Brake adjustment

JohnDanielsCPA

How exactly do you adjust the brakes?  I have a T@B Max S with the Outback axles.  I understood that there should be a small hole on the inside of the hub with a rubber grommet around it that, when removed, will show a "star" gear that can be adjusted to adjust the brakes.  I am unable to find any hole with a rubber grommet, and looking inside what holes there are, I am seeing no star gear.  So, I'm either looking in the wrong place, or my brakes are self-adjusting?

ChanW

I have the rubber plug. Yours may be missing. I wouldn't call the star gear 'visible', but I've never really gotten under there to actually look, I've always simply done it by feel. 
It can be a pain in the neck.  I rigged up an L-shaped pry tool from a piece of flat stock to make it easier to lever it in the cramped space.
Tighten the brakes til they drag, then back off just enough so they don't drag.

JohnDanielsCPA

Thanks @ChanW.  I'll give it another look.  So, it must be the hole at the bottom of the hub assembly, correct?

db_cooper

It's an oval hole on mine, kind of like a Tylenol tablet.  And the rubber cover is missing on half of them.

ChanW

John, I don't remember right now, whether it's at the bottom or where, but I can check tomorrow.

There's a possibility that yours would be different from ours, ours being a 2014 with hydraulic brakes.

If I were you, I'd check the service diagram for your model, you might have it with the axle documentation that came with your Tab. There's a diagram of the inside of the hub, showing the brakes breakdown. It'll give you an idea of what you're working with.

I'm kind of at a loss right now, for various bits of info that I've dug up in the past. My Tablet took a shower the other day, and hasn't been the same since... (rain and electronics don't mix, eh?)

JohnDanielsCPA

Alright, I found it.  Yes, there are two oval holes at the bottom of the wheel.  Neither hole has a rubber cover.  The hole to the rear has the star gear in it.  It was much smaller than I expected it to be; that's why I missed it.  Thanks all!

ChanW

Glad to hear it, John. Now you just have to figure out which way to turn the star wheel....  I always turn it the wrong way, before I turn it the right way...

JohnDanielsCPA

I braved it and went for it last night.  All seemed to go well; e.g. Tighten (by rotating upwards) until the wheels are locked, then loosen (by rotating downwards) until wheels are unlocked.  From what I've seen on the various forums, the wheels should be loosened to the point where you hear the brakes dragging but the wheel turns.  The problem I have, now, is knowing how loose (or tight) that actually is.  Seems there is a bit of art to this?  Does anyone have any suggestions to identify how loose or tight the wheels should be after the adjustment?  I plan to hookup this evening and drive it about 5 miles, then take the temperature of each wheel at the bearing point and drum point of the wheel looking for relative consistency in temperature between the two wheels and to ensure the temperatures are below 170.  If higher, I would conclude the brakes need to be further loosened.  The other problem is knowing whether or not the brakes have been loosened too much!  I'll assume that if they don't work, they're too loose?!!

ericnliz

@JohnDanielsCPA, Hearing a slight drag, and having the wheel still turning is a good starting point. Drive it a little, and re-check to be sure. Side to side adjustment is pretty critical as you don't want one side "gripping" more, or harder than the other. You're on the right track!

ChanW

I avoided mentioning this step because it's impossible to describe... 

I always figure if the drum doesn't feel hot after a short drive, then the slight rubbing is ok.

Then I try a bit of harder braking, maybe on a hill, stopping and checking to see if the brake drums got warm and are doing their job.

I found out the other day that it's pretty obvious when the brakes aren't working, when I forgot to return the 'back up release lever' to enable the brakes again, after backing up. Could feel the Tab pushing when braking on a downhill.

JohnDanielsCPA

@ChanW, I would rather have them too loose than too tight, and I agree.  If they are too loose, I'll feel it!

ScottG

I agree the whole process is a little unclear. My AL-KO manual says something to the effect of leaving enough drag so the wheel can rotate freely almost one full turn. I follow that general recommendation, using a pretty light touch to get the wheel moving.

Further complicating my adjustment is that the drag on the wheels is not uniform--there seems to be a high spot that grabs a little harder than everywhere else. If in doubt, I also err on the side of loose rather than tight. 

BrianZ

I wanted to understand a little better the mechanics of how these drum brakes get adjusted, so sharing some of the illustrations & video images that helped me..

First, here's my view of the two adjustment holes I found on the right/passenger side of our T@B.  On this side, the rear one gave me access, but on the driver side the forward hole may work better.  On ours, neither hole on either side had any rubber plug, which makes me wonder whether we should get some.

This illustration of the part, which I borrowed for discussion, shows the small gear-like "star wheel" that needs to be turned using a screwdriver.  Note that it functions like the head of a threaded bolt, screwing into a sleeve, such that when unscrewed (by leveraging the screwdriver upwards), as indicated by the curved arrow, it pushes the assembly apart.  This adjustment then pushes the two brake shoes apart & against the inside of the brake drum, tightening the grip. 
At least, this is my understanding from studying all the parts in the pictures - please correct me if I am wrong.

This video frame shows the two access holes & the star-wheel rod between the two brake shoes at left & right.  This is a left/driver side brake, so the nearest access hole is the forward one.  

Here is a broader view of a right/passenger side brake assembly, where I've drawn the approximate locations of the access holes on the other side.  Although the closest access hole is different on left & right sides, the adjustment direction is the same on both - upwards to tighten and downwards to loosen the grip. 
Tip:  If you get "up-tight", you won't forget which way to turn it!
Actually, "up tight & out of sight" seems fitting too, since you're pretty much working only by feel.  While you can't actually see the wheel turn, you can feel it click into the next position.

Bayliss

@BrianZ, thank you very much for the brief explanation and especially for the photos with arrows to make the explanation even clearer.  Extremely helpful in understanding how to adjust the brakes.  (Greg)

db_cooper

No rubber plugs on ours either. Caused me confusion the first time since I was looking for a rubber  plug.  Then I couldn't  figure out why there were two holes. Then it clicked. Literally. 😁

DigitalSorceress

Thank you for this post.. I had no idea What to do at all... the official manual literally just says "check and adjust" .. with no further explanation

rkj__

I keep the gain on my trailer brake controller fairly low, so I find the trailer brakes don't need adjustment very often, which is nice!  It's a little awkward getting to those adjusters, since these (non-Boondock) trailers sit so low.

tabiphile

rkj__ said:

I keep the gain on my trailer brake controller fairly low, so I find the trailer brakes don't need adjustment very often, which is nice!  It's a little awkward getting to those adjusters, since these (non-Boondock) trailers sit so low.

To clarify this a bit...you are referring to the boost feature (I believe) in your progressive controller. It is generally accepted that for a towed vehicle that weighs less than the TV that boost is not necessary but that using a low boost setting will cause the T@B to lead the braking, arguably providing better control. The boost is applying an initial braking effort that allows your T@B brakes to brake faster. That helps to control the trailer and keeps it from pushing you.

What needs to be noted is that this does not directly have anything to do with adjusting the brakes. It is possible that using the brakes more carefully and evenly may reduce the pad/drum wear, but it does not prevent it. It also must be noted that the controller does not in any way affect the brake/drum clearance that must be maintained for proper braking. As brakes wear (pads get thinner/drum wears down) the clearance between them changes. The star adjuster procedure that has been well described in this thread explains how to maintain the correct clearance. That the brakes are properly adjusted is a presumption that brake controller manufactures assume as a given. Carefully using controller boost does not eliminate the need to properly maintain the brakes. Not that you suggested that. You didn't. But, just to be safe and make sure that anyone new to folks working on brakes understands, the brake boost does not alter the brake pad/drum clearance. Does that make sense???? I hope so.

BrianZ

Since our missing brake adjustment hole plugs seems to be a common issue (& I have an idea why), I thought I'd share this source for replacements, which are a nice quality rubber & a perfect fit..

Raybestos H1456K Professional Grade Brake Backing Plate Plug https://www.amazon.com/dp/B002EP9U50

I was able to quickly push them on by laying on my back & reaching around behind the wheel with one arm - no need for a jack.  What's nice is that they have a lip at each end of the inner side, and I suspect the commonly missing plugs may not have this lip to hold them in.  They don't cost much, so I got two sets in case any of the new ones go AWOL.

BrianZ

@tabiphile, what I understood @rkj__ to be saying is that using a less aggressive brake adjustment in the controller may reduce wear on the brakes, and thereby reduce the frequency of need for brake adjustment.  I believe there are only two things that the controller settings can change - the timing of the brake signal for how quickly to apply brakes, and the strength of the signal for how aggressively to apply the brakes.  Having brake controller settings too high may result in applying them more than necessary, causing them to wear faster, and thereby requiring more frequent adjustment.  I don't think anyone would expect an electronic controller setting to actually change the brake shoes default resting position like a brake adjustment would do, would they?

tabiphile

@BrianZ...I'm pretty sure that is what I said. Whether someone might believe that, possibly. If someone is unfamiliar with how brakes work and waer and the interaction with the controller...certainly. 

JohnDanielsCPA

@BrianZ Thanks for the link for the rubber plugs!  Just ordered them to replace my missing plugs.

rkj__

tabiphile said:

rkj__ said:

I keep the gain on my trailer brake controller fairly low, so I find the trailer brakes don't need adjustment very often, which is nice!  It's a little awkward getting to those adjusters, since these (non-Boondock) trailers sit so low.

To clarify this a bit...you are referring to the boost feature (I believe) in your progressive controller. It is generally accepted that for a towed vehicle that weighs less than the TV that boost is not necessary but that using a low boost setting will cause the T@B to lead the braking, arguably providing better control. The boost is applying an initial braking effort that allows your T@B brakes to brake faster. That helps to control the trailer and keeps it from pushing you.

What needs to be noted is that this does not directly have anything to do with adjusting the brakes. It is possible that using the brakes more carefully and evenly may reduce the pad/drum wear, but it does not prevent it. It also must be noted that the controller does not in any way affect the brake/drum clearance that must be maintained for proper braking. As brakes wear (pads get thinner/drum wears down) the clearance between them changes. The star adjuster procedure that has been well described in this thread explains how to maintain the correct clearance. That the brakes are properly adjusted is a presumption that brake controller manufactures assume as a given. Carefully using controller boost does not eliminate the need to properly maintain the brakes. Not that you suggested that. You didn't. But, just to be safe and make sure that anyone new to folks working on brakes understands, the brake boost does not alter the brake pad/drum clearance. Does that make sense???? I hope so.

To clarify my comment, the "gain" setting on my GMC Sierra's OEM brake controller adjusts how strong the trailer brakes are applied when I apply the brakes on the truck.  The brake shoes on the trailer should always be correctly adjusted prior to setting the brake controller's gain.  Increasing the gain should not be used to compensate for poorly adjusted brakes.

-Gain of 0 results in the trailer brakes not being applied.

-Low gain settings result in the trailer still "pushing" the truck a little bit when the brakes are applied, but not as much as if the trailer brakes were not applied.

-Mid-range gain settings can result in the trailer braking itself in a way that it does not "push" or "pull" the truck when braking.  This is normally the recommended adjustment.

-High gain settings will apply the trailer brakes very strongly, and can result in the trailer "pulling" the truck back, and slowing it down faster than if the trailer were not connected.

-Maximum gain settings can cause the trailer to lock up its brakes during braking. 

My truck has a payload rating of something like 1,600 lb, and a tow rating of about 9,600 lb.  In most braking situations, it feels like the truck has plenty of braking power to brake the trailer safely on its own.  However, it would be a bad decision to not use the trailer brakes.  They are important for emergency braking situations, and for more demanding scenarios, like stopping at a stop light, at the bottom of a long steep hill. 

What I was trying to say with my comment, was that since my tow vehicle has large, strong brakes, I don't feel I need to apply a lot of braking force to the trailer brakes (low-mid gain) to stop safely and securely.  Thus, since the trailer brakes are not working too hard, the shoes don't wear very quickly, and don't need frequent adjustment.  This is also largely influenced by the fact that much of my towing is on fairly flat highways. 

I'm not meaning for this to be advice on how you should adjust your brakes or brake controller, but rather simply sharing my experience. 

BrianZ

If you need Dexter's brake service manual, here's a link to download the PDF.  It has some good info, not only about adjusting the brakes, but which parts may need some grease & which must not, how to inspect for wear, cleaning, and more about controllers, specs, etc.

http://trailerparts.com/pdfs/Dexter122.pdf

PS:  There is also a more extensive  "complete service manual" ("600-8K_Complete_Service_Manual.pdf"), but I could not get into dexteraxle.com today..

https://www.dexteraxle.com/docs/default-source/dexteraxle/product-documentation/manuals/600-8k_complete_service_manual.pdf

tombeaux

It was mentioned that a flat bladed screwdriver can be used to adjust the brakes. It is a little easier with a Brake Spoon, which can be found at any auto parts store. Hint - you might have to ask an employee with some gray in his or her hair. The younger ones won't know what it is). Should cost well under $10. 

Travelin3D

@tombeaux, I think I still have one of those that I used on my '64 VW bug, which is probably the last car I actually adjusted the brakes on!

GrandmasKid

I really appreciate this thread as I too have not adjusted brakes since working on 60s VWs, two bugs and a van. I'm curious about how many miles folks are getting from their shoes. I'm planning a trip and think my brakes need adjusting because I was getting a bit of a klunk when stopping at low speed in heavy traffic coming back from our last trip. Our 2021 400 BD only has a little over 2500 miles on it in the year we've had it. May I get an opinion on where the clunk mght be coming from? Thanks!

tabiphile

GrandmasKid said: I'm planning a trip and think my brakes need adjusting because I was getting a bit of a klunk when stopping at low speed in heavy traffic coming back from our last trip. Our 2021 400 BD only has a little over 2500 miles on it in the year we've had it. May I get an opinion on where the clunk mght be coming from? Thanks!

Clunks in drum brakes usually happen when the springs are not attached or when a spring is broken. A clunk could also be from a brake that is not set tightly enough. In that case it would need to be extremely loose, enough to allow the shoes to shift under braking. 
If you are certain that you are not hearing a hitch clunk you could try adjusting the brakes. I'd be inclined to pull the wheel and make sure that the drum is properly installed and check that the springs are properly installed. Then I would put it back together, torque the castellated nut, lugs and properly adjust the brakes before taking it for a test drive. If you worked on a Vdub you should have no problem with the T@B. 
It's a good idea to get into the habit of checking the wheel lugs and brakes within the first hundred miles after they are serviced and also if they are new. 

qhumberd

I agree with @BrianZ about adjustment and also @rkj__ comment. I used this approach with my 2019 400 and it is not that hard. I also got the plugs and that just makes sense to keep grit out of the drums in bad weather. But I cannot imagine wearing the pads on the trailer to the point of replacement with the use that the majority of us put on our campers. Anyone have an idea of miles before a brake lining is needed?

Denny16

With trailers it is not so much how many miles you put on it, but rather how often the brakes are used.  We inspect drunks and brakes annually at the start of the season.  This way you will catch any potential issue before it becomes a real problem.
 Cheers 

Sierra

This link nolonger works . Does anyone have a current manual link? Thanks
https://www.dexteraxle.com/docs/default-source/dexteraxle/product-documentation/manuals/600-8k_complete_service_manual.pdf