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Posted By Discussion Topic: Brake Issues -- page: 1 2     46coupe 08-20-2017 @ 4:36 AM reply profile send p.m. Member Posts: 271 Joined: Oct 2015 This thread is a continuation of the wheel cylinder discussion. Previously:I have a wheel cylinder/brake issue. Possibly you all will help me here instead of starting a new thread. The history is: 46 Super Deluxe coupe, rebuilt/ and honed all wheel cylinders, installed new brake shoes, rebuilt master cylinder, replaced front brake hoses as we found the previous ones that looked new but were actually collapsing and locking the wheels. Yesterday I had a weird noise coming from the right rear wheel. Luckily I was only 100 yds from my favorite garage and pulled in to see if I could get the car on the lift. We did and a E-brake retainer fastener had failed and part of the linkage was in the drum. That we fixed. While inspecting the other wheels we found that some were locked up and some were not. Had a devil of a time getting the car in the shop and on the lift. We closed the brake shoes as far as we could and the wheels barely turned. The drums and back plates were not hot. When we finally got the drum off the right front, the left front spun freely. We put the drum back on and could hardly turn the left or right front. We had found fluid in the front cup on the right cylinder. Does the fluid some how equalize in the system? Could this be causing the brake shoes to over tighten and then loosen? I've ordered new front cylinders and will install the old shoes on the front as we think we found a hump in the center of the new shoes. Any Ideas?? 46coupe 08-20-2017 @ 4:38 AM reply profile send p.m. Member Posts: 271 Joined: Oct 2015 A principal of physics that I learned in my junior year in High School in 1954: "When pressure is applied to a liquid in an enclosure, that pressure will be equal at all points. Thus when you put pressure on the brake fluid with the master cylinder, the pressure is equal at all four wheels, Even tho the lines are different lengths. Regards, Steve Lee sarahcecelia 08-19-2017 @ 6:06 PM reply profile send p.m. Member Posts: 234 Joined: Mar 2013 Tom may be right on track. Check the "free play" on the master cylinder.You only need a little, but if there is none, the pressure will build to the point that the brakes will actually "lock up." 46coupe 08-20-2017 @ 4:49 AM reply profile send p.m. Member Posts: 271 Joined: Oct 2015 Sorry, Tom. This is the only way I could figure out how to continue the discussion from the other thread for the new people that might read this. On to the latest response. I understand the physics involved and the definition of "free play". What I want to know is- how much free play, what could have caused it not to have any all of a sudden, and how to introduce, or adjust for it? I've messed with brakes quite awhile and never ran into anything like this. It sounds like this could be the answer as the 4 corners did lock up outside of the garage bay and I had to keep doing little jumps by releasing the clutch at higher rpms until the wheels suddenly freed up. At the time we thought it was the left rear wheel causing it. We didn't discover this 4 corner issue until the car was in the air and we tried to spin the wheels. Is there anyway I can copy this thread to print out a hard copy for my notebook? Thanks again TomO 08-20-2017 @ 8:10 AM reply profile send p.m. Senior Posts: 7252 Joined: Oct 2009 You need the freeplay in order to insure that the piston uncovers the bypass port. To adjust the freeplay, loosen the locking nut on the push rod and then adjust the rod for 1/4" to 1/2" of free play at the pedal. Tighten the lock nut and recheck the free play. You can pull the pedal to see how much freeplay there is. You should be able to feel the rod touching the piston in the master cylinder. The free play would have changed when you rebuilt the master cylinder. Click on "General Ford Discussion" and you should see a topic called "Print a Discussion". Tom This message was edited by TomO on 8-21-17 @ 7:31 AM cliftford 08-20-2017 @ 8:04 PM reply profile send p.m. Senior Posts: 845 Joined: Jan 2014 If you adjust the free play as TomO advises, that should do the trick. If not I would pull the master cylinder and check for incorrect assembly or a plugged port. sarahcecelia 08-21-2017 @ 6:36 AM reply profile send p.m. Senior Posts: 1186 Joined: Mar 2013 How much free play? Just enough so you can feel it when you depress the clutch by HAND! That might be as little as 1/8 inch plus or minus a little. It's not a measurement, it's a "feel."If you can "feel it" it's enough. That, as I said in a previous, thread will keep the system from building up pressure. Believe me, 'caus in"the day" I did literally 100's of brake jobs. Regards, Steve Lee This message was edited by sarahcecelia on 8-21-17 @ 6:38 AM supereal 08-22-2017 @ 2:04 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 The master cylinder has a valve in it that keeps a small amount of pressure in the lines as the brakes are used. This prevents having to pump the pedal each time you stop. If this valve isn't working properly, the first symptom is that the brakes begin to drag, and may eventually lock the car from moving. 46coupe 08-24-2017 @ 3:03 PM reply profile send p.m. Member Posts: 271 Joined: Oct 2015 Just got back from the garage where we installed new front wheel cylinders. My new wheel cylinder kits that I had installed less than a year ago had rust on the pistons [probably wrong term}. Bled the brakes. Also we checked the free play as soon as the car was lifted. It was ok. Test drove the car and it seemed to work ok. Drove the car 4 miles home and pulled into the garage. Checked the front hubs which were hot. The rear was luke warm. Put the car in neutral and it would not budge. Any ideas? The rear cylinders were rebuilt, but after seeing what the fronts looked like, I'll probably replace them with new complete ones. Brake hoses were replaced when this started initially. The new hoses corrected the lock up problem at that point. Could the new hoses be collapsing? The car will go back to the garage next week and the master cylinder valve will be checked. We will also be turning the drums to clean them up and double checking the shoe adjustments {new shoes already installed}. The only things left to replace after the rear cylinders will be all the springs. Very frustrating. Will welcome any other ideas to try. 40cpe 08-24-2017 @ 3:11 PM reply profile send p.m. Member Posts: 472 Joined: Jan 2010 You can check if built-up pressure is the cause of your problem. I would get it to the point of not rolling easily and break the connection of the brake line at the master cylinder. If it bleeds pressure and the car rolls, you have narrowed the problem to the master cylinder. If it is still locked, work toward each end until it frees up. 46coupe 08-24-2017 @ 3:29 PM reply profile send p.m. Member Posts: 271 Joined: Oct 2015 That's an idea we can try with the old MC. Also where is the valve located in the master cylinder? Going to N.C. tomorrow to see family and will be going to Dennis Carpenters on Saturday for new rear cylinders, and possibly a new master cylinder. Any other ideas are appreciated.

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