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AMC brakes and spindles on a....... |
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billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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Posted: Mar/10/2018 at 9:31am |
49 Ford coupe!
I gave my front brake setup, spindles and all, to my neighbor as he wanted larger brakes on his car without the hassle of all the conversions and brackets for disk. He drives this thing everywhere, including the salt flats, etc. He milled a bit off the back mounting area, made a plate so he could raise the spindle up an inch or so, carefully calculated the angles as far as SAI, etc. and now has 10" brakes, the car lowered just a bit, and it still steers and handles exactly as it should - no scrub, easy steering and braking. (manual steering of course) Similarly, anyone lowering their car using plates would be wise to keep the OTHER angles in mind - beyond caster, camber, etc. as once you move things in or out, up or down,, you change the geometry and handling. For longest tire life, ease of steering and avoiding bump-steer and brake-steer keep the SAI and other angles in mind. The tire centerline, camber angle and SAI all intersect and depending on where they intersect, above or below the road surface, can impact steering and cause the car to either toe in or toe out. You can actually cause unnatural things to happen if you change the point of intersection between those three lines or angles. You can make it harder to steer, wear out tires, or cause braking issues. This guy did it right, figured all of those things in. He's another one doing it right. (except I need to talk to him about the order of installing the brake return springs.........rear goes on last, over the front) |
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tomj
AMC Addicted Joined: Jan/27/2010 Location: earth Status: Offline Points: 7522 |
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VERY NICE. that's lovely construction. 10" drums is a lot of brake.
yeah, i try to tell people about kingpin angle, tire scrub, etc, ... i gave up. AMC spindles make good trailers because of that nice flat square flange! just fyi, here's the source of the drum-drilling technique i swiped for my '63 American. i did only a single row of holes, in a simple spiral to sweep nearly all of the shoe surface. i used 9 x 2.5 Gremlin brakes -- they were as good as a Scarebird setup. i even ran a hard rally or two in them, down a notorious twisting canyon road and ZERO fade. they shed water almost as good as discs. http://www.chtopping.com/CustomRod4/ i'd still be running them now except the rear axle came with discs so it seemed easier to deal with discs all four corners. |
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1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com |
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19611 |
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He did a great job! Since the Ford used bolt-on spindles as well, it was prrtty easy to make an adapter/lowering plate.
About the brake shoe springs... I know they are usually installed as you mentioned, but does it really matter? That 1/16" or less (thickness of the spring) shouldn't make an operational difference. Just your OCD showing a little, or is there some reason other than it's usually done that way? I'm sort of picking on you here, but then again you've been at this a long time and I have to wonder if there isn't some "real" reason for doing it that way... or at least some logic I'm not seeing... |
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Frank Swygert
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billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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Gene does great work, and is a perfectionist. You should see some of the stuff that comes out of his shop - he takes barn finds and turns them into show cars, street rods and so on and he spares nothing on brakes, steering, etc.
OK, on the brake springs. IF the springs are different, weaker spring goes on the front - that's a given on self-energizing servo-type brakes. IF the springs are the same, well, note the shape of the anchor pin - it's TAPERED where the springs go. There's a reason for that. The first spring on gets the low part of the taper on the pin, the second spring on gets the larger part of the anchor and is stretched a bit more. That makes the second spring have more "preload" and pulled harder.
The idea is that you put the primary shoe spring on first so it's a bit more relaxed on the smaller part of the anchor and the rear shoe spring on last so it's stretched out more and is stronger. That's a subtle design thing that I bet only the brake companies themselves ever talk about, but it was talked about in college and HS where we used Bendix, Kelsey Hayes,, and other training materials. So if the anchor were not tapered, it wouldn't matter as both springs would be stretched out equally far. But they put a deliberate taper on that anchor pin - and it's not a small taper. The small part has only enough room for the one spring forcing the other spring onto the larger part of the pin. It's not a lot but when things are working correctly when you apply the brakes even though the springs are the same - the front shoe applies slightly ahead of the rear shoe....... So either they used two different springs or they use a tapered anchor and the same springs. At least that's according to the training materials I have and the college courses I went through. I have done every brake job I've ever done according to those methods and honestly, I'd bet it's in the hundreds as far as how many brakes I've done over the years. |
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19611 |
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I'm familiar with the tapered pin... what you said makes perfectly good sense! I thought there might be some subtle reasoning behind your comment about the springs...
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Frank Swygert
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billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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Frank! Remember how I mentioned books and training and such? LOL - I know you have TSMs at home or work, take a look in the 1971 or similar TSM, page 10-12 Brakes and Wheels where they show a TOP view of the return springs, figure 19.
I've never paid attention to that in these TSMs until today when I was looking for "did AMC use FLAT or LOCK washers on DISK brake spindles and where". So they are echoing the spring placement I mentioned. This image may come in handy in case anyone else is doing brakes with equal primary and secondary shoe return springs..... Clearance for the adjusting cable could be yet another reason to do it that way - at least in their picture. |
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THE MENACE
AMC Addicted Joined: Nov/04/2008 Location: So. California Status: Offline Points: 4428 |
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Never mind the springs. Did you see where the eyelet of the adjuster cable is?? |
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Former Owner of:
The Craig Breedlove "AERO AMX" Still Owner: SS/AMX #9 replica (THE BIG MENACE) 70 AMX 416, EFI, Nash 5 speed 70 Javelin 401, 727 (Wife's) 72 Gremlin Autocross Project. |
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billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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Good catch, Dennis - I wonder if he realizes that.
That's not like him at all - I've seen his other work. |
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