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05-03-2011, 10:07 AM | #41 | |
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Re: Mechanical brakes, what i did
Quote:
I will certainly agree with you that for a proper comparison, there needs to be a proper engineering study. Base line test information needs to be determined with a properly restored original brake system. Then change only the front levers and re-adjusted the brakes and repeat the tests. The "base line" test results and the "as modified" test results can then be compaired. If someone would like to undertake this, I would be glad to assist. Actually, it would be real easy to make up a set of levers with two holes in them, one for the "stock" length lever and one for the "Modified" length lever. This way, it would be very easy to switch back and forth between "stock" and "Modified". I would never suggest someone put the longer levers on their car unless the complete original brake system is in very good condition. All the modifications in the world will not overcome a worn out brake system. Again, This is just what I did and I am not suggesting anyone modify there brakes in this manner. Chris |
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05-03-2011, 10:09 AM | #42 | |
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Re: Mechanical brakes, what i did
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Chris |
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05-03-2011, 10:19 AM | #43 | |
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Re: Mechanical brakes, what i did
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Thanks for your input. I tend to write like an Engineer and you have the ability to explain things in a very clear and easily understood manner. Your comments are always valued and appreciated. Chris |
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05-03-2011, 11:41 AM | #44 |
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Re: Mechanical brakes, what i did
Here is a picture of a vacuum setup
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05-03-2011, 11:56 AM | #45 | |
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Re: Mechanical brakes, what i did
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It's been did. Vacuum-boosted mechanical brakes were around in the early to mid 1930's... some of the big Lincolns used them, among others. Maybe not "modern", but they existed. |
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05-03-2011, 02:03 PM | #46 | |
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Re: Mechanical brakes, what i did
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I pondered the idea of using a modern vacuum assist. THAT has never been done to my knowlwdge on an A. Brackets/ linkage/ leverage, etc. It would be a design challenge, as modern boosters are basically "push" operation, and mechanical brake systems are based on all "pull" rods. It would be interesting if was worked out with a new available booster and parts. That would make a leverage change like Chris did to shift the front/rear bias a toe-tappin' delight. |
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05-03-2011, 03:04 PM | #47 |
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Re: Mechanical brakes, what i did
chris,
i didnt say that YOU said that 'ford got it wrong'...reread the thread! it was said by other. impressive resume, indeed! 'homebrew' may have been a condensed description, certainly not meant to be derrogatory, which is apparenyly how you took it..and i now can see why knowing some of your history! i can appreciate your applying your expertise to improve the A mechanicals...and would be right in line to purchase any real improvement thereto! mabe said wrong, and certainly not directed towards YOU, but i read over/over the same past imput to 'leave them there stock mechanicals alone as ford made them'. then some new /differing change idea comes along.....and out the window goes the leave them alone crowd! btw chris, i do not have as great a background as you , in this field. however, i see/understand your method/application! i also have 50 years of driving cars with mechanical and hydraulic brake systems, including fords...practical application! good luck with your efforts ! i'd be interested to hear from an engineer with your background, why a model A with bendix hydraulics and modern materials, i.e.- stainless line, synthetic fluids and PROPER installation/maintenance...why you think it wouldnt last? Last edited by hardtimes; 05-03-2011 at 03:19 PM. Reason: info... |
05-03-2011, 03:25 PM | #48 |
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Re: Mechanical brakes, what i did
I pondered the idea of using a modern vacuum assist. THAT has never been done to my knowlwdge on an A. Brackets/ linkage/ leverage, etc. It would be a design challenge, as modern boosters are basically "push" operation, and mechanical brake systems are based on all "pull" rods.
It would be interesting if was worked out with a new available booster and parts. That would make a leverage change like Chris did to shift the front/rear bias a toe-tappin' delight. Whether it's a modern "co-axial" booster or a 1930's "pull-can", the effect is the same: a vacuum-assisted device, adding to the operators pedal effort to apply the brakes. Adding a vacuum servo to the main pull rod of an otherwise-stock Model A braking system would not change any leverage or alter the front-rear brake bias; it would simply reduce the amount of pedal effort required on the part of the driver. I guess it could be done; the tricky part would be setting-up the reaction valving. The 1956-'62 MoPars did have a similar vacuum pedal-assist power brake: it was a big oval can or bellows mounted above the stock MC, and an operating rod that went through the firewall, acting on a lever attached to the brake pedal arm. Have them on my '60 Windsor... they work pretty well, but it's a real Rube Goldberg-looking set-up. PITA to check the brake fluid in the MC too. By 1963, MoPar came to its senses and adopted Bendix brakes, and coaxial power-brakes,like the rest of the industry. |
05-03-2011, 04:18 PM | #49 |
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Re: Mechanical brakes, what i did
On the idea of vac assisted mech brakes, It seems that many people are having enough trouble getting the vac w/shield wiper to work with the available vacuum, how big is the vac resevoir going to have to be to get anny vac assist to work?
Paul in CT |
05-03-2011, 04:40 PM | #50 |
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Re: Mechanical brakes, what i did
30 years ago i bought longer arms used them for many years last year i redid my brakes took off the arms,i just checked them and they are 5 inches long .I was happy with them and also with orginal ones,
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05-03-2011, 04:47 PM | #51 | |
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Re: Mechanical brakes, what i did
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This is a small diameter (about 6") dual diaphragm unit. |
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05-03-2011, 04:51 PM | #52 |
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Re: Mechanical brakes, what i did
Thanks Mike!!! Love this place, so much info right at our finger tips.
Paul in CT |
05-03-2011, 06:12 PM | #53 |
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Re: Mechanical brakes, what i did
Could it be as simple "inserting" this booster into the middle of the main pedal to cross-shaft rod ? ( Conceptually, at least? )
The stock battery location would cause some issues... Someone could make it work... |
05-03-2011, 07:15 PM | #54 | |
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Re: Mechanical brakes, what i did
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I am not looking for everyone to agree with me, or anyone for that manner. I am open to a constructive discussion. If I came down on you a little hard, I appologize. I try to be very careful about labling people or ideas. Certainly no body knows everything, all of us have some area of expertise and we can all learn. As far as re-working the model A Brakes as Self energizing Hydraulics, I think someone is selling a kit to do this. There is nothing wrong with converting a Model A to Hydraulics but for this car, my personal preference was to leave the mechanicals and see if I can make them a little better. I also understand there is a kit that converts the mechanicals to self energizing. I built this chassis about 6 years ago and this kit was not available or prehaps I would have considered that approach. I also have read on The Barn where some are very satisfied with this modification while others could not get the adjustment right and went back to the original configuration. I am not familiar with this modification so I would not have an opinion. What I did is just a little different approach. This modification is simple, easy to install and adjust. Personally, I like how it works. Again, I am not suggesting anyone else does this, this is just what I did. Chris |
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05-03-2011, 07:22 PM | #55 |
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Re: Mechanical brakes, what i did
Probably need to find a booster like these.
http://www.pbr.com.au/products/heavy...erChambers.pdf Bob |
05-03-2011, 07:22 PM | #56 | |
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Re: Mechanical brakes, what i did
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Somewhere, I have an old kit that re-works the internals of the Model A front brakes. I think the idea was along the lines of making the fronts self energizing. This is an old kit that was sold back '30s or '40s. I will have to dig it out and see what it is all about. Chris |
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05-03-2011, 08:24 PM | #57 |
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Re: Mechanical brakes, what i did
You don't need brakes going up hill
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06-16-2012, 07:17 PM | #58 |
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Re: Mechanical brakes, what i did
I have this question about an after market brake boosting product I've seen mentioned on the HAMB but at that time did not need to know about.
Who makes or sells this item that attachs to the main brake rod bar under the center crossmember and provides braking assistance to mechanical rod brakes. I believe they are made especially for Model A Fords. I've done a search here but come up with nothing. It could have been they were mentioned in a thread about something else. Any help or links would be much appreciated. I am wondering if it is related to the folks in CA doing hydraulic brake conversions for Model A's. Does anybody know where to start looking??? |
06-17-2012, 06:35 AM | #59 |
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Re: Mechanical brakes, what i did
I like what you did. It is basic mechanical advantage engineering and to me seems to be a good change. I assume you all are familar with this change that is available too ?
https://www.youtube.com/watch?v=2EjRe411l3M
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06-17-2012, 04:50 PM | #60 |
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Re: Mechanical brakes, what i did
Very good thread! Lots of info to ponder.
I once fabricated a new diaphragm for the vacuum booster on a '36 Lincoln Model "K." Car weighed 5,990 lbs, 16 inch brakes, built like a ton and a half TRUCK! Stopping was only a FANTASY without the booster!! The booster was gigantic! WAY too big for a light car. Bill W.
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