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Beginner working on brakes (65 Ambassodor)

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Patrick_J View Drop Down
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    Posted: Nov/03/2018 at 4:37pm
Hi..it's my first try with brakes...Since the car sat for so many years, I decided to replace the brake shoes, clean all springs and parts etc.  I put everything back together and now, despite having a full brake fluid container at the master cylinder under the hood, I get no fluid output at either of the rear brake cylinders when I pump the brakes (i disconnected the lines from the back left and right wheel cylinders so I could verify fluid would be flowing through it). Am i missing something? Is there some other switch that controls flow of fluid? it's not likely to be clogged somewhere is it? I am a beginner so if there are other resources you think I should try, please let me know!

Thanks!

Patrick
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Nov/03/2018 at 8:20pm
First thought is your rear brake lines are internally clogged with rust after sitting for years.
First verify the master cylinder is OK by making a loop of line back to the reservoir, pumping the pedal to see flow.
If the fluid flows there then you will likely have to replace the line to the rear, clean the tee and replace the line to the other side.
This is not that daunting of a task. Buy copper nickle brake line as it is the easiest to work with and will last the life of the car. Flaring tools are not to expensive and after practicing a few flares on a short piece of tube you will feel quite good about this.
Take pictures of the old line run, remove it with side cutters and start running your new lines.
Just make sure all lines and connections are clean.
Just gravity bleed the brakes, slower but quite effective.
Buy a TSM.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 6768rogues Quote  Post ReplyReply Direct Link To This Post Posted: Nov/04/2018 at 4:39pm
Trader has good advice. When I am planning to drive a 50+ year old car, I replace everything I can replace in the braking system. You might do all the work you have done and even if it works, you could hit the brakes hard and pop a line or hose, leaving you with nothing but the parking brake and a quick prayer.
Why Ramblers? Chicks dig 'em. Whatever it is, I can take it apart.
Located near Rochester, NY
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Nov/07/2018 at 7:34am
Replace the flexible rubber line between the brake line at the body and the axle first. That's the most likely culprit. You can disconnect it at the body and check for fluid when you press the brakes there. If none, then it's a line problem further up. At that point I'd check at the junction block and see if you're getting fluid there, then also at the master cylinder exit. All that will pin-point where your problem is -- could be a bad master cylinder.

you can get brake line with ends already on it at the local auto parts store. It comes in 12" to 60" (5') lengths. You can get a junction bolt to connect two lines together. you can make a longer loop in a line if it's a bit longer than stock. Unless you want a 100% stock appearance underneath that's the easiest way out.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/07/2018 at 11:37pm
you may not get the results you think by pumping the pedal with a whole line disconnected. brake systems are a bit subtle.

each pump of the pedal doesn't move a lot of fluid, first off. it's not really a pump. when you press down, the piston in the master cyl pushed fluid that expects to push the piston(s) in the wheel cyls -- and when you release it, the springs in each wheel pushes the pistons and the fluid back into the master cyl.

so pushing the pedal doesn't pump fluid like a squirt gun; after the press (and squirt), upon release with the line disconnected, it sucks air into the line and master cylinder.

if you've had the line(s) disconnected so that fluid drained out, especially if you pumped the brake pedal with the line/lines off, you will need to bleed the entire system before you have any meaningful results. you might also need to "bench bleed" the master cylinder separately.

bench-bleeding is a process best described separately not here now. it nust be done to new masters. it must be done if you have pumped the resevoir dry. some folks say you dont need to do this; sorry, but that's just wrong.

brake systems need to be completely, absolutely, 100%, free of air. a small air bubble, even one the side of the head of a paper match, will make the brakes very mushy.

don't let any of this scare you. just follow the Usual Methods (in many threads here; and on the web; or ask) and it always works. sometimes you need to bleed the whole system more than once -- especially if you got air in it.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Patrick_J Quote  Post ReplyReply Direct Link To This Post Posted: Nov/08/2018 at 11:40am
Hi all! thanks for the great advice and Tom, that response really helped me to visualize what is going on here. Update: I removed the brake lines from the master cylinder, only one output (for the front brakes) leaks (shoots!) fluid when I pump. so it seems the piston in my master cylinder is having some trouble (it seems the piston controlling flow into rear brake line is seized? that is chamber closest to front of car by the way.)

Next step, I removed master cylinder and the the retaining ring holding the main piston/spring system, but this piston will not come out! I do have two metal post electrical outputs coming out of a junction half way between the front and rear chambers. This is seized. I presume if I can get this off i can get that piston out to have a look? Getting closer!!  not at home now but here is a pic of what I am talking about (i couldnt find an exact pic, this one doesnt have the electrical output connectors that my actual cylinder has on the siezed piece: https://photos.app.goo.gl/iN4XhG188Y1eqVux8

Patrick
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/09/2018 at 12:50am
i would't bother taking it apart. replace it. it's not wasteful to do so in this case -- if you're not experienced with this stuff and all it's subtleties, the parts are all very old -- the master cyl is likely no good (rust, bad seals) if it's sat for a long time especially if it wasn't in top-notch shape when parked. if it's rusted inside it's not a candidate for rebuild anyway. i'd just ditch it.

i and others on this forum are all for repair where appropriate, and nto generally just "shotgun" old parts for new, but with brake parts it's often the most reasonable path. few of the parts are expensive and all of them rot and/or die just sitting there. and most of them are wear parts anyway.

if it's sat, the lines are very likely rotten inside. replacing lines is a PITA but not expensive or inherently difficult.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Nov/09/2018 at 7:35am
Definitely REPLACE the master cylinder! Even if you can buy a rebuild kit it only $20 or less more to get one ready to go. RockAuto probably has one listed. That switch in the bottom is the brake light switch. Either order one from Ron Francis wiring or convert to a pedal switch, which isn't real hard to do. The replacement screw-in pressure switches from the local auto parts store is junk! They work for occasional drivers/show cars, but won't last more than 5-6 months on a daily driver. I'd just by-pass the headache and order a good one from Ron Francis Wiring.
Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Patrick_J Quote  Post ReplyReply Direct Link To This Post Posted: Nov/09/2018 at 9:21am
ok i hear you loud and clear! Great points - Thanks for the comments... next step, new brake cylinder!


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Patrick_J Quote  Post ReplyReply Direct Link To This Post Posted: Nov/09/2018 at 3:00pm
one more thing!!  I always like to know how things work - can anyone tell me exactly how to get the piston out of the master cynlinder? it compresses when i push it, so it's not entirely siezed.. but it seems to be springing back against a hard edge that simply prohibits removal from the chamber.  I was able to remove the brake light indicator thinking this would free it, but it did not...
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