Bench Bleeding M/c In Car????

[greg g]

Not to make anybody angry but I gotta think taking brake advice from a member with the handle Nonstop is a bit ironic.  Kinda like putting your money in a Bank who's Logo is M T.  Just kidding of course all advice is worth evaluation regardless of source, but that hit my funny bone this AM.  And was especially pointed as my daughter is coming over to do the rear brakes on her car, and my mind was on brakes..................  Again no offense intended.

[greg g]

Speaking of all the advice that has been given here, have you verified things like the actuator arms lengths, the piston lengths, the match up to the grooves on the brake shoes???  You seem to be blasting away with a shot gun at this problem.  You certainly have it surrounded but have you hit anything you have aimed at and ruled it out as a cause of your symptoms.   You should not proceed to D until you have dealt with A, B and C.

 

 

 

So far we seem to be dealing with the "NO" side of the chart......................

Edited July 3, 2013 by greg g

[Merle Coggins]

Good one Greg... that one reminds me of this troubleshooting chart that I've had for a while now.

 

[greg g]

I was gonna use that one but since we are playing long distance word pictures, I thought this one was more appropriate and with fewer choices to minimize our confusion...................

[JIPJOBXX]

Shot gun theory but at least I'm slowly eliminating all possible problems.  My brakes are still soft but at least I know that they really do work and go figure they worked like they were suppose a few days ago.  Now its miller time and take it down and have the old car power bleed.  I installed all those caps on the springs today but still have noise spring brakes or backing plate up front.  I kind of wish I did not replace the old brake springs with new ones as this may be causing the problem.  I never had this befor I installed new shoes and new soft goods and of course springs.  And to top it all the noises goes from one wheel to another any ideas of what is happening?  Maybe these noise problems will go away when I have the brakes professionally bleed. 

[greg g]

Perhaps this will help:

 

[JIPJOBXX]

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? Yes  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. Great Idea

 

As previously mentioned, have you replaced rear brake hose? yes You isolated the front from the back and chased the problem to the rear brakes Yes and no!  Tested rear and front separately and when tested had a hard pedal..  Have you isolated the rear corners from each other to try to isolate which corner?No as stated I tested both the back and front with no problems!

 

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. People here tend to think sometimes that other people do not have any idea of what they're doing?  Well as I see it we were not born with the genius of knowing everything and by trial and error things get done.  At the present time as per this morning I read adjusted my M/C linkage to the factory setting and it seems to be working correctly now and re-adjusted my brake shoes and most of the noise is gone.  Took the car out and brakes work good but not great and as I have read here on this site that probably the final deal of the day will be to have the brakes professionally bleed as the old way of pushing the brake pedal down and bleeding sometime works and sometimes doesn't.   Thanks for you the help and it nice to have someone who is not an authority or a wise guy helping me out just a guy like me who just needs a little help. Thanks

[nonstop]

Hopefully the pressure bleeding will take care of it for you! I have to be honest though, by the time I had gotten to the point where I had ground flats in the anchor bolts and was able to adjust them, I had already decided to swap to front discs. With it being a daily driver, I wanted to not have to worry about it any more (I had gotten the car with no brakes and did not have a base line to compare it to unlike your situation).

I had missed the part where the fronts and rears worked when isolated. With that information, I am inclined to suggest checking brake adjustment again if the pressure bleed does not get rid of the pedal feel. Could just be some fine tuning.

Oh, and as for the name, yeah in hindsight, probably not the best name to have and give brake advice! Although I got it when I was having trouble with my own!

[JIPJOBXX]

After reading about the check vlv in the M/C I decided to take that unit out for inspection and low and behold the check vlv itself had some grite lodged inbetween the rubber seal and the body of the valve itself.  And so after finding that I decided to read up on what that valve does and yep it sort of mimics the problems I have had.  So now I have installed a rebuilded kit in my M/C and flushing out the old brake jucie and reinstall the complete unit.  With all the knowledge here no one suggested that the M/C valve was leaking back and could be causing all these problems.  Here is an article I read about what this little valve does and maybe it is or is not the culprit but it sure sounds like it could be. 

 

"Many master cylinders designed for drum brakes incorporate a residual check valve to keep a slight amount of pressure on the system after the brake pedal has been released. These residual check valves are used on drum brake systems to keep around 5psi up to 12psi of pressure on the wheel cylinders cup seals. They also resist the momentum of the fluid returning to the master cylinder. Since the valve is keeping constant pressure on the system any small leaks will result in fluid leaking out instead of air leaking in. The residual check valve keeps a constant pressure on the wheel cylinder cup seals. This valve is not used on many late model vehicles because the wheel cylinders incorporate a cup seal expander that keeps the cup seals firm against the wheel cylinder walls.

These valves are located inside the master cylinder port leading to the rear drum brakes. They consist of the check valve and a spring that allows the brake fluid to enter the master cylinder only until the designated pressure is reached. Once this occurs spring pressure closes the valve maintaining low pressure on the brake system."

 

Interesting as when I tested haft the system the remember the Master Cyclinder worked like a champ!~ But with a complete system I never could get it the air out and and this is just what is just what this valve is to keep from happening when working correctly.  So this morning back to reinstalling the M/C and adding new fluid to the system.  I noticed that the junk that was stuck inbetween the valve surfaces was kind of like bits of flakes of rust.  I can only see where that could have come from was those original steel lines or when someone installed that copper brake line.  I would have looked at this sooner but with the image of the M/C working like it should with haft the system I got oft in that direction.  And of course what a pain in the but to get that old Master Cyclinder out from under the floor pan.  So its oft to Walmart to buy some more brake fluid and hope that this is the problem I have been searching for-Jon

[JIPJOBXX]

After reading about the check vlv in the M/C I decided to take that unit out for inspection and low and behold the check vlv itself had some grite lodged inbetween the rubber seal and the body of the valve itself.  And so after finding that I decided to read up on what that valve does and yep it sort of mimics the problems I have had.  So now I have installed a rebuilded kit in my M/C and flushing out the old brake jucie and reinstall the complete unit.  With all the knowledge here no one suggested that the M/C valve was leaking back and could be causing all these problems.  Here is an article I read about what this little valve does and maybe it is or is not the culprit but it sure sounds like it could be. 

 

"Many master cylinders designed for drum brakes incorporate a residual check valve to keep a slight amount of pressure on the system after the brake pedal has been released. These residual check valves are used on drum brake systems to keep around 5psi up to 12psi of pressure on the wheel cylinders cup seals. They also resist the momentum of the fluid returning to the master cylinder. Since the valve is keeping constant pressure on the system any small leaks will result in fluid leaking out instead of air leaking in. The residual check valve keeps a constant pressure on the wheel cylinder cup seals. This valve is not used on many late model vehicles because the wheel cylinders incorporate a cup seal expander that keeps the cup seals firm against the wheel cylinder walls.

These valves are located inside the master cylinder port leading to the rear drum brakes. They consist of the check valve and a spring that allows the brake fluid to enter the master cylinder only until the designated pressure is reached. Once this occurs spring pressure closes the valve maintaining low pressure on the brake system."

 

Interesting as when I tested haft the system the remember the Master Cyclinder worked like a champ!~ But with a complete system I never could get it the air out and and this is just what is just what this valve is to keep from happening when working correctly.  So this morning back to reinstalling the M/C and adding new fluid to the system.  I noticed that the junk that was stuck inbetween the valve surfaces was kind of like bits of flakes of rust.  I can only see where that could have come from was those original steel lines or when someone installed that copper brake line.  I would have looked at this sooner but with the image of the M/C working like it should with haft the system I got oft in that direction.  And of course what a pain in the but to get that old Master Cyclinder out from under the floor pan.  So its oft to Walmart to buy some more brake fluid and hope that this is the problem I have been searching for-Jon

If it weren't for bad luck than I would have none at all!!!!!!!!!! And I loved this one back when I worked for a living and that goes! If it weren't for mismanagment than this place would not have an management at all!!!!!!!!!!!!   But at the end of my career I became one of those mismanagers with tons of paper work and direction to go nowhere!!!! Dam I love retirement.!!!!!!!!!!

[Dodgeb4ya]

"With all the knowledge here no one suggested that the M/C valve was leaking back and could be causing all these problems."

It was suggested to check/rebuild the master cylinder. You should never piece meal a brake job. Do a complete brake system rebuild on old funky brakes. If there was a rust flake in the check valve I wonder where else there are rust flakes and where those flakes were forming  .

I think a brakonoscopy is needed!

[greg g]

AH yes!!! Management. 

 

A manager's job is to try to steer a ship of fools through shoals of discontent, surrounded by rocks of peril, through a storm of complaint, with the rudder parted from the wheel.  A thankless duty for which there is always a line of the disgruntled, waiting for the current one to slip. Clamoring to try their turn at the wheel, knowing they can do the job so much better.  Just ask them if you think otherwise.  Full speed ahead!!!!

Edited July 6, 2013 by greg g

[wayfarerstranger]

AMEN THAT BROTHER GREG !

[Don Coatney]

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

 

 

"With all the knowledge here no one suggested that the M/C valve was leaking back and could be causing all these problems."

It was suggested to check/rebuild the master cylinder. You should never piece meal a brake job. Do a complete brake system rebuild on old funky brakes. If there was a rust flake in the check valve I wonder where else there are rust flakes and where those flakes were forming  .

I think a brakonoscopy is needed!

 

Actully Bob you did post residual valve information. Good job! It is posted on the second picture you posted on the first quoted reponse. I think some folks do not read everything if it is not what they want to hear.

[_shel_ny]

Oddities abound in our MoPars.

 

Note the brake shoe clearance spec changes in this chart from 1941 to 1942 to 1946.

 

Parts difference, or mindset change ???

 

 

 

And what was somebody smoking with that 18 and..................49/64"  lining length.

What would a fella do if the lining was only 18 and .............3/4"

[JIPJOBXX]

Well got the M/C back in place and did the factory bleed test and the pedal seems to nice and hard.  What a pain in the butt to pull out the sheet metal to get access and removal of the M/C unit.  Well anyway got to install all that sheet metal and then the rug and then the pedals!  Yesterday when out and about I stopped at a car shop to ask them what it would cost me to have them bleed my brakes and the desk attendent with no hesitation stated that would be $126 DOLLARS!  I had to ask him of course what I got for this amount and boy did he give me a song and dance routine just like some folks here do also.  Anyway that encourage me to read up on Master Cyclinders and how they work with some dollar signs encourgments.  Oh Les Swab will do the same thing for 50 dollars (it pays to shop around).  I know Don is a professional mechanic and I was wondering why when haft of the system was installed and test the brakes worked great!  This kind of lead me down another road with not thinking to much about the M/C or that check vlv.  Any answers to this question? 

[james curl]

When you isolate either end of the system then the master cylinder has more than enough displacement to actuate the brakes and get a hard pedal.  With the whole system hooked up you seem to not be displacing enough fluid per stroke to get equal pressure as required to lock your brakes with the displacement of you master cylinder.  you can calculate the actual amount of fluid required to move each cylinder and all of the brake lines their required amount of movement to actuate the brakes and have a hard pedal.  The volume of the master cylinder for a full stroke must be greater than the amount of fluid required to actuate the brake cylinders and have a hard pedal.  That is why I asked if you had had a pressure check done at each cylinder bleed port at full force brake pedal application.  The pressure at each cylinder will tell you much about what is going on in your brake system.  Somewhere Chrysler should have published the numbers for each of the four front cylinders and for the two rear cylinders since the bore and stroke is different between the fronts and the rears.

[Dodgeb4ya]

OMG  ......... will this ever end?

[JIPJOBXX]

Got the car all back together today and took it down to Les Swab and had them power bleed the system   Got home notice one of the brakes was dragging and so I started to check that out and figure out why it was doing that.  Well took off the hub and really nothing not normal so I went to put it back on and boy it just wound'nt go back on.  Finally I got it back in place and then I went and check the pedal and it was rock hard.  Well I thought this was kind of unusual as I could not feel the M/C going back to the stop.  So I went underneath and wouldn't you know it I misadjusted the the piston was too far forward not allowing the  brake fluid to return to reservoir.  Dam so I adjusted that and then I was back to square one little or no brakes.  It was my fault for getting ahead of myself as I adjusted the piston rod by feel and just moving the brake pedal without looking into reservoir to see where the piston was at.  Well of course I should have and now I haft to go back to Les Swab and explain to them what I did and that I need to have the system rebleed.   Well at least I know the master cyclinder is working and Monday probably have to fork out another 50 dollars to have the car rebleed.  Oh well it only money!

[JIPJOBXX]

I had a passing thought that maybe the fluid in the system just backed up from the brake cylinders and there still is hope just to re bleed the system myself tomorrow!!! There should be brake fluid in the lines but maybe when I adjusted the pedal position the fluid just backed out of the brake cyclinder and there is air only there!!!!! Well tomorrow is another day and I will spend a few moments with my old pal and then do something fun like take my grandson out for lunch or something like that!!!

[P15-D24]

OMG  ......... will this ever end?

+ ∞

[Frank Elder]

Not till the eulogy is read........

[greg g]

and a sealed system from the wc to the mc would suck air in from where????

 

[JIPJOBXX]

Nope it will never end as I'm stuck in a perversional time warp that can only be fixed by my cat!  Think I'm feed up with this situation you bet and what next will happen in the world of Jon?

[_shel_ny]

Keep at it Jon, you are almost there