Jim Yergin Posted September 2, 2009 Report Share Posted September 2, 2009 Looking for suggestions and advice on diagnosing my brake problem. I have disc brakes on all four wheels on my '41 P12 (AAJ Brakes). When I orignally installed the discs I also tried to use a newer style dual reservoir master cylinder but the travel of the push rod in the master was not correct and to make it long enough to actuate the brakes meant it would not travel back far enough to clear the relief port and the brakes would lock up. Went back to the original master and it worked fine for the last year. Now the brakes are back to not fully releasing. At first it was only occassionally and I could get them to release by pumping the pedal repeatedly. I removed the master, cleaned it and made sure the relief port was clear. I also increased the free play on the brake pedal travel as well as cleaning and lubricating the rods the calipers travel on. At first that seemed to have eliminated the problem but the last two times I drove the car the problem was back and getting worse. The drive to the office this morning was a tough one and I barely made it to work. I would appreciate any suggestions or ideas as to what to look for. The master has been re-sleeved and rebuilt and the flexible lines to each of the calipers were new when installed last year. When I got to the office I touched each of the wheels and each of them were extremely hot. I assume that means all four calipers are hanging up. Help. Thanks. Jim Yergin Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted September 2, 2009 Report Share Posted September 2, 2009 (edited) a little more info..are you running residual valves and or even a porportioning valve? It is odd that all four are dragging..that would indicate that the fluid is not return fully to the master as in the master is sticking in a forward position yet in the cylinder...does the pressure eventually bleed off per say when the cars sits idle for a spell? one other question, are you still using the presure sensitive stop light switch and if so, are the brake lights staying on (key on) Edited September 2, 2009 by Tim Adams Quote Link to comment Share on other sites More sharing options...
Jim Yergin Posted September 2, 2009 Author Report Share Posted September 2, 2009 a little more info..are you running residual valves and or even a porportioning valve? It is odd that all four are dragging..that would indicate that the fluid is not return fully to the master as in the master is sticking in a forward position yet in the cylinder...does the pressure eventually bleed off per say when the cars sits idle for a spell?one other question, are you still using the presure sensitive stop light switch and if so, are the brake lights staying on (key on) Tim, I am using residual valves on the brake lines. The pedal becomes very "hard" when this happens and has very little travel. Yes, the pressure does eventually bleed off when the car sits. No, I am not using the pressure sensitive brake switch. I am using a mechanical one. Thanks for your pm, I hadn't thought about there being a residual valve in the master. Jim Yergin Quote Link to comment Share on other sites More sharing options...
james curl Posted September 2, 2009 Report Share Posted September 2, 2009 I had exactly the same problem, i only have disc on the front from old daddy. I e mailed old daddy and asked him if I needed to remove the residual valve in the mastercylinder and he said yes. I removed the mastercylinder residule valve and that solved my problems. Normscoupe says his works very good and he still has the residule valve in his master cylinder. So unless you have the problem of a very hard brake pedal and or the brakes not releasing then you should be ok with all of the valves in place. Quote Link to comment Share on other sites More sharing options...
Jim Yergin Posted September 2, 2009 Author Report Share Posted September 2, 2009 James, Thanks for the confirmation. If I can get the car home from work, tonight's project will be removal of the the master cylinder residual valve. Did you ever notice that the really worse part of having a problem is not knowing what to do to fix it? Thanks to you and Tim I feel much better about my car now than I did this morning. Jim Yergin Quote Link to comment Share on other sites More sharing options...
desoto1939 Posted September 2, 2009 Report Share Posted September 2, 2009 Jim. This is a shot but is the relief hole in the master cylinder cap clean. There is a hole in the filler cap alsoto let pressure out. Check this and cleanout the hole with a small wire. I do not know if this will help but just an idea to check. Could your brake lines be collapsing on you? Rich Hartung Quote Link to comment Share on other sites More sharing options...
Jim Yergin Posted September 2, 2009 Author Report Share Posted September 2, 2009 Rich, Thanks for the suggestions. I removed the master when this problem first started occurring and made sure the relief hole was open. I will check the filler plug. I don't know if the flexible brake lines are collapsing but they are all less than a year old. I am going to try removing the residual valve in the master and see if that will do it. I often think of where I would be if were not for this forum. Then I conclude that actually I wouldn't be having the problems I am experiencing because the car would still be in pieces and I wouldn't be driving it. I'll take the problems rather than a pile of pieces in the garage. Thanks. Jim Yergin Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted September 4, 2009 Report Share Posted September 4, 2009 (edited) Jim, I've said the same thing many times myself. I'd be so far behind it would be totally demoralizing. Keep us posted on the brake situation. Edited September 4, 2009 by Joe Flanagan typo Quote Link to comment Share on other sites More sharing options...
Andydodge Posted September 5, 2009 Report Share Posted September 5, 2009 Jim, I have had 4 wheel discs brakes on my 1940 Dodge sedan since 1976/7 thay are 4 wheel vented discs with a master cylinder from a disc/drum car, the same one that the front discs I use is from, its an Oz only car so theres not much point mentioning the make BUT the principles the same ......when I 1st setup the discs I had the mid 50's style Plymouth rear brakes and ran the proportiong valve on the rear lines, this is with the vented discs on the front and vented disc dual circuit master cylinder and booster......it stopped but not great .......so I ended up adapting vented discs to the Plymouth rear axle and then found I had to remove not only the proportioning valve from the rear brake line but the residual valve that was bolted into the master cylinder as an all disc setup didn't need it...........I have been running 4 wheel vented discs with an inline power booster connected to the rear of the dual circuit brake master cylinder( my car uses hanging pendant style pedals) and my car has stopped fine for the past 30 yrs..........andyd Quote Link to comment Share on other sites More sharing options...
Jim Yergin Posted September 5, 2009 Author Report Share Posted September 5, 2009 Andy, Thanks for the information on your experience. I have removed the residual valve in the master cylinder and reinstalled the master. I still have to get the brakes properly bled before I can try them out. I am away from home this weekend so I won't find out until I get home if that was the problem. Jim Yergin Quote Link to comment Share on other sites More sharing options...
Jim Yergin Posted September 12, 2009 Author Report Share Posted September 12, 2009 I removed the residual valve in the master cylinder. But now I am having a devil of a time getting the brakes bled. I am using a pressure bleeder, Everytime I think I have all the air out and the brakes working, once I put the car back on the ground and try to drive it I have no brakes. Would removal of the internal residual valve make it more difficult to bleed the brakes? I do have 2lb residual valves in the lines to the front and rear disc brakes. I suppose I just haven't gotten all of the air out of the system yet but it is getting frustrating. Any ideas or suggestion would be appreciated. Jim Yergin Quote Link to comment Share on other sites More sharing options...
James_Douglas Posted September 12, 2009 Report Share Posted September 12, 2009 Jim, The link below shows my setup for a disk front-drum rear. I did it by the book. 1. Removed internal residual valve from stock MC. 2. Route the separate front brake line from the MC to a "metering valve" then to the 2 pound residual valve then the front disks. 3. Route the separate rear line from the MC to a proportioning valve then to a 10 pound residual vale then to the rear drums. See my Disk-Drum set up here:http://www.dacoglu.com/desotocd/17_Photos_Not_Catergorized/IMG_0022.JPG John at ECI has a very good description of both Disk-Disk and Disk-Drum plumbing here: http://ecihotrodbrakes.com/brake_facts.html One last thought. I have had and I have talked to a couple of people that have had NEW rubber brake lines bubble and burst over the last two years. Because of this on a single MC system I recommend that people consider getting the Pipe-to-AN adapters and use a high quality racing braided hose in place of the normal auto part replacement brake hoses. They also swell much less and you get a firmer brake pedal. Best, Jame Quote Link to comment Share on other sites More sharing options...
Jerry Roberts Posted September 12, 2009 Report Share Posted September 12, 2009 There are TWO little holes in the bottom of the master cylinder , one is so small that it takes a pin to clear . Quote Link to comment Share on other sites More sharing options...
Jim Yergin Posted September 13, 2009 Author Report Share Posted September 13, 2009 James, Thanks for the info. I looked at the web site and I believe I am correctly plumbed. I have disc brakes on both the front and rear so I do not have a metering valve installed. I do have a proportioning valve on the rear line but as of yet I have left it in the fully open position. That is a good tip on the upgraded brake hoses. Jerry, Thanks for the tip. I made sure both holes were open when I had the master cylinder out. I think it may just be a matter of getting all of the air out. Every time I go back to re-bleed the brakes, I find at least one small bubble of air at a caliper. I will just keep at it. I know I will eventually get it back on the road. Jim Yergin Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted September 13, 2009 Report Share Posted September 13, 2009 I have disc on the front and drum on the rear. The car isn't running yet and I've only plumbed the brake lines in, no fluid in the system. I have the stock MC and residual valves for the front and rear brakes. I don't have a metering valve in my setup. Should I? Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted September 17, 2009 Report Share Posted September 17, 2009 Hey Jim, what's the latest on your brakes? Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted September 17, 2009 Report Share Posted September 17, 2009 (edited) I have disc on the front and drum on the rear. The car isn't running yet and I've only plumbed the brake lines in, no fluid in the system. I have the stock MC and residual valves for the front and rear brakes. I don't have a metering valve in my setup. Should I? Joe..each set up is a bit different..some have to install them..others have no problem..if your rear wheels lock prematurely while braking..then for sure you will have to install and adjust the pressure to balance the system..approximately 60 percent of the stopping is done by the front brakes.. as Enzo said long ago, brakes...they just slow you down..! Edited September 17, 2009 by Tim Adams Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted September 17, 2009 Report Share Posted September 17, 2009 Yeah, who needs them? It will be some time before I'll know all that, unfortunately. But thanks for the answer. Quote Link to comment Share on other sites More sharing options...
Jim Yergin Posted September 17, 2009 Author Report Share Posted September 17, 2009 Hey Jim, what's the latest on your brakes? Joe, Last night I believe I finally got all the air out of the system. The barbed fitting I was using to connect the pressure bleeder to my master was leaking. Replacing it made it easier to bleed the system. Because of the rain today I have yet to really determine if the locking problem has been fixed by the removal of the internal residual valve. Hopefully it will be dry tomorrow. Jim Yergin Quote Link to comment Share on other sites More sharing options...
greg g Posted September 17, 2009 Report Share Posted September 17, 2009 Not withstanding Jim's hopefully fixed brakes are we going to see you guys in Westminster? We will be in the area Wed afternoon, Probably catch up with the POC folks at the Wessel farm collection in Hampstead, MD in the afternoon. Checking in at the hotel wed PM. Quote Link to comment Share on other sites More sharing options...
Jim Yergin Posted September 17, 2009 Author Report Share Posted September 17, 2009 Greg, It turns out that I need to be in Connecticut that weekend. However, I am hoping to stop by Westminster on Friday evening on my way up. Unfortunately I probably won't be driving the woodie but I am looking forward to at least saying hello to everyone in the group at the parking lot on Friday. Jim Yergin Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted September 17, 2009 Report Share Posted September 17, 2009 Is this this coming week? If so, I'll be in Massachusetts. Quote Link to comment Share on other sites More sharing options...
greg g Posted September 17, 2009 Report Share Posted September 17, 2009 25th and 26th. http://www.plymouthbulletin.com/images/2009Fallmeet.pdf Quote Link to comment Share on other sites More sharing options...
Joe Flanagan Posted September 17, 2009 Report Share Posted September 17, 2009 Yeah, will be on Cape Cod. My 27th wedding anniversary. I wish we were driving the Plymouth. Quote Link to comment Share on other sites More sharing options...
Rodney Bullock Posted September 18, 2009 Report Share Posted September 18, 2009 Hey Greg, I have the directions and the 3 page POC national fall meet schedule. I will try to make it on saturday. The day of the show. I'm I to understand that the show will be at the Best western or will it be at the Westminster hotel? I have the directions and will try to get a couple of Plymouth owner's from here to attemd with me. As you can see the guy's are busy. I have preped the 1940 Plymouth for the trip and will drive it. My question is will there be a place for non-show cars? Can I enter the show? I see that the awards dinner is later that day. If you don't stay for the dinner can you still partisipate? Quote Link to comment Share on other sites More sharing options...
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