I just wanted to run something by you. I have worked on cars all my life. First car had 4 wheel drum brakes, many after that had rear drum brakes. I feel I know enough about drum brakes to have diagnosed a problem on my 4 month old 2011 Keystone.
When I first picked it up, I noticed that just before coming to a complete stop (5 mph or less), I felt a slight pulsing from the trailer. Just like you'd feel if your cars brake rotors or drums were out of round. I said something to the dealer then, and they said I'd need to adjust the brake controller. Didn't know any different so I said ok, I'll play around with it. Mind you, it's a new Tekonsha Prodigy controller, only a year or so old, and I never had that problem with the camper I traded in. The pulsing is not severe, but does exist.
Anyway, as the owner's manual suggests, after a couple hundred miles, you should adjust the brakes. I jacked up the trailer, one wheel at a time and spun the wheels. When I spun the wheels (completely disconnected from the tow vehicle; no power to the brakes), not one of them spun freely all the way around. They would spin, but then "catch". If I didn't spin hard enough, they wouldn't make it all the way around. When rotating the wheel between the "catching" spots, there was no brake drag at all. Same on all 4.
The manual says to spin the wheel, tighten the shoes until the wheel won't spin, and then loosen the shoes until the wheel spins and stops within 3/4 to one full rotation. This is hard to guage since the wheel does not spin freely all the way around. I should be able to spin the wheel and watch is slowly lose speed until it stops. Correct? Then, when adjusted correctly, there should be a little brake drag, but free uniform rotation when spun. Ultimately, I did adjust each brake tighter than they were from the factory. All seemed loose.
Ok, so I take it back to the dealer. Of course, they say they found nothing wrong, want to charge me a diagnostic fee. They are once again telling me to adjust my brake controller. Funny, last time I checked, when the camper is not connected to the TV, there is no power to the brakes. Am I incorrect in my assumption that these wheels/brakes should turn true, without any "sticky" spots? If my car did that, I'd have the drums turned or replace them.
The pulsing is not violent, very subtle. But I still feel the drums are out of round, and do not feel I should pay a diagnostic fee for a trailer under warranty, because they "say" nothing is wrong.
Am I expecting too much "precision" from camper trailer drum brakes? Sorry for the long post, I like to give as much info when asking a question as I can.
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2011 Keystone Sprinter Select 29BH
If it bothers you, I suggest you go to a brake shop. They can turn the drums and make them round again.
Thanks powderman, but that really doesn't answer my question. I know I can pay to fix it. I'm asking if the condition is truly normal. Shouldn't I expect them to rotate freely and uniformly? If so, then 1) I'd like them fixed under warranty, and 2) I shouldn't have to pay a diagnostic fee for something that is wrong and should be taken care of by the manufacturer. There's only a couple hundred miles on the 4 month old camper.
What performance should I expect from travel trailer drum brakes?
I'll give you my reality. All the trailers I have had, the drums were similar to the way you describe yours. Came that way from the factory. I felt it was less than desireable, but never felt it was bad enough to have corrected. The ONLY time, I could feel pulsating braking was when I adjusted the brakes and turning the wheels by hand. Like you. But when towing down the road, I could never feel any pulsing from the drums.
I know there is a tolerance on brake drums being out of round. IIRC, it is +/-.030 of an inch. That is enough tolerance to give you the condition you are experiencing, when the brakes are adjusted properly. So if that is the case, then yours are probably within spec. And some people describe that as being "normal". And I guess that is one way to put it.
If you get to the point were you feel the trailer brakes pulsating while under heavy braking, get the drums turned.
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I don't think that you have an issue or a brake problem per se. There are many factors that can lead to a brake drag on a given drum or set of drums. It may be that the drums are perfectly round (at least within the the given tolerances), but, that the drums fit sloppily on the lug posts and the center hole is not actually "centered" (this would be my bet on low cost trailer components). Your brake shoes do not actually mate to the curvature of your hubs when relaxed. There is a leading shoe and that shoe has a leading edge. If the drum is not concentric, that leading edge will contact the drum at the point of lowest rotation. Any turning of the drums would not correct an "off-center" mounting situation. This has also been a problem with automotive drums...many a drum was turned until the minimum thickness was reached in an attempt to eliminate that "rub", when all the while it was "off center" hub manufacturing.
I'm not sure, given that I haven't experienced your "pulsing", but, IMHO, it would be really obvious that a drum was drastically warped in order for you to feel any "surging" while applying the brakes on a 29 something foot trailer that weighs 3 to 4 tons...it would almost have to have corners. For my money, the condition is concentricity and is normal in trailer axles (mine do the same thing, on wheel spin, but I have no "surge" or "pulsing".
My 2 cents, your mileage may vary...
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Thanks Vulcaneer. I just spoke to the service manager. Nice guy. He explained to me pretty much what you said. He said the the pulsing could be related to the way the magnet touches the drum, even when no power is applied. Either way, he said that he'd waive the diagnostic, and for me to drive it a few hundred more miles, and if I still don't like it, they'd turn the drums and try to get the money out of Keystone. He said Keystone is very difficult with brake issues. He also said that camper manufacturers are different from automotive manufacturers in that, if you bring a vehicle in, under warranty, and they deem nothing is wrong, they don't charge you a diagnostic fee. Camper manufacturers tend to charge if no issue is found. He's worked for both, and does not like that policy.
I asked him, doesn't it make it difficult to adjust brakes when the condition I describe is occurring? He said simply, yes. I actually think he seemed to agree with where I was coming from, and becuase of that waived the fee. He didn't argue with me at all.
Mine have pretty much done the same thing on several trailers I've owned. Never caused any problems for me. The only time I notice it is when stopping very gradually but if I apply normal brake pressure they're perfectly smooth. I just adjust them a little looser than normal and do it more often. Good luck / Skip
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Thanks webslave. It's relieving to know this sounds like a normal travel trailer kind of thing. Like I said, the pulsing when driving is very very minimal, just took me by surprise. Just want to make sure that anything that should be fixed under warranty gets fixed under warranty before it runs out.
I think John Barca did some testing on this matter and found that trailer drums were not manufactured to the same tolerances at automotive drums. They were not perfectly round nor concentric with the axle centerline. Maybe he'll check in and comment. Given the standard of quality of the rest of the trailer industry, It's not too big a surprise that good enough is good enough. Mine pulse a tad too since new.
Just another thought, have you accurately torqued the lug nuts? That may help too.
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