Hot Brakes

jwaldrich

jwaldrich

Senior Member
1929 Sport Coupe. On the left front brake I put a new drum/hub (assembled and turned by vendor). It went on very right riding the brake shoes (pretty new themselves). The shoes were adjusted out as far as they could go but are still riding.

Took it for test run and drum/hub is too hot to touch. Dis-assembled and using a wire wheel ground down the obvious riding spots on the shoes. Re-assembled and test drove again.

It is better but still gets too hot to touch.

1. When driving it does NOT pull to the left.
2. No noise when driving.
3. Front wheel bearings are less than 1000 miles old. Probably less than 500 (just put a speedo in).
4. Jacked up the front end and both front wheels have the same "drag" when I spin them.

Ideas?
 
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jwaldrich said:
No they were not. Should there be NO contact between shoes and drums prior to brake actuation?
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When I did mechanical brakes as a kid you spun the wheel and adjust the brakes (with the "spoon") so there was SOME drag but not much.

These are dragging like brakes from my youth. Bad?
 
jwaldrich said:
When I did mechanical brakes as a kid you spun the wheel and adjust the brakes (with the "spoon") so there was SOME drag but not much.

These are dragging like brakes from my youth. Bad?
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There shouldn't be drag except possibly a small 'catch' in the rotation but spinning it hard it should pass those spots from momentum for at least a couple revolutions in my opinion. That is with the brakes COLD. if you have any contact with the drums warm (not hot) then there is something wrong.

You have the brake adjusting wedge backed all the way out?
 
Marco Tahtaras said:
There shouldn't be drag except possibly a small 'catch' in the rotation but spinning it hard it should pass those spots from momentum for at least a couple revolutions in my opinion. That is with the brakes COLD. if you have any contact with the drums warm (not hot) then there is something wrong.

You have the brake adjusting wedge backed all the way out?
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Yes it is.
 
If the adjuster is sticking out of the backing plate considerably more than all the others then there is an assembly issue. If you disconnect the brake rod will it still have drag?
 
I hope the front wheel bearings aren't too tight. Just the slightest snug to get rid of hub end play is what's needed. I saw a hub broken by tightly torqued front wheel bearings. Of course this would have also caused considerable heat before it broke.
 
The front wheel bearings were taken up snug and then backed off to align the cotter key. They were not "torqued".
 
To have great effective brakes you need to have maximum initial shoe contact to the drum with the shoes mated and arced to the drum and centered on the backing plate
I would purchase one if the shoe centering gauges from Snyders or Brattons and first remove the front brake shoes and take the shoes themselves and using about a .005 feeler gauge see how they fit the drum . Hold them firmly into the drum while using the feeler gauge . That will give you a guide if the fit and shape of the linings to the drum . As part of my brake work I always arc and fit each shoe . If you don't have a shoe arc available anywhere you will just have to figure out your own method . Don't grind the crap out if them . Next step is to make sure they are centered correctly using the gauge
Contact should be fairly even all the way around the shoe . Yes there will be a break in period and a couple if adjustments at the wedges once the rods are properly set for drag evenly at all wheels .
You do not want constant full drag without brakes applied . As Marco said a little high spot on a new job may be normal but will quickly disappear .
Wish you were closer . Brakes are one of my known specialties .
Everyone thinks brakes are easy and they are not , but well restored and adjusted properly with all things right can stop in a dime
Use an infrared heat detector to check you drum temps
When broke in and properly done I usually see them within 5-10 degrees of one another
Larry Shepard
 
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jwaldrich said:
The front wheel bearings were taken up snug and then backed off to align the cotter key. They were not "torqued".
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since you backed off the nut to install the cotterpin make sure your hub assy does not have endplay on the spindle. i go the opposite direction
 
Mitch//pa said:
since you backed off the nut to install the cotterpin make sure your hub assy does not have endplay on the spindle. i go the opposite direction
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I AGREE. With close fitting shoe to drum clearance, IF the bearings are loose, with weight on the wheel, the drum "Might" **** & rub enough to cause that 1 drum to get hotter.
This scenario doesn't QUITE COMPUTE, to me & you seem to know what you're doing. Especially when there's NO pulling or abnormal brake action.
Bill W.
 
It is my OP that if you build up the tracks to stock dimensions, use shoes that the roller and adjuster pin holes are in good shape, new pins and rollers, arc the shoes to the drums, centering does nothing.
As soon as you adjust the brakes to your drums the adjuster pins that anchor the shoes are locked so every time you press the brake pedal it's only pushing the shoe out from from the activator end.
Plus the idea of bending the track up or down, I don't get that! You have a nice straight track, then you bend it?
Did centering tools even come out in the Model A era or was that a V8 thing, which used different brakes.
 
BILL WILLIAMSON said:
I AGREE. With close fitting shoe to drum clearance, IF the bearings are loose, with weight on the wheel, the drum "Might" **** & rub enough to cause that 1 drum to get hotter.
This scenario doesn't QUITE COMPUTE, to me & you seem to know what you're doing. Especially when there's NO pulling or abnormal brake action.
Bill W.
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Got you fooled Bill. I DON'T know what I am doing as I am Model T smart but Model A stupid. But I listen and read and then "tinker". I live so far out from "industry" that when I do go I make sure I have my ducks in a row.

When I apply the brakes they do pull to the left but that is little more than a brake adjustment to the right side since the wedge is backed off all the way on the left.

That did seem a little weird to me. I can understand backing the wedge off but all the way? but then turn it back in not at all?

Before I take these shoes in to have them arced to the drums I'll have exhausted every suggestion here and the one that makes sense to me now is the wheel bearings. I'll snug them up and try again as well as check for correct assembly of the backing plate and adjusting wedge.
 
New development:
Now have NEW cast iron drums on both front spindles. Brake adjustment is backed off all the way. Test ran ruturned both front drums over heated.

When I re-install the drum on the right hand side, the minute I tightened the axle nut only finger tight I got drag.

Me thinks I have bearing issues... :(
 
If it turns easy before you finish tightening the wheel bearing ---then when the wheel bearing is adjusted properly the drum binds on the shoes you have a centering problem
 
Could the Brake Shoe be rubbing the vertical part of the Drum? Like to shoes are to wide, or not seated correctly, causing the shoe to rub on the side of the drum, not the braking surface.

My thought is to change something to see if the problem stays or changes. Maybe try a different set of drum if available?

Just a thought.
 
Just went through Cast Iron drums on front of mine. One thing leads to another.
A great guy in our club did the work and has done countless brakes.

1. Dragging drum
a) shoes centered
b) Have you arched the shoes to fit drum

2. Were new drums turned? New cast iron drums need to be turned down around .0020 to fit properly they are thicker than org. steel drums.

3. Worn tracks

I was amazed how many steps it took to get them right. 8 hrs later I have great properly adjusted brakes.

I helped... (grunt work) and realized that is sure helps to have a fully equipped machine shop to deal with issues on these mechanical systems.
( had to build up the tracks (welding) then machine them back to specs.)

I use a temp. gun to check my brakes when touring. Rears warm but not hot. Fronts are cool or slightly warm. (60 percent braking on rear) It will also tell you which brake is doing the most work or is too tight.
 
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Vicky said:
Could the Brake Shoe be rubbing the vertical part of the Drum? Like to shoes are to wide, or not seated correctly, causing the shoe to rub on the side of the drum, not the braking surface.

My thought is to change something to see if the problem stays or changes. Maybe try a different set of drum if available?

Just a thought.
Click to expand...

Was going to check that today by putting a tad of grease on the brake shoe edge. If this is the case is it a centering problem? Newbie here with no brake experts helping.
 
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