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Brakes locking up, have checked most the "check first" things

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Hello all, new to the forum and have some questions about brakes. So first let me give you the back-story. Two Christmases ago my wife and I convinced her father to let us take the 1950 Plymouth Special Deluxe that was originally bought by her grandfather new. It had been sitting in a garage for about 20 years or so and was just going to waste there. The car is in great condition with no major bodywork or major restoration needed. We put it on a Hertz trailer and drove it from California back to Junction City Kansas where we currently live. On the way back my wife found a mechanic that was willing to take a look at the car. Long story short having the car for a few days short of a year we were able to drive it away from the mechanic. In that long wait for the car only a few things were done fuel tank drained and purged, fuel pump replaced (they made it a much bigger project than it needed to be), brake drums and shoes replaced, a few brake lines rebuilt. During the long wait for the car I began to do massive amounts of research (mostly on this forum) and purchased a shop manual. The more I learned the more I realize that were going off their own experience from working on mid 60’s and newer cars. Don’t get me wrong I do think that they did a great job even without fully understanding the intricacies of the Plymouths from this time. So down to the problem, after driving the car to and from work a few times and around town a little bit the brakes began to lock up. I have checked the relief hole in the master cylinder and it is clear, I checked the free play in the brake pedal, and the return lines are not collapsing. I have not tried doing a “minor” adjustment yet and am planning on it maybe this weekend. My feeling is that they did not set the shoes correctly, which would sound right due to the fact that they told me “we had a hard time getting the rear drums off because the hand brake has been on for a long time”. I am thinking that they more than likely put the new shoes on without much if any adjustment so that thicker shoes are set to about the same place as the more worn out shoes. As I said I have the 1/8 to ¼ free play but then there is braking instantly and I know that is incorrect according to the book. It looks like I am going to have to go in and set all the shoes again but of course I don’t have the tool required by the book. I am thinking about a couple of ways that I can do this without the tool based on the book and information on how the tool works but would like some advice as to the best course of action without the correct tool.

 

Thanks, Damon.

 

P.S. I will post pictures of the car soon to show the condition that it is in and because I know from my extensive research on here it is one of the first things asked for.

 

D.

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Hmmmmm!!! Since the parking brake acts on a drum at the rear of the transmission, I would be kind of concerned regarding the comment that the hand brake had been on a long time, making the rear brakes difficult to remove.  There rear drums are on a tapered axle with a key way that are notoriously difficult to remove especially without a proper puller.  Did your mechanic show you the old drums???  If not I might tend to think that they may not have dealt with removing the drums or replacing the old shoes, and took a stab at doing an adjustment, and as is typical of these systems screwing it up?  Not disparaging the shop so much as reflecting on other people's experience.

 

Also your free play should be closer to an inch.  Do as mentioned above, before you start messing with the adjustments especially if the brakes work and do not grab or lock up untill they get some heat in them.   Also make sure there is some room in the master cylinder for fluid to expand and that the caps vents are free and clear.  Have you noticed, when the conditioin presents whether the brake lamp stay lit up when the brake pedal is released???

 

And Welcome to the forum.  As a suggestion, your post here is fine, but you should post to the general discussion section for a more spirited conversation.  The tech section here is more for folks to post fixes, maybe show off a home made tool, or detail a better procedure for doing something.

Edited by greg g

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i have the same thing on my 41 dodge coupe, i removed all the wheel cylinder, change the cup and piston clean it up, change brake line, same operation for the master cylinder and change the 3 brake hoses.

 

my brake fluide was dirty, realy dirty, when i opening the caps of the master cylinder the first time i thinking the fluide is motor oil!!!   the fluide was ebony black!!

 

i take a picture of it!

 

i'm a little bite scared when i saw it :P

adrien-dscf9392-img.jpg

adrien-dscf9391-img.jpg

 

 

after draining, cleaning and changing the cup and pistons everything gona be ok!!

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Hello all, new to the forum and have some questions about brakes. So first let me give you the back-story. Two Christmases ago my wife and I convinced her father to let us take the 1950 Plymouth Special Deluxe that was originally bought by her grandfather new. It had been sitting in a garage for about 20 years or so and was just going to waste there. The car is in great condition with no major bodywork or major restoration needed. We put it on a Hertz trailer and drove it from California back to Junction City Kansas where we currently live. On the way back my wife found a mechanic that was willing to take a look at the car. Long story short having the car for a few days short of a year we were able to drive it away from the mechanic. In that long wait for the car only a few things were done fuel tank drained and purged, fuel pump replaced (they made it a much bigger project than it needed to be), brake drums and shoes replaced, a few brake lines rebuilt. During the long wait for the car I began to do massive amounts of research (mostly on this forum) and purchased a shop manual. The more I learned the more I realize that were going off their own experience from working on mid 60’s and newer cars. Don’t get me wrong I do think that they did a great job even without fully understanding the intricacies of the Plymouths from this time. So down to the problem, after driving the car to and from work a few times and around town a little bit the brakes began to lock up. I have checked the relief hole in the master cylinder and it is clear, I checked the free play in the brake pedal, and the return lines are not collapsing. I have not tried doing a “minor” adjustment yet and am planning on it maybe this weekend. My feeling is that they did not set the shoes correctly, which would sound right due to the fact that they told me “we had a hard time getting the rear drums off because the hand brake has been on for a long time”. I am thinking that they more than likely put the new shoes on without much if any adjustment so that thicker shoes are set to about the same place as the more worn out shoes. As I said I have the 1/8 to ¼ free play but then there is braking instantly and I know that is incorrect according to the book. It looks like I am going to have to go in and set all the shoes again but of course I don’t have the tool required by the book. I am thinking about a couple of ways that I can do this without the tool based on the book and information on how the tool works but would like some advice as to the best course of action without the correct tool.

 

Thanks, Damon.

 

P.S. I will post pictures of the car soon to show the condition that it is in and because I know from my extensive research on here it is one of the first things asked for.

 

D.

  It would  be fairly easy to pull one front wheel and check to see how the shoes are installed. If you have driven it a little there should be some marking on shoe and drum giving some indication how they are set up. If they are not familiar with the older technology it is a good chance the short shoe has been put on the secondary instead of primary side. To do a major adj without a tool is time consuming but possible. First back off adj at backing plate. Turn shoe anchor in proper direction, left  front shoe clockwise and rear shoe counter clockwise until heel touches, turn reg adj until it touches. Repeat until shoe is in total contact with drum. Do secondary shoe the same way. When to set is done back off normal adj and do a normal adjustment.Tighten up anything you have loosened to do the adjustment. Do all four wheel the same and you have completed a major adj without the tool. To do the rear buy or rent the three legged puller you need to remove the drum. It was a wise decision on your part to purchase a manual. TCTRKCA1

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My thanks to everyone who has posted a reply it has given me more to consider with these brakes. Yes the brake lights stay on and have since we got the car back. At first I was thinking that I had an electrical issue but I now understand that it is due to pressure in the brake system. Vent hole in the master cylinder cap? I will look again but I don’t remember seeing one and the cap was hard to get off and took a bunch of aligning to keep it from cross threading so maybe it is not the right cap. I remembered after I posted that when I looked into the master cylinder the relief hole was clear but I could see the bevel on the piston in there meaning that the piston did not return to it’s correct position to allow the pressure to be relieved. Checking to make sure the system is not over full was something that I didn’t think about and I am going to have to take a look at that one. Also I believe that they used DOT 3 brake fluid, is that a problem? I wouldn’t think so but most of the seals are original and there are so many little things about these cars that I don’t know it seems like something to ask.

Greg g. thanks for the suggestion I will remember that in the future. I have been looking around the tech but I think I will go deeper into the general to find more answers.

Once again thanks to everyone for the information. The more I learn about this car the more I love it every day.

 

D.

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The brake light remiaining on is an indicator that pressure is not releasing once the pedal is released.  The brake switch is hydraulic and located in the brake line in front of the MC.  So if it is staying on, it is and indicator or pressure not dropping when you release the pedal.  When you look into the MC reservoir, there should be 2 holes.  On feeds the piston, the other allows the relief.  One is about the size of a mechanical pencil lead, and the other like a medium size paper clip.  If both are ot visible, that is probably where your problem lies.  Take another look and check just infront of or just to the rear of the visible hole, ad even if they are both visible its a good idea to give them a cleaning withthe wire any way.

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my brake light stay on too before the check up the level was high in the MC

 

 

P.S: i'm sorry if i don't write very good, i'm french.

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The one thing that I once had a problem with was the rear brakes only- locking up after a sort of hard stop with more pressure than usual applied to the brake pedal. The problem there was that rear short brake hose.....it looked real good on the outside, but was so old the inside material was collapsing. So when you put a little extra fluid thru it, the fluid could not return to the master cyl - therefore the rear brakes remained engaged. My answer to that at the time was to open each rear wheel bleeder and let a little fluid out to relieve pressure. Have since replaced that hose and all works OK. Regarding the fluid level in the master cyllinder.....I always fill it to the opening and it seems to work fine. You might take a piece of wire and poke into that vent hole in the bottom of the M C to make sure it's indeed open. I don't know if this would have any bearing on your problem, but were the hoses replaced with brand new ones or new old stock ones? Even n.o.s. could have a problem simply due to age.

Edited by BobT-47P15

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Once again thank you to everyone who has replied. As I start to check more of the things that have been suggested I think this may be changing from help to lets see how many ways the mechanic blew smoke where the sun don’t shine. First I was told hard lines were replaced and I cant find a new fitting anywhere in the system. Then I took the driver front drum off this evening and although not gouged there was no way it was new or even turned. Then I decided to measure the shoe lining thickness I got under 1/8 at the toe and just under 3/16 at the heal of both shoes. I know that “new” thickness is 3/16 and I have only driven about 100 miles and just cant see that much wear in that short of time. So it looks to me at least more like I will be doing an overhaul of the brake system. Not too upset about that because I think that it will be fun just need to try to get the parts for everything. So once again thanks to everyone for the information it has been most helpful and has led me to the best thing for when I have my family in the Plymouth.

 

D.

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Now might be the time to install some front disc brakes.......there is a good kit produced by Charlie Akers,

whose business name is RustyHope.  I believe several here on the forum have installed them. 

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have you any plans for dealing with esteemed mechanical emporium?  I presume you were charged for work not performed or performed shoddy manner. If the rear drums were actually recently off they should come off without to much trouble, and an faliling that I would guess they did not perform any work there either.

Edited by greg g

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Once again thank you to everyone who has replied. As I start to check more of the things that have been suggested I think this may be changing from help to lets see how many ways the mechanic blew smoke where the sun don’t shine. First I was told hard lines were replaced and I cant find a new fitting anywhere in the system. Then I took the driver front drum off this evening and although not gouged there was no way it was new or even turned. Then I decided to measure the shoe lining thickness I got under 1/8 at the toe and just under 3/16 at the heal of both shoes. I know that “new” thickness is 3/16 and I have only driven about 100 miles and just cant see that much wear in that short of time. So it looks to me at least more like I will be doing an overhaul of the brake system. Not too upset about that because I think that it will be fun just need to try to get the parts for everything. So once again thanks to everyone for the information it has been most helpful and has led me to the best thing for when I have my family in the Plymouth.

 

D.

When it comes time to play with the wheel cylinders, whether you rebuild the old or go with brand new.......have them sleeved in stainless steel! If your car ends up sitting more than driving pits will be eaten into the cylinder walls and leaking brake fluid past the seals...it doesn't take very long to happen.

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After taking a good hard look at everything I think that I am going to start with rebuilding the MC. As far as a disk brake conversion my wife wants to keep it as original as we can just because it belonged to her grandfather. I am going to look through all of the extra parts that my father-in-law sent with the car and see if there is another MC that i can rebuild without having to take the one off of the car. Again thank you all for the input and information, as soon as I get back I am going to really start into this car.

 

D.

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Oh, and as far as the mechanic at this point it would be more of a headache than it is worth so I don't really see a point in it. 

 

D.

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After taking a good hard look at everything I think that I am going to start with rebuilding the MC. As far as a disk brake conversion my wife wants to keep it as original as we can just because it belonged to her grandfather. I am going to look through all of the extra parts that my father-in-law sent with the car and see if there is another MC that i can rebuild without having to take the one off of the car. Again thank you all for the input and information, as soon as I get back I am going to really start into this car.

 

D.

Good place to start, but if you are going this route, maybe a good time to replace all components, MC first , rebuild, if bore is in nice shape, if not get it sleeved, same with wheel cyls, replace all steel lines, and flex hoses.

Are the brake shoes relined, if old, get em relined, no matter how much material is if bonded and old, they could fall off literally.

Have drums, inspected, measured, no more than .060 over, and have machined if necessary.

Once brakes are all new, with lines, and such, you could use DOT 5 silicone brake fluid, very good for vehicles that have a lot of down time.

Disc brakes, kits can be installed, for superior braking, save old parts, can be put back, if wanted, this is a good idea, in areas of heavy fast traffic and hills. Having said this, stock brakes can be pretty good if adjusted and installed correctly, others will disagree, but many will attest to this.....good luck

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My over all plan is just that to start with the MC and repair or replace everything in the system. I don't anticipate very many issues considering the car has 280 original miles on it. But at the same time this is not an area of the car that I am willing to take any short cuts on. I am currently doing research on total cost for parts with doing most if not all the work myself. I am confident if I take my time and use the book and the plethora of information on this forum I can get the job done.

 

D.

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. . . I am confident if I take my time and use the book and the plethora of information on this forum I can get the job done.

Very true.

 

. . . Once brakes are all new, with lines, and such, you could use DOT 5 silicone brake fluid, very good for vehicles that have a lot of down time. . . .

 

I used DOT5 on my car based on the best information at the time. However I am not sure, now that I've spent a massive $20 to make a pressure bleeder, that I'd use DOT5 again. Reasons:

 

1. With a pressure bleeder it is very easy to fully flush the old fluid out every year or two. That mitgates the issue with DOT3 and DOT4 being hydrophilic.

2. DOT3 and DOT4 are a fraction the cost of DOT5.

3. While DOT3 and DOT4 are poisonous, they do break down in a soil or dirt environment in a few days. While DOT5 is apparently more benign if ingested, it is persistent in the enviroment and the recommended disposal is incineration. So getting rid of the fluid you bleed out is easier for DOT3 & 4.

4. Some manufacturers of brake parts only back them if OEM brake fluid is used and all OEMs use DOT3 or DOT4 so failure with DOT 5, while it should not happen, is an excuse to not stand behind their product.

 

All that said, given the way I spill things, I do like that DOT5 doesn't ruin the paint. Flip side of that is serious painters don't want brake work with DOT5 done anywhere around where they will be painting as the dried silicone brake fluid can contaminate the area and cause issues.

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Very true.

 

 

I used DOT5 on my car based on the best information at the time. However I am not sure, now that I've spent a massive $20 to make a pressure bleeder, that I'd use DOT5 again. Reasons:

 

1. With a pressure bleeder it is very easy to fully flush the old fluid out every year or two. That mitgates the issue with DOT3 and DOT4 being hydrophilic.

2. DOT3 and DOT4 are a fraction the cost of DOT5.

3. While DOT3 and DOT4 are poisonous, they do break down in a soil or dirt environment in a few days. While DOT5 is apparently more benign if ingested, it is persistent in the enviroment and the recommended disposal is incineration. So getting rid of the fluid you bleed out is easier for DOT3 & 4.

4. Some manufacturers of brake parts only back them if OEM brake fluid is used and all OEMs use DOT3 or DOT4 so failure with DOT 5, while it should not happen, is an excuse to not stand behind their product.

 

All that said, given the way I spill things, I do like that DOT5 doesn't ruin the paint. Flip side of that is serious painters don't want brake work with DOT5 done anywhere around where they will be painting as the dried silicone brake fluid can contaminate the area and cause issues.

Yup, there is the Pros/Cons, but in my 1 time only use with the 47 Chrysler, it has been great, and those brakes are excellent.

I have heard others having issues, and some problems bleeding brakes with Dot5, but not me.

The expense is IMHO< not over the top,unless you need gallons of this stuff...

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My over all plan is just that to start with the MC and repair or replace everything in the system. I don't anticipate very many issues considering the car has 280 original miles on it. But at the same time this is not an area of the car that I am willing to take any short cuts on. I am currently doing research on total cost for parts with doing most if not all the work myself. I am confident if I take my time and use the book and the plethora of information on this forum I can get the job done.

 

D.

How about some pics, 280 original miles, this car should be in a museum, never mind fixing up to drive around. Is this a hoax.......LOL

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Pictured below is how new brake shoes look in short order if they are not correctly adjusted. Also I posted pictures of the two small holes in the master cylinder. I have found that there are two different bores on the master cylinders of these cars. One inch and one and one eight inch. The larger is more common but the smaller will require less foot pressure to stop. You can send your shoes to the business pictured below for lining replacement. They are reliable and the cost of there services is fair. Several forum members have used them.

shoe1.jpg

MChole1.jpg

9-8-0421.jpg

Edited by Don Coatney

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Hi, did you ever look at the two holes in the MC? Greg is right about that being where the pressure is releaved, I had that problem with my car and a old brake guy knew right away. Ehen one of those old MC are honed sometimes it get s plugged. It's an easy fix. these cars are not complicated at all usually it's something very simple.

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WOW! I did put 280 I so meant to put 2800 my bad. I have only put about 100 miles on it with driving to work and back for a couple of weeks.  The car was bought then only driven on Sundays and then put in a garage for like 20 years. Sorry about that I was at work and in a hurry. As soon as I can figure out how to make the pics smaller I will post them. I have some interior pics but can't get any good exterior ones because it is in a very small garage.

 

D.

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