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1940 President Stuck Master Cylinder

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  • hwkmn
    replied
    Howdy on 7/13/2020....I posted a question regarding the kit I'm installing in a MC that is also a single cylinder and probably what was used in the President, Dictator, etc for more than a few years.

    I had noted via a Google search prior to seeing your post the Bob Johnstone articles...but it appeared to start in the 1950 era vs 1935. Cylinder construction may have been pretty similar regardless.

    Question (1): Do you happen to know the purpose of the "Compensating Port" (Item 4). I noted a recess in the interior of the body of mine prior to seeing the cutaway view "but" I can't see a pin hole when looking down the tube area of the body. Unsure the purpose and "if" it should be cleaned/reamed out. If so, what drill bit (if one will reach) to create the hole "if" I should either way.

    Question (2): In the kit supplied by SI was a flat rubber washer about 3/16 thick...possibly 1/8. It was in addition to a thicker washer that I know I took "out" of the mc a few weeks ago. I do not recall the other washer and don't have it as saved parts.

    No diagram I've seen to include the chassis parts book shows the flat washer. SI (Leann) was unable to answer this for me. I wondered if it was meant to fit over the Push rod end....but according to the side view of the MC there is as one thinks...a lot of air space and can't see where it should go if anywhere.

    Thoughts would be helpful!

    Thanks!

    Leave a comment:


  • Mrs K Corbin
    replied
    I actually remember seeing an incorrect assembly once on an old WW2 dodge truck that a new MC had been ordered for. The new MC was put together backwards and it stuck too....

    Something to check. If the valve is backwards it may jam.

    Leave a comment:


  • kxet
    replied
    I had an aluminum piston in an old truck swell up with corrosion and stick, brakes would not release. Was a hard to get item so it was all cleaned and new seal fixed it. truck had a big load on it so it had to be done on the spot. Hope the owner ordered new MC. I would have.

    Leave a comment:


  • jclary
    replied
    Originally posted by Okiejoe86 View Post
    Thank you for the responses. Yes, I have replaced all soft lines and hard lines and rebuilt the MC.

    Thank you for the picture. When I said the "push rod" would not return back out, I was referring to the Piston Assembly, see image #9. My brake pedal has a spring on it, attched to the frame which helps pull it back. The issue I am having is the Piston not returning after being pushed in.
    Not meaning to question your skill of assembling the parts correctly, but it might be worth your effort to remove the master cylinder and reconfirm the parts are appropriately assembled. For example, the rubber cup between the piston & spring (not shown in detail)...if it is turned the wrong way, could cause the spring to bind and not move beyond the compensating port to relieve pressure. Also, make sure the check valve is OK on the other end. While your are checking... be sure there is no small bit of trash or build-up clogging the compensating port. If you have installed the correct size parts in the proper sequence, I don't see why it shouldn't operate without sticking or binding?

    Leave a comment:


  • Okiejoe86
    replied
    Thank you for the responses. Yes, I have replaced all soft lines and hard lines and rebuilt the MC.

    Thank you for the picture. When I said the "push rod" would not return back out, I was referring to the Piston Assembly, see image #9. My brake pedal has a spring on it, attched to the frame which helps pull it back. The issue I am having is the Piston not returning after being pushed in.

    Leave a comment:


  • studegary
    replied
    Originally posted by Mrs K Corbin View Post
    2 questions: have you replace/rebuilt the MC?
    Have you replaced the soft lines at the wheels and rear axle?

    I've been learning the hard way to just go ahead and replace everything and get it over with.
    PITA, but worth it in the end.

    Case in Point. I had Drum brakes on my Nova. Weak as pond water. step on them and wait to stop.
    I decided to upgrade to front disk (LS Conversion). Still kinda weak, plus i still had the non-power drum setup that was making them drag.
    So decided to do a Power Brake conversion. Replaced MC/combo valve, add booster, etc.
    could not get the rears to bleed at all...
    so 8 hours of beating and banging to get the rear hose off, and voila I now have fluid flow.
    so replaced that, and everthing on the rear axle assembly(brake wise) wheel to wheel .....
    PLUS ONE AXLE THAT WAS BENT.

    After bleeding, I have excellent brakes.
    Only thing left is the hard line from front to back. and next summer I'll get that too. piece of mind.

    OOPS.... I forgot. the emergency brake cable was jammed and I'm in the middle of that.....LOL



    ON the 2R5 i replaced everthing to start with and went with a Jim Turner Kit.
    I'm hoping he turns up at the Chattanooga international next year, cause I need him to diagnose what's going on. I have to pump the pedal, so there is some problem I can't figure out. maybe I used the wrong MC. Not sure.
    Please read the initial post - only two before yours. He states that he "rebuilt the master cylinder" and "new hard lines", "new soft lines", etc.

    Leave a comment:


  • jclary
    replied
    Over the years, I have serviced and repaired brake systems on lots of vehicles. Especially on my Studebaker collection since there are sporadic occasions where they sit for long periods of time. Problem with me is that, since I don't do it regularly, I usually grab a manual and refresh myself regarding the internals before diving into the components with a fist full of wrenches. So, viewing this thread, I thought I would attempt to find a parts breakdown of a typical single chamber master cylinder as used on most of our Studebakers. I hope this pic pastes into this post without having to jump through a lot of hoops.

    Thanks to Bob Johnstone for his diligence in hosting such a wealth of information. ( https://www.google.com/url?sa=i&rct=...70887869135930 )
    I can see the pic on my computer, but as we have seen, some pics will do that and not post to the forum. Let me know if it don't show. As far as I know, if all the components are installed correctly, only two things are needed for the device to perform correctly. That is that the push rod must be adjusted to allow enough travel for the components to produce pressure when activated, and return far enough to "relieve" pressure. Additionally, the tiny vent in the master cylinder reservoir cap (1) must be clear.

    Regarding the "push rod" not coming back out, it looks to require a connected pedal return spring for that function. I'm not certain, that a fresh cylinder with new components...that the return spring (#10) would push the piston & pedal back out on its own? Looking at the drawing, I'm thinking that the piston would have to return back far enough to clear the compensating port (#4) in order to relieve pressure. Hope this helps.
    Last edited by jclary; 10-11-2019, 06:24 AM.

    Leave a comment:


  • Mrs K Corbin
    replied
    2 questions: have you replace/rebuilt the MC?
    Have you replaced the soft lines at the wheels and rear axle?

    I've been learning the hard way to just go ahead and replace everything and get it over with.
    PITA, but worth it in the end.

    Case in Point. I had Drum brakes on my Nova. Weak as pond water. step on them and wait to stop.
    I decided to upgrade to front disk (LS Conversion). Still kinda weak, plus i still had the non-power drum setup that was making them drag.
    So decided to do a Power Brake conversion. Replaced MC/combo valve, add booster, etc.
    could not get the rears to bleed at all...
    so 8 hours of beating and banging to get the rear hose off, and voila I now have fluid flow.
    so replaced that, and everthing on the rear axle assembly(brake wise) wheel to wheel .....
    PLUS ONE AXLE THAT WAS BENT.

    After bleeding, I have excellent brakes.
    Only thing left is the hard line from front to back. and next summer I'll get that too. piece of mind.

    OOPS.... I forgot. the emergency brake cable was jammed and I'm in the middle of that.....LOL



    ON the 2R5 i replaced everthing to start with and went with a Jim Turner Kit.
    I'm hoping he turns up at the Chattanooga international next year, cause I need him to diagnose what's going on. I have to pump the pedal, so there is some problem I can't figure out. maybe I used the wrong MC. Not sure.

    Leave a comment:


  • Dwain G.
    replied
    Your wording makes it sound like the pushrod is not actually attached to the pedal.

    Leave a comment:


  • Okiejoe86
    started a topic Brakes: 1940 President Stuck Master Cylinder

    1940 President Stuck Master Cylinder

    This brake project has gone on for waay waaaaaaay to long. Long story short to catch you guys back up...

    Last February-March I lost all brakes. Brake pedal went in, but I had to "pump" it back up. Torn down the entire system and replaced/rebuilt just about everything. New hard lines, New soft lines, rebuilt master cylinder, New shoes, Rebuild cylinders.

    When I rebuilt the master cylinder, I made sure to lube everything inside with new brake fluid. The internal shaft appeared to be in good shape. New springs, ect, ect.

    I added fluid and was going to gravity bleed it. Noticed that the fluid wasn't draining into the lines and decided to gentle push the brake fluid to "force" the fluid into the lines...

    After pushing the brake pedal in and out a couple of times, I noticed that the plunger rod that goes into the mastercylinder would not retract back out. Got me thinking that is what caused me to lose brakes possibly. But when would it not spring back? New springs.. Lubes grommet... Did I miss something? Getting frustrated..

    Thoughts?
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