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So here is MY brake story....scratching my head.


Bmartin

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1940 Plymouth P9

 

I bought the car with questionable brakes.  While waiting for it to get shipped, I had a guy out there work on it.  He replaced the master cylinder, adjusted the brakes and fixed a leaky line.  Got the car and it stopped decent, but always pulled to the right when cold.  Got better once warmed up.  I decided to take a look to see if I could just adjust it out.  I jacked up the car and spun the wheels, the passenger wheel was dragging quite a bit so I followed the minor brake adjustment process from the manual.  Take it for a spin and its actually catching worse.  So I decide to pull the front drums.  They come off pretty easy.  Look inside, no obvious issues, but there is a little sludge on the passenger side.  Peel back the dust cover on the wheel cylinder and and there is fluid there.  So I've got a leaky cylinder, put it on the list for replacement.  Mind you, its been stopping with no fade to this point.  Driver side is better but still damp.  Need to replace both.  So I put the drums back on, they go one easy.  I adjust the minor adjustment again and set it back close to where it was.  It was too tight with a lot of drag, but it worked.  Get in the car and now I have no pedal......crap!  I've got the minor adjustment set so there is a lot of drag forward, and some drag reverse.  Similar to before, except the driver is a little more drag. 

 

So whats the deal,  its got to be close to where it was when I took off the drums.  If anything, its dragging a little more.  Where did my pedal go?  Was the adjustment just right on the hairy edge and I lost the sweet spot??

 

EDIT:  Clarification on pedal action.   It pretty much goes to the floor, but the brakes still stop the car, just not very well.  I get a stiffer pedal if I pump it up a few time.  Sorry for the confusion.

 

 

Edited by Bmartin
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Agreed on the reason for the pull.  Definitely contaminated.  Still confused on the pedal though.  Gonna pull em back off after the holiday to see if one of the cylinders magically let go at the perfect time.  Doubt it, no mess of fluid leaking out. 

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You need to do a full brake overhaul. Replace hard and soft lines, wheel cylinders, shoes and turn the drums, then adjust correctly. You can bite the bullet and do it all at once and never have to deal with it again as long as you own the car or try the piecemeal approach and spend lots of time chasing down one problem after another. 

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Yah, thats definitely the best way to do it.  If funds were available, I'd be going disc.  But its just not possible right now.  It was working just fine before I pulled them off.  I see no reason that it couldn't be working just fine again if I can get back there.  The grabbiness was no big deal really, I should not have touched it.  BUT, here I am.  Anyone who is into tinkering got any ideas? 

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Howdy,

My best idea is to replace both front brake hoses.  They rot from the inside and really cause pulling.

Rockauto has them cheeeeaaaapppp!!!!!!!!!!!, but they don't include the copper gasket.

I skipped this step, had the same problem you do, changed the lines and ----Presto!!

Good luck,  W

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A great idea, but mine look a lot newer than original.  The brass fittings have zero corrosion.  I'll keep it in mind, its just hard to understand how removing the drums and then putting them back on can make the pedal go to the floor. 

 

Right now I'm thinking of performing the brake adjustment discussed here:

 

http://www.ply33.com/Repair/brakes

 

My best guess is that the mechanic managed to get the minor adjustment just right.  Either that, or bleed the brakes.  Perhaps taking the drums off somehow allowed the questionable cylinders to ingest air. 

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That sound so strange to me. I would think even if you were damp a bit on the one cylinder, you would still have enough juice in the master cylinder to have some pedal. If you figure out what happened, we'll all want to know what you found so please post it! Casey 

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You can adjust and bleed your brakes all day long but if your wheel cylinders are bad it will do no good. What would you do if this were your daily driver? As has been mentioned fix it right and be done with it. Frequently a disc conversion can be done for less money than a complete rebuild of the original system.

 

It is more important to stop than it is to go.

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If the master cylinder ran dry, that would cause you to not have any pedal. Check the fluid level there. If it is low or empty, that is why there is no pedal. If that is the case, you may get by with just adding more brake fluid, otherwise you will need to bleed the system to get the pedal back.

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First off, the brakes will be fixed properly.  I just want to get back to a baseline if possible   First thing I plan to do is pop the drums off again and make sure I did not have some sort of blowout.  Then check the master and bleed the system.  If no good, go for the adjustment and rebleed. 

 

Other thoughts:  I know that the mechanic who worked on it before I got it had a heck of a time with the brakes and replaced the master cylinder.  I know he pulled the floor to adjust the rod on the master cylinder.  He may have adjusted that incorrectly and I was on the very edge of it being adjusted past that hole they talk about in the manual. 

 

I wonder if he just found a sweet spot with the cyinders in his adjustment.  I adjusted them and they are now in a spot where they let in air. 

 

I'll post up my findings for sure, with the holidays and work, it will take awhile.  But I'll get it figured out.  In the mean time I'll look into one of those home brake bleeders and pricing of disc vs repair of these.  Still need to pull the rears to see their condition too.  After having this awhile, I have little faith in the mechanic who worked on it. 

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There definitely has to be some slack in the push rod. You should check for at least 1/16th to 1/8th" of freeplay at the Master cylinder. You do this from under the car.

You can also see the relief port about 1/4 " behind the main port in the master cylinder thru the filler cap. You could check that it is open with a piece of wire (BE CAREFUL)

The only actual way a pedal hits the floor is a leak, which leads to an empty master cylinder.

The pulling is a classic bad adjustment, bad front brake hose symptom.

There is no "sweet spot "

The adjustment can be very effectively accomplished (at the cost of completely disassembling the brakes) by removing the shoe bolts and slotting them on the threaded end.

You can then do a very good job of adjusting both ends of the shoe with the drums installed! Brake grease is required.

As far as the cost--Rockauto has your front wheel cylinders (listed under 1949 plymouth) for $15 each!!!!!!  Hoses $4 each.

You need an older mechanic to look at it for you. Also, your very best brake bleeder is your wife/girlfriend. Promise her lunch/dinner (or whatever)

Regards, W

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wilbur 46:

 

Thanks for the advice, couple questions.  You say that  the brake cylinders are listed under a 1949 plymouth.  I was under the impression that laer models had dual wheel cylinders, one top, one bottom.  Whereas the 1940 has a single top cylinder.  Where can I confirm that these will work?  Parts cross reference? 

 

When you say 'BE CAREFUL with the wire in the relief port, what damage can happen when I put it in there.  Don't want to screw anything else up. 

 

Also, to be more clear,  the pedal goes almost to the floor and the brakes still work a little.  Just about at the floor.  It helps a little to pump them up.  Not sure if I made that clear in the first post.  Perhaps I should go back and edit. 

 

Thanks

 

Don:  I do not currently have access to the brake tool.  Once I get this figured out, I'll be trying to find a tool with all the new parts.  Or maybe get a disc conversion. 

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I have seen master cylinders leak internally and brake pedal hits the floor, when all else in the equation checks out.

The MC piston rubber has no effective seal, in bore, then pushes right pat fluid, this can happen.

replace suspect wheel cyls, if the hoses and lines are in very acceptable condition, then it

's your call, if not, a no brainer order new hoses, very cheap at Rock auto.

Replace these items, bleed brakes and adjust, they can be very tricky to adjust, but they can certainly be done to a very acceptable level without the Ammco or Miller brake adjusting tools.

Good luck, check the MC reservoir tonight and let us know whats happening.

Either go all new, or piece it together.

The disc brake kit is not a bad idea, but if you are comparing the cost of the kit and parts, versus 2 new wheel cyls, brake shoes, drums machined, and new brake hoses, $500 versus about $200 or less...

Edited by Fargos-Go-Far
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I'd say you have an issue with your major and minor adjustments.. They've been disturbed and unless they're right you'll have a pedal issue.  The other problem is you've had to have one line replaced.  It's very likely the other lines are weak as well and an emergency stop will blow them.  To be safe, ALL the lines and hoses need to be replaced.  Rebuild or replace the cylinders since they've been disturbed as well after sitting for years and if they're now moving over a corroded they will not seal as well as they first did.l

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I got some time to play with it  today.  I checked the master and there was plenty of fluid.  I pulled the drums again and no blowouts or signs of a leak, pics below.  I put it all back together and bled just the front brakes.  Got a little air out of the passenger side.  But the pedal still goes all the way down.  That's all I have time for till the weekend.  At that point, I'll cut some slots in the adjuster cam bolts and do a home adjustment to see if it makes any difference.

 

As for parts, Rockauto does not show anything but rebuild kits for my year.  Only place I know of to get the cylinders is Bernbaum at $65 ea.  No hoses on rockauto either.  So I'd like to narrow down some things before I go throwing parts at it. 

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Here is the info that you need. EIS Brake part number for the brake cylinders RF ew6854 40-42 Ply rl ew6853 40-42 rr ew6128 lr ew6127 hoses front sp292

hose rear sp183 dodge/ Desoto all use the same wheel cyclinders and hoses for the years 1940-42 Check on ebay you will find these.

You do not need to put slots in the two lowere eccentric. Use the flats with a 1/2 inche open end wrench to turn then after loosening the castlen nut on the back of the backing plate.

Contact me I have all the EIS and Wagner part numbers also check on ebay

Rich HArtung

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I can't give any more advice than what's been given already, but if you're interested, here's my thread on my '38 Plymouth front disc brake conversion (with some other stuff that may be irrelevant to your car). Good luck.

 

http://p15-d24.com/topic/26625-new-front-disc-brakes-front-end-rebuild-steering-rebuild-for-the-38-plymouth/?hl=%2Bnew+%2Bfront+%2Bdisc

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Marting:

 

I just checked on ebay for 1940 Plymouth wheel cylinders and there are several for sale  both from and rears.  You should also beable to get the Brake hoses at any napa store now with these EIS numbers.  I do have two Brake catalogs with a lot of information write to me with your home email.

 

Rich HArtung

desoto1939@aol.com

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