More About Trailer Brakes

gdavis · #1 05/14/06, 5:20 PM

Coming back from Restless' GPS Poker Run on "The Rim" last weekend, I noticed my trailer brakes (21' Weekend Warrior Super Lite) weren't nearly doing the job I was used to. It took turning the controller up to almost twice the usual value before I felt comfortable with the braking. I was hoping adjustment, but knew it would be more than that.

When I was questioning an RV tech about the brake system, he made it a point to tell me to check the shoes for cracking. At the bottom of this post is an example of what I found.

The purpose of this topic is to make all aware of the brake cracking, which seems to be a pretty common occurence, as well as to pass on my self education on trailer brakes.

First, you don't need to be a Master Mechanic to work these brakes, though some mechanical ability would be good.

From what I saw of brake wear, and I use my hauler probably 12 - 15 times / year, I would check brake adjustment and wear once annually, and it goes like this......

First check that the brakes are applying while at the same time checking your emergency brake switch. That's the switch that actuates the brakes if the trailer should separate from the tow vehicle. Jack one side (or one wheel) at a time, pull the pin on the emergency brake switch (different makes may vary) and check all wheels for brake actuation.

Now here's where you have to make a decision on weather to just adjust the brakes, or pull off the drums to check the linings.

It's financially important to plan ahead on brake service as it's 30% - 50% cheaper to buy parts on-line, I found that out the hard way.

Another consideration is weather to buy and just replace the linings, or to buy the whole assembly which consists of the back plate, shoes, magnet, etc, all assembled (no drum). With that set-up it's 4 bolts and 2 wires slap the drum back on and you're done. The problem I see with that is expense (2-3 times) and the bearing repack, which should always be done with a brake change. Cleaning and repacking bearings is the most time consuming part of the job, while changing the brake shoes won't take much longer than bolting on that whole new assembly that cost 3 times more than the shoes.

Anyway, after all was said and done, I had one wheel with no braking and assumed it was the magnet after verifying there was power to it. I replaced the magnet and no help. Ended up being a broken ground wire for that magnet.

I guess I could have got lucky and found that broken wire right away......or was I lucky I didn't find it right away?

6 out of 8 shoes looked like these. Is cracking of the lining over rated? Or is it a disaster waiting to happen? I can tell ya from experience, losing just one brake makes a HUGE difference in stopping power, especilly rolling down a 6% grade.

larrynvic · #2 05/14/06, 6:08 PM

[:0] Oh my gosh!!![:0]
Guess it pays ta do the yearly checks.

RathrBdunin · #3 05/14/06, 7:07 PM

Great info Gdavis. Thanks for taking the time to post the info. & the pic's.
I just did the inspection & bearing grease on our trailer.

Thanks again,

Arizona Griz · #4 05/14/06, 7:40 PM

Glen, great information. Thanks for taking the time to post it up. So which way did you go and where did you buy the parts?

gdavis · #5 05/14/06, 7:56 PM

quote:Originally posted by Arizona Griz

Glen, great information. Thanks for taking the time to post it up. So which way did you go and where did you buy the parts?

Since I didn't know what I was getting into and needed to be ready for Memorial Day, I got my parts at Robert Christ in Mesa. Paid $150 for 4 sets of brake shoes, could of got them on-line for about $80 + shipping.

That's the price of education.

azotto · #6 05/14/06, 8:41 PM

I've never seen anything like that before.

Did the RV tech give any cause for the cracking? Or do they just replace the shoes and send folks down the road?
Did you have the drums measured and/or turned before installing the new shoes? Was there any unusual discoloration or "checking" on the brake surface of the drum? Reason I ask is a couple of the shoes look like they have a defined wear pattern indicating there is not 100% contact with the drum (it may just be the lighting in the picture though).

Another tip is to replace the hardware with the shoes. The springs, clips and associated hardware will fatigue and cause problems at just the wrong time.

gdavis · #7 05/14/06, 9:33 PM

quote:Originally posted by azotto

I've never seen anything like that before.

Did the RV tech give any cause for the cracking? Or do they just replace the shoes and send folks down the road?
Did you have the drums measured and/or turned before installing the new shoes? Was there any unusual discoloration or "checking" on the brake surface of the drum? Reason I ask is a couple of the shoes look like they have a defined wear pattern indicating there is not 100% contact with the drum (it may just be the lighting in the picture though).

Another tip is to replace the hardware with the shoes. The springs, clips and associated hardware will fatigue and cause problems at just the wrong time.

Steve,

The RV tech just advised me to check. Next time I'm by there I'll ask a few more questions. I wasn't really expecting to find what I found.

I saw no problem with the drums at all. No discoloring and no uneven wear on the shoes. Everything looked normal except for the cracks. The brakes weren't worn more than 30-40% , if that, so I didn't see any need for turning.

I'll check the new ones annually. Maybe just low quality shoes. Mark had the same problem with his trailer brakes.

Fooll · #8 05/14/06, 9:52 PM

Where can you find the info on what type of brake to buy to replace the old set? or are they a standard type...

gdavis · #9 05/14/06, 10:13 PM

quote:Originally posted by Fooll

Where can you find the info on what type of brake to buy to replace the old set? or are they a standard type...

Pretty standard. I didn't do a whole lot of looking, but everything I saw was replacement parts for Dexter or Hayes.

husky390 · #10 05/19/06, 4:07 PM

I had an old chevy pickup that would do that on the rear drums all the time. The reason why was the drums were over their size limit.

EAB · #11 05/19/06, 8:13 PM

I'd like to hear what the tech had to say about the cracks also.

gdavis · #12 05/20/06, 8:04 AM

I was told it was from over use, setting the controller to have the trailer stop the tow vehicle, rather than even braking between the trailer and tow vehicle. Drum brakes do not disperse heat very well.

I have to say I was guilty of that. [:I]

az350x · #13 06/17/06, 11:27 AM

I've bought two complete sets of backing plates (Dexter axle) from Napa across from Travelon on Main in Mesa in the last year (two trailers). I paid just over $40/wheel from them. Pace trailers charged me over $80 per wheel for the same exact part, so I returned them and went to Napa. The backing plate assemblies include shoes, magnets, EVERYTHING but drum and bearings. Compared to around $30/wheel for new shoes alone, I think the assemblies are the way to go. Like was mentioned earlier, four nuts, two wires, repack the bearings, and you're done.

Toybreaker · #14 06/25/06, 1:36 AM

Whenever you replace brake linings be it on rotors or drums you should give the friction material a "new" surface to ride on. Be it having them "turned" or burnishing the glaze off of it.
If you drums and or rotors are not grooved or out of round and within wear limits you can use a grey brown or red scotchbrite pad to scuff the "varnish" (don't know what else to call it) off of the wear surface.
Then to get a proper job done you should bed in the pads.
For disc brakes it is usually several gradual stops from 30mph. See you manufacturers guidelines for specifics on your vehicles/Brakes requirements.
Not doing things right can have VERY grave circumstances.

Another little tech tip. When cleaning bearings to repack them It is wise not to use Compressed air to dry them. If you get the bearing spinning from the air pressure the bearing can part and cut the fingers off that was holding it.
I saw it happen when i was in Vocational automotives in high school. It was gruesome.

dunenutt · #15 06/26/06, 8:16 PM

quote:Originally posted by gdavis

I was told it was from over use, setting the controller to have the trailer stop the tow vehicle, rather than even braking between the trailer and tow vehicle. Drum brakes do not disperse heat very well.

I have to say I was guilty of that. [:I]

That is fairly common with drum brakes, the cracks are most likley from getting them too hot. Adjust them so that the truck brakes feel normal/ or just a little push from the trailer. Start downhill grades slow, and use the gears to remain slow. Try to stay off of the brakes, and use them in short bursts instead of riding them. Check your truck brakes, if you have drum rears, they may look the same.
I have a 69 c-10 chevy with all 4 drum brakes, When I hauled my camper on it, it would do that about every three trips. Needless to say, it is now a grocery getter. It is alot worse now that there is no asbestos in the linings.
Also, check with arizona brake and clutch, they probably have a better lining material.