TIP #62, BRAKES: The Secrets to Brake Shoe Long Life, or Early Demise….

Submitted: Thursday, Aug 25, 2005 at 20:42
ThreadID: 122203 Views:2970 Replies:2 FollowUps:1
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Well, I think a lot of people would benefit from this, so I have put this one on the Public Forum… There are a lot of things that we "Experienced" take for granted, that "Beginners" have to learn the hard way. I am going to tell you about the hard way, so you don’t have to learn for yourself, but instead learn from the mistakes of others…

Some definitions to conditions…….
Break in on Brakes: First of all you have to adjust your brakes in the first 500 to 1000 km as they wear in… Why? In the old days it was common to use an Arc machine that ground the radius of the brake shoe lining, to fit the inside of each drum neatly…. No more, asbestos and all that stuff, means the brakes have to wear in… First 100km maybe only a few inches touch, then maybe another two inches per 100km after that of more contact as they wear in evenly… The arc of the shoes and the arc of the drum, never quite match perfectly….

Cracking on brake linings: People often get this, and it is three things: Heat first of all from having the Brake Controller wound up a little to far, or Heat from riding the brakes, or Heat from too much braking on hills instead of low gear slow speed engine braking, like trucks, which is the safe way to handle hills… But Heat, Heat, and Heat is the answer. The one other cause is still Heat, as some overly zealous mechanics might wind up the adjustment too much…. We see this once in a while. Had them adjusted a bit too far or one of the conditions above, and now the linings are cracked with heat.

Linings coming off of shoes: This is a mystery open to speculation.. The Manufacturers claim excessive moisture or submerged in water for a period of time… It may be from the other argument of poor bonding practice, but it is open to speculation. Luckily we do not see it often, maybe about six or eight times in ten years… Yes it was better in the “good ole days” when they riveted linings on, but you don’t get as much wear out of those compared to bonded linings and the rivets score the drums a bit and the linings wear out faster as some of the thickness is used by the rivet…

New linings: Most no longer supply new shoes anymore… Instead they send out the old shoes and get them “re-lined”… Most larger cities have a 24 hour turn-around on this service. This is what we suggest, or get a set from us, we usually have a half dozen sets or more in stock..

“Ounce of prevention is better than needing new shoes:”
In general, you want to have the brakes adjusted enough, but not too much.. Not enough to be contacting the drums or “dragging”…. You have to tell the Mechanic this to be sure.. Next, in general, you want to watch how much you turn up your brake controller, as you can have a tendency to lean on the caravan brakes too much in traffic, pulling up the tow vehicle a bit too much… This will save the brakes on the tow vehicle, and feel really good and comforting, but cost you shoes on the caravan.. Next, in general you want to learn how to compression brake on the hills by slowing down BEFORE you get to the hill, not over using your brakes once you are RUNNING down the hill.. You need to learn to drive the van like a truck on the hills, approach slow, and run down slow, not on the brakes; or you will be replacing them frequently… It is safer as well, so coast down slow, or pay the price of haste with money spent on new shoes..

Yes per my “ Tip #54Towing Tips Off-road” there are conditions where you want to turn up the brake controller and have the van brakes come on first in greasy, icy, muddy type conditions… And yes it is nice to have that feeling of the van starting to pull you up before the tow vehicle brakes come on… But if you run like that for a large percentage of the time, you are going to pay for it in brake shoes. They can last you 10,000km or 50,000km (or more), depending on how sensitive you are and how you use them…. OK?

A couple of other incidental problems…. People have left the hand-brake pulled on, we see that from time to time, with overheating or cracking more on the rear set of shoes….

And, one more thing: We have had two people ruin batteries by pulling the emergency brake away switch out when they parked up…. One by accident kicking the cable, one by listening to some “silly Twit” tell him it was a good idea.. This is directly wired to the batteries, no low voltage disconnect, and will definitely ruin the batteries if left that way too long with about a 10-12 amp steady drain. It will run all the way down to nothing to dead batteries!! So don’t do that, ever! OK?

Best Regards from the “Lone Ranger” … Semper Fidelis….

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Reply By: Grumblebum & Dragon - Saturday, Aug 27, 2005 at 23:26

Saturday, Aug 27, 2005 at 23:26
Good one Steve.

Cheers GB and the Dragon
AnswerID: 567046

Reply By: macka the wacker - Tuesday, Sep 20, 2005 at 09:43

Tuesday, Sep 20, 2005 at 09:43
Steve, Just wanted to ask do you have any problems fitting bainbriges disk brakes to a bushtracker?
Ta in advance
macka
AnswerID: 567047

Follow Up By: Bushtracker - Tuesday, Sep 20, 2005 at 18:24

Tuesday, Sep 20, 2005 at 18:24
Hello again Macka!!
Look, I will update my research and do a Tip on this one at a later date, so others can find it... But there are a few problems we encountered on my last look at the disc brakes…

1) On the issue of wanting disc brakes, good! Good idea that is, but totally impractical and here is why: The proper disc brakes are hydraulic to get enough power to the callipers to squeeze the pads on the disc, called a "rotor"… To get that pressure you only have two choices, air over hydraulic to actuate it, or vacuum over hydraulic to get the power to the hydraulic master cylinder. Surge brakes or over-ride, have little adjustment and no breakaway ability, and are illegal over two tonne and don’t work well anyway… Air over hydraulic and vacuum over hydraulic, with the adaptation of the tow vehicle, plus tanks on the van for 15 minutes of brake hold in the "break away provision", would cost about $8000 to $10,000 to do properly.. Also the failure of one brake line would bring down the whole system. If that is not enough, you have to tap into the Vehicle master cylinder, and Toyota said it Voids their Warranty if you do that…

2) So because of the great expense of air over hydraulic or vacuum over hydraulic, they tried to come up with an electric actuator to push on the hydraulic master cylinder.. OK, good in theory… Only one problem…. We did not find the operation satisfactory, lacking in adjustment and speed of actuation. One type of new electric hydraulic actuator that we looked at, was a bit weak, so the rotors had to be a soft bronze so the disc pads will grab with less power, and the wear on the corrugation would be way to excessive chattering along the corrugation… Again, we decided, not practical in the Outback…. It is a workable option for boat trailers and surge brakes, but we do not think the soft rotors will last long enough to make it a practical long term system on a caravan. So we abandoned the consideration, in our opinion just not practical… OK?

The 12” Commercial brakes we use are considerably stronger than the 10” caravan type… They are a two piece hub drum, and are larger and wider, and have a larger heat sink value with such a larger mass of steel, so they do not fade as quickly as the 10”… Also the corrugation does not chatter them to severe wear like the 10” brakes, and we have had some Customers go over 100,000 kms on the original set… And a failure in one does not affect the others, like in one hydraulic line failing bringing down the whole system… In our opinion, there is no practical alternative to what we are doing…

ALSO: Our 12” brakes are even different than the normal caravan 12” caravan brakes, as our are a two piece hub drum, where the bearing hub will take bigger bearings and the brake drum is pressed on, like on a commercial truck drum, over the hub. Ours is the next grade up from the normal caravan 12” which only take the small bearings and are a one piece drum that does not absorb the heat as well, causing brake fade. Others claim they have 12” brakes as well, but don’t use our larger hub-drums and larger bearings…

I hope this answers your question good enough for now, if not ask on... I will check on the latest developments, and make this an original Posting in the future for others reference..

Kind Regards from the Ranger…
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FollowupID: 844912

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