Weld and grind roller tracks

[Bob C]

Thanks Brent for your insight. I see from the print that the magic number is
4.619-4.624. I don't have a DRO on the mill but I could use the co-ax indicator to find
the center of the backing plate and then go from there.

[ericr]

Originally Posted by BRENT in 10-uh-C

While I can show you an alignment fixture, it really does no good as it won't give you the measurement which come from the housing assembly print. This is available at Benson. Additionally, if the track's holes, and the housing holes are not a reamed fit to the same exact measurement of the rivet, then how do you know they are located properly without some type of fixture? While hydraulically setting a rivet that is designed to be bucked appears to do the job, I am not sure if it actually swells the rivet internally to fit the bore differences, -or whether it is just mechanically clamping the plate on much like a nut & bolt will. My initial instinct is hydraulically tightening the rivet does not correctly buck the rivet.

I guess the bottom line in this entire thread is several have pointed out the most correct way, and even given logic/wisdom/advice as to 'why' on those approved methods of the manufacturer, ...and ultimately you are the one that needs to determine what is best for you. There was a time when I would debate someone who was perceived as taking shortcuts however what I have learned is there are many facets of Model-A repair or restoration that used to be deemed correct over the years until research was done to learn the proper specifications and procedures. Folks are only going to believe what seems believable to them anyway, so why bother? Another such area might be the use of lead based babbitt vs. tin based. Many might argue they have successfully used lead-based without a problem but experience has given us wisdom, and just as in this discussion I have chosen to step back and let folks do as they wish as it is not worth the effort for me trying to convince someone differently. Best wishes in whatever method you choose to do.

interesting analysis. if you had to guess, given that speed in production was critical to this Company, don't you think there was some simple jig that held the ear plate in position vis a vis the upper brake shoe wedge holder?


To crank these backing plates out speedily, it could not have been a complex process.

[BRENT in 10-uh-C]

Originally Posted by Bob C

Thanks Brent for your insight. I see from the print that the magic number is
4.619-4.624. I don't have a DRO on the mill but I could use the co-ax indicator to find
the center of the backing plate and then go from there.

There you go. It is never difficult (-DRO or not) when you have the measurement for you. Many quality pieces were manufactured way before a digital readout ever became available.

Originally Posted by ericr

interesting analysis. if you had to guess, given that speed in production was critical to this Company, don't you think there was some simple jig that held the ear plate in position vis a vis the upper brake shoe wedge holder?


To crank these backing plates out speedily, it could not have been a complex process.

Eric, labor was cheap back then, and it was different than today however you are correct in that all of the operations were likely set-up on one machine to be efficient. As Bob quoted the measurement (-I did not verify it but would assume he is corrrect) above, finding the correct numbers is not that hard, but they are necessary to do the task correctly.

[Y-Blockhead]

Originally Posted by daren007

Set the rivets with a hydraulic press. The tracks should not move. If the tracks are exact direct replacements I do not see a need for some alignment tool or fixture.

But honestly, when was the last time we saw a repro parts an "exact direct replacements".

[whirnot]

Interesting, almost all the opinions in this thread are based on either a decent, or in some cases an extensive knowledge of this system. I stumbled on a YouTube video last night of a Master Model A restorer giving a seminar on rebuilding brakes. It is amazing that some folks with such little knowledge can profess to be experts. The guy didn't even know the names or the parts!

[daren007]

Sponsored Links (Register now to hide all advertisements)

Heat the rivet then press. By driving you can shift the tracks.

[aermotor]

All said and done, what is the big deal of all these precision dimensions after a couple hundred miles?


John

[Purdy Swoft]

After the brakes wear in a bit it will be time to tighten and adjust the adjusting wedge . Model A brakes are not perfect , mostly because they aren't full floating but work about as well as drum brakes could be expected to work when properly set up and adjusted .

[BRENT in 10-uh-C]

Originally Posted by aermotor

All said and done, what is the big deal of all these precision dimensions after a couple hundred miles?

John, a valid argument can be made that nothing would change if proper parts are used. So often, cheap replacement parts which are manufactured from poor-quality metals give a bad reputation, but can you name any hard-parts that were worn severely out of tolerance after a few hundred miles, --or even a few thousand miles? I cannot think of any but maybe I am not thinking correctly.


.

[whirnot]

At the risk of beating this thing to death a couple more thoughts. As everyone agrees the last step is centering the shoes. If you put in new rails and they show to be too low, did you gain anything over welding and grinding? They would still have to be built up?
Or another thought, if the rails are too high they will prevent the shoes from making circumferential contact. But if they are a couple thousandths low, it would seem that they would float up to self center. There is nothing keeping them from doing so.

[Jim M]

Wow what a wealth of opinions. I have a 29 std roadster I have been working on for a couple of years. Last year had a cracked axle so I took everything off up to the engine. Replaced the pressure plate and clutch disk, rebuilt transmission, Ujoint and rear end. Took rear spring apart, sandblasted and painted it, used graphite paint between leaves. Got new cast iron drums and new shoes. Put all back together and everything EXCEPT the brakes worked like a champ. I have been tweeking, adjusting, pulling apart and re-assembling for over a month now and still can't get them working the way I think the should. Car on jack stands as I write this and yesterday went to adjust the right rear and it turns forward for about 1/4 revolution it then hits something and comes to a complete stop. Can revolve it backwards many turns and everything is fine but the minute I spin it forward it revolves a short distance then the dastardly "clunk" and abrupt stop. Think I am going to quite working on it for the holidays and maybe Santa will leave me a note under the tree with the solution!!!!....lol. They are so much fun to work on most of the time but this has me pulling out what hair I have. Don't know if anyone else has ever had this problem but feel better just spouting off. Merry Christmas to all!

[daveymc29]

You've all convinced me. Going to stick with hydraulics. I can't weld and don't own a milling machine. Too many places to have failure on such an important function.

[TerryO]

At least with mechanical brakes you don't have to worry about master cylinders, wheel cylinders, and brake lines leaking...


TerryO

[redmodelt]

WE were talking about this subject at the shop today, my question is; Were Model A brakes and suspension really designed for 60/40 braking? Was having the front brakes come on first a Model A thing or was that back dated from the V8 era? Seems to me they were made for the rears to come on first. Wouldn't that put a lot more force on the flywheel housing then what it was meant for?

[daveymc29]

Do any modern cars or trucks use Mechanical Brakes? Just curious.

[BRENT in 10-uh-C]

Originally Posted by daveymc29

Do any modern cars or trucks use Mechanical Brakes? Just curious.

Interesting question, ...but not sure how relevant but I'll play along. While we're at it, include these questions;

Does any modern car or truck use gravity feed fuel delivery?

Does any modern car or truck use a non-synchronized transmission?

Does any modern car or truck use one tailight?

Does any modern truck or car use an updraft carburetor?

Does any modern car or truck use a wooden floorboard?


I can keep going for quite a while, but I really don't see the destination. Maybe I am missing something??

[daren007]

There really is no reason for hydraulic brakes..