Rookie working '67 Newport brakes: Master and Booster findings-

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Not sure what happened to my other thread so I'll do some updates for you chaps on this one. Thanks for all of the help and advise so far. I really am coming into this sort of thing cold and learning as I go. I couldn't do it without you guys.

Recap: After the brake pedal went to the floor on my '67 Newport I came here to ask for help. I was advised to get me a parts/repair guide, inspect for fluid leaking at the lines, under the master cylinder and at the wheels. I found no leaks anywhere in the engine compartment, but the fluid was pretty low in the rear chamber of the master cylinder. I topped it off and pumped a little bit and it was low again. This cycle went on a couple of times before I decided the leak must be into the booster.

I inspected the brakes all the way around, everything looked good, lines on the newer side and no fluid to be found. (Talk about complicated assemblies. Drums all around. Gonna be a crash course one way or another but that's for a different thread.)

I went ahead and replaced the Master Cylinder and booster with some middle of the road parts from RockAuto, but during the install of the new parts the alum spacer filter housing part between the master cylinder and the booster cracked in half. Finding this thing is..... difficult.

I bled and bled and bled the brakes, but the peddle would not engage until it was at least halfway to the floor. Eventually, I discovered the adjustment screw on the booster rod and after monkeying with that for a few minutes I got the brakes engaging right where they are supposed to.

Now when I use the brakes, I can hear the same air hissing sound from the peddle that a few other posters here have mentioned. I assume this is air entering/leaving the vacuum diaphragm in the new booster via the filter piece that split down the middle, but many of the threads I've seen are talking about bad boosters. Mine seems to be working fine, I (carefully) drove her all day yesterday and brakes worked good. Just making some noise.

I've found what looks like the piece HERE.

If this piece fails to fit, or fails to stop the hissing noise, I suppose I'll be biting the bullet and having the original booster rebuilt.
 

Davea Lux

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Not sure what happened to my other thread so I'll do some updates for you chaps on this one. Thanks for all of the help and advise so far. I really am coming into this sort of thing cold and learning as I go. I couldn't do it without you guys.

Recap: After the brake pedal went to the floor on my '67 Newport I came here to ask for help. I was advised to get me a parts/repair guide, inspect for fluid leaking at the lines, under the master cylinder and at the wheels. I found no leaks anywhere in the engine compartment, but the fluid was pretty low in the rear chamber of the master cylinder. I topped it off and pumped a little bit and it was low again. This cycle went on a couple of times before I decided the leak must be into the booster.

I inspected the brakes all the way around, everything looked good, lines on the newer side and no fluid to be found. (Talk about complicated assemblies. Drums all around. Gonna be a crash course one way or another but that's for a different thread.)

I went ahead and replaced the Master Cylinder and booster with some middle of the road parts from RockAuto, but during the install of the new parts the alum spacer filter housing part between the master cylinder and the booster cracked in half. Finding this thing is..... difficult.

I bled and bled and bled the brakes, but the peddle would not engage until it was at least halfway to the floor. Eventually, I discovered the adjustment screw on the booster rod and after monkeying with that for a few minutes I got the brakes engaging right where they are supposed to.

Now when I use the brakes, I can hear the same air hissing sound from the peddle that a few other posters here have mentioned. I assume this is air entering/leaving the vacuum diaphragm in the new booster via the filter piece that split down the middle, but many of the threads I've seen are talking about bad boosters. Mine seems to be working fine, I (carefully) drove her all day yesterday and brakes worked good. Just making some noise.

I've found what looks like the piece HERE.

If this piece fails to fit, or fails to stop the hissing noise, I suppose I'll be biting the bullet and having the original booster rebuilt.

Usually, hissing with the brake pedal is depressed is a sign the booster is bad, probably a leaking internal diaphragm. A leaking master cylinder allows brake fluid into the booster and degrades the internal components which are not designed to be in contact with brake fluid. If the internal diaphragm is leaking, it will get worse fairly quickly to where you will have no power assist at all.

Dave
 

CBODY67

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Usually, when you hear the hissing as the pedal is depressed and held, the engine should be missing too, due to the vacuum leak in the diaphram which is uncovered when the pedal is depressed. With the pedal not depressed, the hiss and miss usually stop. With the engine stopped and you depress the pedal to deplete the residual vacuum in the booster, you can hear a slight hiss from the vacuum being depleted with each pump of the pedal (usually two full pumps will deplete the reserve vacuum).

DO contact RockAuto about your situation and seek their guidance of what to do. Using ANY warranty/guarentee quickly is important!

Please keep us posted,
CBODY67
 

bigmoparjeff

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The booster diaphragm does seal against the aluminum piece, so you will need to replace it before condemning the new booster, but it's also super-common for there to be quality problems with the mass market brand rebuilt boosters. That's why everyone recommends sending your booster to Booster Dewey. He's not perfect either. He did a Midland for me and it was no good right out of the box and he blamed me for breaking it, which I know that I did not.

Jeff
 
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The booster diaphragm does seal against the aluminum piece, so you will need to replace it before condemning the new booster, but it's also super-common for there to be quality problems with the mass market brand rebuilt boosters. That's why everyone recommends sending your booster to Booster Dewey. He's not perfect either. He did a Midland for me and it was no good right out of the box and he blamed me for breaking it, which I know that I did not.

Jeff
This was my suspicion on the seal. The only one I've been able to find is technically for a different car and is linked in my top post and is backordered. Do any of you old wizards have source for this sort of thing? The repair guide even mentions and calls out a part number for a filter that goes inside of it, but I can't find anything like it it anywhere. Maybe booster Dewey has a line on one?

Worst case I guess I can try and sandcast one, or try to repair the one I have, but this being the brakes system and me being so green.... I dunno man.
 
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