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Air disc brake question

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                                   Any of you that are running air disc brakes, what kind of service are you getting as far as mileage on  a set of pads? The trucks we have are running Wabco Air Disc and so far I'm not seeing the advantage

                                  between disc and drum as far as longevity. We are constantly running over the Cascades, Blue Mountains and Rockies loaded 100,000 lbs both directions. Average on pads about 230,000 miles we use to

                                  average 350,000 on drum, some drivers would get 400 to 500,000 miles on a set of shoes. A full set of rotors, wheel seals and pads is $1,180.00 a full set of shoes, drums and kits $465.00. We would change

                                  out a set of drives with shoes and drums in 45 minutes, to change out a full set of rotors 7 hrs.  What are you guys getting for miles of service?

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I’d venture to say our fleet gets about the same as you are on disc brakes. Have you had problems with them seizing up and dragging?  Seems to be very common occurrence in our fleet. The other problem we’ve had is at night when we do our post trips most guys including myself give the brakes 1 to 3 pumps when the truck is off so 1 we can hear if there’s any service side leaks and 2 to give enough pressure so the auto adjusters to work. The thing I love about disc brakes is I have yet to have once freeze in the winter. I try to always back up so my tire is 90 degrees from where it was when I did my post trip and that helps a lot. Nothing worse than getting to work in the wee hours of the morning in negative temps beating breaks loose. 

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Posted (edited)

                               Haven't had any issues yet with seizing or dragging. But we have had two needing pads, one at 113,000 and the other at 134,00 and both drivers have 60 years plus between them. Both of those drivers would average 375,000 plus on drum brakes.

                               The other issue that no one I have talked to, has kept track of tire mileage. We run Goodyear 399's on steer, use to average 110 to 115,000 miles. That has dropped between 93 to 97,000 miles. And the drive tires are running about 12 to 15,000

                               less miles. I keep close track every time tires are changed out. As far as frozen brakes in winter most our drivers dry the brakes out before setting them. By just riding the brakes a short ways to heat the drums.

 

                           Thanks for the reply HeavyGunner.

 

Edited by Truck Shop

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Posted (edited)

probably the biggest pos I have seen in recent years. heavy mechanic and we service a lot of pedal trucks for an oil company. they are beyond junk. Bendix brand. mind you they are pedal trucks and see the harshest of environment runnin the back road but they are getting maybe 30,000 out of a set of pads . compare that to 80-100 thousand out of a set of regular brake shoes. and to top it off when you PM a truck, you cant see they pads like regular lining so you have to pull every wheel and pull the dust cover to inspect the pads. we have even had a few brake cans go bad and burn the pads right off in no time, pair that with a an automatic and a dumb driver and you can actually not push in the yellow knob and take off with the brake on . if one can is broke on a disk brake set up and they burned the pads right off on a single axle truck. did I not mention when  you wear the pads right down with a broken can it gets the caliper hot and burns the seals and rubber out of the caliper and OUR price for a Bendix caliper is $1700. they are junk

Edited by Maddog13407
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The only advance of the disc brakes is they don't fade like a drum.

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                         Thanks for the reply's. One big issue with me is the trucking industry got away from inboard drums 40 years ago and moved to quick change shoes and outboard drums. With disc your right back where we started wrangling a heavy 

                          rotor and hub assembly. I have an attachment for our jack to handle them. With drum a wheel dolly is still quicker and with E-log a driver can be tied up for several hours dealing with rotor change. You have to clean the hub real well

                          where rotor mates to hub, cast steel and aluminum plus road salt, fertilizer corrodes fast.  But like Glen says only advance is the fade issue, and that fault lies with the driver. IMO 

 

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correct me if Im wrong but the disc brake pad does not have as much working surface area as drum brake shoes do. ? if that is true that can be why they wear out faster.

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The advantage of Drum brakes  .... it teaches U how to drive

If U get brake fade from use n brakes all the time 

I say change down a gear or 2 n let the engine brake do wot it's ment to do

n save the service brakes for wen U gotta stop in a hurray

Years ago we Had a Mack 'F' model with the 300 cool power n 6 speed

we did half the gear changes compared to a 8V-92T n RR 18

only problem we really needed an extra gear between each cog

cos it seemed like U cum down hills in to highr gear n use the brakes or the next lower gear twaz to low

cya

 

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                                         I don't know where all this brake fade issue comes from. Selling point I suppose. I haven't  had a driver complain about brake fade with drum brakes. One brake shoe has roughly the same surface area of four brake pads.

                                         One set of pads for Wabco disc is $165.00, eight brake shoes are $145.00. One set of pads does one axle. $330.00 verses $145.00.

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Disc brakes are mostly a safety feature- If they prevent one catastrophic accident they've more than paid for themselves. Like anything new in trucking, there will be higher initial and parts costs until they become the standard and volume production brings costs down.

 

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Brake Fade

When useing the brakes alot on a down hill run  to hold the speed back heat is generated on the brakes

and with the heat the drum grows  in diameter and makes the brakes as not effective ....... like out of adjusted brakes

Meaning the truck will not pull up..... just like out of adjusted brakes ... when the brakes cool the drum shrinks to original size

and the brakes work better.

Here on the udder side of the world in Au

there were problems with disc brakes cos on corrigated (Washboard to U Lot) roads the brake was not supported enuff n

had am aditional support addedtm-1012-product-catec-800b.jpg[/img]

 

 

 

cya

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