Posted: Fri Oct 21, 2005 5:39 pm Post subject: Brake lining alignment
Do to a bad oil seal, I need to replace the oil soaked brake linings on my Jeep. According to the military manual, the shoe with the long lining goes to the front. Currently the shoes on there, on all four wheels, have the long lining facing to the rear. My Hayes service manual shows the long lining facing to the rear. Which way should the linings be arranged?
I went through this last winter when rebuilding the axles. If I remember correctly, Wes and the military manual both told me the long one goes to the front.
I thought it made sense because that side will see more pressure when braking. I am at work right now, but will be able to check my notes this afternoon.
HOWEVER, Wes I am sure will post on here and give us the definite answer as he is more knowlegable about the mechanical aspects than I am. _________________ Ryan Miller
MVPA # 22010
Felix on the G beat me to it. But I'll copy some of the responses here since they offer some good insight into manual useage.
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This is a good oportunity to point out a little something. Please, no one take offense since no offense is meant.
This is why one should buy and use the correct factory manual for the jeep. In this example the modern industry standard is to put the long shoe aft. The Haynes manual probably used the later AMC CJ5 floating brakes as an illustration. Had all folks been on the same page in the correct M38 manual the issue would not have come up.
This also reminds me of all those nay sayers condemning their poor Willys 9" brakes. How many of those folks probably had the long shoe on the back! Smile
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Wes K
45 MB, 51 M38, 60 CJ3B, 60 CJ5, 76 DJ5D, Bantam T3-C MVPA22099
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Actually Wes, I have both the Hayes manual and the correct military manuals. Thats what screwed me up - they disagree with one another.
Rick L
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Now you know, when the dime store manual disagrees with the factory manual you go with the factory manual.
The Hayne's manuals do not buy any factory proprietary information. They use reverse engineering to make their manual. They base their manual on the complete actual teardown and rebuild of a sample of the group. Then they add the specs commonly available in Chilton and Motor's manuals.
Both Chilton and Haynes brag their manuals are the ticket for owners who want to try "do it yourself" maintenance but they clearly are too general and open too many doorways to serious errors. Wink
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Wes K
45 MB, 51 M38, 60 CJ3B, 60 CJ5, 76 DJ5D, Bantam T3-C MVPA22099
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Ryan,
You've been missing awhile! Still working 2 jobs? _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
I do get on and read the messages every evening on this site and read a few on the G503 once or twice a week.
Most of the technical stuff I leave to you, because you know a lot more about the mechanical aspects than I do.
What I know on the mechanical side comes from the manuals and what you taught me!
I am still working quite a bit (extra money for the jeep or a kid! ).
I talked to Jake the other day and he has been busy at work. He works at a company that designs and sells medical information software. His company has been putting out some new programs and he is one of the guys that manages the support teams if I understand him correctly. When clinics switch over to new software, it always takes a lot of support from the manufacturer as people hit glitches when learning a new program.
He said we should have the rest of the information transfered over to the new website by Christmas.
Sorry to everyone for the delay in getting things going, but we are getting a great deal from Jake as he is being a very nice brother-in-law! _________________ Ryan Miller
MVPA # 22010
Joined: Oct 17, 2005 Posts: 17 Location: Ontario, Canada.
Posted: Sat Oct 22, 2005 6:51 pm Post subject: Brake alignment.
Wes, thanks for the correction, is the wheel cylinder in the M38 on the bottom of the backing plate? Could you please email me an explanation so as I may understand?..Thanks so much, Rick.
Since the M38/A1 brake shoes is an issue many members are not sure about I'll just put it all here in one place.
The whole jist of it is when you have a brake setup with a long and short shoe the long shoe goes on the side which when the brakes are applied with the wheel rotating forward will cause the wheel drum to actually push or jam that shoe tighter against the drum. This gives the brake system a very noticable mechanical advantage.
The M38 has a NON-floating shoe mounting. There is a fixed adjustable anchor at the bottom and a hydraulic wheel cylinder at the top. When the brake is applied the TOPS of both shoes are forced out towards the drum. When the drum is rotating forward it will engage with the the front shoe and also try to push the shoe in the same direction it is rotating. This will in effect apply the front shoe even tighter to the drum. Thus making the brake system even more efficient.
The modern floating brake system doesn't anchor the shoes to the back plate. The bottom of the shoes are connected together but not anchored. The top of the shoes each rest against a stop pin but are not anchored to it. The wheel cylinder is mounted slightly below the top pin. When it pushes out on the shoes the front quickly starts jamming itself into the drum but at the same tim pushes the bottom of the rear shoe towards the drum the the rear shoe starts jamming itself tighter against the drum thus both shoes are self energizing or acting as servo type shoes. This happens because the front shoe is effectively anchore at the bottom by being attached to the rear shoe there. The rear shoe is essentially anchores at the top pin because of the rotational effect of the drum. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Oct 17, 2005 Posts: 17 Location: Ontario, Canada.
Posted: Mon Oct 24, 2005 5:27 pm Post subject:
Wes, thank you. Once I saw the stationary bottom anchor, I see why the shoe with the longer lining goes to the front. A pic is worth a thousand words, or two.....lol, ask Rich Saylor...lol...(just kidding Rich).
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