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

[desoto1939]

Brian:

 

MAke sure the rear passenger fitting is sitting inthe back of the wheel cylinder correctly. Remember this isa flared fitting and if it is not perfectly squared then you will get leakage.  You might not have the  screw tighten down enough. Always use a flarenut wrench to make sure you do not bugger up the nut and this provides equal  contact on the nut.

 

So the inner wheel cylinder is not leaking just at the line correct?  Also you had stated that you could not get a front brake block.  These are hard to find. You would only need one of these if the threads got stripped. BAsically this is a box with f threaded and flared holes and a braket to bolt it to the frame. The top hole is for the brake swith, the two rear holes is for the line to the MC and then theother hole is to the rear brake line. The two front go to each franot wheel.

 

Keep me upto date on how you make out with the rear line.  You are getting closer.

 

Rich HArtung

Desoto1939@aol.com

[TodFitch]

. . ..  It also looked like I have seepage from the passenger rear brake line fitting.  Could a very slow leak, cause you to lose the majority of the pressure in the lines?

 

How long can you leave the fluid in the bleeder until it starts to corrode the plastic?  I want to use it through the weekend and would prefer not to clean it out till then.

 

Any leak, no matter how slow, will cause problems.

 

I've been leaving my DOT5 brake fluid in my home made bleeder for months on end with no apparent affect on the fluid or the container. DOT3 will absorb moisture from the atmosphere but I think that since the bleeder's screw top is air tight that should not be a problem. I'd be a little surprised if the DOT3 fluid would affect the plastic or vise versa as it seems that many modern master cylinders have a similar seeming plastic reservoir.

[Don Coatney]

I left DOT 3 in my garden sprayer bleeder and discovered that it ate the rubber used in the sprayer pump.

[Bmartin]

I've got the new hardline on and the pedal is still soft.  So I pumped up the bleeder and I'm letting it sit to see if any leaks present themselves.  The adapter between the hardline and the wheel cylinder does not seem to want to snug up.  I'm afraid to keep turning it as I might be stripping it. Its not loose, but it does not give me that feel good stop when something is tight.  Although I have a habit of overtorqueing things so we will see.  If not leaks pop up.  I'll isolate one side at a time and see if that gives me any good info. 

 

 

Inline tube:  Not real impressed.  I guess I expected the fit to be better for pre-bent lines.  There is still a lot of bending needed to get it to match the factory stuff.  I'm not good at that even with a couple different benders.  Also, when I called and talked to them, the salesmen stated there was no protective coating on the steel lines, then I go back and read online that they are tin coated.  I would have gone with the steel instead of the stainless had I known that.  I assume it would be easier to bend.  The rear line I replaced sits high up over the diff, not snug like the factory line.  And its a few inches too long making the fitment that much harder.  I may have had better luck the more pliable stuff from the auto parts store.  It bend a lot easier by hand. 

[Bmartin]

Well, I feel like I may have lost my frame of reference.  It felt like the pedal was firm last night.  Today I don't seem to be able to get back to that again.  I'm back to having the rears out of the system.  After the 1" of free travel, I can push the pedal through 2" of travel with my hand.  I could have sworn last night that I could only ge like 1/2".  Anyone have any pedal travel references to go by?  Not really sure If the fronts are good or not now. 

[Bmartin]

I've got all the lines capped, just hardline and master cylinder.  I get 1" of pedal travel before it goes extremely firm.  I guess I would have thought it would have been less than that.  But adding 1" extra when the brakes are there makes sense.  Just not sure if that is correct. 

 

EDIT:  To answer my own question, I went back to the manual.  The total pedal travel (after freeplay) should be between 1 7/8" and 2 1/4". so it pretty much not building any pressure when connected to the brakes and its using half its travel with no brakes.  Going to put a cap on the master itself and see if I can get it to have essentially zero travel. 

Edited April 4, 2014 by Bmartin

[TodFitch]

. . . Going to put a cap on the master itself and see if I can get it to have essentially zero travel. 

If you have the hard lines capped then that should be just about the same as having the master capped as far as pedal travel.

 

I cheated a little and adjusted the pedal push rod to be long enough that the relief port was just open when the pedal was all the way up rather than the official 1/2" or so of travel before the rod contacts the piston. That reduced the pedal travel by about 1" before the brakes get solid.

 

On my car you can do that pretty easily with the cover off the master looking for fluid flow out of the overflow when the pedal is actuated. Everything is under the hood on mine, cars with the master under the floor might be more difficult.

 

By the way if you can find some 1930's promo films for either Chrysler products, or after GM went to hydraulic brakes by GM, you'll see the type of pedal travel they were used to back then and it is just about what you get when you adjust to the manual (pedal 1/2 way down or more before the brakes go solid). But if you are used to modern cars it sure seems a long way for the pedal to go down before it gets firm.

[Bmartin]

Yah, I capped the master and its the same.  1" of travel (after taking up the pedal freeplay).  If the total pedal travel is 2 1/4", it does not seem right to use up half just in the master.  Does the last 1/4" to 1/2" of travel do all the braking?  I guess the thing to do is put it all back together and drive it to see what its like.  But it feels just like it did last time I drove it and it did not stop well. 

 

Todd:  I'm trying to quote all my pedal travel #'s after taking up the pedal freeplay.  Just to standardize it. 

[Bmartin]

Well, I think I may be back to where I started.  IMO, the previous mechanic just adjusted out all the slop in the master.  So I did the same thing.  It stops about the same, not great, but stops.  I can lock them up below 30 MPH.  Its weird since the relief port in the master must be at least partially covered if not completely.  But the brakes don't lock up. 

 

The only other thing I can think to try is to buy yet another master cylinder.  It would end up being a new one, made in China.  Not sure I would see any difference in performance and not sure I want to drop another $200 for maybe.  I'm going back to looking into a disk conversion for the front and see if the master cylinder/brake booster combo from Butchs Cool Stuff will work with stock rears.  The big question is if I can find disc brakes to work with my stock wheels that have a 6" inner radius.  ECI's have a 6 1/4" outer radius and do not work.  No info from Scarebird when I asked.  Rusty Hope did not know for sure, but stated that no one has ever told him they did not work.

Edited April 6, 2014 by Bmartin

[fstfish66]

Well, I think I may be back to where I started.  IMO, the previous mechanic just adjusted out all the slop in the master.  So I did the same thing.  It stops about the same, not great, but stops.  I can lock them up below 30 MPH.  Its weird since the relief port in the master must be at least partially covered if not completely.  But the brakes don't lock up. 

 

The only other thing I can think to try is to buy yet another master cylinder.  It would end up being a new one, made in China.  Not sure I would see any difference in performance and not sure I want to drop another $200 for maybe.  I'm going back to looking into a disk conversion for the front and see if the master cylinder/brake booster combo from Butchs Cool Stuff will work with stock rears.  The big question is if I can find disc brakes to work with my stock wheels that have a 6" inner diameter.  ECI's have a 6 1/4" outer diameter and do not work.  No info from Scarebird when I asked.  Rusty Hope did not know for sure, but stated that no one has ever told him they did not work.

we just finished a disc  brake conversion on a 1940  plymouth,, it is a rusty  hope kit,went  on  really nice every thing fit great,,it is not a stock  car it is a street rod,, he is currently  running the rims it came with which are after market  chrome cragar pro stars 14x7  we  couldnt believe the 14 inch rims fit over the disc,s if this helps,,  soon a 15 inch mirada rim will replace the chrome rims,,,,,i dont know where you are measureing  the  6 inch  and  6 1/4 diameter your referring too maybe we can  help with a measurement for you,,,

[Bmartin]

fstfish:  If you could take a measurement from the center of the hub to the maximum outside radius of the caliper, that would be very helpful.  The fact that 14" rims fit is very promising.  Also, any opinions on how much meat is on the caliper if I needed to do any clearancing.  Thanks! 

 

EDIT:  One more thing I thought of.  Could you measure from the wheel mounting face to the outermost point on the hub?  I want to see if I can retain the stock hub caps or if they will hit the hub after the conversion.  Thanks again. 

Edited April 6, 2014 by Bmartin

[fstfish66]

fstfish:  If you could take a measurement from the center of the hub to the maximum outside radius of the caliper, that would be very helpful.  The fact that 14" rims fit is very promising.  Also, any opinions on how much meat is on the caliper if I needed to do any clearancing.  Thanks! 

 

EDIT:  One more thing I thought of.  Could you measure from the wheel mounting face to the outermost point on the hub?  I want to see if I can retain the stock hub caps or if they will hit the hub after the conversion.  Thanks again. 

we may be taking the rims off thursday for  other rims  ill try to get   measurements,,,ill print  it now take it with me

[50desotocoupe]

If it is any help, I am nearly done with my 4 wheel disc brake upgrade on mt Desoto.  I used the kit from AAJBrakes.com.  He asked me if I was going to use the stock wheels as apparently he has a couple options for the front end.  I was planning different wheels at the time but told him I wanted to use my stock wheels just in case I wanted to go back to stock at some point (or any future owners).  I know you are using 14" wheels and mine are 15".  Might be worth a call to them to see what they have. I really liked the quality of their brackets and customer service. 

[Bmartin]

50desotocouple - Thanks, its good to have other options.  I'm actually sticking with the stock 16" wheel, but the inside diamter is only 12" due to the channel for the air tube.  I'll check them out.

 

fstfish66- Thanks again for taking those measurements, its a great help. 

[P15-D24]

Couple points/issues to maybe get you to a successful resolution.  First, brake shoe adjustment is the main factor in pedal height, not the master cylinder push rod. To correctly adjust your shoes the brake drums must be turned and true. The shoes need to arched to the correct size to fit the drums. Last, and most critical, the shoes must be centered and proper shoe to drum clearance set with a gauge like a Ammco 1750. The factory cleareance is typically .006 (heel) to .012 (toe). These clearances can't be set by feel or guessing and are critical to both brake performance and pedal height. I remember when I first got a Ammaco 1750 and I re-adjusted my front shoes on my B1 to factory spec. Brake pedal height came up 1-1/2 inches and brake performance was outstanding. If you don't have the shoes correctly adjusted you brake performance will always suck. 

 

Second, your hydraulic system has to have 100% integrity. 99% won't get the job done. Simple test, pump your brake pedal. Does the pedal get higher or firmer? Then you have air in the system and/or a leak. After you pump it up, let it sit a few minutes then depress again. Did it go to the same height or go lower? If it went lower you have air in the system and/or a leak.  If the pedal consistently returns to the same location and firmness every time your  hydraulic system is good to go. If you are pressure bleeding and the pedal is not firm after 3 times around the vehicle, you probably have a leak. 

 

Remember, first get the  hydraulic system to 100% (Don't worry about pedal height, worry about firm, consistent pedal), then adjust the brake shoe to drum clearance (pedal height will come up with this step) and finally the master push rod to factory spec (final detail). When properly set up the brakes on these vehicles are actually quite good but they must be serviced correctly. 

[50desotocoupe]

I have attached a few pictures of my setup.  I am not sure 12" would clear over the caliper because the rotors are 11".  I would say give Roger a call and he will probably have a solution for you since he is a Mopar guy and sells the kits for lots of different cars.

Best of luck with everything.  I was having multiple issues with adjusting my drum brakes and finally decided that discs are the way to go (for me at least).  It was probably much more expensive than sticking with discs...but my preference.

 

Matt

[Bmartin]

I adjusted the shoes with Ammco brake guage and a .07"  feeler gauge.  It was even top and bottom and center was a little tight, shoes are arced, drums turned.  The pedal does not get stiffer when pumped, I've bled using the pedal, using vaccum, and finally pressure.  Replaced a couple hardlines that may or may not have been leaking.  The master has (what I feel is) excess travel even when its capped right at the end.  Its new and has been rebuilt just to see if it would make a difference.  I've tried everything twice or even three times and they are as good as they are going to get by my hand.  I can live with it in the short term, it may even be back to where it was when I started - been too long to remember (November).  I always planned on going disk for added braking ability and to go with something I'm more familiar with.  So from this point forward I will concentrate my efforts and funds there.  Thanks for the help though. 

[P15-D24]

I adjusted the shoes with Ammco brake guage and a .07"  feeler gauge.  It was even top and bottom and center was a little tight, shoes are arced, drums turned.  The pedal does not get stiffer when pumped, I've bled using the pedal, using vaccum, and finally pressure.  Replaced a couple hardlines that may or may not have been leaking.  The master has (what I feel is) excess travel even when its capped right at the end.  Its new and has been rebuilt just to see if it would make a difference.  I've tried everything twice or even three times and they are as good as they are going to get by my hand.  I can live with it in the short term, it may even be back to where it was when I started - been too long to remember (November).  I always planned on going disk for added braking ability and to go with something I'm more familiar with.  So from this point forward I will concentrate my efforts and funds there.  Thanks for the help though. 

Did you have your brake drums turned? You mention in several posts you couldn't get them back on after adjusting them with the ammco tool. That means they are not centered on the drum or the drum needs to be turned.

 

This is a long thread so where are you right now and what are the issues?  

You have bled it out and now the system holds firm at the same height every time when depressing the pedal?

How far down does the pedal go till it stops and the brakes are fully applied? 

[Bmartin]

I had the drums turned.  I had trouble getting them on because the first time I did the adjustment, I didn't use the feeler gauge, just set it tight against the tool, so there was no room to get the drum on.  After I used the .07" feeler gauge, they went on with a little pressure and spun with a little bit of drag. 

 

I was not happy with the pedal or master cylinder travel.  After taking up the free play, I still had close to 2" of pedal travel before it becomes firm.  Manual states max pedal travel is 1 7/8 to 2 1/4".  So I put a plug on the master to just see how much movement was in it.  I get over 1" of travel, after free play, with the master capped.  I don't see why it would be designed to do that, the fluid would need to be dispaced somewhere if there was a good seal around the piston.  I can see some going out the relief port till its blocked, maybe that is it.  The only thing I had left at that point was a new master to replace the already new AND rebuilt master.  So I made the decision to stop with this setup and save money for a modern master and front discs. 

 

For now, I adjusted out all the mush in the pedal with the push rod and its firm as soon as I touch it, it just does not travel much more than 1/2".  As stated earlier, I don't remember how it braked before, so I have no comparison to find out if its better or worse.  I drive it, it stops, I can lock them up at 30 MPH.  With safe following distances I feel comfortable with it. 

 

I don't think the push rod adjustment took slop out of the wheel cylinders because I did not feel any change in drag after I did it.  Brakes are currently adjusted on the tight side with a fair amount of drag, similar to how a newer drum would be adjusted. 

 

If you see something obvious or have something new to try, I'm all for it.  But at this point, I am a bit burnt out.  I need to drive a little and get my motivation back. 

 

EDIT:  I was thinking about my post while I went for drive.  I think I've got closer to 1" of pedal travel.  So maybe that's not so bad. 

Edited April 11, 2014 by Bmartin

[Don Coatney]

I don't know what your expectation is. I have front discs, modern self adjusting rear drums, a dual chamber master cylinder, and full lock up at about mid pedal travel. I feel very comfortable and I am very happy with my setup.

 

Modern power assist brake systems have a much different pedal ratio and a much shorter pedal travel. If less pedal travel is your objective perhaps you should convert to a firewall mounted swing pedal setup with a vacuum assist.

[fstfish66]

here is what  i found,, remember we are using an  after market cragar  star type rim  15x  7 wide  with a back space of 3 1/2..also the in side of the rim  measures 13 1/4

 

you asked for  center of rotor to out side the caliper 6 1/2

 

you asked from  mounting face of rotor to  end of spindle to the out side of the dust cap that  is 2 3/4 so it looks like you need at least 13 1/8  clearance to go over the caliper,,,

 

this was  a rusty hope kit,,,  if  i remember correctly  scarbirds kit  uses a rotor from a ford probe,,and  i think it  is only  9 inch rotor,,,early mustang ll and pintos  used a  9  inch rotor,,,and they work fine,,, a friend of mine now passed,,,has a  early mustang ll clip under a 37  plymouth with a 413  chrysler motor and it stopped just fine with 9 inch rotors,,, and also  i think the scarbird kit uses the small  GM  calipers  commonly called metric,,,so  e mail  scar bird  and ask him  the  measurements,,or if he knows if his kit will allow a stock  type rim on your car,,,i hope this helps a little,,,don

[Bmartin]

Don - All I would really like to know at this point is where my baseline is.  Have I got them working as good as can be expected or are there improvements that can be made.  I can live with the brakes for now, but eventually I would like improved braking for emergency situations.  I actually plan on buying the kit from Butches Cool Stuff that has the dual master with vaccum booster and new pedal. 

 

fstfish66:  Thanks a bunch for the measurements.  Those sound like the rims will not fit.  I do find it interesting that no one has brought that up as an issue yet.  I'll pull a wheel and measure to be sure. 

[fstfish66]

dont know any thing about butches kit,,,its funny how many  conversions are out there,,,good luck,,, dont sweat it   its a super easy  conversion,,just like changing  brake pads

[Bmartin]

I stuck my head under the car last night to look at the wheel.  The area that has the 12" inner diameter is the furthes towards the face of the wheel.  Then the wheel diameter steps wider at two different steps.  When mounted, very little of the drum actually resides in the small diameter area.  For the disc's, the wheel will mount on the face of the disc hat.  I wonder if the caliper will sit far enough back from the hat face to clear this small inner diameter and clear the wheel? 

 

I'll dig into it more later in the weekend. 

[deathbound]

I'm running Rusty Hope's front disc set-up with the parts Charlie listed. I have stock 16" wheels with no issues on clearance.