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Topic: 74 rear brake locked up

in Forum: C3 Engines, Driveline and Handling


74 rear brake locked up

Posted: 1/25/07 12:06pm Message 1 of 5
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Klamath Falls, OR - USA
Joined: 2/1/2006
Posts: 1059
Vette(s): 74 coupe 4 speed 350, 54K actual miles, all original; paint, interior, engine, split bumper. #'s match. 2nd owner, no stress cracks.
I went out to back my 74 out of the garage and the rear brake on the drivers side was locked up.  I could pull forward and feel a little drag, but when I tried to back up, the brake was really stuck. Not 100%, but stuck.
 
I took the wheel off  and everything looks OK.  No leaks, no brake fluid on the rotor.  The rotor shows a little bit of surface rust.  I just rebuilt the caliper and put new shoes last summer.  Did not turn rotors, but they looked nice and smooth.
 
What should I do??  Spray WD40 on the rotor??
 
Weather might have something to do with it too.  Cold everynight and never gets much above freezing.  Also damp garage...
 
Thanks...........steveSmile   Parking brake was off.




Steve, Lifetime Member #129

74 coupe 4 speed 350, 54K actual miles,
all original; paint, interior, engine,
split  bumper. #'s match. 2nd owner, no stress cracks.
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74 rear brake locked up

Posted: 1/25/07 12:48pm Message 2 of 5
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Are the hoses original? Rebuilding the calipers and opening up the system could have allowed some crud to enter and block the rubber hose. They also have a tendency to collapse over time. I've had 2 hoses clog up on me over the years, both fronts. Tried bleeding the bad brake and got nothing, disconnected the hose from the caliper and still nothing through the hose. Disconnected the steel line from the hose, Bingo! got fluid.  I was able to put a heavy wire through the hose and flush it out with brake cleaner til I was able to replace them. Right now I know I have one hose that seems to be bubbling up at the metal crimp that I will be replacing next time I flush the ststem.

This is usually noticed directly after driving, tho, when the stuck brake gets hot and the car starts to pull in the opposite direction. As you're driving the car will pull in the direction of the stuck caliper but when applying the brakes the car will pull in the opposite direction because the stuck one is not applying any more while the unstuck brakes are holding. As they cool down the stuck one seems to release a little allowing some movement until the next time you drive the car and the brake gets hot again from dragging.

The regular brake pads will always drag slightly, if they are stuck to the rotor they should break free.  Are the parking brakes new? I wouldn't think originals would lock up as so many of them don't even work when you want them to! Look closely and see if the rotor is moving freely of the calipers. If the calipers are locked tight to the rotors I'd bet on the bad hose.

Mike

mkapp78792007-01-25 12:53:16


74 rear brake locked up

Posted: 1/25/07 5:09pm Message 3 of 5
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Australia
Joined: 5/6/2004
Posts: 535
Vette(s): 71 Coupe Black on Black
Are you sure it's not the park brake locked on.  Even if you've released the park brake handle, sometimes the shoes stay locked on.  You will need to drill the rotor rivets out (if they're not already done) and remove the rotor.  If you have problems taking the rotor off (after you've removed the caliper) you've found the problem.  Park brake springs let go pretty easy and if you have a lot of moisture around it wouldn't be the first time a park brake has locked.  Also the cable to that side may be jammed.


74 rear brake locked up

Posted: 1/25/07 6:48pm Message 4 of 5
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20225
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
I was gonna say check the e-brake, too. DO NOT spray any WD-40, or other oily substance on your rotors!!
Can you loosen the bleeder screw on that caliper, and the brakes release? If so, then you probably do have a bad hose there, as Mike pointed out. It does happen. They'll look fine on the outside, but can be collapsed on the inside, allowing fluid pressure to got to the caliper, but not release.

After re-reading the post, the tip-off is the "will move forward, but locks up in rev" part...sound like an e-brake problem. E-brakes always seem to hold better in rev. than they do forward.Adams' Apple2007-01-27 19:19:32


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74 rear brake locked up

Posted: 1/27/07 10:34am Message 5 of 5
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Klamath Falls, OR - USA
Joined: 2/1/2006
Posts: 1059
Vette(s): 74 coupe 4 speed 350, 54K actual miles, all original; paint, interior, engine, split bumper. #'s match. 2nd owner, no stress cracks.
Thanks everyone.  Yes I think you are right.  I think I have a parking brake problem.  I checked the brake pads and they are free and not froze up.  The parking brakes are original, so there must be the problem.
 
I will check the cables and if needed, remove the rotor.  I think the hoses are OK.
 
Thanks.........steve
 
Yep, its the parking brake...I am going to start a seperate thread for help...thanks agian 
steves742007-01-29 11:18:15



Steve, Lifetime Member #129

74 coupe 4 speed 350, 54K actual miles,
all original; paint, interior, engine,
split  bumper. #'s match. 2nd owner, no stress cracks.

in Forum: C3 Engines, Driveline and Handling


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