I worked at truck plant specifically for about 15 years. The vehicle goes on a rolls machine, gets driven up to 70mph to wake up all the electronics. Then the driver hits the brakes to test out the ABS basically.
How are brakes bedded in at the factory?
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+1 PimTac
I would like to understand how uneven lug nut torque or lug nut overtightening leads to brake pulsation. It's hard for me to visualize.
warped rotors according to the tech article.
I installed some power stop drilled and slotted rotors on the front of my 98 F150, with their pads. I followed their recommended break-in procedure but it was still another couple hundred miles of driving before they really came in.
Based off of what ? I did 4 PDIs today and no where on the process does it say to bed on brakes or give a specific braking process on the test drive
AFAIK, the OEs want their cars test driven during PDI, the trip to the gas station and back is usually how it’s done.
Many cars come with organic(“resin” in Japan) brake pads that work on cohesive friction so there really isn’t a need for a break-in, which is more of a bed-in. But, establishing the transfer layer is important - the owners manuals state no panic stops for up to 50-100 miles AFAIK.
Aftermarket brake pads claim “post-cured” or “scorched” or have a break-in coating(EBC, Centric, Bendix/WearEver/ImportDirect and Duralast Elite) on the pads. I still do 10 stops from 30mph in any case.
For the record I am “pro” bed in brakes
Just as far as PDIs go never seen one with that specified. Could be a dangerous suggestion by the manufacturer to ask that especially in some very heavy traffic areas
Just as far as PDIs go never seen one with that specified. Could be a dangerous suggestion by the manufacturer to ask that especially in some very heavy traffic areas
The new ones spell that out too - under new vehicle break-in procedure
or is that the Brake-in proceedure
Carroll Smith, for years a Consulting Engineer for StopTech (now a part of Centric Parts), knew more about all of the arcane aspects of automotive braking systems and their components than any other human who ever has lived. He was the author of this article:
https://www.centricparts.com/media/..._Whitepaper_B1-Warped-Brake-Disc-8-2018_1.pdf
The same page of "Technical Bulletins" contains a specific suggested procedure for bedding in new rotors and pads.
https://www.centricparts.com/technical-bulletins
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My last truck had a pull to the right when I drove it off the lot. The tech never drove the truck, I think he checked it to make sure it was red and then drug his muddy boots around the interior and scratched up a bunch of stuff and that was about it. The salesman said he didnt notice it when he drove it 1/4 mile to put gas in it.
I just took it to a competent repair facility (not the dealer) and paid to have the alignment checked and the right front caster adjusted since it was out of spec. It was easier than allowing the monkeys at the dealer to mess it all up 2 or 3 times.
i always bed in brakes, new rotors, old rotors, if I touch the brakes i test them. I've seen rotors with uneven friction residue on them cause vibration, that went away with a bed in run. I've also seen people with blue rotors that are physically warped, usually right after a trip to the mountains. people who live in the flat areas don't realize that brakes aren't immortal and you can smoke em pretty good by riding them down a mountain.
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When I was a tech and on my own cars now, I always took any brake job for a rest drive. I always get up to 50 or so, and firmly, but not panic stop down to 5 or so, then another 2 or 3 times.
Worst thing you can do with new brakes is a hard stop and just sit there. Then the hot pads just keep the heat in one spot on the rotor. The key is to keep rolling. Then I didn't apply the brakes at all for the return trip and only very gently to come to a stop back at the shop.
It is my very firm belief that most pulsation comes from rotor runout. Where the rotor wobbles back and forth due to hub/rotor lateral runout. Most of the time here in the rust belt it is not properly cleaning the back of the rotor and/or hub.
Wanted a shop to turn a set of rotors for my wife's car. They refused to do it, and said I would be wasting my money as they would be warped in 10k miles. I had the rotors in my hand when I walked in. I told them that I was a master mechanic and they were not doing proper brake jobs if they had that many boomerang vehicles.
I went 3 towns away where I used to work and turned my own rotors on the dusty brake machine. 40k later still perfect. Here in rural country I generally get 50k or more out of a set or brakes. And rotors go 2 brake jobs for me at least, I measure thickness and have no problem turning them if they are within spec.
Worst thing you can do with new brakes is a hard stop and just sit there. Then the hot pads just keep the heat in one spot on the rotor. The key is to keep rolling. Then I didn't apply the brakes at all for the return trip and only very gently to come to a stop back at the shop.
It is my very firm belief that most pulsation comes from rotor runout. Where the rotor wobbles back and forth due to hub/rotor lateral runout. Most of the time here in the rust belt it is not properly cleaning the back of the rotor and/or hub.
Wanted a shop to turn a set of rotors for my wife's car. They refused to do it, and said I would be wasting my money as they would be warped in 10k miles. I had the rotors in my hand when I walked in. I told them that I was a master mechanic and they were not doing proper brake jobs if they had that many boomerang vehicles.
I went 3 towns away where I used to work and turned my own rotors on the dusty brake machine. 40k later still perfect. Here in rural country I generally get 50k or more out of a set or brakes. And rotors go 2 brake jobs for me at least, I measure thickness and have no problem turning them if they are within spec.
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