Hard Brake Pedal - Update on Post #9

[Pilotdave]

I am wrestling with a hard brake pedal issue. I decided to replace the steel drums in the car with cast iron in 2017. Drums were centered and turned. Shoes arced to the drums. System has been adjusted by several Model A mechanics, most recently last week. Worn parts were updated and shoes were re-arced. Still feels like I'm pushing against an immovable object when I step on the brake pedal. The car stops, but I am pushing really hard. This is very different from our other A's.

Today I tried this test: disconnected rear brake rods at the crossbar and test drove the car. Pedal was NOT hard - perhaps a little spongy. Reconnected rear brake rods, disconnected front brake rods at the cross bar. Same result. Reconnected front brake rods and drove it a third time. The hard pedal was back - along with the feeling that the car isn't stopping as fast as it should.

I've spoken with several knowledgeable Model A friends, searched on here, read Andrews Vol II - the results I found today are confounding them all!

I'd love to hear any ideas as to the cause of this problem! Thanks much.

[Marshall V. Daut]

Check your "Private Messages" in the upper right corner of this webpage.
Marshall

[jb-ob]

Dave,

Saw this once with a transmission sagging in the rear enough to stop the full rotation of the brake cross shaft. Very hard pedal with limited brake rod movement.

One item to inspect.

[Pilotdave]

Thanks Marshall and JB-OB. I will check the cross shaft. Would a sagging tranny explain why the hard pedal disappears when only the front or rear brake rods are connected to the cross shaft?

Dave

[arnhemmer]

When only the front or rear brakes are connected maybe you are getting full travel of the rods. Combined the might be preventing full travel. I would check the rod length adjustments.

[Will N]

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Grasping at straws here.... When the brakes were redone in 2017, were the rear backing plates removed from the axle? There is a difference to the left and right plates. When installed the lever point upward and the clevis must angle in toward the center of the car a little bit. Perhaps they got switched side to side, and with the levers pointing upward, the clevis would angle outward instead of inward, which could cause some binding in the movement of the brake rod.

[McMimmcs]

Originally Posted by Marshall V. Daut

Check your "Private Messages" in the upper right corner of this webpage.
Marshall

The purpose of the forum In my opinion is to help everyone rather than one person. Please post answer rather than private message.

[Jim M]

Agree!!

[Pilotdave]

Here's an update. Today I enlisted the aid of my spouse to help me with a static test. She sat in the car and worked the brake pedal while I was underneath checking clearances and connecting various combinations of brake rods. For the most part, I disconnected rods at the cross shaft. Keeping in mind that testing the degree of pedal hardness this way is somewhat subjective, here's what we found:

1. The cross shaft is clearing the torque tube and the floor with considerable room to spare.
2. With all brakes disconnected, the brake pedal and rod to the cross shaft move freely.
3. There's no "hard pedal" with only the rear brakes connected.
4. The hard pedal partially reappears with only the front brakes connected.
5. The hard pedal fully reappears with all four brakes connected.
6. There's some hardness with only the LF brake connected; this increases some with only the RF brake connected.
7. With the brake rods fully disconnected at both front brake units, there doesn't seem to be any resistance when I pull the brake levers by hand on either front brake.

We then repeated the tests with me in the driver's seat....same results.

I realize that these results are different from what I originally posted. My apology for it I got anyone down the wrong path. However, I am wondering whether this MIGHT be a brake rod length issue. [The rods were all replaced last week.] Or more precisely, caused by differences in their lengths.

The backing plates were not removed when the brakes were updated in 2017. I will check the orientation of the brake levers and report back.

Thanks again for everyone's help.

Dave

[katy]

Check the rear motor mounts.
I once had a Model A that the brake pedal was VERY hard to push, found that the rear motor mounts were not holding anything and the trans mission was sitting on the cross shaft. I've seen it on other A's as well.
Easy check is watch the shift lever when you push the brake pedal, if it moves up you know that there's a problem.

[Pilotdave]

Thanks, katy. I've watched the cross shaft while my spouse was working the brake pedal - no interference to the cross shaft motion.

Dave

[nkaminar]

I just did some work on my brakes so this is fresh in my mind. I would check the left front brake for some binding there. It could be that the wedge is hanging up or that something else is wrong. Take the drum off and operate the brakes without the rod connected. It should operate without any resistance.

[Will N]

Are the front levers leaning forward about 15 degrees from vertical at rest, before you step on the pedal? If they are vertical, or leaning backward, that limits the amount of travel of the front rods, which would limit the travel of the whole system if everything is connected.

[Pilotdave]

nkaminar and Will - thanks for your suggestions. I did check both front brakes with rods disconnected at the brake levers and front wheels off the ground - I can spin the wheels and instantly stop them by pulling on the brake levers. No feeling of any interference on either side. Also have checked that both front brake levers are leaning forward 15 degrees with no play in the brake units.

[nkaminar]

I would still be inclined to take the drums off at the front for an inspection of the mechanism. If there is nothing wrong at least you can put that question to bed. Re reading your post it seems like the problem is in the front. Did I get that right?

[Pilotdave]

nkaminar, I believe the problem is in the front. I'll pull the front drums and check.

Will, I checked the rear brake levers. They, as well as the photos in Andrews Vol I, have the clevis angled out toward the backing plate (see p 1-43). Maybe I am misinterpreting your comment?

[jb-ob]

Dave, Two easy questions...

- At rest, the brake cross shaft is perfectly vertical ?

- What kind of material are you using for brake linings ?

[Pilotdave]

Originally Posted by jb-ob

Dave, Two easy questions...

- At rest, the brake cross shaft is perfectly vertical ? Yes

- What kind of material are you using for brake linings ?

Woven

[jb-ob]

Dave,

Since it appears to be the front brakes causing the problem, yet you believe they work perfectly with out the brake rods attached.

Please share with us the technique you used to adjust the brake rods, especially the fronts.

[Will N]

Originally Posted by Pilotdave

nkaminar, I believe the problem is in the front. I'll pull the front drums and check.

Will, I checked the rear brake levers. They, as well as the photos in Andrews Vol I, have the clevis angled out toward the backing plate (see p 1-43). Maybe I am misinterpreting your comment?

Aha, they should angle away from the backing plate. Think about it, the brake lever at the back wheel is further out from the center line of the car than the lever on the cross shaft is. The brake rod (in red in the crude sketch below) has to angle inward from the backing plate toward the cross shaft, so the clevis in the backing plate lever has to be angled to allow that.

[Pilotdave]

Interesting point, Will. I'll investigate.....I'm looking at the photo in the Andrews book which shows the clevis offset from the centerline of the arm and nearer to the backing plate than to the center of the car. This is what I meant when I said they're "angled out toward the backing plate" so perhaps we are speaking about two different things!

[BRENT in 10-uh-C]

Originally Posted by Pilotdave

Interesting point, Will. I'll investigate.....I'm looking at the photo in the Andrews book which shows the clevis offset from the centerline of the arm and nearer to the backing plate than to the center of the car. This is what I meant when I said they're "angled out toward the backing plate" so perhaps we are speaking about two different things!

While you have the front drum off, pay close attention to the brake wedge to see if it is binding on the stud as the brake is depressed. Especially if it has the floater with the pin inside.

[Pilotdave]

Brent - thanks for your suggestion; the wedge moves smoothly - no binding.

I also checked the cross shaft for any binding or looseness at the bushings - there's no binding - the shaft turns smoothly and freely throughout its range of motion. No play in the bushings.

This afternoon I found that I cannot lock up the drum by turning the adjuster in - am investigating that. Doubt this has anything to do with the hard pedal, but I want to correct it.

[jb-ob]

Dave,

Now we are getting somewhere closer to the problem. If your brake shoe adjuster on the backing plate won't lock the drum, you can't possibly adjust the brakes correctly or set the brake rods.

'Been there, done that.' I respectfully suggest maybe it's time to put down the wrenches for the next week and grab a drum stick with the family. Your brake issues will be there next week, but with a rested mind, they may become more apparent. I hope we can help more then, Best.

[Pilotdave]

jb-ob....I agree with you about adjusting the brakes, but how would a worn adjusting wedge affect setting the brake rods? I plan to pull the wedge out for an inspection this morning....if it looks ok, another possibility is that the adjusting shafts are worn or not the same length - will check that as well. Then I'll order some parts and get ready to enjoy pie and turkey!

[jb-ob]

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Dave,

With many ways to adjust Model A brakes, my preference is to be able to lock all four drums with the adjuster screwed in completely. THEN set the brake rods.

More after you enjoy the Holiday.

[Will N]

Originally Posted by Pilotdave

Interesting point, Will. I'll investigate.....I'm looking at the photo in the Andrews book which shows the clevis offset from the centerline of the arm and nearer to the backing plate than to the center of the car. This is what I meant when I said they're "angled out toward the backing plate" so perhaps we are speaking about two different things!

Yes, we're talking about different things. The clevis is offset toward the center, but it is also rotated slightly so that it isn't at a right angle. If you were to stick a pencil through the clevis holes, it would point slightly toward the rear of the car rather than squarely at the center line.


As for the front adjusting wedge issue, I think it's likely one of two things: the thread on the adjuster is gunked up or damaged, and it's binding in the backing plate before it screws all the way in. Or, the adjusting shafts on the shoes are binding in their sockets.

[nkaminar]

I agree with JB OB. "Now we are getting somewhere." If you turn out the adjusters all the way then the shoes will not contact the drums and the wedge will bottom out causing the "hard brake pedal." If the adjusters cannot be turned in to the point where you can lock up the drums then you may have the same situation where the wedge is bottoming out.

Make sure the levers are 15 degrees forward of vertical on the front brakes when the rods are connected and the brakes are adjusted. In my car I back off the adjuster one click from locked and then check for equal temperature of the drums after a test drive. But there are many ways to adjust the brakes on a Model A.

Is it time for new shoes for the old lady? Of is there something else wrong?

[Pilotdave]

Yesterday I replaced the adjuster wedges and adjuster shafts on both front brakes. The adjuster wedges were both badly worn. I can adjust the brakes from free-wheeling to significant friction - but not locked up. THAT makes me wonder if the drums were turned too much when they were trued up. I inspected them when I had them off the car - no noticeable wear.

I've adjusted the brakes as I have been taught....the hard pedal condition is gone. This morning I drove the car. It stops well but doesn't lock up. Pedal feels normal - hardness gone. I suspect that the drums may be past their prime even though only trued up once in Feb 2017. That and the touch of a master at adjusting brakes might do the trick.

I will update this post as I learn more.

Thank you to all of you who have posted questions, suggestions and ideas. I really appreciate the community of FordBarn! Have a wonderful Thanksgiving.

[nkaminar]

Dave,

Thanks so much for following up and reporting your results. I am glad you got it fixed. So may times the resolution of problems is never known.

Neil

[Pilotdave]

You're welcome, Neil. I believe that explaining outcomes and fixes is an important part of a forum like this one.

That said, I have been strongly advised that the inability to lock up the drums by turning the adjuster wedge and not being able to lock up the wheels with hard braking indicates that something is still quite wrong. I'm going to continue to dig at this and will report any new discoveries.

Dave

[Purdy Swoft]

I would adjust the slack out of the brake rods after adjusting the adjustment wedges .

[RonC]

Sounds like it’s time for new forged steel drums

[CarlG]

Originally Posted by McMimmcs

The purpose of the forum In my opinion is to help everyone rather than one person. Please post answer rather than private message.

You can't disagree with PMs

[McMimmcs]

Originally Posted by CarlG

You can't disagree with PMs

I guess we have to agree to disagree then. In my opinion It defeats the purpose of a forum. Purpose of a forum is to inform everyone unless it’s confidential or private.

[Ruth]

Originally Posted by RonC

Sounds like it’s time for new forged steel drums

Where would you find these?? Most (all?) new ones are cast iron.

[RonC]

Originally Posted by Ruth

Where would you find these?? Most (all?) new ones are cast iron.

Brattons sells them

[Pilotdave]

Hope everyone had a good Thanksgiving!

My investigation continues. I replaced one shoe on the RF brake with one I happened to have in stock. This a new shoe with an untouched woven lining with wire running through it and is the standard thickness. The shoe/lining fits the shape of the drum nicely.

With just the one new lining I can lock up the drum by tightening the adjuster wedge. I'm going to try changing the other linings to see if that cures the "non-locking" problem. Will post new information as it emerges.

[Bob C]

Originally Posted by RonC

Brattons sells them

The drums Bratton's sells are nodular iron.
Definition of nodular iron
: cast iron in which the graphite is present as tiny nodules of characteristic structure.

[jb-ob]

Dave,

Re Post 38. Installing one new brake shoe, the drum is not 'locked' but rather it is jammed. If you continued to replace one new shoe on each corner and test drove, I suspect strongly your stopping would be MUCH worse.

Starting with post #1, you stated you had cast iron drums cut & shoes arched to match. I'm going to guess this work was done correctly by a professional machinist.....someone who would have advised you if your cast iron brake drums where unsafely over size.
You should not be changing this drum / brake shoe relationship, it's not the problem.

Where the brake shoe roller tracks either replaced or rebuilt to factory 'specs' ?? You didn't say.

If the roller tracks are correct, the shoes assembled correctly & installed on the backing plates correctly, the brake adjusting wedge will expand the shoes until the shoes lock the drum, hard. If not, something inside is wrong.

After all four corners are locked hard, any free play with the brakes on the backing plates has been removed. NOW go ahead and set the brake rods.

Finish by backing out the adjusters until the wheels spin evenly. Road test making only minor adjustments at the adjuster.
If you need to re-open a brake drum to correct a problem, the brake rod should be reset.

The Model A brake system is very simple but it requires all moving parts to be correct.

Keep checking.

[Pilotdave]

jb-ob, thanks for your input! A couple of things:

1. After installing the new shoe I kept checking the drum as I tightened the adjusting wedge and could feel it progress through stages from free wheeling to locked. I checked each time I tightened it to be sure that the adjusting wedge wasn't hung up on one of its ridges.

2. The old linings have a glazed appearance and feel slick in comparison to the new lining.

3. The internal parts of the brake unit appear to be in proper condition. The tracks are in good shape, the operating pin, wedge, rollers and roller pins are new and in good shape, and the brake unit operates freely and smoothly when I operate the brake lever which is set at slightly more than 15 degrees with free play removed.

4. My plan is to replace all 4 - not just 1 - of the front brake linings. I'll then check the rear brakes, then reset all the brakes.

I agree with you that these brakes are a simple system! I'll report back....

Dave

[1931 flamingo]

Is it possible that the whole problem has been glazed linings??


Glad to see you're still "playing" with the A's. Is the problem on the 400??
Paul in CT

[Pilotdave]

Hi Paul. Nice to hear from you!

I THINK it's possible that one of the problems is caused by the glazed linings. I don't see how the original hard brake pedal would be related to that, but then I don't follow why changing the adjusting wedges would have caused that to go away! I suspect that poor braking power is related to the glazed linings, but time will tell.

Yes, this issue is happening with the A400......though once I get it fixed I need to turn my attention to our Roadster!

[jerrytocci]

I had two stuck front wedges .

[ericr]

exactly what causes glazed linings?

[jb-ob]

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Really Dave, this isn't personal that I keep re-directing your thoughts .....

Glazed brake pads & linings are the end result of brakes working correctly. While it might be possible to heat linings so much they might be fried, ain't happening on your common Model A Ford.
The glazing on the old brake shoes could be sanded off with 100 grit paper.... good only until you hit the brakes again.

You are going to have those 'new' shoes arched to the drums ??

The reason for arching is to have as much brake shoe contact with the drum. Yes, you could toss in new shoes but until they take a seat to the drum you'll have less than perfect stopping. Examine the original shoes to see the amount of contact (glazed surface) around the surface of the shoe.

[Pilotdave]

jb-ob, thanks for your input.

So you are saying that I could restore the surface of the existing linings by doing a little sanding.....I will try it and see if I can now lock the drum with the adjusting wedge. Who knows??? I know that the new lining appears to be thicker than the old one...perhaps the issue is not the glazed appearance so much as the thickness of the lining.

I have checked both rear brakes and can lock the drums with the adjusting wedges. So now it appears that the front brakes are the culprits.

ericr, I'm unsure what might cause the glazing on the linings. I suspect that heat might do it, but if so, I don't know how much heat would be needed nor what would generate that amount of heat.

[RonC]

Originally Posted by Bob C

The drums Bratton's sells are nodular iron.
Definition of nodular iron
: cast iron in which the graphite is present as tiny nodules of characteristic structure.

Yes they are ductile iron

[CWPASADENA]

[QUOTE=Pilotdave;

ericr, I'm unsure what might cause the glazing on the linings. I suspect that heat might do it, but if so, I don't know how much heat would be needed nor what would generate that amount of heat.[/QUOTE]

There is a lot of lining out there that is a lot harder than the original, especially most of the lining material that comes from China. It will glaze especially if it was not arced correctly to the drums when it was first installed. Hard lining requires a lot more pedal effort to get the car to stop than the original soft woven lining that Henry used. I have woven lining on all my Model A's and all of them really stop good.

My opinion,

Chris W.