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Brake adjustments...really, REALLY

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oldracer View Drop Down
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    Posted: 27 Feb. 2012 at 6:15pm

I'm not a mechanic but I reasoned that anything I could take apart I should be able to put back together, and so far, with the forums help, that reasoning has worked.  So let's talk brake adjusting.  Here's what's up:  Everything is new.  The new lines are on and I have overcome 14 different leaks.  I have done the forum search for any help I might use.  I have downloaded all that Dr. Vern has to offer. I have all available manuals.  I spent the weekend going to garage sales and swap meets for brake tools and spent the next day destroying most of them but finally making what I will need.  PROBLEM - Nothing works like everyone says it should.  Whether the anchor eccentrics or the top ones, when I turn the adjuster until the shoe starts to drag, back it off a little and hold it there - when I tighten the lock nut it locks the whole flaming drum tight!!  I tried to compensate by NOT setting the eccentric before tightening the lock nut but then I have no idea where anything is at and sometimes it still locks up the drum.  I have read Sean's post about matching (arcing) new shoes to new drums but I sure hope there are other options.  What am I missing?

T. Nick
If it's not broke, work on it till it is!

48 CJ2A #192834 "Grunt"
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Lew Ladwig View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lew Ladwig Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb. 2012 at 7:39pm
Do you have a tool to hold the eccentric in position while tightening the jam nut?
Lew Ladwig
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldracer Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb. 2012 at 9:20pm
Hi Lew, Yep I made one that will hold the eccentric but even when I hold it in the position I think is correct by the time I tighten the lock nut it evidently changes the attitude of the eccentric and locks up the drum.  It is almost like the lock washers (grade 8) are too strong and I am fighting them for the corect angle on the eccentric.  Anyway, tomorrow I am switching lock washers to see what will happen.  I was expecting this to be a little bit like a horse shoe (not a lot can go wrong with it) but I see I was mistaken.
T. Nick
If it's not broke, work on it till it is!

48 CJ2A #192834 "Grunt"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepRoger Quote  Post ReplyReply Direct Link To This Post Posted: 27 Feb. 2012 at 11:47pm
Nick ... couple of things. First, when you loosen the upper lock nuts only loosen them far enough so that you have to turn the eccentrics with a bit of force. If you loosen them too much, the eccentrics will be allowed to move sideways (changing the attitude of the eccentrics as you said) and you'll get a false read - then when you tighten the lock nuts the eccentrics will straighten up and tighten the shoes more than you intended. Second, be sure to start with the eccentrics in the correct orientation according to the service manual. Then, when you do your adjustment be sure to turn the eccentrics in the correct direction - especially the lower ones. Lastly, better than doing it by feel as you might with current-day brakes, it's best to use a feeler gauge (.005˝ at bottom of shoe and .008˝ at top of shoe. ...R
Roger in California
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'47 CJ2A 142084
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldracer Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb. 2012 at 12:02am
Roger that JeepRoger,  Good advice.  The whole operation had me frustrated so I know I was making it harder than it was supposed to be.  I'll go back to basics in the morning and follow your suggestions.  Some of the frustration came from reading the last sentence in the brake adjustment section of the manual -"This slot was eliminated in later models."  That's when I used the REALLY phrase my Granddaughter uses for the first time.
T. Nick
If it's not broke, work on it till it is!

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Post Options Post Options   Thanks (0) Thanks(0)   Quote houndsman Quote  Post ReplyReply Direct Link To This Post Posted: 29 Feb. 2012 at 9:53pm
yeah i have similar problem that has been on hold for a while[leaking brake T on front axle] have new part now to fix that part of the problem. But when i was trying to adjust mine I was not noticing any adjustment being made, not sure if I should of started on top ecentrics or bottoms. I understand which direction to turn them, but i was told to only turn them a1/16 to 1/8 turn at a time. I was turning a couple of turns at a time, I guess i didn't understand how they actually worked.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JeepRoger Quote  Post ReplyReply Direct Link To This Post Posted: 29 Feb. 2012 at 11:21pm
You have to turn them both a little each time until the shoe moves out to the drum. The upper and lower adjustments work in a similar, but different way. The upper adjustment controls the distance in and out the top of the shoe can travel by having an eccentric that comes in contact with the inner edge of the shoe. However, the bottom adjustment is a bit different: it has an eccentric that goes through the shoe and in so doing, it not only moves the shoe in and out (toward the drum) but up and down as well. So, it controls the concentric contact of the shoe to the drum to make sure as much surface of the shoe as possible contacts the drum at the same time. This is why you need to start with the eccentrics in the right place (especially the bottom one). Using a feeler gauge is critical for this type of adjustment (as opposed to just turning each adjuster until the drum is hard to turn and then backing out out a bit like you do in contemporary brakes or like the Jeep's emergency brake). Getting them just right makes a big difference in having reasonably good stock Jeep brakes, or almost adequate Jeep brakes. The other problem comes from having the drums cut too many times which makes their diameter too great for the adjusters to correct as well as making the radius of the drum not equal to the radius of the shoes (which means less shoe-to-drum contact area). R
Roger in California
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Post Options Post Options   Thanks (0) Thanks(0)   Quote oldracer Quote  Post ReplyReply Direct Link To This Post Posted: 01 Mar. 2012 at 2:44am

Hey there houndsman,  I had the same problem you did today in that a bottom eccentric I was trying to adjust would never cause the brake shoe to contact the drum even if I turned it 360 degrees.  I took another look at what JeepRoger has been telling us and went back and realized that I had the top eccentric completely loose so I pulled the locknut on the top eccentric up tight and tried the bottom one again and she made contact so I had a starting point.  You may be like me and are cursed with having the "later model" brake drums that have NO slot for the feeler gauge to go through.  In one of my many searches for help on these brakes I came across a post by a member named Larry (haven't been able to find it again so I don't know his forum name) and he says with no feeler gauge access we should adjust the bottom eccentric until it touches and then adjust the top one till it touches and that will cause the bottom one to move away from the drum so you have to go back and forth until the bottom one no longer moves and then you can back it off until it doesn't drag and you are ready to do the next one.  I managed to do one that way today and it seemed to work as you can feel the shoe being in contact more and more as you spin it.  Boy am I tired of spinning brake drums by hand.  Good Luck  

T. Nick
If it's not broke, work on it till it is!

48 CJ2A #192834 "Grunt"
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