stuff. I know I've done stuff wrong I thought was fine when someone wiser looked at it and right away spotted the problem.

EDIT: Speedbleeders are the best $20 I ever spent on my car. You can get them in the help section at autozone now too, don't have to order online. I've tried mityvac, compressor powered suction deal, and the speedbleeders and a bit of clear tubing in a coke bottle works by far the best for me.

 

yeah I bought everything as a kit. the disc fronts and drum rear are all s-10 2x4.

What I got going on now is eliminating as many variables as I can. For one. I am not
getting fluid to the end of the hard lines in the front and the rear (before they reach the rubber lines, keep that in mind) reason why is I am trying to get fluid to those points first. I feel if I can get fluid to the rubber lines, then I would be ok. Everything is new expect the front calipers (which are really out of the equation right now).

I have the front p*** hard line (after the T) going into a bottle. I can see fluid rising and falling in the bottle, actually about 4 inches up out of the bottle. It corresponds with pushing the pedal in and out. So I know the booster is ****ing and pushing.

Yes it is power brakes by the way. Push rod had about 1.5 inches of travel. I have checked lines before prop valve and I had a good squirt. Hooked them into prop valve and tried pumping the pedal in slow stokes. This is where I am at now. I have the lines tied into bottles with fluid so I can see what is going on. I am just waiting to see fluid poor into the bottle, that is my goal and I just can't seem to get to that point.

I have no idea how to center this "valve" in the center of the prop valve. If I am understanding, by what V8bob said, I have to hold in that valve to get fluid to my front lines.

 

Man, I can't win for loosing. I feel so defeated and it is really getting to piss me off. Between these brakes and my clutch. 2 of the 3 main things that make a vehicle go. I can't seem to get them going. Next truck, I will get all that going before I waste my time wiring and doing finalizations.

Anyway here is my POS proportioning valve from the front, one pic is with the screw out and the other is with it in. I have tried both ways here with a clamp on it and then tried bleeding. No luck. I would press the pedal 50 times and no fluid thinks of leaving the MC. I would do this over and over and simply nothing.

With a bottle of fluid hooked to the rear lines and or front p***, it will **** fluid up the bottle and then back down when I press pedal in and out. But I can't get fluid to the lines end of the lines in the front and back. I think I have stated this about a million times and I am done complaining on here.

 

Who makes a spacer????

 

I got the part with the M/C from Steve at Sunrise Color in Oregon.
1-541-476-2514
You may be able to get just the spacer or make one, it's 1 1/2" long, fits in the rod bore with a dipple on one end for the rod to sit.................

 

Finally some good news.

So I think I had two problems. First and foremost, my MC had a rubber
boot over the piston (prolly for shipping purposes) Well it got left on
imagine that. So I think I wasn't getting proper plunge and release.

To be safe I took the MC off and bench bled it.

Put it back and on whoof, had fluid flowing in minutes. To the rear I had
fluid in a couple pedal strokes. I then hooked the line up to the rubber line
in the back and pumped pedal a couple times, then cracked a wheel cylinder and had good flow. I then cracked the other and let it gravity bleed and it only took a couple minutes. So I got full fluid to rears.

Got good fluid to the fronts as well.

I honestly didn't even touch the prop valve this time, everything seemed
great so far. It was quite easy. So now I have a rock hard pedal when vehicle is off. I have to start it up and see how the pedal feels and prolly do a bleed all away around and I should be done.

thanks for all your suggestions and input fellas.