Brake failure

[Lonestar]

While checking my wheel bearings and inspecting the brakes yesterday I found an unusual situation. On one brake assembly the magnet had somehow jumped over the adjustment wheel and got lodged between the adjustment wheel and the back brake assembly plate. This prevented the brake activation arm from moving. In addition, the brake shoe pads were worn all the way down to bare metal.

The brake drum was pretty badly abrased both in the area where the shoes make contact, and also where the magnet makes contact. I have never seen this before. Maybe I just missed it on my last brake inspection, and I can't imagine what events led to this.

While not relating to this failure, I was wondering if any lubrication should be sparingly added to the moving parts of the brake assembly, i.e. the arm with the magnet that swings to move the shoes into a braking position? Obviously you would not want to over-lubicate and get oil on the brake shoes.

Any advice appreciated.

[TucsonJim]

Wow, that is a fluke. When I was right out of the service I took a job as a mechanic for Goodyear. They had a pretty good training program, and the instructors all used a small dab of white lithium grease on any moving parts that made contact with the backing plate.

Jim

[Scott'n'Wendy]

Good find.
I use high temp silicone brake grease.
Another example of why you need to lay your eyes on the bearings and brakes, not just a few pumps on the EZ lube zerk.

[Lonestar]

Good find.
I use high temp silicone brake grease.
Another example of why you need to lay your eyes on the bearings and brakes, not just a few pumps on the EZ lube zerk.

Absolutely! This can't be emphasized enough.

I am concerned about using grease because if even a drop fell from the part it would land on the hub shoes the brake shoes make contact. I guess if its high temp that would be unlikely.

[Jlawles2]

Lonestar When greasing something like the brakes where dropping lubricant can be an issue, I try to lube it, put the parts together, the wipe off excess, pull and check for excess again. Caliper grease (IIRC) is stiff and designed for higher temps than High temp grease, so dropping point should be elevated a decent amount.

https://www.amazon.com/Permatex-2412...11&sr=8-4&th=1

https://www.amazon.com/CRC-05359-Cal...s%2C111&sr=8-5

[familytruckster4]

Bill Snider from Dexter mentioned lubricating the pivot/contact points on the shoes during his seminar at the GD rally in September. He may have recommended a lubricant but I dont recall

[Lonestar]

Lonestar When greasing something like the brakes where dropping lubricant can be an issue, I try to lube it, put the parts together, the wipe off excess, pull and check for excess again. Caliper grease (IIRC) is stiff and designed for higher temps than High temp grease, so dropping point should be elevated a decent amount.

https://www.amazon.com/Permatex-2412...11&sr=8-4&th=1

https://www.amazon.com/CRC-05359-Cal...s%2C111&sr=8-5

In this case I would have to disassemble the pivot point where the shoes and the magnet arm come together, then put grease in between them and reassemble. This requires brake tools. I wonder how many folks actually do this.

If using high temp grease, looks like this procedure is mandatory because the grease is not going to liquefy and make it's way between the moving parts.

I'm wondering if just using a common grease like wheel bearing grease, and using it very sparingly would work? Or using a good oil, again sparingly?

[Jlawles2]

Lonestar You are basically rebuilding that assembly anyway. Brake tools are cheap if you are not creative with a set of locking pliers.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 Takes of the disk washer / spring shoe retainer.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 Pretty much everything else you may need
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 adjuster "spoon" for setting brake pad clearance.

https://www.amazon.com/OEMTOOLS-2573...5-56d755c862ba option to replace item 2 above. Never used one, but it;s the same as the handle ends. Big end removes spring over pivot trunion, little hooked one puts them back.


All tools needed total under $50 and will work on pretty much every drum brake out there.

[Lonestar]

Jlawles2

I may get set up with tools, but I've never really had the need to tear down the brake assembly before. I just ordered a new brake plate assembly and I found it for only a few dollars more than what was the best price for a brake shoe kit. By doing that there is no need to do any rebuilding, and any tearing down would only be to lube..

There is obviously not much to it but removing the retainers and springs, but even with folks that do the necessary bearing inspection, cleaning, re-greasing I don't think I've ever heard them mention tearing down the brake assemblies and applying grease. I'm assuming you do this, and if so, how often?

[familytruckster4]

I didnt take the advice to mean that the parts needed to be removed in order to be greased, just a dab of a temp stable grease anywhere there was contact between the shoes another metal surface. That was my understanding, although with my last 3 trailers the objective was to remove the gross contamination of grease from these parts from the overzealous greaser who used the EZ lube.

[Lonestar]

I didnt take the advice to mean that the parts needed to be removed in order to be greased, just a dab of a temp stable grease anywhere there was contact between the shoes another metal surface. That was my understanding, although with my last 3 trailers the objective was to remove the gross contamination of grease from these parts from the overzealous greaser who used the EZ lube.

In Joseph's post #5 and #8 he is indicating he is taking the brake assembly apart to grease. Sounds very effective. Some of the other posts don't necessarily imply this. We all approach axle maintenance differently, and I'm always glad to hear of the different approaches. As much as we discuss bearing maintenance I'm surprised we haven't discussed this before.

[Jlawles2]

I've never pulled apart a trailer drum system to grease it. I have done more automotive brake jobs the I can remember. Parts always get cleaned, inspected, and reassembled If signs of corrosion lube applied. I can see where trailer brakes will need more attention to the rotating interfaces due to the lack of use (sitting for months at a time in some cases).

I will admit than on the BP TT I never pulled the drums. Pulled the cap 1x per year, 1-2 pumps of grease, and way we went. The pumps of grease were more to verify that everything was till in order, nothing leaked out. Wiped off excess before putting the plug back in.

[familytruckster4]

We use our trailer frequently and when its stored its inside an insulated barn so I dont have the same issues that many other do as far as weather.

[Jlawles2]

Just because it's stored inside does not mean that it will not be suspect to humidity and other factors. Being in the insulated barn does help slow down the process.

Guess after this years trip I will pull down the drums and do an inspection, repack.