Can't get front brake shoes to go in so drum will fit on 48 DeSoto.

[MarcDeSoto]

I think I am just going to have to go back to Topping and have them take more lining off.  It's almost there and just needs a little more off.  I wonder if they sell new or used push rods.  Now that I've filed the rods, I'm not sure if they are all equal!  Also, am I right in assuming that you have to loosen the anchor bolt nuts in order to do the major adjustment?  If I tighten the anchor bolts, I can't turn the bolts.  

[James_Douglas]

Marc, You really need to stop and spend a couple of hours both reading and watching the Service booklets and slides. They go into much detail. I suspect you are not following step by step the process or the process has not "clicked" in your head so that you are not "seeing it" in 3D in your head.

 

You need to KNOW not think that the anchors are adjusted all the way in and that the other adjusters are also all the way down.

 

What was the measurements on each of the drums that they made? Did they take the measurements 180 degrees apart to make sure that the drums were in fact round and not off set turned by some shop that did not know what it is doing?

 

James

 

 

[andyd]

I still think the linings are too thick...........andyd

[MarcDeSoto]

I've read the shop manual and watched the MTSC filmstrip many times.  They never discuss or answer any of those questions.  They do tell you how to adjust the shoes, but they assume your drums go over your shoes.  They never discuss whether or not to loosen the anchor nuts before you make an adjustment.  Topping never told me the measurements of the drum.  He said he took of about .030" off the shoes, which I think is too little.  So it looks like I have to back to Topping and tell them to take more off.  

Edited February 26, 2022 by MarcDeSoto

[kencombs]

I would do that only after assuring that the push rods you filed down are the same size as the old ones.  You really have to measure carefully, not just file some off.   I wouldn't prefer to shorten from that end anyway, grinding the pointed end is much faster.  that assumes you have a power grinder of some sort.

[MarcDeSoto]

I have the old ones on the left side and the new ones on the right side.  Using the original push rods didn't make a difference.  I think Andy is right in that my shoe lining is just too thick.  I can get the drums on now, but can't turn the wheel.  So maybe take another 1/32 off?  

[andyd]

Marc........do you still have the old worn brake shoes?.......do they allow the drums to fit on?.............are the actual old/original shoes the same size as the "new" ones that don't fit except that they don't have a new thick brake lining?.......then it must be the new brake lining thats the problem...........from here in Oz it still sounds like the linings are TOO THICK..........andyd  

[allbizz49]

You're making a bigger deal out of it than it needs to be. If you have to shave the linings, do it.  Make it happen. These cars are archaic, not much to them. I'm not trying to be an a hole, just saying make it happen.

[MarcDeSoto]

First of all my brake shoes are the old ones.  I had a brake shop reline them back in the 80s, but never put them on until now.  I am going back to the brake shop in Long Beach on Monday to have them shave them again.  They confused me saying my brake shoes looked OK when I brought them in and only shaved off around 030".  As far as the push rods, the old and the new look to be about the same length.  

 

 

[kencombs]

4 hours ago, MarcDeSoto said:

First of all my brake shoes are the old ones.  I had a brake shop reline them back in the 80s, but never put them on until now.  I am going back to the brake shop in Long Beach on Monday to have them shave them again.  They confused me saying my brake shoes looked OK when I brought them in and only shaved off around 030".  As far as the push rods, the old and the new look to be about the same length.  

 

 

the new one 'looks' much longer to my eye.  But, that doesn't count.  What they actually measure with calipers is what counts. What do they measure  piston end to slot?  Also, the end that seats into the piston has a much larger radius.  that may not be seating as deeply into the piston recess as the original.   take a close look in that area.

 

If the shop measured the drum and shoe I have to believe something else is going on.

[Sam Buchanan]

5 hours ago, MarcDeSoto said:

 As far as the push rods, the old and the new look to be about the same length.  

 

 

 

"About the same length" isn't good enough. We are talking about 0.006" clearance between shoes and drums when properly adjusted. Is your "eye-crometer" good down to a few thousandths? 

[keithb7]

I put some new Andy Bernbaum shoes on the LF wheel this week. Sure, they should have been arc'd. I ran them as-is and went for a few drives. No more pulling to the left! Lol. No they don't contact the drum like they should,  and the contaminated removed shoes are gone! Couple of trips down the hill with ample braking, they'll arc themselves in. I am on the adjusters very often. They are already improving, I can feel it.

 

But no, I had no trouble getting the drums over the new shoes. I did put the new shoe inside the drum and held it in place. I used a feeler gauge. Out at the ends I measured about 0.019 at the toe, and about 0.014 at the heel.  I don't necessarily recommend everyone do what I did. Yet these brake pins.

 

These pesky little brake shoe pins. How often do they really need replacing? For the most part, the are pretty much non-wearing aren't they? If the old pins worked, re-use them. I suppose with leaking brake fluid getting on them, left in a field for 50 years, they rust some. 50 years in a field seems to be a pretty common theme. I have yet to dive into a failure analysis of these brake pins. 

 

Edited February 27, 2022 by keithb7

[Dodgeb4ya]

When I drove my daily driver back in the late 60's early 70's ...a 51 Plymouth I just replaced the shoes too....put them on and drove it after adjusting only the minor  cams.. Doing three or four adjustments as they wore in over a couple months. Brake pedal got to be high and very firm and soon enough were very excellent in stopping that Cranbrook beauty.

Of course todays eco friendly burnt  toast linings are not nearly as good as that deadly asbestos lining.?

Todays owners generally never drive the cars enough in a year to even wear the linings in.

Most all new wheel cylinders generally always came with the push rods.

I remember the MoPar cars new wheel cylinders sometimes had the longer factory length pushrods installed and sometimes the 1/8th " shorter push rods.

This was the case with EIS, Raybestos, United etc.

Those short push rods saved the day when the shoes wouldn't let the drums fit on.

[bamfordsgarage]

Marc, IMO you need to heed Andyd and Allbiz… 

 

This is not complicated. 
 

Factory spec is for 3/16 lining. Your shoes were relined with 1/4” material. Your lining was 1/16” too thick. 
 

1/16” is 0.0625”, roughly 60 thou. 
 

You had 30 thou removed last week, get another 30 thou ground off and you’re ready to go. 
 

Your pins look close enough to the same length… a few thou shouldn’t make any difference. 

[James_Douglas]

13 minutes ago, bamfordsgarage said:

Marc, IMO you need to heed Andyd and Allbiz… 

 

This is not complicated. 
 

Factory spec is for 3/16 lining. Your shoes were relined with 1/4” material. Your lining was 1/16” too thick. 
 

1/16” is 0.0625”, roughly 60 thou. 
 

You had 30 thou removed last week, get another 30 thou ground off and you’re ready to go. 
 

Your pins look close enough to the same length… a few thou shouldn’t make any difference. 

 

The factory spec of 3/16 of an inch is for NEW drums at exactly 11.000 inches. The shoes should be cut to a drum diameter minus 0.030 of an inch.

 

Which is why I asked Marc do DOCUMENT the drum diameter in at lease two planes to make sure some idiot did not mis jig the drums and turned them off center which would cause problems with the shoes.

 

Also the comments about the pins should not be taken lightly. A few thousands will not allow the shoes to seat down and allow the drum to fit down.

 

Just ignoring that there is a problem by cutting and cutting the shoe is kicking the can down the read and will come back to bite one in the butt. Marc should figure out why he is having a problem.

 

James

 

[Plymouthy Adams]

anchor bolt arrows as on the rear these are parallel with the level ground....setting is a no brainer....but per the book and on the front...the shoes are slightly canted....this cant will not allow the greater distance if set as the rear parallel with the ground, these are set in relationship to the heel of the shoe...thus the arrow for greater distance will follow the imaginary line through the cylinder and continue through the anchor bolt following the line of the arrow and greatest distance is the arrow pointing away from the drum.

[James_Douglas]

Marc, as to the anchors...

 

Take your tool and place it at the base of a shoe near the anchor. Then rotate the anchor cam bolt until the shoe moves away from the tool. Then reset the tool and do it again and again. You "hunt" to find an anchor location that has the shoe as far in as it can go on the anchor adjustment.

 

You do this with the minor adjuster, the one in the backing plate with the spring behind the big 3/4 inch adjusting nut all the way down. You can do this without the pin at the top.

 

Mark with a heavy sharpie a line to show the lowest spot on the bolt. Both in the backing plate and even on the rear of the bolt. On mine, I mark the threaded rear side of the bolt and I use two hack saw blades and I cut a groove on the end. I can then adjust the anchors from the rear with the drum on. Yes, you have to leave the nut somewhat loose. But once one is happy with the fitting you back off the minor adjusters and slip the drum off and then tighten the anchor bolt to spec.

 

You then can put the drum back on.

 

The quality of the braking is vastly improved on these drum systems if you get the shoe to be a perfect match for the drum, minus the 0.030 underside of the shoe. If one just puts them in and cuts then to do it then the ends will wear out long before the middle of the shoe as well as the fact that it take several thousand miles for a shoe to "arc itself in". It may feel better after a few hundred miles, I geometry is geometry and the shoes will make maximum contact if not arced.

 

The choice is do it correctly or plan on wasting 1/3 to 1/2 the shoe life.

 

James

Edited February 27, 2022 by James_Douglas

[bamfordsgarage]

Fair enough James, and I stand corrected. My ‘get r done’ method would, I am pretty sure, get those shoes in the drum and the brakes working but would not be optimum and by the book. 
 

I am puzzled however by your statement that the shoes should be a “perfect match” to the drums… no arcing for a bit of clearance at each end?

 

Also, if Marc’s drums have any amount of wear, I reckon a few thou longer pin length will not matter. IMO. 

 

Not trying to argumentative… just trying to offer practical suggestions. I rarely work on stuff this new, so perhaps my standards are too casual ?. 

[desoto1939]

OK so my question when Marc to the shoes to the Brake shop did you also take the appropriate brake drum with you.

 

If they are going to arc the shoes they have tobe arced to match the appropriate drum.  So if the drum has been cut down then the mechanic willmicrometer the inside diamter of the drum with the Ammco 8500 Brake tool that I put in another psot.  This will tell the mechanci the correct inside diameter of the drum.  He then sets up tghe ammco safe-arc tool to be at the 11 inch geneal setting and then does the fine adjustment with the dial on the safe arc tool. So if the drum is and example 11.10 then he sets the truse setting on the fine setting to be 11.10. Then moves the shoe inward to make a slight contact with the sanding material.  He then would rotate the shoe either clockwise or counter clockwise to take any high spot of the drum he would then continue to arc the shoe until there is an entire cut on the lining to insure they are a perfect arc.  This is how they did the job It has to be a complete job.  Ask the brake specialist what he is doing and if they are using the Ammco safe arc tool and if they have the fixed anchor adapters.

 

Rich Hartung

desoto1939@aol.com

 

[James_Douglas]

1 hour ago, bamfordsgarage said:

Fair enough James, and I stand corrected. My ‘get r done’ method would, I am pretty sure, get those shoes in the drum and the brakes working but would not be optimum and by the book. 
 

I am puzzled however by your statement that the shoes should be a “perfect match” to the drums… no arcing for a bit of clearance at each end?

 

Also, if Marc’s drums have any amount of wear, I reckon a few thou longer pin length will not matter. IMO. 

 

Not trying to argumentative… just trying to offer practical suggestions. I rarely work on stuff this new, so perhaps my standards are too casual ?. 

I think I said above that...

 

"The factory spec of 3/16 of an inch is for NEW drums at exactly 11.000 inches. The shoes should be cut to a drum diameter minus 0.030 of an inch. "

[James_Douglas]

4 minutes ago, desoto1939 said:

OK so my question when Marc to the shoes to the Brake shop did you also take the appropriate brake drum with you.

 

If they are going to arc the shoes they have tobe arced to match the appropriate drum.  So if the drum has been cut down then the mechanic willmicrometer the inside diamter of the drum with the Ammco 8500 Brake tool that I put in another psot.  This will tell the mechanci the correct inside diameter of the drum.  He then sets up tghe ammco safe-arc tool to be at the 11 inch geneal setting and then does the fine adjustment with the dial on the safe arc tool. So if the drum is and example 11.10 then he sets the truse setting on the fine setting to be 11.10. Then moves the shoe inward to make a slight contact with the sanding material.  He then would rotate the shoe either clockwise or counter clockwise to take any high spot of the drum he would then continue to arc the shoe until there is an entire cut on the lining to insure they are a perfect arc.  This is how they did the job It has to be a complete job.  Ask the brake specialist what he is doing and if they are using the Ammco safe arc tool and if they have the fixed anchor adapters.

 

Rich Hartung

desoto1939@aol.com

 

Also, make not of my other post about the Ammco unit as some of them has the clearance built in and so you added it in when you did the math. Print out the attachment I have on that comment and take it with you and ask...Rich makes a good point. MOST of the ships have the "simple anchor" on the Ammco and not the fancy one for the fixed anchor jobs like ours. Do ask if they are using the fixed head.

 

James

[bamfordsgarage]

1 hour ago, James_Douglas said:

I think I said above that...

 

"The factory spec of 3/16 of an inch is for NEW drums at exactly 11.000 inches. The shoes should be cut to a drum diameter minus 0.030 of an inch. "

Right you are. I was thinking of arcing instructions expressed as so many thou clearance at each end of the shoe. If the correct shoe-end clearance results from a diametrical clearance of 0.030", that's very handy to know.

 

Thinking further, the 0.030" smaller diameter is not enough of a spec in itself. Those linings could be 1/4" thick and be ground to a diameter 0.030 smaller than the drum, and still not fit.

 

So, for my understanding would the correct formula actually be:

 

Ideal lining thickness = 3/16" + (1/2 of drum diameter in excess of 11.000") - 0.015" (the radial clearance equal to the 0.030" diametrical clearance for arcing)?

[desoto1939]

I just scanned a high level explanation of how the AMMCO Brake Arcing machine works.

 

So everyone should read the article and also Marc so you know what should be done with your brake linings.

 

I also have a more detailed Model 8000, 880, 8890 Ammco safe Arc Manual.

 

 

Rich Hartung

Desoto1939@aol.com

AMMCO Brake Arcing Tool.pdf

Edited February 27, 2022 by desoto1939

[desoto1939]

Here is another ammco more detail instruction manual.

 

Rich Hartung

desoto1939@aol.com

AMMCO Brake Arcing Tool 8000.pdf

[DJ194950]

One question, when checking with what ever tool you are using to get brakes close to proper clearance ( I know you have not got them on yet) but per the book you are also supposed to look at the squareness (level) to the backing plate.

 

When I did the brakes on the 50 Ply. I had 3 of the 4 where just fine. One when angled and not square to the backing plate.

 

My 1946-54 repair manual showed this and how to correct this condition.

 

Tilted shoes may cause this not fitting ? if off much at all.

 

Just a thought to add to the diagnosis procedures.

 

DJ