Vibrations when braking

[jst2878]

when your braking from 100 to 80, its got to be your abs kickin in brotha. thats the beauty of them.

[JCL]

Originally Posted by The Cleaner

No need to bed in pads, that is an internet legend that simply will not die, I wish I could find ground Zero for that myth..... The proof that bedding is BS is in every new car. No new car manufacturer recommends or does “bed in’s” on new cars. If that was the case every factory would need a bedding in facility. I have spent a ton of time at the Toyota plant in Fremont California and I can tell you they do not have a bunch of people running around slamming on the brakes on new cars.

I have done at least 200 brake jobs and I have never bed in a job. With the exception of a couple jobs where the owner used junk parts I have never had one come back. I drive the car up to highway speed and check for vibration and squeak, that’s it.

Rant off, sorry

The solution is to replace the pads and rotors with OEM Jurid in the front and Textar in the rear. .....

I have to disagree here. I have done a lot of brake jobs as well, and I have found that bedding in is an important step. The degree to which it is required varies quite a bit with pad composition and rotor surface finish, but I consider it part of the brake job.

My experience with the Axxis Deluxe pads was that they required bedding in more so than many other pads, but that once it was done the pedal feel was equal to the OEM pads. That may have varied with my specific new rotors, as well, as that is the other half of the equation for the deposition of pad material on to the rotor surface.

Jurid is owned by Bendix. Bendix does recommend bedding in new pads, sometimes more stridently than other times. It depends entirely on the pad material. Bendix has also promoted new pad designs that include a metal strip on the pad surface, designed soley to reduce the bedding in time (their words).

Too many brake pad manufacturers (and the SAE) talk about the initial transfer of pad material to the rotor surface for me to discount it as a myth. I do think that it varies so much with pad composition that it is more of an issue with some pads than others. If I was a manufacturer I would specify a pad with less requirement in this regard, soley to reduce warranty claims for noisy brakes.

Jeff

[Quicksilver]

Maybe so but i gotta tell you the cleaner is right. No one at that toyota plant does this ( spent a few years there also) and no where will you find in the instructions for new car owners to do this, and finally i have never ever received these instructions when a brake job is done. A lot of scientific gobbley gook imho.

Originally Posted by JCL

I have to disagree here. I have done a lot of brake jobs as well, and I have found that bedding in is an important step. The degree to which it is required varies quite a bit with pad composition and rotor surface finish, but I consider it part of the brake job.

My experience with the Axxis Deluxe pads was that they required bedding in more so than many other pads, but that once it was done the pedal feel was equal to the OEM pads. That may have varied with my specific new rotors, as well, as that is the other half of the equation for the deposition of pad material on to the rotor surface.

Jurid is owned by Bendix. Bendix does recommend bedding in new pads, sometimes more stridently than other times. It depends entirely on the pad material. Bendix has also promoted new pad designs that include a metal strip on the pad surface, designed soley to reduce the bedding in time (their words).

Too many brake pad manufacturers (and the SAE) talk about the initial transfer of pad material to the rotor surface for me to discount it as a myth. I do think that it varies so much with pad composition that it is more of an issue with some pads than others. If I was a manufacturer I would specify a pad with less requirement in this regard, soley to reduce warranty claims for noisy brakes.

Jeff

[JCL]

Originally Posted by Quicksilver

Maybe so but i gotta tell you the cleaner is right. No one at that toyota plant does this ( spent a few years there also) and no where will you find in the instructions for new car owners to do this, and finally i have never ever received these instructions when a brake job is done. A lot of scientific gobbley gook imho.

OK, I'll bite. I like scientific gobbley gook, especially if we can use terms like tribology, boundary layer, pad deposition, failure mode, etc. Friction is such a neat subject.

Short version: It is apples and oranges, comparing new manufacturing processes to aftermarket brake jobs.

At the factory, the driver is cost. Cost of the part, cost of the installation on the assembly line, and cost of the warranty if there is a problem after shipping the product. Thus, brake pads (and rotor finishes) are spec'd almost exclusively based on cost, with particular attention paid to warranty costs for noisy brakes. It is a significant issue for new car manufacturers. Ultimate performance of the pad isn't one of the selection criteria for most new vehicles, excluding high end performance models.

Aftermarket pad designs, like everything else, are results of decisions and compromises. Better performance, better initial bite, pedal feel, less fade, less dust, etc. One of the ways to get improvements in those areas is to give up a little on another area. So, many brake pad manufacturers have two product lines, one for OEM and one for the aftermarket. They can plan for, require or recommend that installers bed in pads in the aftermarket, whereas they can't get away with that in the factory due to manufacturing costs. This is why Bendix recommends bedding in their pads after a brake job, and at the same time develops a special pad that doesn't require bedding in, for the factory customer.

IMO, as a vehicle owner you won't get told to bed the pads following a brake job, since the mechanic already did it (following the instructions of the pad manufacturer). For those friction pad manufacturers that cater to the DIY market (Axxis, Hawk, etc) you see a lot of chatter on the forums about the need to bed pads. If you work in a dealership using only factory parts, there is far less discussion about it, it isn't much of a factor. Still, any mechanic doing a brake job is going to do a test drive, usually with a couple of good stops to check that the vehicle isn't pulling, and that there is a reasonable pedal feel. For most pads, that is all they need. For a pad that is designed to require bedding in, it often isn't enough. This goes one step further on the track. Pads not only require bedding in, they require warming up. Again, another example of design decisions being made that improve one factor at the expense of another.

This is just speculation, but The Cleaner has suggested that his preferred pad is the factory pad. That would suggest that bedding in is far less important than if his primary business was installing Axxis Deluxe pads, as an example. It doesn't mean that bedding in isn't important when the manufacturer of the pad recommends it.

Jeff

[MarkingTime]

Soooooo, follow the recommendation from the manufacture if I decide to DIY.

If I go OEM "forgeta bout it", the bedding.

jst2878, if that's all it takes to get killer abs I should have washboard abs by now.