Sticking caliper or something else?
Thread Starter
Instructor
Joined: Nov 2018
Posts: 193
Likes: 70
From: Chicago
Sticking caliper or something else?
1968 L68 with a AT and NO power brakes. New car to me and trying to determine if I have a sticking caliper or something else. Intermittently, after braking, I will get what feels like a caliper sticking of the rear drivers side. It will give me a little shutter/ resistance and then break free. Overall, I have a great brake pedal and the car brakes straight and smoothly. So today, I jacked-up the rear and spun the wheels. Everything turns easily. Jammed on the brakes over and over again, and once released, the tires spin freely. I could not duplicate the 'sticking' at all. Should I be looking somewhere else? The lines are all new, so I do not think a rubber line is bad, but I am open to suggestions. Also, no leaking is visible. Thanks for the help!!!
Thread Starter
Instructor
Joined: Nov 2018
Posts: 193
Likes: 70
From: Chicago
This is intermittent, but will happen when hot or cold. I did a nice long drive and then put the IR gun on them. All four calipers were about the same temperature and the rims were not hot to the touch. It seems if I come into a stoplight slowly with little brake pressure, I do not get this stickiness. However, if I am on the brakes a bit more, this issue comes up. Again, seems like a caliper hanging, but I cannot recreate the issues while on the jack.
Le Mans Master
Joined: Aug 2005
Posts: 6,529
Likes: 1,964
From: Temple Terrace Florida
I know the car is new to you, but can you ask the previous owner if and when the rubber brake lines were changed. It is not uncommon for the lunes to be corroded inside and act like a check valve and hold pressure. The result is that the brake will stick. I would focus on the lines first. Jerry
Just another Corvette guy
Joined: Feb 1999
Posts: 8,518
Likes: 3,865
From: Palm Springs, CA.
Hard to diagnose without "feeling" what you're feeling but are you sure it's not your posi clutches dragging?
This is a common issue with these cars, and often overlooked, but generally shows more when the differential is up to temp. It can feel just like a sticking caliper, and many swear it's brake related. But this issue will usually show more when the car is being turned rather than going straight. The posi additive breaks down after a while and the clutches can grab and stick very hard but, if this does happen to be your issue, it's an easy fix. Drain and refill the diff. But be sure to put two bottles of the posi lube in before re-filling with gear lube, rather than the recommended one bottle. This will correct the clutches in 40 or 50 miles worth of driving.
Cheers, Greg
This is a common issue with these cars, and often overlooked, but generally shows more when the differential is up to temp. It can feel just like a sticking caliper, and many swear it's brake related. But this issue will usually show more when the car is being turned rather than going straight. The posi additive breaks down after a while and the clutches can grab and stick very hard but, if this does happen to be your issue, it's an easy fix. Drain and refill the diff. But be sure to put two bottles of the posi lube in before re-filling with gear lube, rather than the recommended one bottle. This will correct the clutches in 40 or 50 miles worth of driving.
Cheers, Greg
Thread Starter
Instructor
Joined: Nov 2018
Posts: 193
Likes: 70
From: Chicago
Greg... interesting point. Now that I think of it, the grabbing does happen more when I was turning. In the end, it probably it good to flush it out and put in new lube. Thanks for the tip.
Thread Starter
Instructor
Joined: Nov 2018
Posts: 193
Likes: 70
From: Chicago
Update... I took out the gear lube, added two bottles of posi additive and refilled with fresh gear lube. Went out and did my figure 8s and then a short drive. So far, no issues. Fingers crossed this was it. Thank you Greg for the diagnosis.
Team Owner
Joined: Jun 2001
Posts: 43,136
Likes: 155
From: Thomson Georgia
Good news? I need some solution for my rear brakes.
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Joined: Apr 2021
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From: East Central Tennessee
I know the car is new to you, but can you ask the previous owner if and when the rubber brake lines were changed. It is not uncommon for the lunes to be corroded inside and act like a check valve and hold pressure. The result is that the brake will stick. I would focus on the lines first. Jerry