# Warning - Replacing Brake Assemblies!



## TimU

Just a warning to all...

Background - yesterday I replaced all of my brake assemblies with new ones purchased from etrailer. Also purchased the nuts and lock washers to use.

When putting them on, I found that with the lock washer - you couldn't get a "full nut" on the stud. Was shy about 3-4 or so threads. Without the lock washer, Only about 2 threads show when tightened down.

Well - the old ones didn't have lock washers or nuts, so I just put the new nuts on, and called this morning to find out the torque spec. Well - they don't know the torque spec, but also said you MUST install lock washers or lock nuts. They suggested nylock. "You can buy them at any hardware store". Unfortunately, you can't. The nuts are 7/16" x 20TPI. You can find 7/16" x 14TPI - but NO 20TPI nuts. I've been to 5 of the "main" hardware/bigbox stores - no one has that size in ANY kind of lock nut. Two different auto stores - ain't got 'em either.

I've called back etrailer to complain, and they say they've never heard of this before. I'm betting a lot of people just don't use the lock washers when they find they didn't work, or put them on, not realizing the "full nut" theorem, or used locktite red or blue (neither of which I'd use in this application). I'm near an "aircraft" town, so I can probably find them from someone that sells aircraft parts - for something on the order of $6-8 EACH, since they are "aircraft spec'ed". Meanwhile, I'm screwed, and not able to find them. etrailer says they'll look, but I have no idea if they'll find them. Oh, yeah, I did find some grade 2 nylock nuts at Fastenal, I'm not putting grade 2 on there either. I'd suspect a grade 5 at least.

Anyway, several hours wasted as I now need to take off/put on again, in my gravel drive (so it isn't pleasant or necessarily easy to do). I'm extremely pissed at etrailer right now - they didn't even send a note saying "MUST USE LOCK NUTS EVEN IF THESE DON'T FIT", or torque specs (I guess with lock washers you don't necessarily need torque specs - but something should have been said). I was hoping to get it out next weekend, but with two jobs, that ain't gonna happen, and the last bit of easy work I had for next Friday night isn't going to matter since I've got a few hours of work re-doing all the work I've done before.

And no, I didn't call yesterday since I was up to my elbows in grease and brake dust/rust, I was alone, and the old assemblies just had normal (not locking) nuts. I could take a gamble - but don't really want to.


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## Leedek

Dexter Axle Maintenance Manual here: Dexter Axles Page 78 list brake mounting torque specs. Have you considered replacing the stud bolts to 1/4" longer? If it a possibility? Good luck. Just for my information, which brake assembly did you buy?


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## TimU

Leedek said:


> Dexter Axle Maintenance Manual here: Dexter Axles Page 78 list brake mounting torque specs. Have you considered replacing the stud bolts to 1/4" longer? If it a possibility? Good luck. Just for my information, which brake assembly did you buy?


These are completely NEW assemblies, so no, I'm not too interested in pressing the studs out and getting others.


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## TimU

Update:

etrailers emailed late today, and they are sending new lock nuts. Appear to be from Redline Trailer. So - I'll at least get what I need, since I can't find anything locally, it appears. Or, at least I can't locate them without LOTS of phone calls, etc.

Just a word to the wise if getting new brake assemblies from etrailer (these include a new backing plate, studs, brakes, electro magnet, etc.) - ask and make SURE if you are going to purchase the lock washers and nuts from them - that they will FIT. I'd honestly suggest just getting a lock nut. So, make sure, or procure your own. I do not know if the plate on the axel is slightly thicker than they expect, but I can say that the original nuts were less thick (only about 3/4, maybe 2/3 of the thickness of the new nuts).

So - I'll get them, just not happy I have to crawl around on the ground again on uneven ground to take stuff off to put it back on. I hope I don't have to - but I'm sure I will.


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## TimU

Oh - and why is it this stuff is so hard to find? It should be easy to find, etc. I can't even find torque specs for the lug nuts in the trailer manual, anywhere.

Reminds me of AMC - let's just get a loose assemblage of Ford, Chrysler, GM (and who knows who else), and slap a car body around all that. Have fun finding parts for those.


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## Leedek

Dexter Axle Maintenance Manual here: Dexter Axles Page 78 list brake mounting torque specs.


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## Hitcher

Give this a try Buddy http://www.americanboltcorp.com/tech/techtorque.pdf


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## treadlite

McMaster Carr has a 10 pack of grade 8 nylon lock nuts for $3.45 They also sell a variety of distorted thread nuts, which would be my choice. Where I live it takes a day with standard ground shipping. I'm with you though, you shouldn't have to go though all of this, thanks for sharing.


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## TimU

Leedek said:


> Dexter Axle Maintenance Manual here: Dexter Axles Page 78 list brake mounting torque specs.


Yeah, but the problem is - one has to KNOW you have Dexter parts. The replacements I got were. The issue is still one of - are the Dexter manuals "non application specific"?

I come from the tech world - you get the info from the guys that you bought the stuff from - you don't use generic manuals for specifications for specific applications.

For instance - a company I worked for 20 years ago built amusement rides. We had ALWAYS used hydraulics for actuators and lifters for seat locks. Bunch of new engineers came in with all the new stuff, and a whole new ride created using 3D CAD, stress analysis - you name it. We got lap lock lift actuators from an aircraft company, specs were perfect. Number of cycles, we were only lifting 1/4 the weight they were rated for, etc., etc., etc. Everything was good to go. These were air actuated, not hydraulic. Not one doggone thing wrong with anything that was going on. Not too much air pressure - nothing.

Ride gets done - goes out, actuators fail within 36 hours (on Memorial Day Weekend). We send new ones out - they fail within 24 hours. Only cycled maybe 80-100 times, out of a supposed life cycle rate of 40-50,000. We go back to manufacturer. Oh, they wouldn't warranty, because we weren't using them in an aircraft specific application. Didn't matter that everything else was kosher - no guarantees (even though they knew what we were using them on, etc., etc.). Fortunately, I was in IT, and not Engineering.

So - I have simply learned not to trust "generic" manuals from this and dozens of other similar experiences relating to computers, networks, etc. I've seen too many surprises where one could say, "a trailer is a trailer is a trailer" - "oh, you never said it was an RV! That's different!"


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## TimU

etrailers did send me a torque spec - 1/2 of what Dexter's manual shows - 35 ft. lbs and DO NOT OVER TORQUE ABOVE THAT UNDER ANY CONDITIONS. I got the manual from the link Leedek put on his post, sent it to them - well, now they say 45-50. ABSOLUTE max of 50 ft. lbs.

About what I would have guessed. The Dexter manual shows 45-70.

So - application specific is 45-50? Or these parts are of the quality they will only be 45-50? An original Dexter part would be 45-70? Or ???

Not trying to be fussy with anyone - just that this is the kind of stuff that makes me pause just using a generic manual.


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## Leedek

TimU said:


> etrailers did send me a torque spec - 1/2 of what Dexter's manual shows - 35 ft. lbs and DO NOT OVER TORQUE ABOVE THAT UNDER ANY CONDITIONS. I got the manual from the link Leedek put on his post, sent it to them - well, now they say 45-50. ABSOLUTE max of 50 ft. lbs.
> 
> About what I would have guessed. The Dexter manual shows 45-70.
> 
> So - application specific is 45-50? Or these parts are of the quality they will only be 45-50? An original Dexter part would be 45-70? Or ???
> 
> Not trying to be fussy with anyone - just that this is the kind of stuff that makes me pause just using a generic manual.


TimU - No problem from me on this boondoogle.







My think on this: the studs and nuts are there to hold the plate to the axle. The 7/16 20tpi nut/stud torque found in the PDF Hitcher supplied aligns well with the info from Dexter. 45-70..... heck I'd set the torque at 60 and go camping!









Guess we got wrapped around the axle on this one!


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## Leedek

TimU - Do I need to get one of these for you? T-shirt or does your tech world mean technician?


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## CamperAndy

Generic or not bolt torque specs originate from extensive empirical testing. As long as you know the nut and stud material grade then you can with 100% confidence use a generic torque to set these bolts/studs/nuts. Now to the all caps notice to not over torque under any conditions. This was not aimed at the likes of you, you plan on using a torque wrench and even if you are off by 5 or 10 lb/ft it would not be the end of the world, it is aimed at the guy using a 250 lb/ft air impact gun or 18" breaker bar to tighten them. BTW I work in a high tech and precision field and just because you use a torque wrench does not mean it is done correctly (can you say parallax? Classic beam wrench) or accurately (I am sure it was cal checked in the past decade!). There are many other things that affect the torque such as doing it dry or with some type of anti seize (this can change the true torque by 25% or more depending on the anti seize base). Also if you use deformed thread nut then there is a built in drag that has to be added to the final torque.


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