Brake pad contact footprint.
Discussion
Random question. My brakes are squeeling, so I poked my head underneath when I had 5 minutes yesterday.
New discs and pads. Old calipers.
On the rear, the marks on the discs are wider on the outer side of both rears. The contact patch looks smaller on the inside of both rear brakes.
Is this normal? Same pads. The fronts look even.
New discs and pads. Old calipers.
On the rear, the marks on the discs are wider on the outer side of both rears. The contact patch looks smaller on the inside of both rear brakes.
Is this normal? Same pads. The fronts look even.
Richyvrlimited said:
Please don't use copper grease for that. Use an appropriate slider pin grease, (red rubber for example). Copper slip is an anti seize compound for fasteners. When used on brake components that get very hot it gums up and causes the issue you describe.
Good advice about which lubricant to use correctly.Effectively cleaning and lubricating the Calipers and their Sliders can improve brake operation so much so it can give the impression of a brake upgrade.
I was reminded of this on my daily driver Rover 620ti recently which I've had for ten years now. Drives and brakes well and no brake problems come each Mot test. Even so, decided to give all four brake calipers some TLC when fitting new pads all round. I was very thorough with the cleaning and using the correct lubricant and grease on the various parts of the Calipers and pads paying particular attention to the sliders and the way they move. For good measure used fresh Brake Fluid and bled the system all round.
What a difference! Brakes now superb! Forgotten how good they can be.
It is so easy to assume everything is as it should be when brakes are not even an advisory on the MoT each year. However, the loss of efficiency is so very gradual over the years that it passes unnoticed. I think fresh fluid in the system played a good part here in addition to the TLC and new pads.
I use Castrol LM Grease for the sliders after thoroughly cleaning up the slider pins and their locations to ensure good sliding movement. I do this because I have known poorly maintained calipers to have one or more sliders seize solid and thus unable to move, that's bad news for Brake operation. I have seen one side of a ventillated disc surface worn right through beyond one friction side of the disc completely into the ventillation webbing owing to seized sliders. Not my cars, but when someone asks..
Can you look at my brakes John, they're making a funny noise.
Not as bad as this image of a disc worn right through to the vents I've pulled off the web but almost as bad :~
Keep in mind some manufacturers, BMW for example, do not recommend lubrication for their sliders. Some BMW Caliper Sliders slide in rubber housings which do not need lubricant according to manufacturer guidelines.
Have a look at this thread I put up on the subject. I have always used LM Grease on the sliders in my Rovers and MGs with excellent results. Never Copper Based grease on the sliders.That is designed as an anti seize lubricant and that or other greases could be harmful to the rubber slider housings on some BMW Brake Calipers. My MG ZT 1.8t has numerous BMW Components on it, including the front brake calipers which clearly show BMW. I have used Copper based grease for many years as an anti-seize measure on threads, shanks, shafts etc of nuts and bolts and similar fasteners to aid remove at a later date. I hate working with corroded and seized fasteners. can put a hour or even a day extra work on a job.
Here's the thread. Some of the advice on it I would stress needs to be thought about rather carefully. Certain lubricants will degrade rubber components like those the BMW slider are house in.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Have a look at this thread I put up on the subject. I have always used LM Grease on the sliders in my Rovers and MGs with excellent results. Never Copper Based grease on the sliders.That is designed as an anti seize lubricant and that or other greases could be harmful to the rubber slider housings on some BMW Brake Calipers. My MG ZT 1.8t has numerous BMW Components on it, including the front brake calipers which clearly show BMW. I have used Copper based grease for many years as an anti-seize measure on threads, shanks, shafts etc of nuts and bolts and similar fasteners to aid remove at a later date. I hate working with corroded and seized fasteners. can put a hour or even a day extra work on a job.
Here's the thread. Some of the advice on it I would stress needs to be thought about rather carefully. Certain lubricants will degrade rubber components like those the BMW slider are house in.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff