It's been about 30 years since I had to bleed the brakes on a car and I've got a pretty good memory, but apparently I've forgotten something because I'm in a real pickle.
The 61 D100 ute had a bad master cylinder - it was leaking back into the cab. I put up with it for about five years, but this weekend I decided to put a new one in. Got a replacement Cardone master cylinder, bled both the output and brake switch sides until there were no bubbles, then capped them and installed it. Got everything hooked up, then bled the brakes with one of those hand pump vacuum things. Started at the right rear and pumped until the brake fluid was clear with no bubbles. Added fluid to the master cylinder, then did the left rear, same way. Then right front, then left front.
The pedal goes to the floor. There's a bit of brake. It doesn't pump up at all. I double checked and all of the bleed screws are closed. I don't see anything leaking around the master cylinder connections. I didn't touch anything else in the brake system. Did I forget something?
Brake bleeding
Re: Brake bleeding
They don't put residual valves in the rebuilt master cylinders anymore I found out recently due to new designs in wheel cylinders they now sell when you redo your brakes. I had to go buy a 10lb residual valve and plumb it inline to the rear drums on my '62 Newport today as I have a new m/c but the old style wheel cylinders. Perhaps someone who knows more could chime in. Just a guess in your situation though.
Re: Brake bleeding
I don't think that it needs a residual valve because the master cylinder is above the wheel cylinders. I remember that was a problem with my old VW bug because the master cylinder was under the floor.
I'm wondering if the replacement master cylinder has a smaller bore than the original - just looking at the brake and clutch MCs side by side, the brake MC looks smaller than the clutch one now. If that's the case, I'm not sure what to do, other than to replace the wheel cylinders with smaller bores. I guess that since they're also over 50 years old, it wouldn't be a terrible thing to do, but I don't want to start throwing parts at a problem without understanding it first.
The master cylinder is a Cardone Select Part# 1336063 from Rock Auto.
I'm wondering if the replacement master cylinder has a smaller bore than the original - just looking at the brake and clutch MCs side by side, the brake MC looks smaller than the clutch one now. If that's the case, I'm not sure what to do, other than to replace the wheel cylinders with smaller bores. I guess that since they're also over 50 years old, it wouldn't be a terrible thing to do, but I don't want to start throwing parts at a problem without understanding it first.
The master cylinder is a Cardone Select Part# 1336063 from Rock Auto.
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dodgeboykim
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Re: Brake bleeding
Have someone gently work pedal up and down at top of stroke while you peer into reservoir. If air bubbles are present then you may need to re-bleed master. Don't get fluid in eyes if it squirts up in air. 
Re: Brake bleeding
..nevermind.. deleted this post..
Re: Brake bleeding
Yep, there are bubbles. I spent a few minutes this morning trying to bleed it in the truck. It raises another question - can I just bleed from the brake switch sensor, since it's higher than the output port? It's a little easier that way and a lot less messy.dodgeboykim wrote:Have someone gently work pedal up and down at top of stroke while you peer into reservoir. If air bubbles are present then you may need to re-bleed master. Don't get fluid in eyes if it squirts up in air.
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dodgeboykim
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Re: Brake bleeding
Hardcase wrote:Yep, there are bubbles. I spent a few minutes this morning trying to bleed it in the truck. It raises another question - can I just bleed from the brake switch sensor, since it's higher than the output port? It's a little easier that way and a lot less messy.dodgeboykim wrote:Have someone gently work pedal up and down at top of stroke while you peer into reservoir. If air bubbles are present then you may need to re-bleed master. Don't get fluid in eyes if it squirts up in air.
I see no reason you cant do that. You will know if its successful as you re bleed all of it.
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earlymopar
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Re: Brake bleeding
I had a similar problem that was simply caused by the push rod from the brake arm not being adjusted with the correct free-play at installation. The result was that the master cylinder would not fully close the ports and there was no pedal.Hardcase wrote:It's been about 30 years since I had to bleed the brakes on a car and I've got a pretty good memory, but apparently I've forgotten something because I'm in a real pickle.
The 61 D100 ute had a bad master cylinder - it was leaking back into the cab. I put up with it for about five years, but this weekend I decided to put a new one in. Got a replacement Cardone master cylinder, bled both the output and brake switch sides until there were no bubbles, then capped them and installed it. Got everything hooked up, then bled the brakes with one of those hand pump vacuum things. Started at the right rear and pumped until the brake fluid was clear with no bubbles. Added fluid to the master cylinder, then did the left rear, same way. Then right front, then left front.
The pedal goes to the floor. There's a bit of brake. It doesn't pump up at all. I double checked and all of the bleed screws are closed. I don't see anything leaking around the master cylinder connections. I didn't touch anything else in the brake system. Did I forget something?
- EM
Re: Brake bleeding
Bingo! The rod was too short. The brakes worked, but there wasn't enough push rod to get 'em to come on all the way. Now the truck stops on...well...a quarter, I guessearlymopar wrote:
I had a similar problem that was simply caused by the push rod from the brake arm not being adjusted with the correct free-play at installation. The result was that the master cylinder would not fully close the ports and there was no pedal.
- EM
Thanks!-
dodgeboykim
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Re: Brake bleeding
Hardcase wrote:Bingo! The rod was too short. The brakes worked, but there wasn't enough push rod to get 'em to come on all the way. Now the truck stops on...well...a quarter, I guessearlymopar wrote:
I had a similar problem that was simply caused by the push rod from the brake arm not being adjusted with the correct free-play at installation. The result was that the master cylinder would not fully close the ports and there was no pedal.
- EM
Another thing to check. That's happened to me back in the day.
Re: Brake bleeding
Just had that happen to me. Swapped in a 69 dual pot master cylinder and pedal rod was too long, didn't let the master cylinder open all the way. I was wondering why I had such low flow out of the wheel cylinders when I was bleeding it... Adjusted rod with just a tad bit of free play, rebleed and its all good. And never forget to bleed master cylinder first.