Bench Bleeding M/c In Car????

[Plymouthy Adams]

do look for brake system design...

[Plymouthy Adams]

do check you PM folder....

[Plymouthy Adams]

while I agree that the scenario does not really make sense per theory we also have to acknowledge that in fact there have been observed pressure difference and brake behavior related to line change.  Long ago I tried to start a talk on this was not greeted with anything by criticism and not a round-robin to determine any other outstanding fact or attribute and thus I dropped it as it was apparent the forum at large was not interested in trying at that time to discover the truth and wherefores of the associated fix.  Now we come full circle and we have another person in need.  Information here is from far away I will admit I have not performed any test myself in person...and, that more than one person has worked the issue on the car, one avid Mopar owner with right tools, two shops..  Seems the brakes were set up proper with the 1750 tool.  Man who did this has long been servicing his own car with the tool and to that end we place some confidence.   Seems after not being able to establish the brakes that person threw in the towel.  Also it seem two shops have done likewise if my information is correct.  I am not here to argue one thing against another but here to help try to get brakes on the mans car and throwing out the last ditch resort that did get brakes on my car and three others.  Some test have yet to be made that I would like the results on...the one test is quite critical to the entire system.  The second also involves the very symptom Jon is having and that piece of data has not been related to me yet.  Till then..there  is little can be said for done except by Jon and his timely reporting back of specific data,  As his system is supposed to be stock...there should be no real issue...but till all the facts come back to me I have to stay opened minded and hope that it is something simple like  mismatched components..Jon has been very good to phone me a few times and trying to keep me in the loop and provide answers to my questions.  WE are slowly getting a few more fact together.

[wings515]

I'm about to install a rebuilt rear end with new wheel cylinders and brakes.  There are multiple mentions of a power brake bleeding tool.  I have a 39 Plymouth PT81 pickup.  What type connection is used to attach the bleeder to the Master Cylinder?  I see most of the 'modern' bleeders attach to the male threaded port on M/C, my M/C has a female thread and male plug.

Any thoughts?

 

Regards,

[JIPJOBXX]

Ok bleed the brakes per instruction from my Dodge Shop Manual with a friend to pump the brakes.  I followed the instruction to the letter except I made up a reserve tank to allow a larger volumm of  brake fluid to be used in the master cyclinder.  I attached this to an extra fill cap by drilling a hole in the cap and then tapeing a treaded hole down the center.  Now with this device in place an a clear polly hose I could tell that my M/C reservor would not run empty.  Like I said befor I just did what the manual stated and bleed the sytem.  After bleeding the system and noticing that my pedal was still kind of soft I readjusted the setting on the port opening on the M/C and that in turn put the "C" port 3/4 closed and brought relief port closer to being closed also.  WIth this setting I'm getting the power stroke to push the brake fluide sooner and noticed that my brakes were better "Much better!".  The only thing wrong here is that piston is not resting stop plate but the piston rod itself.  I talked with Adams about this and he thinks that cup washer might be missing??? I bought his unit brand new rebuilt many years ago and have never opened it up but maybe it is missing piece 15 Piston Cup washer.    Well now its time to remove the M/C and check for that washer.   Boy if it weren't for bad luck than I would not have any at all.  Who would not go by the factory setting in setting up the Master Cylinder and remember it works for haft the system!  I called up Hagen automotive and there brake specialist told me that the cup washer is only .010".  Don if you following this could you varify that this washer is that thickness? Because If that is the fact than something else is mest up in my M/C.. Could the secondary piston cup be worn out or just to soft to keep the piston in the proper position?  Well it time to remove the M/C and we shall see what we shall see.  Thanks Adams for helping me along and the rest of you guys.  This has been along road to something that should have been very simple and fast.  Jon

Please excuse my typing mistakes as my word check seems to be on the blink.

[Dodgeb4ya]

Watch you M/cyl cups for being the correct ones... some pics

[Dave72dt]

Shouild be the correct thickness for the cup washer. It's really thin and in the rebuiold kits is often glued to the cup itself.   

[JIPJOBXX]

Bought a rebuild kit just for shits and giggles. The book I have states that the rear screw in rear plug should not be removed is there any real reason for this?  It would be alot easier to just install the new soft wear and new internals into the Master Cylinder with removing this plug item.  What is the reason?  I would rather do that than remove floor pan as that requires alot of work.

[JIPJOBXX]

Interesting as when I was working on the frount brakes drivers side I could bearly see the brake line leading to the passenger side and it looked like copper!  Well it is as today I went in from the top and had a small dull scraper in hand and determined yes it is copper. Why on gods green earth did they put in copper lines back in 1942,  Oh well changing that out this week and one more mystery of brakes and old Dodge will be done.

[seabee1950]

Hi

Jon

 

Copper brake lines in the good ol' USA are strictly illegal. Not only can vibrations work harden and subsequently crack and fail, but the simple act of applying brakes and releasing them provide a cyclic stress that does the same thing over time; say 10-20- or 30 years.

Cunifer looks like copper if not side by side with real copper. It has been tested to all known standards and found to be safe. Copper has not. Some brakeline kits are Kunifer (AKA, Cunifer, Cupro-nickle, etc) and not mentioned as such. Unless you KNOW that your brake lines are copper, don't assume that it is so. And if you have replaced your brake lines with known copper lines, just because you haven't had a problem in say, the last 10 years, don't assume you won't run into problems further down the road. It is sub-standard material for in brake lines.

 

Jon this is one of the things I read so make sure what your looking at is real copper not Kunifer.

 

Bud

Edited July 1, 2013 by seabee1950

[JIPJOBXX]

Well got the mysterious copper brake line out and it looks like the old farmer in the past replaced the original steel line with a copper line.  It ran from just about where the steering wheel column is on the bottom to the front on the car.  So maybe that gal that ran into the barn also smashed the steel brake line in the process or it just rusted away and started to leak.  Anyway got that bear out and have replaced the line to the steering wheel brake side and tomorrow I will install another new brake line to the other side.  Well what can you expect as I think this car has over 200,000 miles on it but with all the stuff that I have done to it mechanically it will run for at least another 10 miles without problems (I hope)

[Don Coatney]

Was that copper line thick wall? Was it double flared? What kind of flaring tool are you using on your new steel lines?

[JIPJOBXX]

My new line are directly bought in lengths to match what I took out.  I have not had to flare any of the tubing as it all fits fairly well.  I took a look at that copper tubing and you know it funny it has an overspray of gray just the same color of the car when it was first built.  The old copper tube just had those fitting that you slip on and compress by using a flaring tool.   Well who ever did this patch up job or did it in the factory was dead wrong and I'm lucky that I did not have an accident with that one length of tubing. 

[JIPJOBXX]

Oh yes it was thinkwall at least!

[Don Coatney]

You said,

 

"The old copper tube just had those fitting that you slip on and compress by using a flaring tool."

 

Jon; A flaring tool does not compress, It flares the end of the line and that is all. I am very much convinced that you know nothing about what a flaring tool is and how it works and you are much better off buying pre flared lines.

 

One more question before I shut up. How did you measure or how do you know the copper was thin wall and I assume thinkwall referes to thin wall?

[JIPJOBXX]

Don need not worry as I spent 42 years working as a Marine Machinist and have retube many gages in my past.  Sometime I may not be able to explain myself correctly but then I do believe in safety above all else and never had anything go wrong on anything i worked on durring my career.  I was subsafe qualified and that meant that anything attached to a skin of a nuclear submarine I could work on.  Now that being said I used pre made tubbing like you stated as that was the easiest to use and no I have never used a double flaring tool.  Never had a chance to use one and at my age I guess I never will.   Anyway glad this part of the program is just about completed.  I'm going to put new software goods in my M/C just to make sure that unit is in good working order.  But the big thing here is that I have done everything to the best of my abilities and I may not be a perfectionist but I do try my best.

 

I think you would actually be surprised to know I served a four year Naval Apprenticeship which included all aspects of Marine Machinist work.  I have been called on a number of times to go out on sea trials from Submarines to Aircraft Carriers.  I enjoyed what I did and I thank god that he directed me in this direction.  Jon

[Don Coatney]

Jon;

Sounds like you have had a lot of training in the Navy. And safety is a huge issue. Good to see you finally attempting to make your brakes safe after all the years you have owned your car.

 

Do they teach tap dancing in the navy?

[JIPJOBXX]

Oh one more this our pipe shop personel would plumb up various gages and so I really did not have much to do in that area of work.

[JIPJOBXX]

You know I never remember having bad brakes just brakes that would stop but not on a dime.  I have worked on different brake systems befor but Chryslers product haft to be the pits.  Having to set the brakes up to  .012" befor installation of the brake hub is something else.  I was about to take my car over a shop that does nothing but speciality cars but my buddy Don bought oft of ebay the tool used to fit these shoes to the hub.  He paidalot of money for that tool but it works well and I thank him for setting my brakes up to the proper specs.  I have heard from alot of people that these old Mopars get air in the system and it hard as hell to get it out.  So its been a uphill battle not knowing if the soft brakes is a air problem or something else.  I just wish four wheel brake was still business as then they could have my problem child.  The car itself runs like a top but then you haft to stop.

[JIPJOBXX]

Oh I worked for the Navy not in the navy! 

[JIPJOBXX]

First of all i'm trying to stop the long tread about bleeding of brakes.  So this is why I started this

I just want to know if you need two caps per spring on the anchor bolt that hold the brake shoe in place?  I can see in one photo where there is a brake down of the parts for this installation but in other photos  I cannot tell if there is a cap on bought ends of that spring.  If so I'm missing one cap per spring on the bottom.  This is for an early Dodge 1942 and I would like know if I'm missing some parts on my brakes. Thanks Jon

[JIPJOBXX]

Figured it out myself by looking in my parts book and saw schematic and yes it suppose to have washers on both ends.

Edited July 3, 2013 by JIPJOBXX

[JIPJOBXX]

Again the old farmer strikes as I know it never had that second washer on the bottom of the springs.  Oh well just another little problem to fix.  I was told by my buddy who has the old 42 dodge  that those caps are availible at our local parts store and so high ho, high ho its oft to the parts store I go.  Getting pretty good at working on old Dodge brakes but don't think there is much of a future in learning this stuff to pass on.

[nonstop]

I know that I am new here, and many of these guys have a lot more experience with the Lockheed brakes than I do, but can I throw in my 2 cents? 

 

I rebuilt my brakes last year, including wheel cylinders and the master.  Did you rebuild your wheel cylinders?  One problem I ran into was the cups that sit behind the pistons were not flat, but rather, had a hole in the middle.  This caused all sorts of problems with air intrusion.  I replaced them with the flat ones and put in new pistons, and there was no more air intrusion from there.  Another problem I ran into was a cracked adapter fitting, which gave a poor seal.  Also, did you replace the residual valve in the master when you rebuilt it?

 

After I went over those areas with a close eye, and was sure there was no more air intrusion, I still had a low/soft pedal.  I did not have one od the Miller or Amco tools.  I ground flats on the back of the anchor/adjuster bolts, perwhat I read from one of the sites.  I slid the drums on and adjusted the brakes with the drums on the car, turning the anchor bolts with the flats ground on them.  I slid the drum off and tightened the bolts.  This was the trick for me to getting rid of the soft/low pedal. 

 

As previously mentioned, have you replaced rear brake hose?  You isolated the front from the back and chased the problem to the rear brakes.  Have you isolated the rear corners from each other to try to isolate which corner?

 

I know I am throwing a lot, asking a lot, but you are down to replacing the steel brake lines chasing the soft pedal.  It sounds as if there is something else that might have been overlooked.

[james curl]

Have you used a brake pressure gauge at each cylinder to see what kind of pressure you build through your system? You can buy the kit from Speedway that has all of the fittings to adapt the gauge to the cylinders and includes the gauge. With the gauge you can isolate the problem, if you get a lower reading on one cylinder from the others then you have a starting point to work from.