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.
Wanting to rebuild my calipers. 1970 L46 car. This summer when I would brake, the car would pull hard to the left. I assume that means the front right caliper is not working? Plus, I have had the car for 20 years and have not done any brake work on it.
Pulled one caliper off and am attaching pictures of what I see. I have a few questions.
1 - based on the caliper castings, are these original to the car?
2 - what could the crap be that is inside one of the piston bores?
3 - these appear to be stainless lines, so that's good, right? Means I should be able to rebuild these?
4 - I noticed holes in the casting... Both of them are behind where the bolts are that hold the calipers together. Should I be concerned about these?
5 - I think these are the lip seal type? Is that correct? From research on this forum, it appears the prevailing opinion is I should change to o-ring type, correct?
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
My castings have "holes" also. That's ok. Are the piston bores pitted? If so, you may want to get stainless steel sleeved calipers available on an exchange basis. Lots of us have switched to ss sleeves. If done correctly, lips seals are every bit as good as 'o' rings. I still have my lip seals and they don't leak. So, it's a matter of opinion.
Not likely original because they are already sleeved, so thumbs up on that one. If there is no pitting on the pistons, a new seal kit should fix you right up. I believe going to o-rings requires new pistons. I've had lip seals for 40 years of Corvette ownership and had zero problems with short life - but then again, I tempt fate using DOT 5...
The holes in the casting are nothing to worry about - it's just the bore and threading for the bolts and very common.
While you're at it, replace the rubber hoses, and flush the entire system. You've got sludge down at the bottom that needs to be removed - I'd recommend rebuilding all 4 calipers because if this one has sludge the others more than likely do too. (I believe it's moisture and dirt contaminated, gelled brake fluid.)
Last edited by barkingrats; Dec 6, 2020 at 02:37 PM.
Not likely original because they are already sleeved, so thumbs up on that one. If there is no pitting on the pistons, a new seal kit should fix you right up. I believe going to o-rings requires new pistons. I've had lip seals for 40 years of Corvette ownership and had zero problems with short life - but then again, I tempt fate using DOT 5...
The holes in the casting are nothing to worry about - it's just the bore and threading for the bolts and very common.
While you're at it, replace the rubber hoses, and flush the entire system. You've got sludge down at the bottom that needs to be removed - I'd recommend rebuilding all 4 calipers because if this one has sludge the others more than likely do too. (I believe it's moisture and dirt contaminated, gelled brake fluid.)
I agree, just use lipped seals, and replace the pistons if they are pitted at all or they will leak. It's pretty strait forward.
Those pistons are shot. Thoroughly clean the calipers and do a final rinse with denatured alcohol. Use pipe cleaners to clean the passages. Assembly is straight forward with an O-ring kit. Since the system has not been touched in two decades, replace the four rubber lines. I would also check and if suspect, change the master cylinder as well and flush the hard lines with alcohol. Jerry
I am 50% success rate on lip seals.. about 50 bucks a caliper replace pistons and o rings on those that have good smooth bores...if bores suspect do a core trade in if you want to stay delco moraine...although some have stories of bog box stores having delco..i have not seen any in my area..went with best priced sponsor and they go to lone star
Thanks for the comments. I was planning to replace the rubber lines with stainless flex lines...and I was also planning to rebuild the master cylinder...thanks for the suggestions!
The correct casting numbers will all begin with 545. 5452270 and 5452273 for the fronts and 5452281 and 5452284 for the rears. My research revealed these were ductile iron castings and installed on the 67-72 model years. For the 73 and sub, GM switched over to grey iron. Those casting numbers all begin with 547.
I have a set of stainless hoses that I installed in my car years ago but recently decided to revert to the rubber lines. They have never had fluid in them. PM me if you are interested.
Brake caliper rebuild
