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EFV-8 Club Forum / General Ford Discussion / Puzzleng Brake Problem

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Posted By Discussion Topic: Puzzleng Brake Problem     40 Coupe 08-28-2015 @ 4:36 AM reply profile send p.m. Senior Posts: 1679 Joined: Oct 2009 This is the Ford diagram of the MC. 40 Coupe 08-28-2015 @ 4:32 AM reply profile send p.m. Senior Posts: 1679 Joined: Oct 2009 here is a picture showing the MC rebuilt kit parts and assembly. This shows the rubber seal for the valve. The Ford MC usually has a steel washer between the wire stop and the piston. This message was edited by 40 Coupe on 8-28-15 @ 4:34 AM 40 Coupe 08-27-2015 @ 5:15 AM reply profile send p.m. Senior Posts: 1679 Joined: Oct 2009 Very early rebuild kits have the valve and rubber washer molded together. So the early diagrams for rebuilding do not show a separate washer. I have not seen one of these early rebuilding kits in a long time. The kits available now need clear instructions. The modern power bleeders for the brake system can work well. Back in 40's they were not available and the job was done by pumping the brake pedal. Now it can be done in a number of ways, but if your using the more modern DOT 5 brake fluids be aware they can trap air and hold it much longer than the DOT 3 & 4 fluid. Do not let the MC run dry and do not pump the pedal a lot. The power bleeders work especially well with DOT 5 fluid. This message was edited by 40 Coupe on 8-27-15 @ 5:27 AM Dustbowl 08-26-2015 @ 4:48 PM reply profile send p.m. Member Posts: 74 Joined: Feb 2011 Special thanks to Supereal and 40 Coupe as I believe they have identified my problem. When I rebuilt the master cylinder, I was left with a spare rubber washer. I looked carefully at several diagrams of the master cylinder components and could not find where this should go. I now assume that the part number 2198 consists of both the metal valve AND the rubber washer while I previously thought it only showed the metal part. So am I correct now? In any case, I will open the MC and insert the washer. Separately, I am interested in your comment about using a "power washer". I have one but have not used it because it doesn't have a connection piece to the top of the MC. However, I am unsure why a power washer is better. Doesn't it just build pressure in the hydraulic system just as pushing on the brake pedal does? What is different? Many thanks for any further advice. 40 Coupe 08-25-2015 @ 5:28 AM reply profile send p.m. Senior Posts: 1679 Joined: Oct 2009 If you have rebuilt the master cylinder the newer rebuild kits have a rubber type washer that seals the outer diameter of the output valve. Without the washer the valve will leak around it's perimeter. The washer usually has a hex shaped hole in the center. It is the first thing to install in the empty MC when rebuilding, second item is the valve. supereal 08-24-2015 @ 8:53 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 There is a valve in the master cylinder that keeps a small amount of pressure in the system so you don't have to always pump the pedal. It is a good guess the your problem is there. Also, it is very difficult to get all air out doing the "pump and hold" method. We use a power bleeder to save time and fluid. cliftford 08-23-2015 @ 8:52 PM reply profile send p.m. Senior Posts: 845 Joined: Jan 2014 Is the pedal spongy or solid when you pump it? If spongy, it is probably air as the the last post suggests. If solid , it sounds like an adjustment problem. Try pumping it with the emergency brake on. If it comes up, the rear shoes probably have too much clearance. Have you removed the wheels and checked the condition of the drums and linings? If good,I would readjust all 4 wheel so that they have a very slight drag on them and see what that does. fla48 08-23-2015 @ 6:24 PM reply profile send p.m. New Member Posts: 128 Joined: Nov 2011 It sounds like there is still some air in the system. Have you checked for leaks at all of the connections. It can be difficult to get all of the air out of the break system. Do you ever get a full petal after pumping the breaks? Dustbowl 08-23-2015 @ 4:35 PM reply profile send p.m. Member Posts: 74 Joined: Feb 2011 The 39 hydraulic brakes in my 36 Ford show all the signs of air in the system: -on first pump of brakes, pedal goes almost to floor, -on second pump, pedal stops halfway and stops car well. But two factors suggest there must be some other cause as: - the problem initially developed slowly over time when system was not opened to get air in, and - subsequently, I have rebuilt master cylinder and bled system successfully and extensively from all four wheels. And after this, the system still responds as before I opened it to rebuild master system. I have also adjusted all the brakes in the normal way. And adjusting the plunger on the master cylinder does not help. So I'm stuck. Please let me have any ideas you may have for another cause of my problem other than air.

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