When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I'm taking apart my brake system for the first time. I am new to working on cars but have been reading up on the forum and service manual/AIM/Haynes manual.
I've only taken apart the rear driver's side caliper so far, since that one was leaking. I am trying to figure out if the caliper is rebuild-able. It seems to be sleeved w/ SS, which I have seen from the forum that it makes it a good candidate to be rebuilt. A few questions:
Do the bores look rebuildable? There is some discoloration but not sure if that would come off with light sanding. Some parts feel a little rough but I don't think it's pitted, maybe some surface rust. Not sure though since I am new to this. All I did was use brake cleaner and paper towels and microfiber cloth
See images below (I took 2 images per bore). I have them numbered. Image 5 seems to have some build up, but maybe it could be removed with light sanding? The tops of each bore are also a bit rusty.
Service manual suggests using crocus cloth and I've read on the forum some use 600 grit emery cloth to clean the bores. Any recommendations on where to get it from, and if there's any special technique in cleaning the bores?
Thanks in advance for the help, the forum really helped me get off the caliper bolts... I almost rounded one of them off before reading how to properly remove it (6 point socket instead of 12 point, and 2ft breaker bar with hammer).
It is hard to tell if all of the bores have been sleeved. I have never seen stainless steel rust up like that. I think you are beyond sanding the bores, I think they should be cleaned up with a hone. If they clean up, consider using O-ring pistons. They are more forgiving then the lip seal pistons. In the end, it may be in your best interest to trade them in for rebuilt O-ring Delco Moraine calipers.
i would at least though...get some 600-800 wet dry sandpaper a little brake fluid for lubricant and clean up better to evaluate...this after confirming they are sleeved...not sleeved..i would trade for o ring rebuilt gm ones...
if saving/ rebuilding i like to soak over night in evaporust..clear or paint flat black epoxy..
Whatever course you decide to take, I can only offer one bit of advice.
These are not lightweight cars, so when you need brakes, you need 'em.
Don't skimp.
Here’s a pic of a sleeved bore. Note the clear difference at the outer edge between the stainless sleeve and the caliper casting. You may also be able to feel a “step” at the back of the bore (as indicated by the pick) between the sleeve and the bore.
Take a small wire brush to the outer edge/seal surface and you should be able to positively determine if sleeved or not. If they are indeed sleeved, the discoloration is likely associated with contaminated brake fluid. Brake fluid is hygroscopic, meaning it absorbs moisture. I’ve seen extreme examples where the fluid is like a brown sludge. Whatever you end up doing with the calipers, completely flush the fluid from the entire system. (Do NOT replace it with silicone (DOT 5) - use DOT 3 or 4).
Crocus cloth is available at most hardware stores but if you can find some 2000 grit sandpaper, that is a good alternate. However, be careful to use it sparingly, just enough to clean up the discoloration. Thoroughly clean the passages (use CRC Brake Kleen) and blow everything out with air.
Personally here is my take. Calipers rebuilt by a professional rebuilder that have stainless sleeves and O-rings are $120-ish each. This isn’t even something you should be considering. Perhaps my phone is deceiving me but I see pitting, not just staining. Any kinda leak means you can lose your brakes. IMO NOT AN OPTION......
You could even opt out on the Mexican rebuilds from Napa/Autozone/Advanced/O’Riellys calipers and be better off.
Some things you can “just run it” and be fine. Anything steering, suspension, or brakes you need to know it’s as right as it can be.
Personally here is my take. Calipers rebuilt by a professional rebuilder that have stainless sleeves and O-rings are $120-ish each. This isn’t even something you should be considering. Perhaps my phone is deceiving me but I see pitting, not just staining. Any kinda leak means you can lose your brakes. IMO NOT AN OPTION......
You could even opt out on the Mexican rebuilds from Napa/Autozone/Advanced/O’Riellys calipers and be better off.
Some things you can “just run it” and be fine. Anything steering, suspension, or brakes you need to know it’s as right as it can be.
agree..but after cleaning and a re assessment and good pics..an o ring kit is 40-50 per wheel...i just replaced one of mine after screwing with lip seals and no sleeve ( a true rabbit hole).. one needed replacement..120 plus tax, plus 80 core (get back after evaluation) and the cost of shipping your core back..both sides must be ac delco moraine... it is worth an o ring kit shot..
and your own paint job will be 10x better than what comes back from rebuilder..my lone star (zip) and o ring kit wheels are solid..waiting for the other two to leak now
I’ve been down that road as you. I rebuilt mine, cleaned mine up used all new lip seals, pistons and parts. After 6 months one rear leaked. Went to Oreillys and picked up their Brakebest reman unit, it came with an original delco case. If I were to do it again I would have bought all 4 from Oreilly, save my time rebuilding and they have a lifetime warranty. Don’t get me wrong I learned a lot and satisfaction of rebuilding myself, but save your time and buy the remanufactured BB.
I’ve been down that road as you. I rebuilt mine, cleaned mine up used all new lip seals, pistons and parts. After 6 months one rear leaked. Went to Oreillys and picked up their Brakebest reman unit, it came with an original delco case. If I were to do it again I would have bought all 4 from Oreilly, save my time rebuilding and they have a lifetime warranty. Don’t get me wrong I learned a lot and satisfaction of rebuilding myself, but save your time and buy the remanufactured BB.
totally agree but....at least in my state..there are NO delco remanufactured at any chain store...all china.
forgot to add for OP...time to replace rubber brake lines if over 10 years old ..vendors sell usa made ones..you can buy all 4 new with washers and havechange left over if you can rebuild just one with o ring kit vs remanufactured ac delco. Yes many pictures showed ac delco but on the shelf ..no way..
yes of course non delco also economical..from chain stores...lifetime warranty etc..but so is china craftsman tools... its a choice that can prove great paths
Your first photo shows the casting numbers begin with 547 which is correct for your 73. The 547s are grey iron which replaced the “543” ductile iron castings used in the 67-72 model years.
Back in the day when I got into working on Corvettes, I never had to worry about imported parts. Whatever you bought was Made In USA. Now, unfortunately, we all have to deal with the Rolex watch equivalents, including parts that your life depends on. If you decide to replace them with rebuilts, be sure to question the seller/supplier as to the pedigree of their parts. If they aren’t willing to share that information, move on - there are many, many sources for calipers.
I am actually in the process of replacing a portion of my caliper halfs as I have a complete cluster**** of casting numbers from a “reputable” builder I got them from 35 years ago (long story-don’t ask). I have a mix of 543s, 547s, and one actually has a 546 outer (65-66 1st design) and a 547 inner! If originality is important to you, you want all 547s.
As for lip seals vs o-rings, that debate has countless posts and is about as old as Chevy vs Ford. Read and weep (no pun intended).
Welcome to the world of infinite opinions and infinite possibilities!
Your first photo shows the casting numbers begin with 547 which is correct for your 73. The 547s are grey iron which replaced the “543” ductile iron castings used in the 67-72 model years.
Back in the day when I got into working on Corvettes, I never had to worry about imported parts. Whatever you bought was Made In USA. Now, unfortunately, we all have to deal with the Rolex watch equivalents, including parts that your life depends on. If you decide to replace them with rebuilts, be sure to question the seller/supplier as to the pedigree of their parts. If they aren’t willing to share that information, move on - there are many, many sources for calipers.
I am actually in the process of replacing a portion of my caliper halfs as I have a complete cluster**** of casting numbers from a “reputable” builder I got them from 35 years ago (long story-don’t ask). I have a mix of 543s, 547s, and one actually has a 546 outer (65-66 1st design) and a 547 inner! If originality is important to you, you want all 547s.
As for lip seals vs o-rings, that debate has countless posts and is about as old as Chevy vs Ford. Read and weep (no pun intended).
Welcome to the world of infinite opinions and infinite possibilities!
great point..and to one of your sourcing points... one of the calipers on my car when I got it has one side delco moraine..and the other China lol
Further, for what it is worth... I'm now about to replace the third caliper in 2 years. All done by a well-known rebuilder located in a great Southern State. The first, right front, began leaking within weeks. Replaced, under warranty, by the shop that did the work.
The second, left front, no warranty as the above referenced shop had closed as the owner had died. The well-known rebuilder offered nothing. Purchased replacement from Willcox. A Delco casting. So far, so good.
Now the right front is leaking. This will be replacement #2 at right front. No, I did not bother to ask that well-known rebuilder, I just ordered another from Willcox.
My efforts at rebuilding them in the long ago days were not uniformly successful.
I’ve been down that road as you. I rebuilt mine, cleaned mine up used all new lip seals, pistons and parts. After 6 months one rear leaked. Went to Oreillys and picked up their Brakebest reman unit, it came with an original delco case. If I were to do it again I would have bought all 4 from Oreilly, save my time rebuilding and they have a lifetime warranty. Don’t get me wrong I learned a lot and satisfaction of rebuilding myself, but save your time and buy the remanufactured BB.
Also, if you are going to replace the brake hoses go for stainless steel, they will give you a firmer pedal and last longer.
Awesome, thanks all for the suggestions. I used some 1000 grit sand paper w/ brake fluid as lubricant to wet sand one of the bores, see pictures below. Inside is shiny like SS, however I can't find the discontinuity b/t the cast iron & SS. What do you guys think, does it still look sleeved in the new pictures below? Note the pictures show the same one bore, just different angles.
The bore is pretty smooth, but does have some lightly rough parts. I'm not sure how smooth it needs to be. I am almost ready to call it a day and get new/rebuilt calipers w/ o-rings for all wheels, but am willing to try honing the bores to see if I can get them really smooth. And one more question, where can I find info on how to hone the bores (what tool to use, what size, where to buy it, etc)? I can't find any posts with "caliper honing" that have the relevant info. I'm guessing it's something you can attach to a drill.
By the way, I do plan on replacing the four brake hoses since I'm not sure how old they are. Hopefully I can get all the brake parts I need from one vendor
Hard to tell. New SS sleeved calipers have radius at bottom of bore, same as original machined cast calipers. Only a sleeve-repaired caliper has the undercut at the end of the sleeve.
If you use 400-600 grit wet-dry (with brake fluid on it) and the corrosion cleans up, follow with 800, then 1000, then 1500 and call it a day. Then rebuild them. If they don't clean up with 400-600 paper, pitch them.
Here’s a pic of a sleeved bore. Note the clear difference at the outer edge between the stainless sleeve and the caliper casting. You may also be able to feel a “step” at the back of the bore (as indicated by the pick) between the sleeve and the bore.
...
Since it was hard to see the edge features inside the bore, I took a toothpick and traced the bore from top to bottom. I don't believe there was any radius that matched the original cast calipers. The diameters down there seemed too small, in the above picture it seems like the original cast iron bores had a larger radius than the sleeves (as indicated by the pick).
Originally Posted by 7T1vette
Hard to tell. New SS sleeved calipers have radius at bottom of bore, same as original machined cast calipers. Only a sleeve-repaired caliper has the undercut at the end of the sleeve...
Given I couldn't find a step (or undercut) at the bottom of the sleeve, I believe that leaves me with two possibilities (please correct me if I am wrong): these are not SS-sleeve repaired calipers (and therefore are originals), or they are new SS sleeved calipers. As @69L88 pointed out, the castings numbers are correct for the car (which is a 73), so that leaves me to think that they are not new SS sleeved calipers and therefore are not sleeved.
I have rebuilt quite a few of those brakes , but I never bothered to recondition any "original" castings , which yours are . Imo its a waste of time to do anything with them except exchange them for some that have been re-sleeved .Unless you care about the date casting , then get those relined .
Even if you can sand the bores smooth enough , which is doubtful , looking at your pics , some pitting is evident so they will never work properly nor last for any real length of time .
I agree with Baz. sorry but these DO NOT look sleeved . and they are pitted beyond use. if you do get them to clean up, the bores will be to large. there are no "Over sized" caliper pistons.
The sleeve is pressed to the top of the fluid passage hole(s) thus the gap shown in 69L88 photo.
No gap not sleeved.
Some may have a more visible gap than others. The machining for the sleeve on mine were done close to the top of the fluid hole, but there is a gap.
Is this caliper rebuildable?
