Brake Caliper Maintenance

[JHZR2]

We wear down pads, even in aggressive designs or heavy vehicles, seemingly very slowly. It looks like for our use, >100k will be the norm.

Especially since we have a lot of vehicles thst spread the use, annual mileage is less than average per any one vehicle, with many being much, much less. Even though as a family we drive more annual miles than average.

Im very proactive with brake fluid changes, but think it’s worthwhile to be more proactive, as time allows, on brake services related to the caliper and pads.

What made me think about this is because I need to go investigate a minor squeal from the right rear brakes on my 135i, only when cold and light pressure at speed.... Something isn’t quite right I guess...

So whats the right preventative maintenance on calipers and pads? Seems there are so many variants, each might be somewhat different.

Im assuming that the right thing to do is at minimum, remove the slide pins and grease them/check the boots... but what about removing the pads and lubing surfaces thst they slide on? Anything else?

Whats the recommended process for maintenance?

 

[40w8]

It took me awhile to understand the rear tire and brake pad wear, but it seems the strong ediff on the rear is jerking wheels that spin to a stop, and burning out back up to speed. My X1 s28i runs so much better when I simply put some Akebono Euro ceramic pads all around.

OEM pads will grab like mad, and were great for a few track days, but I didn't drive to ragged edge. Still the front pads had an approx 2" fried interior circle of crumbling crystal which would occasionally squeal and score.

Now it's low dust, smoothing flatter the rotor better, and best of all, I can feel the brake getting firm, but little braking until pressure is applied. Brake feel is perfect for my weak foot.

But, there's more. The rear MP4S are wearing not much faster than the fronts in my staggered 8x18 and 9x18's. First OEM Pirelli summers were worn in back, when front were still over 5/32.

 

[AutoMechanic]

Always check the slide pins for sure. If they dry up they can make the caliper seize up. For pads I don’t bother with them till they start squeaking because they are getting worn down. I’m sure it would not hurt to add some extra grease around the ears though.

 

[Snagglefoot]

Ditto as above and look at the metal inserts that the pad ears ride on. They are supposed to be clean and shiny. If they are grimed up, I would remove the pads and clean up the inserts and the pad ears. A rotary 3M fibre disk mounted in a drill works great.

 

[doublebase]

I always find that rear brakes seem to have more problems regarding rust, seizing up, noise, etc. I think it’s because of lack of use...the fronts do 70% of the stopping...the rears are smaller, cheaper, thinner rotors and pads. I don’t know? I just see rear brakes having more issues.

But yeah, I’d pull them apart, inspect, clean and lube your caliper pins. Check your mounting hardware. Inspect your rotors (I find that they corrode and pit a lot more frequently with limited use). Check your pads, look for usual grooves. Any sign of anything really, because something is making that noise. check the backing plates and hub and bearing surface too. Look for any signs of rubbing.

 

[wwillson]

My friend Bill, the mechanic with 50 years of experience, always checks to see that the pad ears slide freely in the caliper and if they don't he takes a bit off with a grinding wheel. He also says the slide pins need to be cleaned and relubed every time the pads are changed. If the pins have any pitting, then replace them. The pads must slide freely.

 

[Trav]

My friend Bill, the mechanic with 50 years of experience, always checks to see that the pad ears slide freely in the caliper and if they don't he takes a bit off with a grinding wheel. He also says the slide pins need to be cleaned and relubed every time the pads are changed. If the pins have any pitting, then replace them. The pads must slide freely.

He is spot on. I would add using a bottle brush hone on the pin bores if any pin shows any sign or corrosion and change the pin boots if any fit loose (usually expansion from using the wrong lube) or shows damage.
5/16( 8mm) is a common pin size but there are many others, they make these types of hones even in smaller sizes. Just clean out the bore with brake cleaner then lube with WD40 and a few seconds of honing with a portable drill will take care of the corrosion, flush with brake cleaner and lube with silicone paste and a new pin and seal. No need to remove the caliper from the car.

Just measure the OD of the pin and get the same size hone. These are 1/4 and 5/16.

Brush Research - BC8M240AO BC Standard Flex Hone for Brake Cylinders, Hydraulics and Valve Guides, Aluminum Oxide, 5/16" Diameter, 240 Grit (Pack of 1): Amazon.com: Industrial & Scientific

Brush Research - BC8M240AO BC Standard Flex Hone for Brake Cylinders, Hydraulics and Valve Guides, Aluminum Oxide, 5/16" Diameter, 240 Grit (Pack of 1): Amazon.com: Industrial & Scientific

www.amazon.com

Amazon.com: Brush Research 1/4" (6.4mm) Flex-Hone Cylinder Hone Tool 240 Grit (Silicon Carbide) : Industrial & Scientific

Buy Brush Research 1/4" (6.4mm) Flex-Hone Cylinder Hone Tool 240 Grit (Silicon Carbide): Flex Hones - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

[MasterSolenoid]

I always sleep better at night when I have an 'extra' Hardware Kit for my brakes.
They don't cost much money and contain all the parts needed when changing Pads.

It would save time when doing PM on your brakes.

 

[supton]

I get similar miles from brakes. In the spring I break them loose and relube the sliding surfaces. I've taken now to removing the caliper bracket and chucking into a vise, it's just easier to clean under the pad clips (or whatever those SS parts are called). Might as well check to make sure the rotor isn't stuck. There is probably value in pushing the piston in, just a bit, to see if it's still loose; I guess you could crack the bleeder while doing that.

IMO it's important to run a pick around the pad to backing area, make sure delamination is not occurring. I had 5 or 6 year old pad fall off from that, and it was not fun. I've had to replace at least one more set since then, same reason, but because of inspection, I could replace it on my own time.

Reassemble and apply some sort of grease (been using M77 moly for the last few years, seems to do the trick) to the sliding surfaces.. Make sure the pins move freely, relube as necessary.

I like to do a brake fluid flush at this time too.

 

[The Critic]

Always check the slide pins for sure. If they dry up they can make the caliper seize up. For pads I don’t bother with them till they start squeaking because they are getting worn down. I’m sure it would not hurt to add some extra grease around the ears though.

Not all slide pins need to be lubed. For a number of years, BMW spec'ed no lube on the guide pins.

 

[Hall]

the fronts do 70% of the stopping...the rears are smaller, cheaper, thinner rotors and pads. I don’t know? I just see rear brakes having more issues.

In modern cars, I don't think the 70% number is accurate anymore. Systems are closer to 50/50. That said, the automaker still are using smaller calipers, pads, and lighter-duty rotors and this is why people see faster wear on rears.

 

[SubLGT]

My friend Bill, the mechanic with 50 years of experience, always checks to see that the pad ears slide freely in the caliper and if they don't he takes a bit off with a grinding wheel.

Some manufacturers, like Honda and Subaru, want a specific moly lube on the pad ears.

 

[supton]

Some manufacturers, like Honda and Subaru, want a specific moly lube on the pad ears.

You have to wonder what they are doing different to require something specific--or if it even matters.

 

[SubLGT]

You have to wonder what they are doing different to require something specific--or if it even matters.

I use Dow Corning Molykote M-77, a silicone based moly grease, on my Subaru pads. The pad ears can corrode at the contact point with the bracket, and get frozen in place, especially at the rear pads.

Honda also recommends it:

Amazon.com: Honda HN 08798-9010 MOLY PASTE (M77) : Automotive

Amazon.com: Honda HN 08798-9010 MOLY PASTE (M77) : Automotive

www.amazon.com

 

[The Critic]

You have to wonder what they are doing different to require something specific--or if it even matters.

It is probably just a cultural decision at one company to do things a certain way.

 

[JeffKeryk]

I dropped a friend at San Jose International airport last Thursday. I drove his 2007 TSX (104K) home and noticed a slight pulsation in the brake pedal.
This car was purchased new by my sister so I know the history. The back pads have been replaced one time by my BIL; they current pads were nearly done for, so I purchased a set of Centric ceramics from Amazon.
The driver side inboard pad was worn unevenly, possibly causing the pulsation, not sure. After replacement, the car feels good.
So an inspection, cleaning and proper lubing of brake components seems in order to me.

 

[KGMtech]

For most cars and CUV. SUV, the OEM's have shifted the braking to be more rear axle based for most stopping. Less front end dive, less chassis upset for general driving. IF heavy braking is requested, then fronts get the call.

 

[Rand]

I use pastelub on the pad ears. one tub is a lifetime for me.

Pastelub™ Synthetic Hi-Temp Brake Lubricant | BPL-2400

Pastelub High-Temp Lubricant from Goodson is OE recommended and won't melt, rub or wash off brake parts. No silicone or petroleum products.

goodson.com

and sil-glyde on the pins.

sil-glyde is also great for door and truck seals.. for that guy who wanted 100% silicone and not a spray lube.

 

[Hall]

sil-glyde is also great for door and truck seals

I put a tiny dab on light bulb threads. They don't get "stuck" this way. Also, on outside lights as well as the garage door opener lights, the bulbs seem to be lasting longer

 

[Donald]

In the rust belt I think its best to clean and lube the disc brakes once a year. I am working on a better solution and that is to move to an area where little salt is used.

I remove the caliper and bracket. Pull pads from bracket. Remove the SS clips. FIle then wirebrush the areas under the clips. Or bead blast. (Optional is to paint that area with primer). Then pastelub in that area and clips back on after cleaning with brake cleaner. Wipe off the ears of the pads and use a little Permatex purple lubricant and push back into the clips.

Remove caliper pins & remove boot from caliper bracket. Clean both in brake cleaner. I also fill the bore the pin came out of with brake cleaner and get out and grease and dirt. Caliper pins should be pristine, no rust or pitting. Do not wire brush replace if not pristine. Inspect boot for swelling or tears or cracks. Grease could have been used that would cause the boot to swell. Replace if any swelling. Sil-glyde on pins.

Slap it together and your good for another year in the rust belt.