I just had the brake pads replaced in my car. As I left the shop I noticed coming to a complete stop took longer distance or needed a fair bit more force on the pedal.
Is this normal?
Will the brakes 'work themselves in'?
-
Braking distance won't change but pedal feel yes, until the brake pads (ie friction) are not bedded to the discs : 100 x 0.3g every 4 km in theory. In practice, just don't burn them, drive carefully and brake "slowly ".– hornetbzzCommented Nov 29, 2014 at 4:37
Add a comment
|
3 Answers
Actually, yes. For one reason and one concern (sort of related):
Reason - The pads and rotors need to become "used" to each other or have a break-in period. The pads will brake down slightly until the point where the mating surface has full contact with the rotor. It takes a little while for this to happen.
Concern - The brakes need time to "bed". This is the period where they go through heating/cooling cycles. It is a period of time where the "glue" (bonding agent) has time to fully cure. If you are not easy on the brakes during this time, the glue will move toward the surface (towards the heat). In doing so, once the thicker portion of glue is worn through, this will cause the brakes to wear out quickly. EDIT: After reviewing some information provided by @Larry, it was brought to my attention what I provided is not complete in the sense the main reason for bedding the brakes is to evenly distribute brake material throughout the rotor. Properly bedding the brakes will help prevent what most of us consider warped brake feel, which is very often mis-diagnosed. Please review these three links about bedding in procedures or follow the manufacturers recommendations as you see fit. Just know, it is a very important step. Bed-in procedural sources: Centric Parts, Tire Rack, and Zechhausen Racing (which also has a video about the importance of the bedding in process from Stop Tech). Thanks Larry for providing the links - I thought they should be here in the meat for common consumption.
In both cases, you need to allow approximately 100 miles (~160km) for both things to occur. Give yourself longer braking distances so you don't have to do emergency braking unless ABSOLUTELY needed. It's still there if you need it, but just try to be gentle. If after the hundred miles they still feel "squishy" or aren't work working up to expectation, I'd take it back to the shop to see if there are any issues.
answered Jul 8, 2014 at 15:26
-
Disagree, while your correct that they have to bed-in, if done properly it doesn't take a hundred miles, and should be done before the car is given back to the customer. Anything less and you put the customer at risk for an accident and open yourself up to liability. Commented Jul 8, 2014 at 16:39
-
@Larry ... and yet, it's the way it is. Bedding does take 100 miles or your pads will give you about 1/3 of the life they should. The shop which did this work seems to believe the same about break-in time.– Pᴀᴜʟsᴛᴇʀ2 ♦Commented Jul 8, 2014 at 17:13
-
@Larry ... Please understand the OP is suggesting "a fair bit more force" to stop in the same distance. They can stop in the same distance, it just takes a little more force, which I don't think is unreasonable considering what I've already stated.– Pᴀᴜʟsᴛᴇʀ2 ♦Commented Jul 8, 2014 at 17:28
-
2After some research it seems it depends on the type of pads and application. See Centric Parts, Tire Rack, and Zechhausen Racing Commented Jul 8, 2014 at 17:35
-
You need to 'bed' the pads. This involves the series of medium-hard braking, followed by a period of cooling the brakes after each slow-down (do not stop!). This will help transfer the brake material onto the rotor and allow better adhesion between the pad and the rotor face.
Yes, because once bedded, friction particles embed. That is, bits of the pad become stuck in the rotor. This increases friction, which explains why broken-in, well bedded brakes have a shorter stopping distance than brand new brakes.
The details are here. The author, now departed, was a top brake consultant for the Ford GT program and many race teams.
http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths
