The Resurrection of Foam Car - 63 T6B

[Phil Planck]

Jack
Read your post just before going to bed. That sure made for a restless nights sleep. How about a 1 or 2 sentence hint?
Watson

ps - I have resorted to creating a Word document for the few longer posts I make. Then cut & past it to the post. Each forum seems to have it's own quirks that can be very frustrating. In your case, probably because Justin wasn't minding the store

ps 2 - aha, ebrake rods on wrong side, that's one.
ps 3 - shoe ends not centered on actuators, but why? That's 2

Phil

[roy mawbey]

Phil

I looked at a very old photo of my back brake and you will see the bottom two springs seem to be clipped in a different position to yours or is it my eyes?? every thing else looks the same??



No wish to confuse you just see if you can see a difference the camera position is important to see detail.

I am as interested as you to see what Jack advised.

Roy

[Phil Planck]

Roy
Repro springs don't have hooks at right angles like originals, at least the ones from Stoddard.
Phil

[JOP]

Its been a while since I did a drum brake but isnt the circled metalrod to be switched...
To have the "BIG" end on the inside of the shoes....
Look at the photo to the right!
That is the correct way
Oups, just saw that I was looking at the jointbolt for the handbrake on the right photo... but the rod still look diffrent....

[Jack Staggs]

Phil, I'm sorry to have caused you any great consternation!
It looks like the stepped ends of your shoes may not be fully seated in the wheel cyl slots. The shoes must bottom out in the slots, with adequate clearance where the shoe gets wider near the tip of the cyl. If the shoe gets wedged in the slot, they will not be able to center themselves during use. This phenomena also holds the shoes too far apart for the hand brake cross bar to be in the correct location for proper operation of the hand brake. It also can cause difficulty in fitting drums. BTW, shoes need to move freely in ALL slots, upper and lower. Be sure that your cables are fully backed off for maximum slack where they enter the chassis at the rear, as well as in the front where it attaches to the pull mechanism. Cone nuts at the rear need to be fully tightened to the chassis threads to achieve slack, the reverse of what seems natural. The brake cross bar should have very little fore and aft movement when tugged either direction when all is set up well. This may be easier to check with the upper spring detached from one end. Free play there can change when shoes are in proper adjustment after drums are installed, so you will need to re-check that as you progress. On the other hand, if there is zero free play, the cyl pistons could be slightly extended. This is not OK. They need to be fully retracted to their stops prior to brake application. Bang the shoes for and aft with a soft hammer to assure full seating. Watch for slight movement. These are non servo systems, not Bendix, so this is important for even shoe wear.
Did you have your shoes arched? Even if you did, I would check them by laying them in the drum they will be fitted to. 100% contact is ideal, but not realistic. If they only touch at the ends, you can bend the metal part of the shoes by standing them on end, like a crescent moon, and whack the tip with a soft hammer to achieve a better fit. Conversely, if they only touch in the center, lay the shoe down, like the St Louis Arch, and put a piece of wood on the friction material and whack. You can also perform these operations in a press if you like. Err towards slight gaps at the ends of the shoes, not the center. This will allow the shoes to flex to a more full contact during hard braking. Remember, better is the enemy of good, so tread lightly here. After you have all this sorted out, install the drum and tighten the nut a bit to squish everything together. Adjust one brake shoe by fully tightening the spur as much as you can. This will help shift them in the slots to where they need to be. Now back off 5 or six clicks on the spur. Rotate the drum. If substantial binding is felt in one area, mark the drum and axle orientation, and try a different location to see if a better pairing can be found, adjusting again if needed. If so, mark the axle and drum so that repetition can be possible. I lightly mark with a cold chisel.
Proper bedding of the shoes can take many, many miles and brake applications. For this reason I prefer to fit new shoes on one end of the car at a time, with several hundred miles between. To speed up the process, I sometimes sand blast the iron liners to give a rough surface. By the time the liners are smooth, the shoes have a pretty good arch. A bit grippy at first though, and dusty.
I know this is a lot of info, so take your time and don't skip through. We often have the shoes, drums, etc. off multiple times before any test drive. After all, this is a very critical system.
Hand brake adjustment next time. This one took over 2 hours.

[Phil Planck]

Wow, none of this in the factory manual or my "brake handbook"! Thanks a ton Jack. Sorry you had to do this twice.

The shoes were arced by Vic Skirmants. I gave him all of the drums, and shoes were labeled by drum with the drum ID marked on drum and shoes. As I stated earlier, the linings are 1mm thicker than stock new, so I had to file the ends of the shoes to get the drums on. I also used a Dremel to move the thinner portion back the same amount as I filed the ends - at least that was my intent. The bottom thin section has plenty of clearance, the tops are close, maybe too close. I will recheck that clearance, as I will probably need to remove the shoes anyway to correct the ebrake bars. They do seem to move freely up and down, but that may not tell the whole story.

Again, thanks a ton, and hopefully this will be useful to a few others.

I have been thinking about all of the great input from you and Bruce, and how to preserve that and try to get it in one spot. If each of us could cut and paste all of those inputs in our threads, maybe we could start a new topic - "Jack & Bruce's Secrets" and put them all there.

Phil

Phil

[bbspdstr]

Jack teaches me, too. Thanks, Jack.

Let me thank you, Phil, for the recognition of what I merely call 'fun.' I wish I had more time to participate.

Here is a thought about 'arcing.' I have whole sets of drums and shoes redone by J&G. They come back matched. The relined drums are 11" and the shoes are arc'd to that, but each carefully measured enough to be individual. This is "all good" if the money is spent to be like 'new.'

The one time I thought there was a 'screw-up' it turned out to be a bad cylinder, so now, even if the brakes were working OK before the major rebuild of the drum and shoes, the cylinders get rebuilt, usually honed.

One trick for the "new shoe sizing" is to use the sticky roll sandpaper we in the body shop biz use all the time and place that in/on the clean lining of a drum and just sand the shoe to fit. Doesn't take long and about all we can do for a finishing fit after a gross amount is taken off with a big belt sander (if necessary)...now that the old arcing machines are hard to find. Fortunately, I have a business neighbor with an old drum cutting machine. He can take a skim cut on a 356 drum that will make 'em round again....for a while, until another bi-metal corrosion 'hot spot' reappears.

As Jack sez about how crucial the brakes are, "if ya can't stop, ya shouldn't go"!

[Phil Planck]

More great info - thanks Bruce.

Removed all 4 shoes and as Jack observed, 3 of the 4 did not fully seat. Thought I had checked this. Part of the problem is the new cylinder slots are tighter than the original one that I used to check fit. I filed the slots open a little more to match the originals, and also did some more filing and grinding on the ends of the upper shoes. Now they all seat and slide easily in the slots. Thanks for catching that Jack. Also got the ebrake bars on the correct side of the car.

Here is passenger side, with close up of upper shoe fit:





And here is drivers side:






Phil

[John Pierce]

Phil,

I'm glad this worked out for you. I am a bit challenged in this situation as I've never worked on drum brakes before, only calipers, but would like to learn. Could you put arrows on your pictures of the areas that are not seating well? This will come in handy when I get to this point in my build.

Cheers and Happy Holidays.


John

[Phil Planck]

John

I hope Jack will chime in here, as my sample size is only 2 356s. The ends of the shoes are narrower than the rest of the shoe - why, I don't know. This narrow portion fits in the slots in the wheel cylinder pistons or fixed adjustable bases. You can see this in the picture I "borrowed" from Stoddard:



This should not be an issue with "standard" parts, but I screwed up and ordered linings 1mm too thick. Could not get the drums over the linings, so I filed the arced ends down about 2mm. This put the thinner end closer to the edge of the slot, so the shoe would not fully seat in the slot since the thicker part was hitting the slot opening. To remedy this, I thought I had ground the thinner section back far enough, but as Jack(Sherlock) quickly noticed, the shoes did not appear to be fully seated. First I did a penlight test and could see light shining up through the slot, so that confirmed they were not seated, except for one slot. Note, this is only a problem at the top of the shoe, as the bottom end is narrower for a longer section. Also, the repro cylinders have narrower slots, and some versions of shoes will not fit in them.

Phil

[John Pierce]

Thanks for the reply. I understand that the ends of the shoes must seat fully, but for the life of me I can't see what Jack was seeing on the first image you uploaded. I've included the before and after pictures below and see little difference that the ends have moved into the pistons. What am I missing? It's like "Finding Waldo"

JP

[Phil Planck]

"Elementary" John. If you look at the top left shoe interface to the wheel cylinder you will see a slight gap in front of the rubber boot/seal. After the alteration, that gap has disappeared. I am not out of the woods yet, as the ebrake bar which I had on the wrong side, fits in slots on the shoe. Because I removed material from both ends of the shoe, the slots on both sides are now closer to the bar, so the bar slop disappears sooner. I need to understand what controls the inward movement of the wheel cylinder piston. My best "guess" right now is the arced end of the shoe compressing against the rubber boot, as there is no internal stop in the wheel cylinder(surely not that little spring behind the cups). I may have to deepen the ebrake bar slots, when I go through the process described by Jack above.

Phil

Ps. You can see that the right shoe in both pics is not touching the rubber seal. I'm assuming because of the ebrake bar.

[Jack Staggs]

Phil, the 356 wc has a two piece piston, an inner one that fits in the bore, and an outer one with the slots, that fits on top of the inner one. The outer one has a flange that contacts the housing when bottomed out. You can easily see it if you remove the boot. I would be inclined to file the slot deeper on the SHOE without the hand brake lever first. Follow the steps carefully. Don't get greedy!

John, you must apply Sherlock Holmes' methods of observation and deduction. Of COURSE I was unable to see the gaps in the picture, but I did see that the slotted wc ends were very close to the step in the shoes, too close for me. Since I have seen this problem before on unaltered parts, coupled with Phil's description of grinding the shoe ends, I deduced that a problem was highly likely to exsist. As Dr. Watson is wont to say, "It's all so simple!" Ha!
I highly recommend reading the entire Holmes collection to those that want to sharpen their skills of observation, even on such arcane disciplines as auto repair. "Zen, and the Art of Motorcycle Maintenance" is also required reading.

[Phil Planck]

Jack
Ah, you are right, except the repro cylinder piston I believe is one piece. Still has that flange.
Ref. Sherlock - besides what Jack has said, the stories are also very entertaining and historically interesting.

Phil

[Jack Staggs]

Phil, haven't seen any updates lately, and trying to figure out where you are heading on this. Are you assembling the car as a roller, fully detailed on the underside before paint? Tom and I were discussing your project while driving out to see his car and Craig's (now back in original ivory after 40 or so years in red).