Last week my brakes got spongy. I saw no evidnece of a leak at the wheels,and then after aday of that,the next morning the pedal went to the floor. Looked and then saw the right front was just alittle wet. Pulled the caliper and the ourboard front piston seal was leaking. After splitting the caliper and pulling the pistons, I inspected the cylinders. The cylinders looked smooth and clean and then looking at the seals, I could see that they were all worn smooth and the lip was next to gone. I cleaned the entire caliper body, pistons and springswith degreaser and hosed them off. I then blew them out completely with air. Like always, I used light emery cloth on the cylinders andagain degreased the whole thing and after blowing it out with air, cleanedthe outside of the caliper with thinner, tapedit up and shot a coat of rustolemsilver on it. I then coated the cylinders with brake fluid along with the pistons and new seals, put the seals on the pistons and installed the pistons in the cylinders. (Keep in mind that this particular caliper is one of the two originals from the factory that I rebuilt, now that I looked up the receipt for the last rebuild kit for that caliper, I thought it was more recent, three years and ten months ago. Time is getting away from me. LOL But it really is!)I put the halves together with the new O-rings, bolted the caliper to the bracket, dropped the pads in, inserted the pin and locked it in with a new cotter pin. Got my wife to sit in and pump the brakes and after the fourth time of pumping and holding, there went the fluid from the same cylinder. Even after taking the caliper apart again twice, each timechanging the seals around to another piston in another cylinder, the same one leaked.
I finally had to give in to the fact that the caliper is finally just too worn totake another rebuild. I suppose that 27 years of service is an acceptable amount of time for a part's servicability. I broke down and bought a new caliper feeling like someone who had given in to the enemy. LOL What can I say, I'll always try to keep the original part going if it'll stand up to the specs.
This doesn't mean that I'll give in any easier the next time...

 

Big Texas Jim,
sounds like your allover this. let us know what you learn, especially anything about rotor runout and the air problem. maybe the o ring design may solve this problem. i'm guessing the rotors warp when the wheel lugs are over tightened.

 

Hi again, It's good that your handy, a caliper will leak now and then or something else will need some attention. If you own your car long enough, some things get fixed 2 or 3 times. PG.

 

I installed front bearings about two years ago and have repacked them twice since then. The rear bearings I checked this past summer, when I was asking about "the slight sway when I hit the gas quick" which I haven't addressed yet, and the dial gauge showedthey're in good shape. I've had no problems with the discs except for replacing one last year as it was grooved just alittle and wouldn't take another cut. I've rebuilt the calipers before and they're not hard to do. Like anything else, cleaning and prep is the most time consuming part of it, and ofcourse the most important.
This most likely alot of you guys know; They are alittle different in the way that the seals go on the pistons instead of "in the groove of the cylinder and the pistons are spring loaded. The caliper separates into two halves and takes two smallo-rings in recesses on both ends where the fluid travels to and from the opposite side of the caliper from the inlet port. All the pistons get equal pressure at the same timeunlike the regular one piston caliper where the piston/pad makes contactwith the disc and the other pad actually slidesand is forced to make contact from the pressure of the piston side, hence more wear on one pad than the other.
For me, when I have a rebuildable part, a brake caliper, master cylinder, slave cylinder or what have you, especially one that's never been rebuilt, I'm going out to get a rebuild kit. I don't believe in buying parts that I really don't need. Again, the beauty of the old 'Vettes; simple, basic and parts on hand in most all parts stores.
Also again, in most cases, the brake system on the older 'Vettes is NOT rocket science. Just get everything up to snuff one time, and maintain it as needed like any other vehicle. Not just when something fails, but prevent the failures by maintaining your 'Vette on a regular basis. You therefore get the longest life out of your parts and will be warned before any short-comings occur.

( I deleted the big empty space at the bottom of the post. C3 Starship)

 

That slight sway when you "hit the gas quick" is most likely the front bushing in the trailing arm, it won't be to hard for you to replace that. PG.

 

yea, pg, that's what came to be the concensus when I posted the question. I really need to go through the whole rear suspension, but since we've moved in September, and were gone from this house for six years, I've been only catching up on non-maintained this, that and everything since. I only two weeks ago got the other side of the garage in shape of any kind and then the holidays hit.
I'd love to find a big garage with a small house attached, but the family...Oh well...

 

Hi again, with shorter daylight, bad weather and the holidays there's not a lot of time to do any work on our cars.
I have a small house and a small garage but I'm allowed to use the kitchen and DR table as a work bench. So one day I pulled the distributor to do some work on it and she says can't you at least clean that greasy thing first! So I went to the garage and cleaned it.
Only when I went to reinstall it did if find out I cleaned the mark where the rotor was lined up and cleaned off the mark where the base lined up! But we are still together. PG.

 

That's funny, pg!

Been there.......
We're still together too.

"H-honey,..... please don't clean up behind me, 'till I'm done....."

 

"Heeellloooo! I'm not done with that yet!" As she folds up your drop cloth and deposits it in the trash. [:@][:@][:@]

 

How about "Gee Hon, if you can do your craft stuff all over the dining room table, then why can't I rebuild the carb in the kitchen?"

Somehow that always gets the "That's different" response.

Happy New Year! [sm=icon_cheers.gif][sm=happy046.gif][sm=groupwave.gif][sm=groupwave.gif]