Shoe contact on drums

[Jipjob]

Just wondering what kind of material that I should use to check the contact from the drum to the shoes.  Being an Retired marine machinist We used a blueing agent but with brake shoes obliviously this can not be used.  Any ideas or what you have used in the past?  Also I'm going to glue sand paper on the drum to get as much contact of shoe possible. What grit should I use? If you haven't seen my post on this break evolution I posted it n 1949goat subject on bleeding brakes. Oh one more thing I used the proper tooling for installation of the brake shoes to the drums.  Jon

[Plymouthy Adams]

if you have used the correct tool for positioning the shoes true to the drum and within the .006 contact...this should not be a real concern...if this contact patch is of a major concern, the main thing you should have done prior is to arc the shoes prior to install....even if you found a slight variance now, arcing is the corrector...do you have a shop/facility that can arc shoes.....?  the arc should be a couple thou less than the drum arc to prevent heavy toe and heel drag and placing main contact patch to the center of the shoes...

 

Edited October 26, 2016 by Plymouthy Adams

[knuckleharley]

24 minutes ago, Jipjob said:

Just wondering what kind of material that I should use to check the contact from the drum to the shoes.  Being an Retired marine machinist We used a blueing agent but with brake shoes obliviously this can not be used.  Any ideas or what you have used in the past?  Also I'm going to glue sand paper on the drum to get as much contact of shoe possible. What grit should I use? If you haven't seen my post on this break evolution I posted it n 1949goat subject on bleeding brakes. Oh one more thing I used the proper tooling for installation of the brake shoes to the drums.  Jon

Why can't you just use the Dykem Blue on the drums and let the shoes tell you where they are rubbing?

[Plymouthy Adams]

leave the drums it off for a night or two and dampen them just prior...that way you have a small film of rust that will cause no damage as they typically will surface rust a bit in heavy moisture laden environment and on use will self clean..

Edited October 26, 2016 by Plymouthy Adams

[desoto1939]

JipJob:  Did you use the Ammco brake gage 1750 to set the brake shoe adjustment?  Also did you look in the tech section on the setup and use of the ammco brake tool?

Rich Hartung   desoto1939@aol.com

[_shel_ny]

13 minutes ago, desoto1939 said:

JipJob:  Did you use the Ammco brake gage 1750 to set the brake shoe adjustment?  Also did you look in the tech section on the setup and use of the ammco brake tool?

Rich Hartung   desoto1939@aol.com

OP stated in a post years back that he had 90% shoe/drum contact.

OP asked how to check contact before. Same answers should still apply:

 

[_shel_ny]

And if you have the time , and fortitude you can check out the brake fix here:

 

 

[_shel_ny]

Or:

 

[_shel_ny]

More suggestions.

JIPJOBXX

• Zen Master, I breathe vintage mopar!
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ID: 5   Posted May 25, 2009 · Report post

I think your overcompensating the oust of the tool. All you are trying to do is to get the shoes inside the drum to fit. If its anything like I have done at work than just do a sweep of the drum (Inside Diameter) and then take that tool and take a sweep of the shoes in place. All you are trying to do is to get the shoes to match as much surface area on the inside of the drum. Plain and simple don't over think the tool. Some guys here just cut a window in an old drum and use feeler gages to get the shoes to fit. I used just a tool I made at home to get the shoes in a concentric round patter and then installed my drums. You can also check after you have gotten your brake shoes concentrick with the drum with chalk to see how the shoes match to the drums. Good luck!!!!

[Plymouthy Adams]

hole in drum will work..GIVEN the wear in the drum with the hole is greater than the wear in the drum you setting and you can accurately measure the diameter of both the drum you will be using and the one you have the hole in, the take the time to do the simple math with allowance for the .006 fitted clearance and Bob's your uncle...

Edited October 26, 2016 by Plymouthy Adams

[55 Fargo]

5 hours ago, Jipjob said:

Just wondering what kind of material that I should use to check the contact from the drum to the shoes.  Being an Retired marine machinist We used a blueing agent but with brake shoes obliviously this can not be used.  Any ideas or what you have used in the past?  Also I'm going to glue sand paper on the drum to get as much contact of shoe possible. What grit should I use? If you haven't seen my post on this break evolution I posted it n 1949goat subject on bleeding brakes. Oh one more thing I used the proper tooling for installation of the brake shoes to the drums.  Jon

Jon, it appears you have installed and adjusted your brakes as per spec, what is the problem currently?

You have other posters digging up your past dealing with the same issues, did you not resolve this at that time?

Do you have decent brakes, or are you now displaying uneven brake shoe wear after several years?

Please enlighten us with what is going on , before others blow a head gasket....LOL

[T120]

Jon, Nice to see you are once again active on the forum...

[desoto1939]

I am not sure if people are expecting the brakes on out 1930-40 and 50's car and trucks to perform and stop like our modern 2000 ish vehicles.  Back before power brake and vacuum assisted brakes all we had were the manual and if the case of rod mechanical brakes. When our fathers drove these cars the speed were not as fast and the roads were not as good, in certain terms, in which we can average 70+ mph on a super highway and then can come to a complete stop without any fading or softness in the brakes as to be compared when driving on the technology that 80 or so years old.

I think everyone has to get back in the car and then think about what they are going to be driving in the next few minutes. It is not your current car but an antique car. The cars do not stop on a dime but can, they do not have the acceleration like the current cars and lighting of halogen bubs and 12 volt system if they are a stock antique vehicle.  So if you brakes have a good pedal with the proper amount of travel in the pedal as per the spec's for your car then you should be good go.

BUT and I say BUT you have to be in the frame of mind that you are driving an old car and they act slower and anticipate situations, like noticing that a green light has been green for awhile as you get closer to the intersection.  Did the light just turn green now you have a much longer time to get through the intersection, anticipate additional stopping distances be aware of the extra distance that might be needed to stop remember the old safe diving lesson keep 3 car lengths between you and the other car.

You need in more so reason to be a defense driver in the older cars. We have to have that understanding in our minds before we even venture out of the garage and everytime we start up the antique car, These are older and they do not act like our modern cars.

So think of driving your modern 2016 car with a v6 coming home from work and then on the next day you had to use you old Model A to get to work an entirely different driving situation as a prime example.

Rich Hartung

desoto1939@aol.com

[_shel_ny]

dye, or the interior surface rust removal test of the drum may only show some of the story. If the shoes are not square to the drum it will be readily evident when you pull the drum back off after testing as there would be areas untouched, but it may not be readily evident as to how well the shoe is arced to the drum other than how much transfer from drum to shoe is seen.

The chalking of the shoes that has been suggested to the OP, and also suggested to others by the OP should be a good test.

OP has referenced the post made in another thread about bleeding brakes.  As bleeding, and adjustment are interdependent for good braking, including the spongy ?/soft? problem would also be helpful here in this thread to take some of the guesswork out of what is going on   Playing 20 questions takes a long time.

[Plymouthy Adams]

if rotating the drum you cannot get a true test of the shoes as the various highs and lows (out of centric alignment and possible contact of the shoe at an angle) will erode the dye on the drum as it gets turned...INSTEAD you would get a better picture by transfer of the rust or dye if you chose to use it by reading the shoes...both are redundant in all reality given the man has stated he used the proper tool and followed the adjustment procedures....but as you and I were not there....that is up for interpretation also...

[DJ194950]

I thought I had it made with replacing the brakes on my 50 Ply. 4dr.

I had totally lucked out several years ago buying a set of all four brake drums on EBAY, very reasonable and shipping form southern US to CA. was almost unbelievable

When time came to do brake job I measured my old drums then the purchased.  Old were + .020, +.040, +060 x 2. New were all smooth as new  and 10" never been turned!

New bonded brake shoes, new wheel cyl.'s, hoses AND was able to borrow the Ammco adjusting tool.

After bleeding 2-3 times brakes were solid but low. Removed drums and adjusting again- I had missed the shoes had a unlevel  in to out tilt. Reread the repair manual about this condition and how to correct this, were the tool showed what was need to level the shoe to the drum. Recentered all with the Ammco tool and reassembled. Better and drove for about 30 miles. Solid brake but not at the top with the correct free-play. Very workable and felt safe but not perfect?

Raised car did minor adjustments only -front and rear drove and repeated after another 50 miles-- Perfect.

3 years later still very good.

DJ

[Jipjob]

Well we go again but today a good friend came over to check out my brakes.  Now here is what we found on the right front break drum and brake shoes.  First of all I have heard a slight noise coming from the break drum for along time.  It sounded like the backing plate was twisting a little when depressing the brakes.  Upon removal of the drum we notice the rear shoes was .040 smaller on the inside of the shoe than the outside this might be what's causing the noise issue.  When we put the drum and tire back on and I applied brake pressure the brake drum and tire would move out as if it were being pushed out by the misaligned shoe.  But I have double checked all the misc. parts that hold the shoe in place but everything looks ok.  What can cause this to happen?  But tomorrow I'm going to take the brake shoe oft and measure the shoe with a mic and get a more accurate reading.  These are new shoes and they should be within specs.  If this shoe is wearing out on one side I will make sure that it is floating right in the brake cylinder.  I did notice one more thing is that minior adjustment for setting the brakes was tight on the forward adjusting screw and the rear one had play in it after reinstalling the break drum and tire. This i would surmise because of the major setting on those adjustments.   Anyway thanks for the help so far and maybe just maybe this shoe position might just lead into the resolvance of the air n the brake issue.   Jon 

[sser2]

To the OP question of what kind of stain can be used to check drum-shoe contact, I think chalk can be used on shoe linings. It may help finding and filing down high spots, the same way as old time machinists fitted babbit bearings. Could be a poor man's substitute for arching on Ammco machine. Chalk can be easily brushed off and won't hurt the linings. Prussian Blue is no-no, its oil base will soak into linings material.

BTW, this coming weekend I am picking up a free Ammco shoe arching and liner riveting machine. A floor model. When I set it up, members nearby are welcome to come and use it. I am in central Cali.

[_shel_ny]

Uneven wear.

[Dodgeb4ya]

And you thought you had shoe lining contact issues?

This P20 Cpe was really hard to stop.

This car had  brand new Chinese brake shoes with less than 500 miles on them... they have never been arced- installed as they came from the far east. What a lining surface wear pattern!

We had to replace all the new starting to leak Chinese black piston wheel cylinders with old stock USA W/cylinders ( the china ones hadn't yet dripped onto the linings) and also  had to replace the (8) new brake shoes  with old stock softer linings and arc/fit them to the recently turned drums.

Most all of these new brake brake parts being sold for our old MoPars is absolute junk! You see them all over Ebay, Rock Auto and the local parts stores.

Sleeve your wheel cylinders for no leaks and longevity. As for brake shoe linings use a commercial brake reline company... get asbestos! Yea I know....

I'm really getting tired of seeing this poor quality parts situation over and over again

[Jipjob]

Is there a secret to why my 42 frount brakes rear shoe tend to want slide over to the

 outside?  The only thing that holed the shoe is a spring. Two caps and a small rod that goes through the backing plate.  Nothing else to holed the shoe in place. What can I do to resolve this problem? This causes a noise when I depress the brake. Thanks

[knuckleharley]

I have a confession to make. My ignorance on this subject is complete. As a self-taught mechanic (too poor to buy good cars or to have anyone else fix them when I was a kid),I did several brake jobs because I had to if I wanted to drive the car or truck,and never once had a problem with shoes wearing on one side. Never heard of anyone else having that problem,either.

I'd put the new shoes on,adjust the brakes,and go driving.

All the stuff I worked on as a kid were either Ford or GM. Is this a Mopar thing,or was I just lucky?

[Plymouthy Adams]

no knuckle...some folks just have to dig too deep sometimes not really knowing in truth what they dealing with and it relationship to the system as a whole and bother not to read the repair manual.

[Jipjob]

Good old mopars and there braking systems! Why on gods green earth did they haft to use such an abortion for stoping there cars in 1942! Adams stated to read the manual for problem and yes I have many times.  Something's are just plain as day and others well that another story.  This morning I started to check out the pin and springs that had hold the shoe in place and notice the wear marks on the brake shoe was only ridding on one side.  So I put some sand paper attached with glue to the inside of drum and proceeded to even out that wear pattern.  Took awhile but the shoe is at least sitting on the drum at 90 percent contact.  But that dam hold down spring has got me whooped.  It still slides to the outset of the drum and makes kind of a sound like the main spring that keeps the brake cyclinder together.    I'm tired tonight and so good night.

 

 

[Niel Hoback]

I think you should check the inside diameter of the drum at the outside edge and at the inside. It sounds like you could have a bell-mouthed drum. If you do, and you can get it turned within the limits, it should solve your problem.