Lincoln brakes and lines.

[chris_kriner]

OK..Want to pick peoples brains................On my Lincoln (46) we replaces all brake lines front and back. New cylinders and all the rubber brake hose sets. Shoes are 90%. trying to bleed the brakes and the rears are not getting fluid or "enough" fluid to them. making them very spongy. Am I doing something wrong? what to look for? Booster? 

[Matt Harwood]

There is no booster on a '46 Lincoln, so you can cross that off. Did you replace the rubber flex lines? Those can swell up and reduce flow. Are all the lines the proper size? Is your master cylinder new? Is it leaking (even fresh rebuilds can leak--I'm on master cylinder #5 on my wife's '56 Chrysler)? No kinked lines or cross-threaded fittings? Brake light switch tight and not leaking? Bleeder screws all snug but not over-tightened? I don't recall whether these cars use a proportioning valve, but that could be another culprit. And not to insult you, but are you sure it's full of fluid? The reservoirs are TINY and I typically refill mine after every two pumps just to be sure it doesn't start sucking air.

 

Lots of little things to check, but the system itself is very simple and should work if everything is in order.

[chris_kriner]

Sorry Matt misspoke....You are right, Not Booster but master Cylinder. and thats not new. Everything else is brand new. and the lines were even pre-bent from shop...( I know i know doesn't mean they didn't mess up)  Good point on a small reservoir and not holding a lot of fluid. I will check that out. Bleeders are snug. I agree its a simple system, so thats why we are lost and scratching our heads.

[auburnseeker]

All good advice on Matt's part.

 

Did you bench bleed the master really well? I have even had to bleed it again in the car after.   Also if you are using Silicone you have to pump it very slow and let it sit as it will foam up the fluid.  If it does,  you just have to let it sit a while then go back later and do it again nice and slow.  I have also had brakes shoes that weren't properly adjusted. You need to pump them a few times just to get them to square everything up then readjust them.  Pulled my hair out figuring that one out as it had never happened on other jobs I did. 

 

[chris_kriner]

No we did not bench bleed. Never removed the master. Doing it in car. Hmmm we are pumping slow, so i dont think its foaming 

[Ray500]

I am in the process of replacing the brakes on my 41 Club Coupe.  I have new brake lines (stainless steel) to use, and rebuilt master which will need to be checked carefully.  I did buy some aftermarket brake parts earlier that would update the brake system, but it requires a lot of modifications to get it installed and working.  You can get vacuum boosters that will fit with some effort too to increase the efficiency of the braking system. And no, originally there were no proportion values to balance the pressures from front to rear.  It's always a temptation to put on a more modern dual master cylinder and the valves, but you have to remember you're altering the vehicle even though some will argue that is't safer in modern day traffic which is hard to argue with in some places.  And remember as in all of these types of brake jobs your wheel drums have to be machined as perfectly round as possible, and you need to make sure the brake shoes are properly 'arced' to fit the drums for good contact in stopping.  Not sure who have brake shoe arcing machines anymore.  I will also change all the flexible brake hoses at each wheel too.  With all the components replaced with good items  and not aftermarket components you should have good working brakes if you remember you're not driving a modern power  disc brake system and treat it as such!

[chris_kriner]

Ray. Thank you. Stainless here as well. Not modifying anything. . keeping it stock. But like I said only thing "not" new is the master. 

[Bloo]

Is this DOT 5 fluid by any chance?

[chris_kriner]

Bloo.......No using DOT 3

[auburnseeker]

I would hook the lines up to "bench Bleed" it in the car.  That will cause the problems you are having.  You need to get all the air out of the master.  Sometimes just when you think you got it,  you find you weren't quite there with the next pump.  Dot 3 Won't Foam so you don't have to worry about that.  I would have completely rebuilt the master and gone dot 5 so you never have to worry about moisture again.  Every car I touch I just go through everything and use Dot 5.  It's nice knowing you will never have a problem again,  plus if you spill anything,  it won't ruin the paint.  Even the paint on the cylinders.  Nothing worse than looking at a 2 year old restoration or brake job and seeing rusty looking cylinders, 

[19tom40]

If you are not getting a good stream of fluid out of both rear bleeder screws when you open them a full turn, the problem is likely the flex hose or the junction block after the flex line. Disconnect the flex line at the junction block and direct the hose into a container. Press the brake pedal and look for a good stream of fluid. If you get the fluid there,the problem could be the junction has debris in it or both rear wheel cylinders could also be bad. It is not unusual to get new defective parts

[chris_kriner]

I was thinking about the Junction, Ill check that out...thanks! 

[abelincoln]

I've had fair luck with a parts store suction tool.  I finally found an old master cylinder lid and plumbed it with an air fitting to force 10-15 lbs pressure, get a nice flow at bleeder screws.  Much easier.

Abe

[chris_kriner]

OK.... update....It came down to two issues. Bad Master and rear junction (T block) box in the rear. In the processes of fixing the master, the pressure switch and bolt were damaged. Have new ones coming with new copper rings/seals. That should be the end of that issue hopefully. Thank you everyone for your thoughts and suggestions. Now to start a new thread about wires and plugs! lol 

[19tom40]

It is a good idea to bench bleed the master cylinder. It will let you determine if the part works correctly before you install it.

[Cokekid]

I keep reading about bench bleeding the master cylinder. Can someone explain how this is done.

 

I also am interested in replacing my brake lines. Did you buy them already assembled  at each end.?

 

Gerry

[Ray500]

Check out www.classictubing.com as the have replacement stainless steel lines already properly bent and ready to install.  

[chris_kriner]

Classic tube is the company I used to redo my lines. Very good company and they fit perfect. I do recommend calling up Boos for other parts that the kit does not come with. Example: The Junction boxes. Clips and I ended up getting everything new past  the Master (Copper washers/bolt and pressure switch) this was my mistake and couldn't figure out why I was getting no fluid in the back. Tried to reuse older parts that (you couldn't tell) were clogged. So whats a extra $50/60 from Boos....Make it all new, save the headaches and time 

[Ray500]

On these old cars, some of them over 80 years old you can't trust anything when it comes to safety equipment like brakes!  Spare nothing to get the best brake job with the best parts you can find.  I do have an original NOS master cylinder built in the USA, so I think it will work well.  I do bench bleed as air can trap in any part of the brake system.  You'll eventually get it all out if you keep bleeding.  I have a pressure tank I will also use in the bleeding process just as soon as I get all the appropriate fittings to I can bleed without having to have someone stomp on the brake pedal over and over which can also cause more air bubbles.  That way all the components that are brake related will be renewed and properly installed so the thing will stop when it's supposed to!   What more could one ask for???   

[19tom40]

Cokekid, bench bleeding the master cylinder is done by clamping the master cylinder in a vise, blocking the output of the master cylinder, filling it with brake fluid and use a punch to slowly actuate the brakes. Push in slowly and release slowly until you can no longer feel any softness when you push the punch in. If you cannot reach that point after several pushes, the cylinder is defective.

 

You will still have to bleed the brake system after you install the master cylinder.

[Cokekid]

Ray500

Thanks for the info were to buy lines.

 

Tom.

I will give it a try when I am going to do the brakes

 

Gerry