no rear brakes and hard pedal?

[70396CST10]

By hard pedal I mean when the brakes did work you would push down on the pedal and it was free, like powerbrakes should be, until about 2 inches from the floor board and then it gets hard.. And by hard I mean from my leg pressure pushing downward on the pedal.. Last Saturday when I started working on this again the pedal got soft while driving meaning it would go all the way to the floor with hardly any resistance and no brakes..

I was hoping to avoid this but I guess I will just start throwing parts at the truck until the brakes work.. I think that is stupid but what else is a man to do.. I mean, it could still be the MC, prop. valve, booster, wheel cylinders, calipers, and who knows what else.. I would think it is the prop. valve or MC but I get fluid out of both with no problem?

Thanks..

James..

[cableguy0]

if theres nothing visibly leaking fluid like calipers or wheel cylinders than you have a bad master cylinder. if the pedal sinks completely to the floor you either have a bad leak somewhere or your master cylinder is leaking internally

[70396CST10]

I will buy another MC then and try it.. The MC on the truck now is different from when I started but it wasn't a new one.. Just one I had on the shelf that came off a working vehicle..

but I will buy a new one maybe this evening and try it..

Thanks..

James..

[68speedalert]

Originally Posted by 70396CST10

But, still no brakes.. Did a complete bleed on the system again and still no brakes..

I do have fluid to the back brakes now.. But no brakes..

Aggravating truck..!!!!

I wasn't clear on my question. When you say you have no brakes NOW, what does that mean...pedal goes to floor or is hard but won't stop. My guess is that your pedal is low.

Does the pedal come up when you pump it?

I think you may have found your hard pedal/no stop problem. It sounds like the rear hose was restricted. Since that has been like that for a while, it's likely the rear brake & wheel cyls are out of adjustment or bad.

[70396CST10]

Correct: I have absolutely no brakes at all now.. Even with changing the rear rubber line from my camaro and rebleeding the brakes.. The pedal goes to the floor or very close to the floor and it doesn't matter how much pumping you do on the brakes the truck has no brakes at all now.. I still do not understand why the front brakes will not pump up at least????? They have always had fluid at the front brakes and use to work a little? Very confusing.. I think I just do not understand the theory of brakes well enough. I assumed MC pumps fluid to calipers and wheel cyclinders and you have brakes.. Booster just makes it easier to push on pedal?

I guess I will check the rear brake cyclinders also..

I can't believe the price of a new rear rubber brake line??? Almost 40 bucks at CarQuest...

The MC isn't that bad.. About 20 bucks with exchange..

Man, I was hoping the metal lines would fix my problem but I can see this is heading toward a complete brake overhaul.. Oh well, I hope eventually the brakes will work again.. lol....

I never ever imagined this brake issue would take so long to fix.. But I have been avoiding putting a lot of money into fixing the problem..

Thanks for all the help..

James..

[68speedalert]

Is the MC on it now, the right one for the truck?

Put the original one back on first and retest. You've found enough stuff to cause your initial problems w/o it being the MC.

When bleeding the order of the wheels bled is not that important.

[70396CST10]

The MC I have on the truck right now came off of a 1973 V8 chevy nova with power disk brakes in the front and drums in the rear.. It bolted right up with no problems and everything looked basically the same..

I will try the old MC and see how it works now that the hard line is fixed... If I see no changes I will buy a new MC at the parts store tomorrow..

I agree it could just be the MC from what I have researched..

Spongy pedal, hard pedal, and no brakes at all from my research.. I did not know a MC could leak internally without me knowing it...

I guess the aggravating part is thinking you have found the problem and then that not being it.. Like the hard line being broke, or the rubber line being clogged shut... But it will eventually show itself..

Thanks..

James..

[70396CST10]

Finally some Progress

MASTER CYLINDER WAS BAD!!!!!!!!!!!!!!!!!!!!!!!!!

I took the advice and put my old MC back on and bammmmm, I have some brakes now.. Front and back..

Feels so great to finally see a little progress on the project...

Brakes are pretty good but I believe a rear driver's side wheel cylinder is sticking but that is no big deal.. And I may still need to change the MC but I am so relieved to see some progress..

Thanks guys and I hope this thread will help someone in the future..

Here is what I went through..

Hard pedal with just front brakes only and no fluid in the rear bowl

Problems found:

Hard line broke on rear and
Rear Rubber line collasped
MC I put on I had on the shelf was bad.. what luck huh..

symptoms of MC:

spongy pedal
no brakes at all

thanks again..

James..

[68speedalert]

Originally Posted by 70396CST10

symptoms of MC:

spongy pedal
no brakes at all

I want to add the most typical symptom of a bad MC. Good pedal, relax your pressure a little, increase your pressure and pedal sinks about 2-3 inches. Repeat until pedal finally bottoms out. That is what happens an internally leaking MC. It's hard to describe, but once you feel it, you can duplicate it every time.

I am impressed with your tenacious desire to not throw parts, aka money, at it....Camaro rear hose?!?!? It's harder try and figure out the problem, than to guess and start hangin parts.

Glad you got it fixed, and for posting your findings. Everyone should do this.

BTW, Make sure check those rear brakes soon.

[70396CST10]

I agree and that is what I was meaning by spongy pedal.. Thanks for the better explanation and help..

I will examine the rear brake shoes and cylinders and drums now and continue on this project..

And now I get to figure out this fuel gauge problem..

Thanks again for all the help

James..