How can I tell if a hone job will work for my wheel cylinders and master cylinder? Does the surface have to be smooth like a prom queens thighs or can I get away with some small imperfections(pits). I have a larger truck so the Cylinders are expensive.

 

A .005" feeler should not fit between piston and cylinder. At least that's the general rule I've heard. Kinda depends on the width of the feeler gauge though.

Craig

 

I have internal bore mics but I have never seen fine specs (+/-.001) on wheel or master cylinders. Like you said, the width of a feeler gauge would be a problem.

 

Any pitting left will soon tear up the seals. Overhoning that produces oversized bores, a taper or barreling of the bores will also result in rapid failure/ air getting into lines. My question would be are new cylinders more expensive than your life (or someone elses?)? There are places where corners can be cut, brakes and steering are not those places IMHO.
PS: If you understand how a wheel cylinder works, use of a feeler gauge doesn't make any sense what so ever. sorry!

 

Where do you stop with safety? Some people say that single master cylinders are extremly unsafe. Other people say that if you dont have ABS you are unsafe. If rebuilding cylinders was unsafe dont you think the FDOT would ban the sale of rebuild kits.

 

DOT does not certify repair/replacement parts, if they did you would never be able to afford them.
I have had the misfortune to have first hand knowlege of losing my brakes with a single chamber MC due to a ruptured line ("emergency" brake use was a joke), and have often experienced just how far a vehicle will travel before stopping even with good brakes (and ABS) on the AX course. Neither is something I'd ever want to do on the road in traffic, especially with a heavy vehicle.
My philosophy about drawing the line with safety (especially after facing death twice!) is I'll do everything and anything needed to make me as safe on the road as possible. I'd NEVER want to have to say "I'm sorry, but I saved a few bucks." to someone I injured or killed, especially a loved one.
If you put that little value on life, you are too young and/or have never experienced preventable death close to you.

Rebuild kits are fine, I've installed probably around a 100 myself, if they are used for their intended purpose: to repair a worn or damaged seal, not to reclaim an oversized cylinder bore. There is a reason there are no oversized tollerences available, cylinders requiring boring should be replaced, honing is to restore the sealing surface for a new seal.

 

I have to agree with AX on the issue of safety; it's not only important to you but to the innocent others on the road.

I have attached a rebuild/honing procedure for you to review. Note the highlighted area on honing. It may not be specific to your vehicle but it does stress the point that pitting and excessive honing require cylinder replacement.

Hope this helps.

 

The highlighted area states excessive or deep pitting. That is the point of my original question. As I recall the hones put light scratches in, right, like an engine hone. Seems like everyone is saying if its not prestine, chuck it.

 

No if it takes more than a few passes to clean it up, chuck it. It's a hone, not a boring bar.

 

If there is any pitting in the area that the rubber cup rides (not the aluminum pistons), it will eat the rubber really fast. I've had good luck honing where the cylinder is not pitted, where the rubber just went squishy. Pits and rust out at the outer ends isn't so critical, but it will wear the pistons. I would mike the pistons, wear is not so obvious on them.

The purpose of the honing is to create a surface that will lightly "hone" the rubber cups to a tight seal, so it should be as close to "thigh-smooth" as you can get it. It is extremely important to get all honing oil out of every crevice afterwards.

 

Great information guys! This is why I follow this forum religiously. Thanks for the lesson

 

 

That's ugly for sure, but it's only the bore that matters.... if you can get the piston out.

Just buy a new one, life is too short to mess with that.