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i guess i would have to ask why you need some high-tech method of measuring the thickness of you brake pads. just a quick eyeball check should tell you what you need to know. i usually start getting suspicious of mine when i can see that there getting down to about 3/16" thick or so (or if they start making noise). now, if you're wanting to measure the thickness of the ROTORS, that's another story. however, what you have to concern yourself about here is warping. you may get a good read of the rotor thickness with the right equipment, but it's hard to take into account for warping. only good way is to throw the rotor on the lathe and see what happens. a word of caution: 00-04 brake rotors on non-SVT foci were so thin that they were highly prone to warp and left little material thickness to machine off to compensate. most just end up buying new rotors.

and you can find calipers and micrometers pretty cheap nowadays. a decent digital shouldn't be more than $20-30.

Mike

 

Well, I would like to know exactly what it is, not just a guess.

What is the minimum pad thickness for rear focus disc brakes? What is the thickness of the backing plate (for reference)?

 

If you want to know "exactly" then you will probably have to take the pads out and measure with a ruler. What the eye can measure is "exact"enough. Also, you might be able to peek your head in there and use draftsman dividers. But exact is not necessary. Technically, you can leave then in until they wear off the metal, but don't know if the piston will move out too far. A good measure is 1/8 inch. Generally one of the pads wears faster than the other because while the piston will pull back into the caliper, the caliper might not center itself on the slide surfaces because of rust, dirt, or just plain friction. If they get down to 1/8 inch, change them and don't worry about the fine tuning.

 

Well, I would like to know exactly what it is, not just a guess.

What is the minimum pad thickness for rear focus disc brakes? What is the thickness of the backing plate (for reference)?

i'm not aware of any min. thickness on the pad. there's one for the rotors, but pads are generally an "eyeball" thing.

Mike

 

According to the Haynes manual the minimum thickness for the front pads is 1/16 of an inch. Doesn't list it for the rear disc brakes. Right now my pads are slightly thicker than the backing plate (maybe a mm thicker than them). I know on other cars the minimum thickness can vary for both front and rear brakes.

Anyone know the published figure for the rear brakes?

 

you can get brake thickness gauges from Mac tools for 16$. Matco sells then for 21$, and snap on for about the same.

 

just use you mm sockets for reference. anything less than 3-4 mm meeds to be replaced soon.

 

Follow this link to get a brake pad thickness gauge. Its about 15 dollars I hope that this helps!

http://www.etoolcart.com/brakethicknessgaugekdt3962.aspx

 

A decent dial caliper is $20 from your local machine tool supply house... no toolbox should be without one. For brake rotors, a micrometer works well.

If you're eyeballing pad thickness, toss the old ones when the friction material is at or just slightly less than the backing plate thickness for normal road service. If you're road racing an enduro, new pads should go in before hand, every time, along with a four-wheel brake bleed.