AC brake linkage installed today

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Model T Ford Forum: Forum 2011: AC brake linkage installed today
Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace on Saturday, November 12, 2011 - 11:07 am:

Finally got to the fitting of the brake linkage I found at Hershey in Oct to mount the new Larry Sidmore repro AC small drum brakes.

Larry sells a nice brake setup, but no linkage to placate liability lawyers!

So my best find at Hershey is now attached.

The parts I found included a wrap around plate for the brake pedal, so fitted it first. My pedal already had a hole drilled for brake lamp switch wire, that's why the welding rod is there to keep that position when I fit the brake switch.



Also the setup came with a bellcrank and linkage rods, to the rear, which are looped metal but some wear in places. Plus the linkage to the torque tube including a nice bracket that fits secure to the tube. That bracket has the slide fitting for the pedal attachment rods.



Instead of the bellcrank, I elected to use a pulley and wire rope to the rear brake lever. The rod fittings were worn, one end was originally threaded for nuts to secure, but I like the cable attachment better. That was the way original AC brakes were fitted, with a cable.



So with the pulley fitted the cable pulls the brakes.



The brake pedal linkage is adjustable to get things right. It clears the Ruckstell shifter too which is a plus.




The torque tube bracket fitting had some wear in the collar that the pull rod slides in. The original fitting must have had a grease cup, as half threads were there, but broken, so I fitted a oil cup with JB Weld to hold it, and that will give the slide rod its lube from time to time. Had to rotate the collar some to present unworn surface for the slide rod.






So now the set up works, pulls the cable great.




Close up of Larry's AC small drum brake mounted.
My test fitting is with the small drum fitted over the emergency brake and into the external lined AC brake to test fit, easier than have the whole wheel in place, with the drum I can spin it and see the contact surfaces on fitting up.




Larry's adv, sorry if this is like a commercial plug :-), have to post when you find nice repro parts being offered today....its only polite to mention the vendor..



As for that cable, its coated vinyl and will be replaced with regular wire rope, as the vinyl covered isn't correct and can't be fastened as well with cable clamps.



Using pulley and cable will be fine with AC brakes. You could use solid rods like the repro Rocky Mtn brakes, but cable is ok. The pull power is less than 100 lbs with these external brakes. Here is clip from external brakes of the period, this one dates in the 20's and gives est of the pressure in lbs that occur around the drum with external linings. Describes how the linings really only grab in certain places.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Lance Sorenson on Saturday, November 12, 2011 - 11:40 am:

Thanks Dan! This is one of my winter projects and it will be much easier with your great pictures to guide me.

Do you feel the angle of the cables from the pulley will pull the levers forward OK? Can't wait for your report on how they work!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kohnke Rebabbitting on Saturday, November 12, 2011 - 01:45 pm:

Looking Good Dan, get it going, and give us your report. Herm.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill in Adelaida Calif on Saturday, November 12, 2011 - 04:21 pm:

I used a slightly different route with my linkage although I did use cables. I mounted a lever assy to my drive shaft and used an old parking brake cable guide (off a 52 Buick).#2
The angle iron is clamped to the torque tube with a muffler clamp and is notched to fit over the radius rods. I found some heim type pivots and with the help of my good friend Mickey Mouse got it installed.

Bill


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Saturday, November 12, 2011 - 05:11 pm:

Just sorta' "thinking out loud" while studying the great photos you guys posted:

I like Dan's way of attaching to the brake pedal as it does not rely on a weld. I always think that while a bolt will usually give some warning of failure (loose, additional "play", rattling, etc.) while failure of a weld us usually sudden and catastrophic).

I like the set-up that Bill uses as it eliminates the angle of the "pull" in the linkage. Nice to see a linkage that pulls straight. However, it seems like the notched angle iron attached down over the torque tube with one muffler clamp would allow somewhat of a bending moment to the angle iron as brake application applies tension to the linkage. I'm wondering if Bill's set-up would be better if the angle iron was replaced with a length of channel, notched at front AND rear edge of the channel and attached to the torque tube with TWO muffler clamps in order to better resist the bending moment (twisting) of the channel iron as tension is applied to the linkage upon application of the brakes, especially in the case of a more forceful emergency brake application.

Again, not being critical; just "think'n out loud" (which I probably shouldn't do.) Noth'n like an "armchair quarterback", right? Interesting post,...........harold


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill in Adelaida Calif on Saturday, November 12, 2011 - 05:46 pm:

Harold. I agree that is the weak point, and I have a u-bolt for one of the radius rods. The "U" that fits the torque tube sits tight against the front bushing housing and does not want to rock or move.
I didn't have access to a stamped steel bracket for the brake pedal and the weld should be much stronger than sheet metal.

I was trained by Rube Goldberg and I always seek advice from my friend Mickey Mouse :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Saturday, November 12, 2011 - 06:00 pm:

When it comes to steering, brakes and suspension, that's no place for "Rube" or "Mickey"! Sorry Bill, couldn't resist!

All kidding aside, in regard to "stamped steel bracket" vs. welding, I suppose in basically comes down to the gage and quality of the steel used for the stamped sheet metal bracket and/or, the skill of the welder, huh? Ya' just can't be too careful with brake parts, right? Chain only strongest as weakest link,..... blah, blah, blah........


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace on Saturday, November 12, 2011 - 06:03 pm:

My set up is really similar to the original mfg design and from what I have seen other owners do to hook up pulley cable systems for rear external brakes.

Here are photos of original parts ( saved from eBay offerings) and owner installs.....







Really would be many ways to do it, the forces are not really too much in these external brake systems, its just a Model T, not a heavy truck or big Lincoln!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Saturday, November 12, 2011 - 06:53 pm:

Dan

Is there any problem with pulling the brake actuator rod at an angle? Is the AC brake unit designed for this?

BTW thanks for posting - a great thread. I would like to hear more about your experiences and satisfaction with this setup.

Cheers
schuh


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Saturday, November 12, 2011 - 07:04 pm:

I have been recommending the AC setup since I put a set on my first speedster about 40 years ago. I am very glad that Larry Sidmore is continuing to provide them (despite Califunny's stupid courts). Although they are a smaller braking surface than the Rocky Mountains, they are more than adequate for most T situations (as long as we're only talking two wheel brakes). You may have to re-line the brakes more often, but that is easy. They solve many installation problems such as shock absorbers and look better on early cars.
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Sutton on Saturday, November 12, 2011 - 07:56 pm:

This is great. Thanks for sharing.

I think I'll pick up 2 sets for my trucks as soon as I can afford it. The plan was to use my old Pikes Peak (big drum) brakes on my restored truck, but it has clinchers and the big drums would have looked out of place. Now that I have the '27, I'll put the originals on it and use these slick AC brakes for the older vehicles.

Craig


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace on Saturday, November 12, 2011 - 09:24 pm:

Bud

Is there any problem with pulling the brake actuator rod at an angle? Is the AC brake unit designed for this?

By design probably not any issue. The angle to the brake pedal is needed, as the pulley setup needs to be centered over the drive shaft, that is the center line to obtain the even pull to each outboard external brake. Other systems use bellcrank or longer equalizer bar or something for the same result.

Some use a cable to the pedal, and fit the pulley vertical or on a swivel to let the cable reach the pedal attachment. That would seem to be a good way too.



The original AC pull rod to the brake pedal is angled, one reason is that you must have the rod or other mechanism under the floorboards, so you have to angle it down some, or come up with a rod actuator setup that can clear all the body parts, floorboards, and other stuff on the chassis.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill in Adelaida Calif on Sunday, November 13, 2011 - 01:51 am:

I just noticed something interesting in the pictures of the brake actuators. Dan Treace's first set of pictures shows a direct acting brake mechanism. My belcrank shows a short brakepedal travel creating a greater travel on the cable actuating the A/C brakes. The last picture posted by Dan shows just the opposite, a long travel by the brake pedal causing a short travel on the cable brakes.
My brake actuating system is still a work in progress, but I do know that I CAN stop the car on a steep hill going forward with this setup. Now to refine the adjustment.

Bill


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Sunday, November 13, 2011 - 03:01 am:

Dan, I am going to use a setup very similar to yours on my '25 coupe. What did you use for the bracket and pulley at the front for the cable? Many thanks, Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Sunday, November 13, 2011 - 09:58 am:

Would I be correct in assuming that the AC system suffers from the same problems as RM brakes? i.e. Poor wet brakeing and no brakeing in reverse.

Regardless, its still a far better brakeing system than stock.

schuh


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve in Tennessee on Sunday, November 13, 2011 - 11:08 am:

I installed a set of Larry's AC Brakes a few months ago and posted some of the results. I don't think I have posted pictures of my solution for linkage. I was not so lucky as to find an original linkage to use so I went to the local TSC and came up with the following.

First Step - weld a tab on an extra brake pedal I had. Got it right the 2nd attempt. First time it was too high and hit the floor board. You can see my attempt to give it more room with a rat tail file on the bottom of the floor board. I used a threaded clevis i bought from a boat supply place online. Then a 1/4 inch rod which I threaded and bent pretty much like the originals in the pictures shownin the previous posts.

Clevis Connected to Tab Welded on Brake Pedal


Then the rod comes down to the drive shaft. You need something to hold it down when activated. I found that a gate hinge worked pretty well.

Gate hinge Serving As Rod Holder

From there I connected the rod to a turnbuckle, which in turn connects to a flat pulley. Steel wire rope goes from each brake to the pulley which serves as an equalizer. (The extra cable you see going through the pulley is excess cable I have yet to cut off.) I put two cable clamps on each end. I found all of this except the clevis at TSC.


Turnbuckle and Pulley

Talking to a few folks on the forum I've been advised correctly that you need these set up banjo string tight. There is very little travel going on here when you push the brake pedal so you have to make the most of it. I found that in order to do that you need some hold back springs to keep the brakes open when not in use. Once again I went to TSC and found some springs which I was able to loop on the rear spring hangers and back to the cable on each actuator arm. This seems to work fine. Jack Daron has suggested replacing the original springs on the brakes with old Model T valve springs (two per brake) and he was kind enough to send me some but I've not yet tried that. I have seen some pictures in original AC Brake marketing that show springs use to hold them open...running back to the spring perches.

Mine work pretty well. I think if I really knew what I was doing I could get more from them but I keep tinkering. I of course still have the tranny brake in operation but have tried to set it so that it activates after the AC brakes do.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace on Sunday, November 13, 2011 - 09:00 pm:

Steve

Your install looks nice, good pics, and parts description.

Also, appreciate the info on the 'assist' spring for the AC brake lever, good idea.

Saw this install with a type of small drum brake, and noted the 'assist' spring going to the brake lever arm...



So, I'm off to the hardware store tomorrow to get some springs to do this same to my AC brakes to have good tension on the pull cable.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Sunday, November 13, 2011 - 09:19 pm:

The cable clamps in that picture are installed incorrectly, well one is. The one closest to the rearend should be installed the same way as the other one, they should never be installed opposite of each other. Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Sunday, November 13, 2011 - 09:30 pm:

Dave's right - never saddle a dead horse.

schuh


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