Brake pedal travel

Ed,  I have, what I'm guessing, the same setup. When I started bleeding from the back, all was good with a firm pedal, using the conventual way of opening and closing the nipple while pushing and releasing the pedal.

Then I got to the fronts. Not so good. I tried bleeding them the conventual way, but the pedal stayed down when I pushed on it. I was flushing the system, so I pulled the pedal up and repeated until flushed.

To get a firm pedal, I ended up using a syringe that I use for bleeding bicycle brakes. I'm sure any syringe with a bit of clear hose will do. I filled the syringe almost full and attached it to the bleed nipple. Holding the syringe so that it was higher than the caliper, I drew a vacuum on the caliper to draw out whatever air was left then pushed fluid in. I repeated this until there wasn't anymore bubbles coming out. The pedal came up when I pushed fluid back in and I had a firm pedal in the end.

I'm sure one of those bleeders that Gordon came up with might do the trick, but I had to use what I had.

My 2 cents.

I don't have the EMPI brakes, but I do have 4 wheel discs, and the same M/C.

I could get a hard pedal, but low with standard bleeding practice of push down, hold, bleed, close bleeder, then release pedal. Repeat......check fluid, DON'T LET IT RUN DRY!

I could not get the pedal to be where I thought it should be. Until I VIOLENTLY PUMPED THREE TIMES, and held on the third pump. The amount of tiny bubbles that trickled out were miniscule, but there. That was the only way to get all the air out. Try it, Ed.

I always bleed with a clear hose over the bleeder into an old brake fluid bottle. The bottle has a mechanic's wire cage wrapped around it with a convenient hook for brake hoses or suspension parts. It's so easy to see the air coming out with the hose, or lack of air when you get it all out.

If your pedal comes up on second pump higher than the first pump, you've still got air. If the pedal height stays the same no matter how many times you pump, but it's low,  you've got a mechanical issue with the pedal ratio or M/C size versus caliper piston size.

My experience was much like Danny's when I updated to a 2 circuit M/C last summer. 

Another tip coutesy of my M/C mechanic son: tap on the master cylinder with a ratchet if small hammer in between "bleeds." Knocks loose bubbles that can be clinging to the walls of the cylinder I guess.

BTW, did you pre-fill and bleed your master cylinder?  I didn't last year and it was a PITA. I wised up last week when I put in a new clutch master and the bleeding process took under ten minutes. 

Yeah, bench-bleeding the master can help tremendously. Most people don't know what this is, but they usually supply(or used to) plastic adapters and tubing to go from M/C outlets looping right back to the reservoir. Pumping the M/C gets rid of a lot of bubbles this way. On some cars it's difficult to do, because of the brake fluid mess that will result from trying to neatly install a full M/C. 

I almost forgot(OK I did forget) that raising one end of the car can also help in a stubborn bleed scenario. I can't remember which end I raised, but that helped also.

Also, if you completely fill the master, you can just slightly crack open the furthest bleeder, and GRAVITY bleed. You must put a long clear hose on the bleeder into a container a couple feet below the caliper. Raise the front of the car a foot or two compared to the rear. Wait. Try a couple hours, it takes a WHILE. 

I've never had any luck with either vacuum or pressure bleeding. Maybe it's me.

"I've never had any luck with either vacuum or pressure bleeding. Maybe it's me."

Nah, it's not you.  I've never been successful either.  In my case the pressure bleeder leaked at every junction.  The idea is good, but my experience says it's more trouble than it's worth.  Besides, doing it the old-fashioned way gives you an excuse to have a buddy come over and help out.

Danny, I did do the "3x violent kick the pedal" thing the last two tries. 

I did not bench bleed the MC but I did prime it, and it did take a while to get any pedal at all when I first hooked everything up.

Going to try the Gordon power bleed method next and start over again from the back. 

Or, instead of the pressurized bleed system I use, you could try a "MityVac" and pull fluid and bubbles through at each wheel:

https://shop.advanceautoparts....ke%20bleeder%20tools

I used to use a MityVac before I built my pressure bleeder and it worked OK.

@DannyP posted:

Wait. Try a couple hours, it takes a WHILE. 

I've never had any luck with either vacuum or pressure bleeding. Maybe it's me.

I think it took three tries to get my brakes done last year. Bleed, tap, tap, tap, bleed again, drive. Let it sit overnight, do it all again. Each day my pedal got a little stiffer and I got a few more bubbles out. 

I even tried both, simultaneously. Pressure on the reservoir end, suction on the slave. All it seemed to do was pass more fluid. 

I've tried just about everything from Speed Bleeders, to MityVac, to expensive pressure bleeders from ESC.. IMO, nothing's works as well as the good old two man brake bleed. 

And it gives you an excuse for beer with a buddy afterwards.  What could be better?

Ed, I once had the opposite problem, that of not having quite more than 3” of pedal travel and thought that was way too little.  My DD had more.

I ended up messing with the pushrod stroke on the brake pedal (even though every service manual I had said “don’t mess with this!”) by pulling the pushrod back a turn or two and gaining a bit of added stroke that way.  You might do the opposite by extending the pedal pushrod (turning it in), say, 1/2 turn at a time til it brings your pedal up a bit higher.  
Of course, there is this thing about the optimal gap between the pushrod and the piston when the pedal is released.  If the pushrod is too far in it can make your brakes drag all the time - Not good, so there is that to consider, but if you currently get a hard pedal, rather than a squashy one, but it has a lot of travel before it hits bottom, this might be something to consider.  Worked for me.  In my case it wasn’t air that needed bleeding, it was just a Mechanical mis-adjustment.

Thanks, Gordon, it is a bit squashy still. I'll keep bleeding the bugger. It's good to know that a regular VW Super Beetle MC can and will deliver a high hard pedal with these brakes, when the stars align.

What is the part number on your master cylinder?

Are you using a stock length brake push rod?

The push rod free play stroke to master cylinder contact point should be about a 1/16th of a spacing ,  this spacing allows for the master cylinder piston to be fully released. If you have the slightest pressure against the cylinder you'll never be able to properly bleed the brakes. Sometimes it's a dance between that adjustment and the floor mounted pedal stop bracket.

Hey @chines1 the number on the MC is 12361101580. I made the pushrod and it's (as I recall) just a hair under 5 1/2 inches long (per VW specification of 5.433 inches +- .019 inches). Freeplay is set to just a tick. It was slightly more than 1/16 before the other day; I turned the rod in about 1/2 or 3/4 of a turn and it feels like about 1mm. The pedal barely moves before there's contact with the plunger now—I think! 

I also measured and set the full possible travel of the pedal to be sure it conformed to the VW spec for dual MCs, though I can't remember what that distance is just at the moment. 

Pretty sure I just have air in there, somewhere. It does feel spongy when it first picks up. And it goes down about twice as far as Bridget's brake pedal, which is stock VW with front discs and rear drums, but Bridget's pedal shaft itself is Z-bent to make more room for wider feet which reduces its arc of travel some.

I've bled the system quite a lot & get no air out the bleeders but I did not bench bleed the MC first.

I am getting into this late and haven't read the entire thread but I had a car that gave me fits to get the system bled of air and the pedal felt spongy until I finally got the system completely purged of air. I started with the purge valve furthest from the MC. I used a two person system of pump up and release the valve. I hade to do each caliper at least 5-8 times working furthest to nearest using an entire large bottle of brake fluid  during the process. I finally got the hiding air pocket out. Good luck I know how frustrating this can be. I have never had luck with the one person vacuum purge system. 

I just went through this with a VW sand rail. Two wheel cylinders were frozen, the car pulled hard to one side. I replaced all 4 wheel cylinders, shoes, and drums. Also replaced the MC, it had a ton of corrosion from NOT replacing the fluid. It was a 3/4" single action Wilwood with integral reservoir. All steel lines were solid and I replaced the hoses a couple years ago, they are still very pliant.

The only weird or different thing was a CNC cutting or turn brake(turn brake still works but buggy is only street driven). Even following the CNC bleed procedure, we still had a low pedal after a WHOLE QUART of fluid. On second pump the pedal is plenty high and hard. But that low pedal on first pump is pretty scary.

At this point, the only fix can be to remove the turn/cutting brake, and install a Tee where it was. I also bought a 10 pound residual valve just in case we can't get a good pedal. It had a good pedal before after I changed all the hoses and adjusted the shoes.

Also he had almost no clutch, hydraulic not cable-operated. It had a 5/8" Wilwood MC and an old(ancient?) 7/8" Neal slave. The MC insides looked bad, and the slave was even worse. The pitting looked like craters inside. Replaced them both and that pedal came up nice and quick after little bleeding. 

Well, at least the clutch was easy.

Bleed the master cylinder

Update. I pulled the MC out tonight and measured the pushrod and it was adjusted to only a skosh more than 5.25 inches. I must have forgot about the importance of that 5.43 inch length when I installed the pedals; I adjusted the brake and clutch to an even plane. 

So I readjusted the pushrod to be a little less than 3/16ths longer.

I'll see if I can bleed the MC tomorrow and then put it back together and flush and bleed the system. 

I've got a good feeling about this.

Fingers crossed. 

...and toes.

Your master cylinder number doesn't seem right, but the numbers/letters in the casting can be hard to read, especially as the tooling gets older.  The end of your number is the most critical.  I think your "80" on the end may be a "BD" instead...

The 2 most common are 113.611.015.BD

and 113.611.015.BDD (note the second "D")

The latter is for 4 wheel disc brakes and is a 21mm bore cylinder.  The former (with one "D") is a standard 19mm cylinder and made for front discs/rear drums. It WILL work somewhat on a 4 wheel disc system, but pedal height is low and pedal feel is spongy.

Well boy howdy! Thanks, Carey! You're saying a BDD master cylinder will get me where I want to be? Hmmm.

I happen to have a pile of new master cylinders. Will check the numbers presently & order a BDD model if I don't have one on hand.

Ed  You must be the one in a hundred who knows how to use the word 'presently' in its correct meaning.

:-)

It comes from all that swearing at stuff that he's been working on.

He's learned to swear eloquently with proper diction, too.

"My father worked in profanity the way some artists work in oils. He was a true master." Christmas Story. That line reminds me of my dad every year.

@Boothy posted:

"My father worked in profanity the way some artists work in oils. He was a true master." Christmas Story. That line reminds me of my dad every year.

~ I can associate with that quote in every particular  ~

Welp.

Here's the one that was in there. One D:

Box O' brake stuff:

1 D:

No Ds:

I could swear I had at least two more of these but I might've given them to a neighbor. The Spyder came with two dual master cylinders, one marked "Use This" (which I did), plus two aftermarket single masters that came with the pedals:

I had at least one more in the shop--a Brazilian one I bought for Bridget years ago and never installed (and lost and then found). That one has gone missing again but I doubt it's a DD since that car has discs/drums.

And so: ordering yet another. 

On the bright side: I found a totally new wiper kit for Bridget in a chip can I got from Alan. Never even looked in there in five years; it's a legit late MG TD wiper rig, looks like, with the motor on top of the windscreen. Thanks, Alan!