The car in question is a 1971 Olds Cutlass supreme with a 350 and 4 wheel power drum brakes. About as basic as it gets.

How can I tell if My master Cyl is ok/bad? I've replaced all the lines, wheel cyl's, shoes, & master(twice). I've bench bled the master, and gone through over a gallon of brake fluid, and the brake pedal still goes nearly to the floor with almost no resistance.

Could I have done something to ruin the new masters? If so, how would I know if I did? Could there be another problem I haven't thought of?

I've spent about three days on what should be about a 3 hour(or less) job (replace/bleed master) and am at my whit's end on this. I really don't want to have come so far on this project only to be defeated by my brake system. Any help/insight anyone can offer would be so super greatly appreciated!!! Thanks!

 

Sounds about like my luck...
Sounds like you are doing it right. Did you get most to fht ebubbles out when you bench bled the master?
Are you using the tried and true 2 man bleeding operation? I found the vacuum bleeders and check valves not too effective.
Did you get the master for drum brakes and not disc?
Bad new masters (esp if rebuilt) are not unheard of.

 

Thanks Rob! I've been following your brake troubles in hopes of resolving my own. I am glad to see you got it solved.

Yes, it's a 4 wheel drum master, but now that you say that I will double check the p/n to be sure. The first master was reman, the second I went "new" from Napa. I did get all the bubbles out.

I have done the 2 person pump & hold deal, then tried the gravity thing. Tomorrow I am going to double check all the fittings to make sure there are no leaks where the new lines attach. If I find anything, I will try bleeding them again, if not, I will be scratching my head and stare at it hoping it just fixes itself.

Thanks again Rob!

 

Damn cutlass brakes are nightmares. I will sound like a broken record but the only way I ever got mine to work right was getting them pressure bled. In my book it is well worth the money. Whenver I get around to fixing the brakes on my Cutlass I will take it to NTW and have them pressure bleed the brakes. I won't spene 2-3 days screwing with them like I have in the past.

 

Wow. That's baffling.

It sounds like you're doing everything right. You bench bled the master LEVEL, right?

I would look at it this way: there are only four things that will give you a soft pedal -
1. Leaks. If you've got one, you will see it. Just don't forget about the wheel cylinders, which can leak a fair amount without showing on the outside of the wheel.
2. Air in the system. Aside from the master there's not a lot of places where it can hide, so if they've been thoroughly bled, it should be gone.
3. Bad master. Fluid seeps under the seals and travels from one reservoir to the other, or into the booster, ad you can't see it.
4. Bad hose. A structurally damaged hose can, in RARE instances, have a section where the braiding is shot, and blow up like a balloon when you push the pedal. You could see it if you looked.

Think about these for a while, and see if they ring any bells.

Good luck!

- Eric

 

One other thing - since you rebuilt your brakes, did you adjust the shoes to be as close to the drums as possible?

I cannot say it is solved, as the pedal still feels spongy. Gravity and vacuum methods failed. Pump and hold helped but its still spongy.
The pressure bleed would be a good approach, however I fear the techs getting brake fluid all over everything, and bad techs are not in season yet...

 

Good one, Rob! I didn't think about that. Obvious, but someone who's new to drums might not think of it. I know I didn't, but I always adjust drum brakes before I put the drums back on. Shows that to be able to help other people, you've got to be able to think beyond your own personal experiences.


No, but I think you can still shoot them if they come onto your porch, so long as you don't take the meat or the pelt.

- Eric

 

Thanks Eric & Rob!

Yes, the drums have been snugged in. That was a great suggestion, because when I first put everything back together I didn't do this, and the pedal went straight to the floor.

I bought a Mityvac today. on sale @ NAPA. I'm having trouble getting the hose to seat on the front drums, but have at least gone from no resistance to spongy, so I may be moving in the right direction......

I had replaced all 3 soft lines, the long line to the back brakes, and the left front line, as well as all four cyl's & shoe sets, so I still have to inspect all the fittings to be sure there is no leakeage. I was going to do that today, but got too excitd about my new purchase. I will have a better look at it tomorrow.

Thanks again!!

 

I got a good tip off the mityvac help section - pull, check, & clean the bleeder screws/passages in case any debris may get in the way, or factory bur/blemish might hinder a smooth open/close of the bleeder.

I did that to the front this morning, and got decent results. The pass side was bubble free, the drivers side is still not there, so I am headed out to get some pipe cleaners, and will hit it again Sunday.

While the Cyl's & most lines are new, the rest of the car is old, rusty, and still a bit grimey, so it is entirely possible that debris could have gotten into the bleeder passages, so I am hopeful Sunday will yield the results I am looking for.

To get a good seal on the front bleeders, I replaced the funky attachments that come with the mityvac unit, with a 1 foot length 3/16 bleederhosen. Heated it up lightly with a cig. lighter, and snugged it on, voila, no more bubbles (at least on the pass side) With a little luck, on Sunday I should be able to report a solved problem......

Thanks again for all your help Eric, Rob, & Red!

 

Using the proper hose clamps, not a vicegrip, clamp off all 3 brake hoses and then hows the pedal then? If is good or better with the clamps on the bleeding procedure is at fault, if its still low, the master has air in it or has failed.

Hope this helps

 

Thanks DJS, That was my original question, what are the proper clamps for that procedure?

Update: I think I am done, the 3/16 tubing works great on the mityvac, and the pedal feels much better. I'm going to get the wheels on & drive it around the block to see how it feels on the road, but I think I'm finally done with my brakes.

Thanks for all the help!

 

there are a lot of different styles, but ones like these work best for me.

http://www.harborfreight.com/4-piece...set-65116.html

Sorry I didn't respond sooner, did you get things sorted out yet?

 

Thanks DJS! I took it for a short spin up the street & back Tuesday. It does feel better, but still not right. I will see if I can get those clamps locally & give it a try.

Brakes aren't new to me, but I have never replaced a master before, so it's my biggest unknown. I won't be able to try it til Monday, but it will be nice to at least have an answer. I may actually pull the master & try bleeding it again.

Thanks again!

 

Holy moly, I don't think I realized it had been 9 years that I have had these issues. I had a brake though (pun intended) and thought I'd better share with anyone else who may be experiencing a similar issue. It was not the Master Cylinder after all. it was the bleeders themselves letting air escape. I was so close when I mentioned being sure the bleeders were free of debris. Here is what happened...

after years with "still not quite right" brakes, by passenger side rear brake cylinder froze. I swapped it out and bled it. wouldn't you know the brakes immediately felt better. Still not perfect, but better. I then turned to bleed the drivers side, just to see if I could improve the pedal feel even more. It was deja vu all over again. I was going on 2 pints of fluid with bubbles still trickling out. I always have music on in the garage, and have now realized that is not always the best practice. Something soft was playing and I heard a faint noise coming from the drivers side rear wheel as I backed off the pedal. It occurred to me that I in fact was hearing air being let into the system by the loose bleeder. I tried to think of something that would stop it. I tightened the bleeder, dried it off the best I could and applied a liberal amount of bearing grease around the bleeder. Knowing this wasn't the optimal solution, I then pushed down the brake pedal at the pace of a drugged snail, and let off the pedal in the same fashion. By the 5th push of the pedal, I had bubble free brake fluid flowing from the drivers side rear.

What had occurred to me in that moment was that even the "new" brake cylinders are most likely reman's, and will likely have "wiggly bleeders"

Oh, and the do it yourself bleeder I used (a 28 ounce power aid bottle, and a piece of clear tubing) and the instructions on how to use it are here: Now I'm going to do the same on the front and see if I can get the pedal to be the best it can be. Cheers!

 

Air in the system will always cause a spongy pedal feel. Glad you figured your problem out after all this time.