Brakes appear uneven

TresK3 · September 21

I have a 2019 Tab 400 Boondock. It’s on its third set of tires and second set of brakes. Had the brakes done last spring. Late last year, I noticed that the brakes heated up unevenly when stopping. If I touched the left side drum it could get pretty warm (depending on how hard/long we’d been braking); hot enough that I didn’t want to hold my hand there for more than a second or two. On the right side, the drum would be barely warm.

I took it to a local trailer repair shop, who said everything looked good. They claimed that they adjusted the brakes, which I have no reason to doubt. However, the temperature difference remained. The trailer is now in my back driveway, jacked up so the wheels will spin free. If I spin the left wheel (the hot one) and apply the brakes with the controller turned all the way up, it locks right up. If I do the same to the right side, the wheel stops spinning (clearly the brakes are being applied, somewhat), but not nearly as quickly as the left side. If I take the brake controller down to a more typical level for my driving, it’s hard to tell an obvious difference in how quickly the wheels stop spinning - but that’s just with spinning the wheel by hand and no load on the tires.

I’ve looked at the wiring and don’t notice anything frayed or pulled out. My next step is to pull the drums and look at the brakes themselves. I have one wheel off, but I can’t get the drum off. I’m hesitant to bang on it too much, since I don’t want to have to replace the drum and I’m not sure how that would affect the bearings. Should I go rent a puller, or is there a trick to this?

Also… any thoughts on why the brakes seem uneven? It’s mostly noticeable after significant braking or if I have the controller at a higher setting.

How concerned would you be? The only real difference I notice is temperature. The trailer seems to handle and stop fine on the road.

Oh… and a final question. My son, who’s helping, suggested tripping the emergency brake wire to see if both sides lock up equally under those conditions. We tried tugging on the wire but did not get it to trip. Should we try this? If so, how difficult is it to reset the emergency system?

Thanks!

pthomas745 · September 21

The emergency break away brake only works if the trailer battery switch is on. So, check that item and maybe you can test the break away brake again.

You can have a look at your brake adjustment yourself. These are really pretty simple setups. The thread below has a description of "how to adjust", and also plenty of info on other things that might be happening inside the brake itself.

https://tab-rv.vanillacommunity.com/discussion/comment/75348/

vhollow · September 21

On my 400 the emergency break-away brakes are wired to the 12 volt side of the converter, so the battery needs to be on, as noted above, or the trailer needs to be plugged in to shore power for the brakes to activate. Pulling the break-away plug, attached to the steel cable, is difficult, if it hasn’t been done regularly or greased when checked. I used vice grips to spread the force where the cable attaches to a black plastic ring and still scraped my forearm on the frame the first time I checked this. Regarding drum removal, the star adjuster should be backed off pretty much all of the way to allow enough play between shoes and drums for removal. Conversely, when adjusting the brake shoes, the adjuster should be tightened until the wheel doesn’t turn, then backed off until there is still a little bit of drag.
This manual explains the process, and is a very handy resource for Dexter electric brakes:
https://www.dextergroup.com/user_area/content_media/raw/LDServiceOnline.pdf

swiftwave · September 21

Is it possible that different lengths of electrical wire to each brake results in a voltage drop on the longer wire, thereby reducing brake effectiveness on that side?

tabiphile · 3:27PM

swiftwave said:

Is it possible that different lengths of electrical wire to each brake results in a voltage drop on the longer wire, thereby reducing brake effectiveness on that side?

Once the longer wire fills with electrons, the difference in length is equalized and the brakes will then work identically.

tabiphile · 3:50PM

@TresK3, it would be interesting to learn mileage if it is known. You have seemingly gone through quite a few tires and brakes on a 6 year old rig.
From my perspective, I would be keen on making sure that the parts (drums, pads, springs) are all good and also lean towards making sure that the actual adjustment of the clearances is done carefully. Even when a brake adjustment is done by a shop, the degree of care and precision can vary greatly. It is very likely that one wheel has always been set a bit more tightly (less clearance} than the other. That will result in uneven braking and wear and also a difference in how warm they get when they are used. And....brakes are not super precise parts so it is possible (likely) that in order to get both wheels to spin freely, the tech may have had to adjust one looser than the other. If this was my Bdock, I would pull both wheels and have a look at things. As has been suggested, to pull the hub, you must back off the adjusters. Use a proper brake spoon to do this. A screwdriver can damage the soft metal adjuster. When the adjuster is loose, the hub should come off. If the hub has worn significantly you may need to use a puller or beat it loose with a hammer, hopefully not, but possible.
After assessing the parts, you should carefully reassemble taking particular care to adjust both sides equally. It is during this adjustment that you will learn if the sides are the same. It has been my experience with trailers and cars that it is rare for two wheels to "feel" exactly alike. If you know that one side has a tendency to run hot, run it a bit more loosely and snug up a touch on the other side to offset it. Then tow and see what you get. The tighter side (don't overtighten it) will turn, and break in with a closer clearance and may run a bit warmer. Then other side should run cooler. As long as the rig stops well and feels safe when you are towing you are good to go.
Brakes are not an exact science. There is a bit of mechanics "feel" to setting them up.
It is worth mentioning, if you have been through that many tires, the bearings and hubs on your Tab should be repacked and possibly replaced while this brake job is being done. Be certain that you are taking a look at those and also that the castellated nut has been properly adjusted to insure that the bearing races are correctly pre-loaded.

vhollow · 4:25PM

Great suggestions from Tabiphile! Also, it might be helpful to measure amperage to the magnets, applying the brakes (gently, but consistently) with the hubs off. If the two sides are different, due to an abraded wire or other problem, breaking force would be applied differently to the two sides.

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Brakes appear uneven

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