Brakes locking up!
Thread Starter
Heel & Toe
Joined: May 2002
Posts: 23
Likes: 1
From: los angeles ca
Brakes locking up!
Just got the car running today :cheers: I was driving, and applied the brakes hard, and they locked up on me. Before storeing it, I remembered I had replaced the back wheel cylinder, and adjusted it with out much play. I backed it off today, but still locked up when driving. Am I not backing it off enough? Still some what tight, not sure how much play it should have. Also when turning the back wheels, there are some tight spots, while other spots move more freely. Is this normal?
Steve
Steve
Melting Slicks
Joined: Oct 2001
Posts: 3,025
Likes: 12
From: Pleasant Grove AL
Re: Brakes locking up! (steves60vette)
The tight spots aren't "right", but they may be "normal", or at least sort of normal. If the shoes are fairly new, they probably have not been "radiused". In the olden days, when I was a mere lad, and everyone had drum brakes, etc, etc, brake shops had a grinder which would grind the high spots off new shoes prior to installation. A good brake shop will still have one of these, since a lot of cars and almost all trucks still have rear drums. Other possibility is that your drums need turning/replacement.
As to the lockup, make sure all the retracting hardware is in place and operating freely.
As to the lockup, make sure all the retracting hardware is in place and operating freely.
Drifting
Joined: Feb 1999
Posts: 1,808
Likes: 28
From: CA central coast
Re: Brakes locking up! (steves60vette)
Which wheel is locking up? I assume you mean while you have them applied, then frees up when you release them?
Assuming you have everything assembled correctly (did you remove the shoes last year? Put 'em back correctly with the longest lining facing the rear of the car?), and that you made certain the emergency brake didn't interfere with the rear brake adjustment (loosen the emergency brake adjustment nut until they are absolutely not a factor), you really need to adjust the brakes at all 4 wheels rather than only one or two.. It's not unusual to feel the initial drag at only certain places in the wheel rotation.... once you've adjusted the wheel to just feel a slight drag, then back off the screw about 12 notches. Then adjust the emergency brake linkage by first tightening the linkage forward nut until the rear wheels just drag slightly, then adjust each rear cable to equalize the drag at each wheel, then tighten the adjustment lock nuts.
Assuming you have everything assembled correctly (did you remove the shoes last year? Put 'em back correctly with the longest lining facing the rear of the car?), and that you made certain the emergency brake didn't interfere with the rear brake adjustment (loosen the emergency brake adjustment nut until they are absolutely not a factor), you really need to adjust the brakes at all 4 wheels rather than only one or two.. It's not unusual to feel the initial drag at only certain places in the wheel rotation.... once you've adjusted the wheel to just feel a slight drag, then back off the screw about 12 notches. Then adjust the emergency brake linkage by first tightening the linkage forward nut until the rear wheels just drag slightly, then adjust each rear cable to equalize the drag at each wheel, then tighten the adjustment lock nuts.
Race Director
Joined: Nov 2000
Posts: 10,347
Likes: 672
From: Beverly Hills (Pine Ridge) Florida
Re: Brakes locking up! (steves60vette)
Steve,
If readjustment does not help. then you may have replaced the wheel cylinder with an incorrect size. Is the wheel that locks up the same one you replaced the cylinder on? Did you compare the bore size on the old and new cylinders?
Understand that you may not know if it is one, or 2 wheels that are locking up. Recommend going to a empty parking lot and try locking up the brakes and seeing which wheel(s) are leaving a dark patch. If both rears are locking, then probably not different size cylinders. If only one locks, then can be adjustment, but also can be the bore size difference, or perhaps a spring/shoes/etc. located incorrectly (or a weak spring). Also, I assume the the brake shoes are the same brand/type on each side (I know you didn't change just one set of shoes!). Note that contaminents on the shoes (such as axle grease) can make the shoes act grabby as well.
Good Luck,
If readjustment does not help. then you may have replaced the wheel cylinder with an incorrect size. Is the wheel that locks up the same one you replaced the cylinder on? Did you compare the bore size on the old and new cylinders?
Understand that you may not know if it is one, or 2 wheels that are locking up. Recommend going to a empty parking lot and try locking up the brakes and seeing which wheel(s) are leaving a dark patch. If both rears are locking, then probably not different size cylinders. If only one locks, then can be adjustment, but also can be the bore size difference, or perhaps a spring/shoes/etc. located incorrectly (or a weak spring). Also, I assume the the brake shoes are the same brand/type on each side (I know you didn't change just one set of shoes!). Note that contaminents on the shoes (such as axle grease) can make the shoes act grabby as well.
Good Luck,
Thread Starter
Heel & Toe
Joined: May 2002
Posts: 23
Likes: 1
From: los angeles ca
Re: Brakes locking up! (Plasticman)
I have not checked the shoes, but I will today. I had all brakes done a few years back a mechanic that knew corvettes well. I think it may have something to do with the parking brake if that's possible. Had it readjusted tight. I will check everything today...Thanks to all.
Steve
Steve
Melting Slicks
Joined: May 2000
Posts: 2,743
Likes: 146
From: Chuckanut WA
Re: Brakes locking up! (steves60vette)
How long was the car in storage? Lot of times after an extended period of storage the drums get a light coating of rust on them and when you drive it the first time you will notice wheel lockup. If you think this may be the case drive at a steady speed and lightly hold the brakes on for awhile to scuff off the rust. Do this a couple of times and it cleans up the drums and then they will work normally again. If this doesn't work you have other problems which may require pulling the offending drum and seeing if something is incorrectly assembled or adjusted. :cheers:
