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mechanical brakes and the long haul

Discussion in 'The Hokey Ass Message Board' started by SUHRsc, Jan 12, 2007.

  1. SUHRsc
    Joined: Sep 27, 2005
    Posts: 5,077

    SUHRsc
    Member

    thanks for the input everyone
    i didnt mean to start a debate over whats right and wrong to run on a car
    i just was hoping to get some good ideas from people with experience....and i have
    my idea of a "hot rod"
    (even though this is before they were called that)
    is as some have said...an "improved" car
    my plans for a car....and the reason for this post
    i am going to start on a project that revolves around a "hot rodded" stock car circa 1936
    I'll take the car back to original on most aspects and only make changes that i see necissary or possible for the time
    probably only using technique possibly during the time also
    no MIG welding for instance
    hop-up the motor, reverse the spring eyes, remove the fenders, cut the windsheild down, add a hand pressure pump, maybe some extra guages.....all in the thinking of someone who would have bought a stock roadster and planned to run the dry lakes
    the fenders and whatnot would be able to be bolted back on
    i plan to make the car be able to pass for an antique license plate here in PA. but yet be improved enough to go and stop with modern traffic
    if i can make this project happen it will in my eyes be the "perfect car"
    and i am not going to skimp in the form of modernization
    it will 100% be a time machine to what could have been just like riding in a restored car which is 100% as it was also
    thanks everyone for the help
    Zach
     
  2. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,410

    Flat Ernie
    Tech Editor

    You are right. However, increased pressure does help when the drums begin to heat up & fade starts to set in. With a mechanical setup, you may no longer be able to exert enough pressure due to fade, yet at the same temp, a hydraulic system might. There will reach a temp where even the hydraulics can no longer exert enough pressure & brake fade reduces the ability to stop almost completely.

    Granted, probably not a factor most of the time, but with my luck, it would happen when I needed it most!

    You're doubly right about rebuilding the brakes being more than just new shoes! Every part in mechanical system needs to be a good shape for it to perform well, but when properly maintained/rebuilt & adjusted, they're fine for a light car.

    FWIW, I'm going to build a banger-powered modified that will have mechanical brakes...
     
  3. I have the Early V-8 Garage conversion on my 36. It is a complete bolt on system that I could remove and no one could tell the difference, but why? I like the peace of mind the hydraulics give me.
     
  4. I think that the reason that they used mechanical brakes is because they didn't have hydraulics. But if you want a resto rod.....
     
  5. Not so Hiboy. The reason Ford stuck to mechs while all around him ran hydraulics was because Henry was a stubborn old cuss. He only changed because public pressure eventually forced him to.
     
  6. BRENT in 10-uh-C
    Joined: Apr 14, 2004
    Posts: 502

    BRENT in 10-uh-C
    Member

    Whoa, whoa,....whoa!! You see, THAT is the fallacy in all of this!! It clearly stated in the service bulletins that under no circumstances were the original drums to be machined, --they were to be replaced. A Model A drum MUST be no larger than 11.005" however many over the years have "turned" the drums and weakened them. When they are weak, they will heat and expand. When they are within specs, they won't. If someone complains about fading brakes, very good chance either the drums are excessively worn or the shoes are not correctly adjusted. Usually it is the first problem.

    There is a item called a brake band that allows a mechanic to install around a used brake drum that cures this problem. There is also brand new cast iron drums being mnufactured from two sources that cure this problem too. Either item, --or N.O.S. drums will eliminate any brake pedal fade.

    A good way to tell if there are problems with brakes is to push the pedal down half-way. If the pedal is hard then things are close. If you push the pedal another two inches and you do not feel a "spongy feeling" pedal, then you know drums and rods are in good shape. Now remember that hydraulics that are "spongy" during the same test will provide marginal braking too ...but that's a different topic for another day.

    "What do you mean I can't use copper tubing and rubber fuel hose for brake lines?" [​IMG]

     
  7. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,410

    Flat Ernie
    Tech Editor

    Brake fade affects all brake drums regardless of thickness, it is a function of heat. You are 100% correct that turned drums will heat up & fade quicker.

    We're talking apples & oranges though. The question we're debating was which system will provide more pressure. You correctly stated that once you stop the drum from rotating, you've achieved all the pressure you need. When talking about brake fade, it's another matter as pressure required will exceed pressure available sooner on a mechanical system than on a hydraulic one.

    One other thing to consider is folks are driving these old cars much faster than they were originally designed to. Stopping cars requires heat. Stopping from a faster speed requires more heat. More heat means fade sets in sooner.
     
  8. BRENT in 10-uh-C
    Joined: Apr 14, 2004
    Posts: 502

    BRENT in 10-uh-C
    Member


    With all due respect towards you when reading your last sentance, 'Is this your opinion --or proven fact?' If it is not your opinion, can you provide written data where you learned this?

    To a certain extent, I see where you are coming from however there are some circumstances that make the original Ford hydraulic brakes a tad substandard too when making this comparison. While I agree that a pump or two more on the hydraulic brake system pedal may gain you some added shoe-to-drum pressure, there is a point of "no-return" where the master is not capable of exerting any more pressure. But again, comparing back to the "era-Apple" :)D I like that term!!:D ) technology of pre-1940, those braking systems were not as good as the brakes of the 50's or later.

    Therefore for this test, if I allow you to be able to modify the original hydraulic system (i.e: better master cyl, better pedal ratio, etc.) where you can apply more shoe pressure to the drum, ....then you should allow me to modify the original mechanical braking system where I can also apply more shoe pressure over stock. I truly believe I will be able to keep pace to the point where we are equal. I trust you see my point.


    Well, now this gets interesting again because the Model A was designed, --and advertised to be able to maintain 60 mph all day long!! This advertisement was a direct quote written to the public from ole' Hank himself. There were many dealers and potential customers alike that tried to prove him wrong. Guess what, ....those cars would do it all day long back then. They'll do it all day long today.

    Now I know many here may try to argue this point but this is printed in several advertising campaigns, --and while many would say that it is either impossible or unsafe to drive 60mph in a Model A, I go back and re-emphasize that any worn or used-up vehicle would/could be unsafe. If readers would come drive a very low-mileage or properly restored Model A, then they would see they are very capable of the 60 mph. So, exactly what speed are we traveling today that would be considered "much faster"?


     
  9. abonecoupe31
    Joined: Aug 11, 2005
    Posts: 696

    abonecoupe31
    Member
    from Michigan

    I ran my Early 30 coupe 100% stock (except for a 6V GMC generator...that's another story...) with mechanicals. I relined the shoes and welded up the tracks and replaced all the bad parts. Welded up the links and cleviisis and replaced the pivot pins. I did a lot of playing around to get them adjusted right. Today there is a lot better information out there. And new cast iron brake drums by Plasimeter Corporation. I feel that the old steel drums are a big problem as to why they're not the best in the world. You'll spend a lot of money to get a set of mechanical brakes working right.

    They do work, but a lot of times it's a Hail Mary stop...with the emergency pulled all the way back....as other HAMBers have related....

    The first time I was able to get a set of juice brakes and mount them to the coupe was after a year of driving it 100% stock. I bought the entire chassis of an A Fordor that had the conversion, the brakes on it were from the junkyard and pretty much shot.

    The adjustments were a lot better, and I used a 64 Ford Falcon master off my first car. Last Labor Day I added a 1971 Maverick dual compartmented master for drum/drum brakes...

    Stopping power isn't much better than the mechanicals, as they're not and inertia style braking system...as in the mechanicals, the lower shoes are held to a fixed pivot point. That is where the F-100 brakes shine....

    Ed Iskenderian, by the way, used Chrysler brakes on his famous T...this was prior to the 39 Ford brakes being used. I don't know what it took to adapt them....

    Ford traded their soybean enamel paint formula for the Wagner-Lockheed brakes in 1939...

    The rest is history.

    Myself, I'll use Modern brakes, Disc/drum on my car and save the antique brakes for others that want to use them.

    Traffic is so much faster moving today than it was in the 70's...I added turn signals and cowl lights on my 28 Woodie because none of these idiots seem to know what a hand signal is anymore....

    Nothing like a white knuckle ride when you're in the middle of a turn and some idiot still insists on passing you in the oppostite side lane you're making your turn in......
     
  10. abonecoupe31
    Joined: Aug 11, 2005
    Posts: 696

    abonecoupe31
    Member
    from Michigan

    Brent is right, a stock A was designed to do 60, I found mine ran out great at 55 or so, I even got stopped once for speeding (71 when it was 55 mph back in 77)..but I was let go because the officer told me, "these cars were designed to only go 45 or so...my grand dad had one of these"....he then had me open the hood to show a stock 4 banger, and said he had to get his detector back to the shop for repairs....he said if I had a V8 he was going to write me up.....He "just knew" his radar detector was off that day...

    Evil Grin....:)
     
  11. I was talking about hot rodders of the day. Henery didn't like to change anything.:)
     
  12. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,683

    Bruce Lancaster
    Member Emeritus

    Issues to think about:
    Brent mentioned the tracks--those on an A are critical. The various banger books mentioned on here earlier give directions for rebuilding them, a weld&grind operation. Floaters are partly popular as a way of very partially compensating for the fundamental problem of shoes in the wrong place caused by bad tracks...I say don't fool with floaters UNTIL you have stockers working well. Otherwise, you don't know if your alleged improvement is really that or just a bandaid over fundamental bad geometry probs. Brake handbooks from back in the thirties covered the track work. Ford would have just sold you a new backing plate ($1.50!), but is likely out of stock now...
    Arcing: some also work on curvature of the shoes themselves, using bodywork tech to change arc of metal.
    KRW adjusting gauge or likelier an old drum cut into a replica will help you see what shoes are actually doing.
    Equalization--big hydraulic advantage! Basic equalization requires painstaking adjustment, and the next prob is going to be twist of the crossshaft under hard braking. Ford kept making the cross shorter and shorter during the thirties...
    Lowering...at the axle, simple bracketry needed. Frame clearance for rods will eventually get to be a problem in drastic lowering. The cable brakes were partly a response to cars getting too low to run all the rods.
    '32-4 brakes are larger, iron-drummed versions of A, with simplified E-brake too. Good stuff. Don't know much about '35-6 brakes, but would investigate!
     
  13. TRuss
    Joined: Jan 7, 2007
    Posts: 549

    TRuss
    Member

    Enzo Ferrari was the same way. He absolutely refused to make the change to disc brakes. Once he started losing too much time per lap to cars with discs (especially as the wore the things out) he finally and reluctantly changed his position. The race cars ended up having disc brakes.

    I also like the idea of having a car as close correct as the period that you are trying to replicate. I plan on doing my '46 Dodge as if built in 1953-55. But it may end up with discs on the front if I'm not comfortable with the four drums. It is a big car. Hopefully the drums will work out.

    I would say if you can build a reliable and safe mechanical system that you can drive confidently then go for it. But if it just doesn't feel right to you, then maybe you should go another route. You should also keep in mind that you are building a period correct hot rod. A hot rod isn't stock, and hot rodders have always used what was available to them at that time, and what they were able to fabricate on their own. If there were hydraulic brakes available at that time, then it is unreasonable to think that hot rodders would not have taken advantage of them if they could. So if you wanted you could build a perfect period correct hot rod with juice brakes. Either way you go, I know we all look forward to seeing what you come up with.
     
  14. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,410

    Flat Ernie
    Tech Editor

    Brent, I guess we're going to agree to disagree since I'm failing to effectively communicate my point.

    I can't provide hard data for my statement that pressure required will exceed pressure available for mech sooner than hydraulic. Call it an opinion, gut feel, or common sense (or stupidity if you like). There's only so much leverage you can provide with a mechanical system before you begin to bend & twist the metal in the linkages. Hydraulic systems don't typically have this issue & generate 1000+psi repeatedly & up around 1200-1500psi during max-effort stops - with their seals typically being the limiting factor (usually rated to 3000psi). The majority of your stopping power comes from hydraulic multiplication with properly sized components. Yep, early Ford hydraulics were probably only marginally "better" than mechanicals - their superiority lies in the ease of maintenance, balanced brakes, & fewer friction points. However, the choice of MC & Wheel Cyl sizes made this only marginally better (this is opinion only).

    As for the Model-A being designed to do 60mph all day, you're right again. My assertation was that the majority of driving "back in the day" was done at slower speeds due to the condition of the roads - or lack thereof, not necessarily a car's capability. And while I don't have any first-hand experience from back in the day, it's probably safe to say original Model-A drivers didn't commute 45 minutes in stop & go, bumper-to-bumper traffic. Today's cars are capable of over 100mph (well, most of them!), yet we very, very rarely drive them near their potential due to roads (and the fear of jail). ;)

    I do not contest anything you say with regards to mechanical brakes' stopping ability. I agree with all of your assertations regarding proper maintenance & repair. This discussion ensued because you stated that once you stop the wheel from turning, extra pressure doesn't matter. I agree with that statement as-is. However, when heat is introduce at a higher rate than can be dissipated (higher speed stops, stop & go traffic, running down the mountain, etc.) and brake fade starts to set in, it requires progressively higher pressure against the shoes to compensate.

    OK, I accept your challenge. What will happen is you will reach the elastic deformation point of the metal in your cross-shafts before you can generate the same amount of pressure. Such is one of the disadvantages to mechanical brakes - you're twisting a shaft - it is a spring (think torsion bar) - to exert pressure.

    A better challenge would be to allow you to increase the size of materials used so there is little/no deformation of the steel anywhere in your linkage at the forces being used - then you'd be limited by your leg muscles! ;)

    I guess what it comes down to is I believe that a properly set up hydraulic brake system will generate higher point pressures at the shoe contact area than a properly set up mechanical system and you disagree with me. I doubt either of us have documented proof. Again, call it stupidity, common sense, gut feel, whatever... ;)
     
  15. tommy
    Joined: Mar 3, 2001
    Posts: 14,758

    tommy
    Member Emeritus

    :D:D
     
  16. buschandbusch
    Joined: Jan 11, 2006
    Posts: 1,260

    buschandbusch
    Member
    from Reno, NV

    thanks Brent- it DOES get pretty confusing with all the parts available and I have been burned on some cheap crap in the past. I get most of my stuff from SNyder's as it is, so I will shop for the parts there and also check out Brattons.
     
  17. OLDSMAN
    Joined: Jul 20, 2006
    Posts: 1,975

    OLDSMAN
    Member

    There is no way that mechanical brakes are as effective as hydraulic brakes. Do yourself and everyone else on the road a favor-change to hydraulic brakes.
     

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