I thought the dust shields on the newer Freightliners were bad enough.
But our newest trucks use disc brakes (ummm, Yay!?)
The first thing that caught my eye was that the air cans are almost perpendicular to the wheels. (a few degrees off axis for clearance I imagine) and there are NO slack adjusters (Hooray!) but I can't figure out how I'm supposed to fit my "mark 1 eyeball (government issue)" into the wheel to check the pads for cracks and the like.
Also it seems like there's some sort of dust housing on these brakes too.
I have no problem checking brakes as part of my PTI (obviously) but there's got to be a more realistic way to inspect them than pulling off all the wheels every morning.
Tips anyone? (I'll probably go to the manufacturer's website later today too. I'm just not sure if they're Bendix units or Dana's and I'm not at work right now)
Oooookay, how am I supposed to inspect Disc Brakes?
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In the shop we use a lighted telescope mirror,poke through the holes in the wheel and you can see the pads. No way to see other than pulling the wheels. No adjustment(except initial).
Do check that the drain holes in the brake cans are either all open or at least the bottom one,some got through with the top open and then they collect water.
I was thinking the same thing when we got our new trucks with DISC brakes.. It's seems as though it's very hard to find information on the internet... It's not a common thing you can find the information about how to check the components.. I mean who is going to take wheels of a truck/trailer everyday to check brakes.. Not only is it time consuming it's just not practical.. Since the brakes are more effective when they are heated (unlike drums which are the totally opposite) if your brakes are working great at start-up then they will be way more effective as you motor down the road... It's hard to inspect them because of the dust caps in the way.. There is no adjustments on these brakes because that happens as the rotor heats up and all parts are internal in the caliper... All I could find was from a site called "CCJ - Commercial Carrier Journal" which is a fleet management magazine.. They have outline the CVSA requirements for disc brakes.. Like I said it's not easy getting the information on these, not even the CVSA website says anything.. Which is kind of hard to believe considering there needs to be some time of outlines that people can follow to check these brakes safety . Some sort of guideline as they have with the drum brakes.... Right now it just seems like we are going "blind" into the world of disc brakes.. We know they are safer and give us far better stopping distances.. Plus now you will be able to feel brake wear in the brake pedal (much like a car) where as in drums you cannot tell brake wear by the feel of the brake pedal.. Anyhow on with what I have found on the world of the internet...
CVSA - Out-Of-Service Criteria - Air Disc Brakes
Air disc brakes
Broken or missing caliper, brake pad, pad retaining component, pushrod, yoke, clevis pin, brake adjuster, parking brake power spring or chamber return spring air chamber mounting bolt.
Loose or missing brake chamber or caliper mounting bolt.
Rotor has evidence of severe rusting or metal-to-metal contact over the rotor friction surface or on either side.
Evidence of oil or grease contamination of the friction surface of the brake rotor and the brake friction material.
Brake pad thickness is less than 1/16 inch or to wear indicator if pad is so marked. External crack that is visible or opens upon brake application.
Rotor with a crack in length of more than 75 percent of the friction surface that passes completely through the rotor.
Portion of drum/rotor missing or in danger of falling off.
So how do you check this stuff when you can't really see it... This is the million dollar question... Upon my reading I heard of a tool that would slide in from the back and I guess it would contact the disc or something and you would measure this to know pad thickness.. Is everyone going to be carrying a little measuring tool like that?? I doubt it... Also there isn't a standard side thickness of pads as well among different manufactures , and even within the manufactures different models etc.... I can't believe how hard it is to get information about this. It's like pulling teeth..
I hope I at least helped out a little bit.. I provided a link to the webpage I went to.. It's got 5 pages of different OOS criteria on it...
When I had a truck with disc brakes, I went through two inspections, on each the inspector just noted "disc" in the brakes section, neither one of them checked anything with them, just kinda skipped over it.. One was in CA and the other was in NV..
Even the CA inspector told me not to worry too much about them, since there's nothing as a driver that we can do with adjustments of any kind.
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