VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Hone or Replace Brake Calipers?

So I'm wondering what the deal breaker is determining if a caliper should be honed, or replaced.

The bore of the caliper has some significant pitting right where water and/or contaminants would settle by gravity inside the bore. There's also a ring of stains/pitting about half way up the bore, all the way around. Shop manual says clean up with crocus cloth and if that won't clean it up, toss it out and get a new caliper.

And yet I know some people hone them...

So I need to know, how much marking/pitting is considered acceptable (if any), and if none, is honing a solution? Wouldn't honing change the characteristics of the bore, and could it interfere with the square-faced inner seal? (I noted this seal area has a slight chamfer to it, honing would probably reduce that chamfer...) If I just replaced it, anything I get will be re manufactured anyway, so would that mean that someone else just honed them out and re-sold them?

Not really trying to do this the cheap way, but don't want to throw away my original Delco calipers either if they can be safely saved. Any info would be great!

The seal sits in the caliper & the piston glides through it if you're working with the 69. You want the piston to be in good condition without pits but the square ring is what holds back the fluid so no honing would be necessary unless the piston won't slide in the caliper freely (without the sealing ring). If you have pitting in the seal bore then you may need to replace caliper. I think I got that right. It's been a long time...Joe

Yeah..the piston itself is in fantastic shape...I mean it appears as if it were new, no wear at all. The bore does have pitting in one spot. I tried placing the piston in without the ring, it's a sung fit. Only went part way since I didn't want to risk scoring the piston.

So I think you've confirmed my thought that it isn't a great idea to re-use the caliper as-is. I'm willing to guess the other caliper is in the same shape. So...I do hear about honing...is that a good idea? Pros & cons? I would prefer not to have my car on axle stands for a week while I wait for replacements (but it has to be safe bottom line, not willing to hone if it's a bad idea)

If using it as-is all you can have is slight seepage.

I would think you could go to any of the better parts houses & have a replacement the next day but maybe that's only here..Joe

If the pistons are still shiney and smooth you only need to clean the bore and replace the rubber components. The bore only loosely guides the piston, the square ring holds and retracts the piston while sealing the fluid in.
Tony

I would advise against honing unless the pitting is very minor and can easily be cleaned up. If you can't find rebuilt or new replacements then honing may be your only option. Leaking calipers is not a good thing.

Thanks everyone for the input.

As much as I hate to toss them (this car survived 44 years and only has ever had the water pump and starter changed)...it looks like replacement is the best option. I realize the walls of the caliper bore don't contact the piston or create the seal, but it does appear that pitting and irregularities in the surface trap moisture and any contaminants that will inevitably accumulate with time, which can lead to sticky pistons or inner seal failure. Also, it seems the surface finish is also important, since honing will leave surface rougher which will hold fluid, as opposed to being a solid surface to re-direct fluid force to the piston. Sounds minor but some have said this can leave a mushy pedal feel. Just not willing to take a chance so I'll be ordering new (rebuilt) ones!

Two things to never,never skimp on. Or try to save money on.
Brakes And Tires. HAPPY

69Chevyguy,
I applaud your decision. Brakes are the most important mechanical feature on any vehicle. Stopping is NO. 1 in my book.