Stripped caliper bolt hole
Thread Starter
Navigator
Joined: Nov 2017
Posts: 9
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From: Buffalo NY
Stripped caliper bolt hole
Hi all,
So I took the rear passenger caliper off my '80 vette because my parking brake isn't working and when I was removing the caliper I noticed that one of the caliper bolts was gone and rigged up with a like a carriage bolt or something inserted through the front of the hole and then a nut was screwed in on the back.
I can still see threads in the hole but they're pretty worn down and rusty. I was thinking about trying to tap it but not sure if that's the way to go. Any thoughts/suggestions?
So I took the rear passenger caliper off my '80 vette because my parking brake isn't working and when I was removing the caliper I noticed that one of the caliper bolts was gone and rigged up with a like a carriage bolt or something inserted through the front of the hole and then a nut was screwed in on the back.
I can still see threads in the hole but they're pretty worn down and rusty. I was thinking about trying to tap it but not sure if that's the way to go. Any thoughts/suggestions?
Thread Starter
Navigator
Joined: Nov 2017
Posts: 9
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From: Buffalo NY
Thanks. Do you know what size tap it would be? Also, I only have a parking brake assembly on the passenger side. Googling replacement parts...should there be one on the driver side, too?
Last edited by Tim McNamara; Nov 15, 2017 at 07:39 PM.
Le Mans Master
Joined: Oct 2006
Posts: 7,123
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
There should be parking brakes on both rear wheels. As stated before, calipers are pretty cheap and available so changing one should not be a deal. If you're really committed to keeping those calipers, once you figure out what size the bolt is, you might be able to install a helicoil.
Thread Starter
Navigator
Joined: Nov 2017
Posts: 9
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From: Buffalo NY
There should be parking brakes on both rear wheels. As stated before, calipers are pretty cheap and available so changing one should not be a deal. If you're really committed to keeping those calipers, once you figure out what size the bolt is, you might be able to install a helicoil.
and, I'll look into a helicoil. I've seen it mentioned a few times in other posts but don't have any experience with them.
Drifting
Joined: Apr 2010
Posts: 1,857
Likes: 332
From: Cartersville GA
If it's the same as a 72 it can be tapped....You have to use a button head bolt or at least I did....Not enough room to get a socket on the larger bolt head after tapping it to the larger size. Not the easiest job but it is doable. If someone else doesn't answer before tomorrow afternoon I'll look and see what size tap I had to use....Get a good one, the cheap ones will just break.
Brian
Brian
Intermediate
Joined: Aug 2017
Posts: 42
Likes: 2
From: Dushore Pennsylvania
I was able to run a thread chaser tap into mine and remedy the problem caused by P.O. carelessness. Access really isn't too bad. Pull the rotor and caliper, use an 8 point socket and extension on the tap (my '75 was 7/16-20) - and plenty of tap lube.
But Corvette Central (and every other vendor) will sell you a caliper bracket. CC price is 46.00. It's a time consuming but not real difficult install.
If it can't be re-tapped, and 46 bucks sounds high... It's your BRAKES!!! When I repair something like this, I just imagine my daughter driving it - and make sure it is right - whatever the cost.
Good luck.
But Corvette Central (and every other vendor) will sell you a caliper bracket. CC price is 46.00. It's a time consuming but not real difficult install.
If it can't be re-tapped, and 46 bucks sounds high... It's your BRAKES!!! When I repair something like this, I just imagine my daughter driving it - and make sure it is right - whatever the cost.
Good luck.
Last edited by bwbrown; Nov 15, 2017 at 10:16 PM.
Tech Contributor
Joined: Aug 1999
Posts: 15,173
Likes: 3,982
From: Connecticut, USA
The caliper brackets are the same from 1965 - 1982. The thread size is 7/16-20, the bolts should have a shoulder on them, the same bolt used on the 1/2 shaft flanges to rear spindle flange. I find them from time to time rebuilding arms and many times they can be repaired. I do not increase the bolt size since I want to use the same bolts as came with the car. I do this repair with the bracket off the arm but that will mean you will end up rebuilding the arms. If the bearings are worn then it may be time but if they are still good and the overall arm is good then you might be able to repair it on the car or with the complete arm on the bench.
Here are some pictures, while I still have 3rd party hosting. I use a common SS insert that requires a larger tapped hole in the bracket. I use Loctite and stake them with done. I have been repairing these for many years now you can too.
Here are some pictures, while I still have 3rd party hosting. I use a common SS insert that requires a larger tapped hole in the bracket. I use Loctite and stake them with done. I have been repairing these for many years now you can too.
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Race Director
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From: SW Florida.
I don't think GTR's repair is actual helicoil. Same basic idea. Either way, that insert or Helicoil is the only way to do the repair. Tapping bigger is not really any better than using smaller bolt with a nut behind it. The correct bolt with shoulder seats caliper correctly and stops it from moving around. So, not only do you need the correct thread, you need actual bolt, not a 7/16th fine thread from Home Depot.
Burning Brakes
Joined: Sep 2017
Posts: 1,219
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From: Tolland CT
I don't think GTR's repair is actual helicoil. Same basic idea. Either way, that insert or Helicoil is the only way to do the repair. Tapping bigger is not really any better than using smaller bolt with a nut behind it. The correct bolt with shoulder seats caliper correctly and stops it from moving around. So, not only do you need the correct thread, you need actual bolt, not a 7/16th fine thread from Home Depot.
Tech Contributor
Joined: Aug 1999
Posts: 15,173
Likes: 3,982
From: Connecticut, USA
I would not trust a coil in this application. The insert, if done correctly works fine. Incorrectly, well it will spin out when installing the caliper. I torqued the bolts to the bracket as shown and the repair was/is good.
Sometimes the original part is wanted over a new one, other times it isn't. What works best is what the owner wants and can do. Replacing it is $40 but requires pulling the axle out and that will lead to replacing the bearings and a lot more money. If a rebuild is needed then it is something to review. If a repair is needed, as in doing a caliper replacement then this will work- as long as it is done correctly.
Sometimes the original part is wanted over a new one, other times it isn't. What works best is what the owner wants and can do. Replacing it is $40 but requires pulling the axle out and that will lead to replacing the bearings and a lot more money. If a rebuild is needed then it is something to review. If a repair is needed, as in doing a caliper replacement then this will work- as long as it is done correctly.
Thread Starter
Navigator
Joined: Nov 2017
Posts: 9
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From: Buffalo NY
Thank you all for the input...very much appreciated. And, It's not about the cost of the part. It's more about pulling out the TA being above my ability. I've been leaning towards just jumping in and giving it a shot but if I can't complete the job, how am I getting a car with no TA or wheel out of my garage and on to a flatbed to take to a shop.
Anyway, thanks again to everyone that replied.
Anyway, thanks again to everyone that replied.
Race Director
Joined: Jul 2015
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From: SW Florida.
Thread Starter
Navigator
Joined: Nov 2017
Posts: 9
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From: Buffalo NY
