One brake grabs

[Steph and Dud B]

Just got home from OTT with Hull #1150. Noticed that one brake is more aggressive than the other three - locking up before they do. These are the Dexter Nev R Adjust brakes and, from what I've read, there is no manual adjustment to back them off, only to tighten them during the initial install. I don't think it's actually dragging - the drum temp was consistent with the other axle throughout the trip (per IR thermometer) - it just grabs harder than the others. I did notice that overall braking of the trailer was getting stronger throughout the trip - had to back off my brake controller twice. Looking at how these brakes work I'm wondering if the other 3 were set looser at the factory and are now starting to catch up as they auto-adjust? Thoughts?

[John E Davies]

There are lots of issues with these brakes, when they work, they seem OK but there is a lot of extra stuff that can fail, or start dragging or binding, compared to the old fashioned manual version. And they are difficult to reassemble once you strip all the parts down.

You really need to look inside at all four brakes, you may have a failed inner grease seal. Grease on the lining will cause serious lockup problems. And if that is the case, you are looking at a pair of new brake assemblies. Never replace just one side of an axle. Don’t bother trying to replace individual parts, it is very cost prohibitive and dealers don’t carry them anyway.

You can indeed adjust the automatic type, look at this article. … https://olivertraveltrailers.com/forums/topic/2778-brakes-auto-adjust-vs-manual-adjust-what-are-the-differences/

Good luck. Drum brakes suck…..

John Davies

Spokane WA

[Ghostriderc227]

There is much to be desired in the design and operation of those brakes, especially after they get some miles on them.

I suspect you have nothing wrong with the brakes since they are still relatively new.  The brakes adjust themself by applying short pumps on the brake at lower speeds.  I would guess it may take 15 or 20 slow speed brake applies to get the adjusters to set in correctly.  You mention that the brakes seem to perform better after you had used it, and that is the self adjusters at work.

The entire brake assembly inside the drum will actually try to rotate front to back inside the drum as you apply and release the brakes…….each time that assembly rotates during brake apply, a ratchet adjuster moves to shoes out towards the drum closer.  This will happen until the brakes have reached their optimum adjustment and then they no longer “rotate” enough to ratchet any further.  As the shoes wear, the adjuster will once again ratchet a click or two in an effort to self adjust the brakes.

Under ideal conditions and when the brakes are still relatively clean, rust free, and have enough lube on the small metal pads that hold the shoes out away from the backing plate, then the brakes can work fine.

My Ollie has about 25,000 miles on it and is an older model……so when I went to replace all the wheel bearings and races this past winter, I discovered my brakes were doing the same thing (unequal braking on each wheel).  I quickly found out how the brakes worked and spent a good bit of time to completely disassemble the shoes, springs, and adjusters to clean and lube the points that needed to move in order to adjust.  I used a good high temp silicone based brake grease on all the stamped pads in the backing plates, as well as all the contact points for the adjusters, springs, etc.  The brakes are once again working fine, however I suspect that I will need to give those brakes a good inspection each time that I grease the wheel bearings.  It was a bit of a puzzle for me to understand exactly how the brakes worked and self adjusted…..but one I did, it was not an extremely difficult effort to clean, lube and adjust the brakes once again.  I had very little brake wear on the drums or the shoes…..but I suspect that most of the braking was done by one or two of the wheels.

By the way, you can adjust the brakes manually if need be.  There are a few posts from the past on how to do that.  There is also an electromagnet that must be checked as well (an easy thing to do).  That magnet is what actually makes the brake assembly want to rotate when the brakes are applied.

I would suggest that you take your Ollie out for a low speed ride and apply the brakes a good number of times, and relatively hard apply at slow speed.  This should allow each adjuster to reach its optimum point of adjustment.

If i were to order a new Ollie, I would get the standard brakes and just live with adjusting them once or twice a year.  That is much less complicated than the Nev R adjust brakes.  In my opinion…….a very poor design.

It would also be suggested that you order the small rubber dust covers/plugs to protect the back side of the backing plates where the adjusting slots are located.  There are two of these slots on each wheel.  In Dexters infinite wisdom, they decided not to install the rubber plugs at the adjusting slots any longer.  I guess they just assume that dirt, water, etc getting inside the brake assembly is not critical.  That or they just want to save about .80 cents per axle.

Good luck and I don’t believe you have anything serious to be concerned about.  Just do the hard brake applies a good number of times at slow speed and you should be ok.  If not, then you will need to remove the brake drum and get inside each assembly to find out what is not working correctly.

 

Steve