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Topic: How long did your brakes last.? (Read 12 times) previous topic - next topic
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How long did your brakes last.?
Yahoo Message Number: 111230
Yesterday, I pulled the wheels off, one by one, to check the brakes on our 2003 FL.
At 51,000 miles, 60% of that towing a 4000 lb Jeep, I thought it might be time for a brake job and accumulated the needed parts over the last week or so in case my suspicions proved correct.
I was surprised to find 40% of the pad lining remaining and everything wearing evenly. A little lube on the slides and back together it went.
I will check them again in another 10,000 miles.
 My only complaint about the brake is how loud they squeak, especially when driving around campgrounds.
2001 MB
* Not to be confused with Larry W (3000 of my posts are actually from expert Larry W due to Yahoo transition mis-step)
Re: How long did your brakes last.?
Reply #2 –
Yahoo Message Number: 111319
I have a 2000 24 foot FL with 71000 miles.   I did  a brake job yesterday and had about 1/16 inch of pad left,  So I assume that is beyond the thickness which is safe.  I'm glad the Ford dealer caught it on a routine inspection.  Hope this helps.  I think 50k would be a good time to start checking depending on your driving conditions.
And BTW, don't pull the wheels, thats a big job, just crawl under it with a flashlight and you will see the pads.  Tx as needed. I replaced the calipers while I was at it.
Re: How long did your brakes last.?
Reply #3 –
Yahoo Message Number: 111324
We have an 02 MB with 73000 miles. I just replaced the rear disks and calipers which were totally worn, pads in the front were also replaced. I bought this unit with 71000 miles knowing that this was a possibility.
I think that being the first brake change is pretty good for a rig of that weight.
Re: How long did your brakes last.?
Reply #4 –
Yahoo Message Number: 111326
Stephany, If you search the Searchable Archives for the Sender, Kenn Sann you will find a number of threads regarding Ford brakes.  As for your brake noise check message number 64864 for one theory.

Malcolm Blue02MB With Periodic Squeaking Brakes
2002 Mid Bath
Re: How long did your brakes last.?
Reply #5 –
Yahoo Message Number: 111341
Just out of curiosity what was worn in the calipers. I am not sure I even know what that means..
Do you mean the calipers were dragging and had worn the rotors?

Thanks
Re: How long did your brakes last.?
Reply #6 –
Yahoo Message Number: 111344
Suffice it to say that all brake parts (disks, rotors, pads) were replaced in the rear of the coach. In the front only the pads were replaced.
Re: How long did your brakes last.?
Reply #7 –
Yahoo Message Number: 111348
The most common cause of caliper failure is actually that it stops sliding.
Keeping them properly lubed is of huge importance, too many people just swap pads during a brake job. In reality the calipers should be inspected (slides, dust boots, pistons (if phenolic, to look for chipping/cracking, but Ford truck calipers use a Stainless shield for the piston face)), rotors measured*, and visually inspected for blueing and fissure cracks, and brake hoses for flexibility and visual condition (brake hoses usually fail from the inside, not the outside, but if they are still decently flexible, you have a better chance that they are not disintegrating internally).
I have worked for foundation brake manufacturers most of my life (until just a few years ago)(I was at Kelsey-Hayes, then we were bought by Lucas, then by TRW), I have also spent a part of that time in the caliper (and other parts too) remanufacturing (4-6k calipers per day were being rebuilt in that facility), and I will tell you definitively that the huge majority of calipers changed (they were sent in to us for rebuilding, but we would inspect them), and almost always they were fine. Customers were oversold.
But to a mechanic, he makes more $ in less time by selling these (high markups, few comebacks, and lots of labor). Now actuated calipers (where the parking brake is a part of the caliper assembly) were almost always bad when we received the cores.
Basically the way that a caliper works is that it has a small chamber filled with brake fluid, and when you press on the pedal, the Master Cylinder displaces fluid downstream (well, anywhere that it can go, but path of least resistance...), one side of this cylindrical chamber has a piston, as it is easier to push the piston instead of flexing the actually casting, it puts pressure on the piston, the opposite side of the piston is the inboard pad, this pad then pushes against the rotor, which being a relatively hard iron, doesn't deflect (race cars use floating rotors, totally different story), so the back of the caliper body deflects back away from the rotor, as the caliper casting crosses over the outside of the rotor and retains the outboard pad, it pulls on that pad, against the opposite side of the rotor.
The key here is that the caliper can slide (plunge technically) in and out, inflicting an equal amount of pressure on the inboard and outboard pads. If the slides are not lubricated, they will start to seize, and you no longer have equal pressure on both pads. This is called a 'sticking caliper' by most people. Quick indicators are unequal pad thickness, and or one side of the rotor blued and checked (small cracks in the surface of the rotor, usually not penetrating deeply). This does not mean that the caliper is bad, it can easily (unless the slides are rusted already) be saved. Btw, none of this applies to 'Opposed Piston calipers', but this does apply to almost all cars and trucks, and to all Ford & Chevy Trucks/Vans.
Now, rotors. On trucks such as these, they are extremely heavy, this is not for strength, but rather so that they can act as a heat-sink, temporarily absorbing more heat than they can rid themselves of. Think about a panic stop, you are adding an enormous amount of heat into those rotors in just a few seconds, it might take them minutes to cool back down. as rotors wear, they become thinner, and as they become thinner, they have less mass, so they can no longer retain as much heat, so they run hotter, and wear faster, and get thinner, and get hotter, rinse, and repeat. At some point, since they can no longer deal with the heat, they warp, and you get a pulsing pedal. Cast into the rotor is a 'Discard thickness' spec, and that is the point that the manufacturer no longer feels that they are able to sustain a safe system. Many people machine them ('turn rotors') below that point, and that is dangerous. Do NOT skimp on rotors.
There are many junk rotor manufacturers out there, and there are some quality rotor manufacturers. The vast majority are made in China, and there is some good stuff, and some really bad stuff. Often cheap rotors are made from a lower quality iron, and poor castings, they will not last nearly as long. Btw, many mechanics tell the end customer that they are buying the best rotors available, but in reality are buying the cheapest. Sad.
Brake fluid, it is very special stuff. It is a hygroscopic liquid (meaning that it absorbs water, even out of air, truly). Flushing the system is very important for the life and performance of the system. Insist on a high quality brake fluid (DOT 4 or DOT 5.1, never DOT 5 (silicone, it will exponentially extend the life of the system if properly installed (that means the entire system is disassembled and cleaned out first) but you will never get a firm pedal with it, making it feel mushy, a great trade-off on a restored classic car, but not something like these vehicles)). The most important measure of a brake fluid is called the 'Wet Boiling Point', as that means that it has a small amount of moisture (which is reality) as opposed to a Dry Boiling Point (who cares how well it does in a lab, I care in my vehicle), the higher the better.
I assume that most people have already deleted this email as it is boring, but for the one or two that are interested, brakes are a pretty simple system.

Ken Sann

still a wannabe in SoCal
Re: How long did your brakes last.?
Reply #8 –
Yahoo Message Number: 111349
On Mar 27, 2010, at 7:14 PM, Ken Sann wrote:

Quote
I assume that most people have already deleted this email as it is boring, but for the one or two that are interested
Thank you Ken for a most informative post.
I am going to print it out and file it in my maintenance folder under "Brakes".

Cheers, Don
Don & Dorothy
Sold our LD in June of 2023

Our boring always non-PC travel blog
Traveling Dorothy
Re: How long did your brakes last.?
Reply #9 –
Yahoo Message Number: 111350
I should add that I have toured many brake manufacturing facilities, on several continents, and one of the absolute leaders is Akebono, which is a Japanese company, that has not only their own manufacturing facilities in the US, but also has several joint venture facilities (under the names 'Ambrake' and 'Amak' (if memory serves me)) and they made the Ford truck brakes for many model years. I am not sure of which years, but I can easily get that information.
 Also, on a typical car, the front brakes do 70+% of the stopping, so the front brakes are much larger, but on a truck, the rears actually do more, so they typically wear faster. Think about it this way, when you brake in a car, not only does it transfer the weight forward, increasing the front tires contact patch (so they it has more potential traction, can brake harder before locking up), but most cars already start with a forward weight bias. Now, truck, are the opposite. The rear wheels carry close to twice the weight of the fronts, offering more potentiality traction, hence more braking ability.
An extreme example of this phenomenon would be a sport-oriented motorcycle like my BMW (K1200S) which has two fully-floating front rotors of 13.2" diameter, each squeezed by six-piston calipers, and a tiny (less than 9" diameter) rear brake with a tiny rear caliper, but in extreme braking, bikes loft the rear tire (called a 'Stoppie', the opposite of a Wheelie), so there is absolutely no braking effect from the rear, 100% from the front.
 Really saddens me to see customers being taken advantage of by unscrupulous mechanics/salespeople.
 Having seen destructive testing on brakes, from calipers, to pads, to rotors, it is incredible. They will literally run a rotor red-hot for days straight. Amazing, but also comforting to know that these are protecting us.
 If anyone has specific questions, feel free to email me or post it here.

Ken Sann
626.590.3384
Re: How long did your brakes last.?
Reply #10 –
Yahoo Message Number: 111352
Ken

Ken Would you use rebuilt calipers? I always have and I had never actually seen a worn our caliper. Usually only a sticky piston and I usually trade in for rebuilt calipers.

For drum brakes I almost always just install new cylinders. I have found that rebuilding at home isn't worth the effort any more. I don't do work for others but until day before yesterday had 5 vehicles all but one with well over 100k and some with over 200k so get more practice than I care for.
 I have used several of the cheap rotors over the years and I guess I have been lucky as I haven't had any problems.

Are the cheap rotors dangerous or just wear faster?
 I know that Workhorse is having some real legal issues over the Bosh brakes they used.  And though as far as I know Workhorse is the only one with large legal problems the Bosh brakes were used on many other brands.

Thanks Garry
Re: How long did your brakes last.?
Reply #11 –
Yahoo Message Number: 111353
Bosch is the worlds largest brake manufacturer (when I still worked for Lucas, we were at that time #2).
Yes, I do, and plan to continue to use Rebuilt Calipers. I like them, they are clean, slides are properly greased, and pistons move well on the square-cut-seals.
And like you, if I am doing anything more than a shoe and hardware swap on drum brakes, I will just replace the wheel cylinders. I wouldn't rebuild unless a classic car and they were hard to find (in which case I would probably have them sleeved).
On a caliper (excluding a few American cars from the 60s with four piston calipers), the actual caliper casting doesn't wear out. There is a slightly tapered groove in the casting, in which sits a square-cut-seal, and the piston slides in and out only contacting the seal, never the bore of the caliper. So in reality, a caliper never wears out, only the piston wears (and with hard plated pistons, they usually do no, but phenolic pistons do (however phenolic pistons have some huge benefits, if given the option, I would take Stainless faced phenolic pistons as the perfect material).
Therefore, the only other parts of a caliper that are susceptible to wear are the slides (and if they are properly lubed, they shouldn't be an issue), and potentially the bleeders (but if using a proper flare-nut wrench, they shouldn't either).
 Cheap rotors are not dangerous per say, just do not expect the life-span of a higher quality rotor, and they will also reduce the life-span of the pads, by not dejecting heat as efficiently. But again, not a huge difference. I am lazy, I like my brakes to last a long time, I drive a lot of miles, and ride my bike a lot of miles.
 Btw, as brake squeal has been mentioned, let me explain that in another way.
Simple, noise is vibration, pulses of sound waves in the air. To eliminate audible brake noise, you need to figure out what is vibrating. Very often the pad to rotor interface is the culprit. A combination of glazed rotors and over-heated (surface heat-treated) pads that cannot 'bite' into the rotor. all quality pads have shims (usually a constrained multi-layer shim, which is a thin sandwich of several different materials), the idea of the shim is to reduce the frequency of the vibration, hopefully to a much lower, less noticeable pitch. Not really curing the actual problem, but they do a great job of masking the symptoms. Nothing wrong with it, as most original pads are shimmed too. Often the leading and trailing edges of a pad are tapered, which actually has several effects, not only does it reduce the size of the contact patch between the puck and the rotor, but it also can reduce the vibration by lessening the initial bite of the rotor. Pads do not actually so much slide against the rotor surface, but at a lower level they are transferring material to the rotor, and glazed rotors are a very slick surface, making this friction harder to attain, so the pair vibrate as they try to grab, slid, grab, slide.
 Finally, I will briefly touch on 'Slotted' or 'cross-drilled' rotors. The first street car to utilize these was the 1978 Porsche 911(930) Turbo.
Everyone was in awe, but most people do not realize that these holes were not drilled into the rotors, but actually cast in. Rotors that are designed to be drilled or slotted, are fantastic (I will explain why in a moment), but rotors that are drilled or slotted by anyone that has not first done the engineering analysis, is just looking for trouble. A lot of the holes do not line up properly with the internal vane structure (most rotors use straight, not curved vanes, but even back in 1978, those Brembo brakes on the 911 turbo were curvilinear vanes, with cast in ventilation holes). In my personal experience, most aftermarket drilled rotors crack, causing noise (way before the point at which they fail).
Now the benefits of drilled or slotted rotors are twofold, one being that they evacuate water very well, so offer a better intial bite in wet weather, secondly, they allow the pads to vent gasses (all pads are gaseous when they get hot) without trying to force the gas out between the pad and the rotor face, reducing the boundary layer of gas. As the rotor spins, the slot (or holes) pass by the pads, allowing this escape. If properly done, they also offer slightly more surface area, for heat dissipation, but inversely offer slightly less mass for a heat-sink. For the street, slotted has all of the benefits of drilled, and less chance of cracking. Btw, if you ever see a cross-drilled or slotted rotor, run your finger along the hole or slot, if it is a sharp edge, put the rotors back in the box and walk away. This should be chamfered, reducing the stress risers in the area, reducing the chance of cracking.
On my daily driver car, I use slotted rotors (although my current car, i have not yet changed them, the originals are not worn out yet). My motorcycle has cross-drilled holes (it is not a cast rotor like a car or truck).

There, a bit more to glaze peoples eyes over.

Ken Sann

still a wannabe, that currently camps with a motorcycle and a motel
Re: How long did your brakes last.?
Reply #12 –
Yahoo Message Number: 111357
Quote
I assume that most people have already deleted this email as it is boring, but for the one or two that are interested, brakes are a pretty simple system.

Ken Sann
A very informative and understandable post.  Thanks for taking the time to do this, Ken.

Ed
Re: How long did your brakes last.?
Reply #13 –
Yahoo Message Number: 111358
On Sun, Mar 28, 2010 at 1:32 AM, Ken Sann  wrote:

Quote

There, a bit more to glaze peoples eyes over.

Ken Sann still a wannabe, that currently camps with a motorcycle and a motel

On Sat, Mar 27, 2010 at 9:52 PM, Garry Foster  >wrote:

A whole lot of snipping for bandwidth conservation..
Ken Thanks For all the great information.
Eyes aren't glazed and I believe you could keep me interested for a whole book on brakes. Rare to find some who actually knows! Garry

[Non-text portions of this message have been removed]
Re: How long did your brakes last.?
Reply #14 –
Yahoo Message Number: 111359
Thanks everybody for the comments.
I have a decent understanding on most areas of the vehicle, but please do not ask me about either automatic transmissions or electrical systems. I have long ago decided that they cannot possibly work, so there must be some voodoo or something involved. Seriously, those are two areas that I just cannot wrap my head around.
Suspension, steering, engine, got it, those are as easy as brakes. When I was at TRW, I was heavily involved in suspension and steering.

Ken Sann still a wannabe that let all of my ASE Certificates lapse many years ago