My problem is I don't get a firm pedal until the SECOND push on the pedal.  The first push goes to the floor with no slowing of the car, then the second push stops about 4-5 inches from the floor board and stops the car well.   Why two pushes of the pedal?  What am I missing?

Don't worry I've only driven 12 ft back-and-forth in the driveway, roads in Wisconsin are still safe

Air in the line or a leak somewhere.

Cheers

Warren

Eddie, i,m with you on that procedure, nate, theres no need for person pumping pedal to try and push it through the floor, just a light firm pressure is enough and is less messy when cracking the bleeder. you will find one that just has more air than the rest and problem should be solved.

I will have to wrangle my brother into helping me.  I used Master Cylinder's method to bleed the system, using a hose submerged in a clear jar of brake fluid.  Starting at the right rear I would pump the pedal until no bubbles would come out of the hose. (I'd have to lay across the seat with my head hanging out the passenger door to see the jar!)  Then I would walk back and tighten the bleeder valve before removing the hose from the bleeder.  I would continue, ending at the front driver's side wheel.  I could see fluid filling the jar with no bubbles, so it seemed even a slight push of the pedal was moving fluid quite well.  I could actually see the fluid level rise in the jar as I pushed the pedal.

Before assembling the system I did bleed the master cylinder back into itself using some extra scrap brake lines.

I'm 99% sure there are no leaks, I've left her sit for a couple weeks after bleeding the brakes and there isn't a drop of fluid anywhere on the cement under the car, and the level has remained full in the master cylinder.  So it seems my only option is to just re-bleed with a helper.  Most times I've bled brakes in the past I have asked for help and had the person hold the pedal down as I tighten the bleeder screw...so maybe that will do it.  It has just been so hard to schedule time to work on this so it has been hard to schedule help.  usually I'm just swinging by the garage when I have a few extra minutes.  But I'll get someone to help this weekend hopefully. 

Any other bleeding tips I should try when I get back out there?

I had troubles of getting all air out for a corvette. The working tip was to run the engine so the break booster helps as well. Use the trick of master cylinder. I'll put over a tramsparent silocone hose, and just open the screw, so it has to squirt out. The hose is rising upward for the first section, so the air can go up and the fluid down.

Keep the master cylinder well filled or you have to redo the job.

I hope it helps.

Stephan

/quote]

Nate,

I'll stress again that any leak, no matter how small, will prevent you from getting the pedal pressure that you need. A leak that shows up on the floor is major. A leak that you can only detect by an oily feel by touching a line joint is enough to get air in the system. A brake system must not leak any fluid at all. 

Check for leaks in the system closed by pressing the brake pedal as hard as you can and checking each joint with your hand. Any wet or oily feeling indicates a leak. Keep your hands clean and use a clean cloth to remove and old oil.

Keep with it you'll get it sorted.

Cheers

Warren    

Warren, i dont nates arms are that long, lol.

Bill,

He should get the general idea. The idea's to get the joint to leak then look.

Cheers

Warren 

The 68 Bronco MC is from the local parts store, I was under the impression all 68 Bronce MCs were all 4-drums.  But it has crossed my mind that maybe it was a front disc MC, what would it feel like if it didn't have the check valve up front?

I'm thinking about fabricating a pressure bleeder using an extra master cylinder cover and installing a tire valve stem or barbed fitting and modifying a small pressurized pump-up sprayer to pressurize the system and keep extra brake fluid so I don't have to keep checking the master cylinder fluid level.  Something similar to this http://faculty.ccp.edu/faculty/dreed/campingart/jettatech/bleeder/index.htm.  The master cylinder rear resivoir runs out so quickly I only get four full strokes of the pedal before I have to stop and refill.  Although I hardly need it as the fluid runs out rather freely just from gravity when I open up a bleeder screw.

http://www.autozone.com/autozone/accessories/OEM-Liquid-siphoning-vacuum-pump-kit/_/N-25j2?counter=1&itemIdentifier=70116_0_0_

And the bleeders:

http://compare.ebay.com/like/130461810016?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

Hope this helps. Chuck

What do you guys think?  How do you get new brake line to feed under the steering mechanism, it is very little room.

I agree the loop looks bad, but I was doing some more thinking over the lunch hour and the same thing happens at the rear axle straight from the factory, the brake line goes down along the frame rail, then up under the body of the car and then down to the axle through the rear hose so creating a high spot in the line like that shouldn't be a problem, and the length shouldn't be a problem either as the rear brake line is obviously much longer.  So other than looking bad I can't imagine that is my problem.

My little brother is going to meet me at the rental garage this friday so I'll try some 2-man bleeding and maybe together we can firm things up.

Nate, after all this you now mention you are bleeding this by yourself! it can sometimes work if only doing 1 cyl , but you havent a chance the way you,ve been mucking about. with someone applying light but firm pressure to pedal and you cracking the bleeders should have success.

You mentioned that the rear reservoir is only good for 4 pumps before running out.  Is the front reservoir a lot bigger than that?  That to me is a hint that it is a disc/drum master, and as you said, no check valve in the front.

stuey

Yeah Hoosier, the front resvoir is a lot bigger.  I thought all 68 bronco's were 4-wheel drum master cylinders?  I got the idea from this post

http://www.y-blocksforever.com/forums/Topic26295-9-2.aspx

In either case, even if the master cylinder was disc/drum wouldn't it still have residual pressure valve for the rear circuit?  If so I should be getting a firm pedal for the rear circuit anyway right?   The last time I bled a disc/drum car, once I tightenedthe bleeder on the rear wheel cylinders, the pedal got much harder to push for bleeding the fronts.  I'm getting no firmness after closing off the rear bleeders.  Hopefully a big air bubble will burp out tonight with by brother at the pedal.

I'm worried that I need a residual pressure valve in the front circuit.  I'm not sure why, everything I've read says that all 68-75 Brocos were drum/drum and that is what this master cylinder is listed for.  Most things I read say a drum/drum MC should have residual valves built in?  It is very frustrating that I can't find specific specs on this master cylinder.  It is a Cardone 10-1390, even the data on the cardone site is worthless...it says nothing that gives me any confidence that this has residual valves on both circuits.

The other question I have is when adjusting my front drums, I can spin the wheel backwards quite easily...the wheel spins almost freely....but as soon as I switch direction and try to spin in forward, it stops immediately.  Which direction should I be spinning to when adjusting the brakes.  It seems when I sping the wheel foward the brakes are grabbing, but they spin too easy in the reverse direction.

Which push rod did you use from the pedal to master cylinder? They come in different lengths and can affect the pedal travel. The bolt that holds the rod to the pedal arm should be an eccentric so you can turn it to get more or less travel on the brake pedal. Turn that for max travel (higher pedal) and see what happens. Chuck in NH

Nate, dont know answer to whatever you,re doing but old mechanics trick is to squeeze off rear brake hose at diff with vycegrip type clamp and check if pedal pressure becomes firm, that indicates problem is at rear brakes. If that doesnt change then try same thing at front hoses, one side at a time. this is to rule out the problem is at wheel cyl area.

Driving in the driveway this wasn't noticeable, it wasn't like the front wheels were dragging or anything.  In fact, other than having to pump the pedal twice the brakes really work well.  The car stops abruptly as soon as I get the pressure on the second pump of the pedal.

I'm using an adjustable rod I had laying around, I adjusted it so that it is just contacting the master cylinder pistone when the brake pedal is in the completely retracted position.   The MC came with a push rod, but it was like 4 inches too long for the brake pedal set up in the car.

Man...I always get a sick feeling when my troublshooting gets to the bottom of the bucket and I start considering my new (re-furb) part may be faulty.  That possibility is always in the back of your mind when you have a mystery problem, but the few times I've followed through and replaced a brand new part, it didn't solve the problem.  Nine out of ten times it is something really obvious.  But this one has me stumped for now, maybe this will become my personal experience with a faulty new part.

All things said You probably need to try another MC to make sure yours is working. The internal leak by in the pump assembly will do what you are experiencing. Chuck

I was just being too sensitive when I was adjusting the brakes, in the past I was tightenening the adjuster just until the brakes started to grab...then I backed 'em off a little.  Well things must not have been lined up inside the brake drums becuase this method was not getting me close enough.  But moonshadows advice to tighten 'em all the way first revealed my problem!

Since I have very little knowledge on Y-blcoks to share with you guys, I made you guys a thank you video instead.

http://youtu.be/fpcWFL4Lksk

Good one mate

Now for something more complcated

Cheers

Warren