Mechanically Inclined

[Delw]

Don't be so sure what people havent done for a living schmalts, been there done that for a number of years. don't forget most of us are talking older type stuff, they used different materials than they use now. I havent touched a car in 15 years? don't want to see another one either.

Also done a bunch of big rig/air craft/and other heavy equipment brakes on 72" lathe. a simple 10 min turning job goes for a few hours not to mention making production disc brake rotors for various vehicle companies over the years in my machine shop and a machine shop I worked at, made rotors out of everything from cast to 4130 and even alum. from 4" dia all the way up to what that 72" machine can hold( i think they were like almost 60" dia.) almost every piece called out a no better than a 125v- or 250v- finish with the exception of some specialty stuff and it was usually small. oh yeah there was also brakes for billy boats race car back in the early 90s it was one of Aj foyte's cars when billy first started racing the indy ciruit. I did lots of there car work.

Remember I don't make parts with out a print and call out, so I am ust saying this is what has been called out.

 

[schmalts]

Then answer this... If the F'in brakes are not pulsating, why would you cut or replace the rotors? Smooth or "glazed" rotors will not make brakes underperform. The finish is a mute point because any glazed finish will somewhat be altered by the roughness and metallic content of the new pads within a few miles! Glazed and warped are different things, but a surface finish can never be too smooth to cause a problem when just installing pads.
You state that you print called out for "No Better" than 125-250V finish. There is a reason for it, there was no reason to spend the time to make it any smoother because the pads will do it in short order anyway. Take your 125-250 finished rotors, go beat the crap out of your truck for 100 miles and measure the finish and tell me that it isn't smoother. And it will still stop. You got it in your head that too smooth of a rotor finish will effect braking in Ovis's case. That you are wrong on. In fact, on the rougher end it will stop worst because it will get hotter from the rougher finish and end up with brake fade.
Sorry, but making a rotor doesn't make you a mechanic. Thats like saying making an aircraft rotor makes you qualified to fly it

 

[elk_hunter]

Damn guys, this is one of the best threads ever!

 

[guppie9]

OK, here's my question than. I am getting ready to replace my pads (my buddy is showing me how, I've never done it before). How do I know if the rotors are OK? I know huge gouges would be bad, but what else should I look for? Do I need a special kind of caliper to measure the thickness?? Any pointers/suggestions for changing the pads on a 2004 F250??

 

[TLC]

for a 2 wheel drive, take the bolts out that hold the caliper in place. remove the caliper. compress the piston. pop the old brake pads out. put the new pads in and put the caliper back in place. check the brake fluid reservoir and make sure its full. pump the brake peddle a couple times. then open the brake lines on the calipers one at a time to bleed the air out of the lines. when the peddle is hard again, refill the reservoir and finished. hope this is how they still do it. been a few years(25-30)since I did it last.

as far as the rotors, unless you have major ruts in them, you should be fine. how many miles do you have on it? and how do the old pads look? if smooth, would think you'd be OK. and if all else fails, take it to a walmart or somewhere and have the tires rotated and ask them to measure them for you.

 

[Delw]

Then answer this... If the F'in brakes are not pulsating, why would you cut or replace the rotors? Smooth or "glazed" rotors will not make brakes underperform. The finish is a mute point because any glazed finish will somewhat be altered by the roughness and metallic content of the new pads within a few miles! Glazed and warped are different things, but a surface finish can never be too smooth to cause a problem when just installing pads.
You state that you print called out for "No Better" than 125-250V finish. There is a reason for it, there was no reason to spend the time to make it any smoother because the pads will do it in short order anyway. Take your 125-250 finished rotors, go beat the crap out of your truck for 100 miles and measure the finish and tell me that it isn't smoother. And it will still stop. You got it in your head that too smooth of a rotor finish will effect braking in Ovis's case. That you are wrong on. In fact, on the rougher end it will stop worst because it will get hotter from the rougher finish and end up with brake fade.
Sorry, but making a rotor doesn't make you a mechanic. Thats like saying making an aircraft rotor makes you qualified to fly it

Hey peckerwood I'll let you have this one the newer brakes do require a 32-63 finish. just did a long search for them.

http://www.aa1car.com/library/brake_rotors.htm

the finish requirement wasnt due to a time factor it was due to the contrants the people wanted there brakes at. cause time between a 125-250 finish and a 32-63 finish would have been less than a tenth of a second on most parts.

however reading more about it I believe the surface requirement was due make the brakes seat better and more evenly. As you know back in the old days the run out was pretty bad on producton work, new machines set-ups and everything else run out of .0005 or less anymore is nothing.

I turned wrenchs for 2-3 years on vehicles ( and 6 -8 years on outboards)but I was into cars back then, hell now I dont even check the oil I just send it to the garage for a oil change. wouldnt care if I didnt looked under the hood of another vehicle for the rest of my life. well maybe with the exception of another 69 rs ss 396 camaro that The Warden wants to get again.
Its all about fast bass boats now they don't have brakes so I dont have to worry about them LOL.
Heres my latest project one that I have to complete LOL
http://www.azbasszone.com/forums/showthread.php?t=77621

 

[schmalts]

"You don't want smooth)as in shiny) rotors as they will not brake properly"
So, now your admitting i am right about pad break in and a smooth finish will actually help brake performance. Also admitting your called out finish was not asked to be smoother for breaking performance, but because it didn't need to be for cost? Sad thing is you had to research it and are back pedaling now. If you polished your rotors to a mirror, it would brake fine, and wouldn't stay that way because the pads would scuff it out to what they want anyway.
Dude, I didn't even get theory and mechanical on you yet. Back to the whole "glazed" bullshit, thats where i will want to hear you admit your wrong, that too shiny a finish will not make pads stop a car worst than a rough finish.
And comparing that theory to a flywheel?? Just absurd as they have such a different application it is funny. As to a flywheel, in your theory if it is too shiny or "glazed" it will not work because it will slip is also bullshit. It won't slip, it actually will chatter. reason?? because it grips too well on light pressure with that nice smooth finish and that is where you get chatter.
As for brakes? too smooth is never an issue for braking compared to clutch performance. Why?? the mechanical advantage. Do some research and look up how much psi is exerted by a hydraulic caliper via vacuum assist, VS a mechanical spring pressure plate of a clutch. Then there is the fact you do not want brakes to actually grab, or you get less stopping performance in a lock up situation so they are made to "slip" instead of grab.
So when are you going to tell Ovis that is his rotors are true and there is no pulsation that he need not cut them just to rough them up so the brakes will work? Because that is what you have been pushing until just now

 

[pa mt man]

Schmalts, I'm starting to like Elkgunner more than you.

Del is right as far as not assuming we are just machinists.

I am just giving my opinion.

I'd like yours on replacing a leaking caliper. I have replaced quite a few over the years and I just replace the leaking one. No problem. My friend is a mechanic and said you have to do both.


What's your opinion and why?

Hey, now I'm even sounding like the gunner!

 

[JoseCuervo]

Schmalts, I'm starting to like Elkgunner more than you.

Del is right as far as not assuming we are just machinists.

I am just giving my opinion.

I'd like yours on replacing a leaking caliper. I have replaced quite a few over the years and I just replace the leaking one. No problem. My friend is a mechanic and said you have to do both.


What's your opinion and why?

Hey, now I'm even sounding like the gunner!

But you'll never be as good lookin'......

 

[Delw]

So when are you going to tell Ovis that is his rotors are true and there is no pulsation that he need not cut them just to rough them up so the brakes will work? Because that is what you have been pushing until just now

I havent been pushing anything just answering your dumb questions

as far as when I am going to tell ovis, that would be equally dumb as just like you I havent seen his application, you can only go on the words that are written......so how can someone tell someone the properay to fix something if they havent seen the parts to be worked on, that would be like a customer calling you up and saying my car is making a funny noise whats wrong with it....

that would be an "E" mechanic wouldnt it.?

 

[cjcj]

everything else run out of .0005 or less... Delw... did you mean .005?

 

[schmalts]

Schmalts, I'm starting to like Elkgunner more than you.

Del is right as far as not assuming we are just machinists.

I am just giving my opinion.

I'd like yours on replacing a leaking caliper. I have replaced quite a few over the years and I just replace the leaking one. No problem. My friend is a mechanic and said you have to do both.


What's your opinion and why?

Hey, now I'm even sounding like the gunner!

well if it is a factory replacement caliper you should not have to do both. if it is a remanufactured unit your putting on, sometimes the piston bores are larger from the honeing and they may use an oversize piston. The difference in piston size between a factory and reman will cause a difference in the pressure applied to the pads and you can get a brake pull.
Hope this helps. One thing to consider is it may be cheaper to buy the factory part rather than 2 remans

 

[cjcj]

But you'll never be as good lookin'......

Show us a pic... from the 80's or recent

 

[schmalts]

I haven't been pushing anything just answering your dumb questions

as far as when I am going to tell ovis, that would be equally dumb as just like you I havent seen his application, you can only go on the words that are written......so how can someone tell someone the properay to fix something if they havent seen the parts to be worked on, that would be like a customer calling you up and saying my car is making a funny noise whats wrong with it....

that would be an "E" mechanic wouldnt it.?

Bottom line, all I said was you do not cut or replace rotors unless they are undersized, or pulsating. I know enough to know that any brake rotor that is not making noise, or pulsating, is not warped, gouged, or hard spotted enough to do so. If it was working with worn pads, it will work with new ones. That "glazed" finish is perfect for stopping although it may take 30 miles longer to break those new pads in, I bet Ovis has strong enough legs to push the brake pedal that extra 5% until then. That's where experience comes in. No offense, but 3 years as a mechanic? You still had a lot to learn, as being a good mechanic takes a lot longer, and the learning curve and new technology needed never ends. I don't work in car dealerships anymore, haven't for almost a decade now and I will admit that changes already are so great that It would take me a couple years just to get back up to speed on cars. Even more so in the area I specialized in the most, Drivability and electrical. Really I wasn't a mechanic, I called myself an auto technician and there is a big difference between the schmuck at Midas Muffler and someone doing warranty repair in a dealer on engine, trans, fuel and emission systems. I feel bad for the guys working in dealerships. They are underpaid for what they have to know, and the amount they have to spend on tools to just do the job. The bad thing is there is so many Hacks working there as well, because good technicians are so hard to come by that they fill open spots with any warm body and those guys give them all a bad name.

 

[schmalts]

for a 2 wheel drive, take the bolts out that hold the caliper in place. remove the caliper. compress the piston. pop the old brake pads out. put the new pads in and put the caliper back in place. check the brake fluid reservoir and make sure its full. pump the brake peddle a couple times. then open the brake lines on the calipers one at a time to bleed the air out of the lines. when the peddle is hard again, refill the reservoir and finished. hope this is how they still do it. been a few years(25-30)since I did it last.

as far as the rotors, unless you have major ruts in them, you should be fine. how many miles do you have on it? and how do the old pads look? if smooth, would think you'd be OK. and if all else fails, take it to a walmart or somewhere and have the tires rotated and ask them to measure them for you.

Correct, nothing much has changed. If you have no pulsation when braking, and no deep gouges or brake pulls the only thing you would need to worry about is if the rotors are undersized. Very small chance of that though if they are working fine. You can take a micrometer and measure them, or even a caliper from your reloading bench but the micrometer is better as it will measure past the rust groove on the outermost surface area if you know what I mean. The flat jaws of a caliper will hit that rust groove where the pads do not ride on. You should be able to get the discard thickness spec from your parts store that turns rotors, and most many are stamped on the inside surface sometimes.
A lot of cars the aftermarket rotors are cheaper than turning them, so price around before turning any rotor. I remember when I had a 1994 Chev Cavalier, I could get them for 12$ why the hell would I even turn them even though I had a lathe to do it! Oh the good old days...
Another reason turning brake rotors every brake job became common was the fact that the old cars you needed to take the time to take off the rotor to repack the bearings anyway. While you had the seals out, and the grease cleaned out it just made more sense to take the extra time to turn them. But in those day, they gave you some meat on them rotors and you could get away with them being turned a few times before they went undersized. Now they are so cheap they are close to discard even if they clean up in one pass on the lathe

 

[guppie9]

How long can you reasonably assume rotors will last? If you haven't gouged them or worn them down due to your pads being worn out, what is an approximate mileage? I just wonder, because I have about 65,000 miles on my truck and am going to replace the pads myself. I know if there are big gouges and such, that I will need to either turn them or replace them. I'm just wondering if there is any way to kind of "eyeball" them. I don't have a micrometer and am assuming that might be kind of a spendy item.

 

[schmalts]

Guppie, no answer to that. It is crazy, some guys will get 60K out of pads, and another guy with the same truck will get 25k. Driving habits matter a lot on brakes, as well as HWY vs City miles.

 

[Delw]

Guppie, no answer to that. It is crazy, some guys will get 60K out of pads, and another guy with the same truck will get 25k. Driving habits matter a lot on brakes, as well as HWY vs City miles.

I'll even agree to that 100% and add in it all depends on where you got your vehicle worked on and whats parts they use.
There is some real crap out there which can be mostly found at checker pepboys and autozone. Agree Schmalts ?

 

[schmalts]

.
There is some real crap out there which can be mostly found at checker pepboys and autozone. Agree Schmalts ?

Yea, aftermarket pads can very a lot in quality. Some will squeel like crazy, some not. Rotor life should be a looong time unless they are cut, or abused from neglect the rivets or backing contact.
But.... some rear rotors (if equipped) need to be replaced from lack of use of all things. Since they do not handle much of the braking, and usual crappy sticking caliper slides they have a habit of getting a lot of rust spots and pits that can get real deep and actually start to flake apart in the northern states.
Anyone ever had a Chevy Lumina or Olds W-body from the 90's?? I bet you loved those rear disk brakes

 

[TLC]

Guppie, going to add one thing to Scmalts' post. in addition to what he said, hauling will put a strain on the brakes when used. harder to stop a load than not. if you have used your vehicle for mostly every day driving, you should be fine with the rotors. because there is a trailer behind my truck almost every day, ranging from 12 to 16 foot work trailers, to 14 or 20 foot boat trailers, have mine turned around 90-100,000 miles. and I usually keep them for around 200,000 miles. go thru roughly 4 pad changes and 1 rotor turn in that time. and have 3/4 ton 4x4's. ford and dodge.