88 with brake problem
07-28-2018, 11:50 AM
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88 with brake problem
Newbie old man forum member and Corvette owner. Took an 88 on trade for my boat and he threw in some cash as well. Car has 136000 kilometers on it and has sat (with occasional around the block drive) since 2015. Condition is less than ideal although the motor runs strong and transmission is a new rebuilt unit. On the first drive I made in it, I went approximately 50 miles and the brakes started to drag in city traffic. First symptom was me being able to smell the pads then after another few minutes of very slow driving, the pedal went to the floor and had to pump to stop. When I got it in the garage, I felt the wheels and all four were hot to the touch with the passenger side rear being slightly hotter than the rest. After some liquid refreshments and beating myself up for doing the deal (three hours later), I fired the car back up and the pedal pressure had returned to normal. Not sure if this matters but I found two vacuum lines disconnected, one at the vacuum pot above the battery, one that looked like it should be attached to previous line and one on the intake just behind the throttle body. After reconnecting the first two together and jerry rigging the one on the intake, I fired it up and went for a drive. Coincidentally the A/C was blowing harder after this. Couple other notes, the emergency brake cable does not appear to be connected either at the handle or possibly the rear wheels (could not get lug nuts off with socket-need a breaker bar-today's project). Took it for a short drive the next day and brakes feel okay not great but pedal pressure is still up. The all four wheels being hot has me confused and does not lead me to master cylinder issue but rather the ABS pump/relays. I could really use some input to help me diagnose the problem.
07-28-2018, 12:23 PM
#2
Intermediate
" vacuum pot above the battery "
That is either the cruise control vacuum pot or the brake servo vacuum pot but I guess that you´ll recognise the latter.
But let´s get to the topic:
I´m quite sure that the ABS stuff isn´t your problem.
I guess that your brake calipers are slightly sticking and that "hot run" you did has loosened them up a little.
You said that it hasn´t been driven much since 2015. That is typically a car that has got som corrosion in the brake calipers, causing them to bind slightly. I suggest that you keep using the car for a while, keeping an eye on the problem. If you are lucky the problem has disappeared because you heated the calipers just enough but most likely you will have to rebuild the calipers sooner or later.
Emergency brakes can be a difficult job. I don´t remember if -88 is the last year with the old emergency brake (brake shoes inside the discs) or the first with the new type (using the disc brake liners as emergency brakes). Anyway, the new type is a real pain in the *** with a construction that cannot work unless all parts are new and shiny or you have make shims to make it work. I have some photos in a thread somewhere here on the forum about the emergency brake.
But I suggest that you start with checking the e brake cables as you say that the e brake feels like not connected at all.
I have seen wires broken from rust but my -90 had the cover rusted so the cover compressed so much that the emergency brake wouldn´t work at all. If the wires seem to work but the covers seem rusty under the plastic, be prepared to get some new emergency brake cables.
And another tip:
A left/right hand threaded shackle instead of the 10 (?) inch wire under the prop shaft makes it easier to do that small final adjustment.
That is either the cruise control vacuum pot or the brake servo vacuum pot but I guess that you´ll recognise the latter.
But let´s get to the topic:
I´m quite sure that the ABS stuff isn´t your problem.
I guess that your brake calipers are slightly sticking and that "hot run" you did has loosened them up a little.
You said that it hasn´t been driven much since 2015. That is typically a car that has got som corrosion in the brake calipers, causing them to bind slightly. I suggest that you keep using the car for a while, keeping an eye on the problem. If you are lucky the problem has disappeared because you heated the calipers just enough but most likely you will have to rebuild the calipers sooner or later.
Emergency brakes can be a difficult job. I don´t remember if -88 is the last year with the old emergency brake (brake shoes inside the discs) or the first with the new type (using the disc brake liners as emergency brakes). Anyway, the new type is a real pain in the *** with a construction that cannot work unless all parts are new and shiny or you have make shims to make it work. I have some photos in a thread somewhere here on the forum about the emergency brake.
But I suggest that you start with checking the e brake cables as you say that the e brake feels like not connected at all.
I have seen wires broken from rust but my -90 had the cover rusted so the cover compressed so much that the emergency brake wouldn´t work at all. If the wires seem to work but the covers seem rusty under the plastic, be prepared to get some new emergency brake cables.
And another tip:
A left/right hand threaded shackle instead of the 10 (?) inch wire under the prop shaft makes it easier to do that small final adjustment.
Last edited by Robban_C; 07-28-2018 at 12:24 PM.
07-28-2018, 12:52 PM
#3
3rd Gear
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" vacuum pot above the battery "
That is either the cruise control vacuum pot or the brake servo vacuum pot but I guess that you´ll recognise the latter.
But let´s get to the topic:
I´m quite sure that the ABS stuff isn´t your problem.
I guess that your brake calipers are slightly sticking and that "hot run" you did has loosened them up a little.
You said that it hasn´t been driven much since 2015. That is typically a car that has got som corrosion in the brake calipers, causing them to bind slightly. I suggest that you keep using the car for a while, keeping an eye on the problem. If you are lucky the problem has disappeared because you heated the calipers just enough but most likely you will have to rebuild the calipers sooner or later.
Emergency brakes can be a difficult job. I don´t remember if -88 is the last year with the old emergency brake (brake shoes inside the discs) or the first with the new type (using the disc brake liners as emergency brakes). Anyway, the new type is a real pain in the *** with a construction that cannot work unless all parts are new and shiny or you have make shims to make it work. I have some photos in a thread somewhere here on the forum about the emergency brake.
But I suggest that you start with checking the e brake cables as you say that the e brake feels like not connected at all.
I have seen wires broken from rust but my -90 had the cover rusted so the cover compressed so much that the emergency brake wouldn´t work at all. If the wires seem to work but the covers seem rusty under the plastic, be prepared to get some new emergency brake cables.
And another tip:
A left/right hand threaded shackle instead of the 10 (?) inch wire under the prop shaft makes it easier to do that small final adjustment.
That is either the cruise control vacuum pot or the brake servo vacuum pot but I guess that you´ll recognise the latter.
But let´s get to the topic:
I´m quite sure that the ABS stuff isn´t your problem.
I guess that your brake calipers are slightly sticking and that "hot run" you did has loosened them up a little.
You said that it hasn´t been driven much since 2015. That is typically a car that has got som corrosion in the brake calipers, causing them to bind slightly. I suggest that you keep using the car for a while, keeping an eye on the problem. If you are lucky the problem has disappeared because you heated the calipers just enough but most likely you will have to rebuild the calipers sooner or later.
Emergency brakes can be a difficult job. I don´t remember if -88 is the last year with the old emergency brake (brake shoes inside the discs) or the first with the new type (using the disc brake liners as emergency brakes). Anyway, the new type is a real pain in the *** with a construction that cannot work unless all parts are new and shiny or you have make shims to make it work. I have some photos in a thread somewhere here on the forum about the emergency brake.
But I suggest that you start with checking the e brake cables as you say that the e brake feels like not connected at all.
I have seen wires broken from rust but my -90 had the cover rusted so the cover compressed so much that the emergency brake wouldn´t work at all. If the wires seem to work but the covers seem rusty under the plastic, be prepared to get some new emergency brake cables.
And another tip:
A left/right hand threaded shackle instead of the 10 (?) inch wire under the prop shaft makes it easier to do that small final adjustment.
07-28-2018, 03:16 PM
#4
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Congrats on your "not so" new '88 Vette, welcome to the Forum and "save the wave".
Indeed the parking brake does use the regular rear brake pads. I find that a breaker-bar piece of pipe is very handy for removing wheels, until they can be torqued to the proper 90 lbs-ft.
If you wrench on your Vette a copy of the FSM, both volumes, will be a great asset.
Indeed the parking brake does use the regular rear brake pads. I find that a breaker-bar piece of pipe is very handy for removing wheels, until they can be torqued to the proper 90 lbs-ft.
If you wrench on your Vette a copy of the FSM, both volumes, will be a great asset.
07-28-2018, 03:25 PM
#5
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Congrats on your "not so" new '88 Vette, welcome to the Forum and "save the wave".
Indeed the parking brake does use the regular rear brake pads. I find that a breaker-bar piece of pipe is very handy for removing wheels, until they can be torqued to the proper 90 lbs-ft.
If you wrench on your Vette a copy of the FSM, both volumes, will be a great asset.
Indeed the parking brake does use the regular rear brake pads. I find that a breaker-bar piece of pipe is very handy for removing wheels, until they can be torqued to the proper 90 lbs-ft.
If you wrench on your Vette a copy of the FSM, both volumes, will be a great asset.
07-28-2018, 06:24 PM
#6
Safety Car
If the car mostly sat theres a good chance the calipers are sticking and in need of a rebuild. Its cheap and easy for these cars. Then you'll have fresh brake fluid afterwards.