Just wanna share some thoughts ..
07-08-2015, 03:11 PM
#1
Racer
Thread Starter
Just wanna share some thoughts ..
I just downloaded a HOW TO: Bleed your brakes paper from Performance Online, Inc which seems pretty straightforward but there are a few items that are still unclear.....#1 in what sequence are the calipers bled for a 78 coupe???
My son and I just swapped out my front pads by opening the master cylinder cover and using a 4" stiff putty knife were able to push back the pistons enough to replace the pads....Although it still needed to be bled by my corvette person the pedal is now ok..But he says that most corvette calipers will eventually leak anyway..
When we did the front we never did find any bleeder screws at least that were visible and we opted not to loosen the hose that feeds into the top of the caliper...So my next questions is where are those mysterious screws or is the caliper bled by loosening that hose....
Maybe we are missing a few steps here but I want to be able to do it myself next time..
In advance, we appreciate any and all help tips etc.....And I am so sorry for such a long post/thread....
mk's78
Mike
My son and I just swapped out my front pads by opening the master cylinder cover and using a 4" stiff putty knife were able to push back the pistons enough to replace the pads....Although it still needed to be bled by my corvette person the pedal is now ok..But he says that most corvette calipers will eventually leak anyway..
When we did the front we never did find any bleeder screws at least that were visible and we opted not to loosen the hose that feeds into the top of the caliper...So my next questions is where are those mysterious screws or is the caliper bled by loosening that hose....
Maybe we are missing a few steps here but I want to be able to do it myself next time..
In advance, we appreciate any and all help tips etc.....And I am so sorry for such a long post/thread....
mk's78
Mike
07-08-2015, 05:31 PM
#2
Melting Slicks
Member Since: Apr 2009
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With the lid off the master cylinder gravity bleed the right rear first then the left rear then the right front then the left front. And the front calipers just have one bleeder screw that sticks straight out.
07-08-2015, 05:48 PM
#3
Racer
Thread Starter
Alrighty then....well....
Perhaps I am not sure what you mean by gravity bleed???? Are you saying that the rear calipers have no bleeder screw??? Maybe you can expand on that procedure???
When my son and I dd the fronts, we did remove the MC cap and we still had to have the system bled....toobroketoretire am I lost in space or just to much of a novice to even attempt it???
Mike
JIC ya wanna get personal my email address is dafb169@hotmail.com and leave CF out of the loop.....
07-08-2015, 06:16 PM
#4
Safety Car
you do not need to open hydraulic system (brake fluid) to change caliper pads)
you have created a big can of worms...
Proper pad replacement:
leave system closed. remove caliper, remove old pads, use clamp to open the caliper pad opening, install new pads, put caliper and wheel back on, done. no bleeding required.
Corvettes require specific bleeding procedures not the same as regular car, plus some tricks to get a firm pedal.
you now must locate the bleeders on all calipers, and use the correct top bleed valve, and with correct procedure.
good luck.
you have created a big can of worms...
Proper pad replacement:
leave system closed. remove caliper, remove old pads, use clamp to open the caliper pad opening, install new pads, put caliper and wheel back on, done. no bleeding required.
Corvettes require specific bleeding procedures not the same as regular car, plus some tricks to get a firm pedal.
you now must locate the bleeders on all calipers, and use the correct top bleed valve, and with correct procedure.
good luck.
Last edited by 69Vett; 07-08-2015 at 06:19 PM.
07-08-2015, 06:48 PM
#5
Racer
I never owned a 'Vette 'til Jan. of this year.....but I AM mechanically inclined...am a mech. engineer, and have always worked on my own stuff....
I had to replace the rear calipers, rotors, brake pads, complete parking brake assemblies, and both the steel and rubber hoses on both rears, as well as GRAVITY bled them BY MYSELF....I took several times reading & watching videos on others that did this, and found out, even though the 'Vette IS a bit different than others I've worked on, it was not that hard, and I STILL have a nice firm brake pedal, with NO leaks! FWIW, I also had the original brass radiator fixed (new core, but kept the tanks, etc) & replaced the fan clutch, belts, & fixed the tach & clock MYSELF.....Suspension grommets/cushions are next......I'm looking forward to all of it....cuz, after all, it IS a VETTE....MY 1st VETTE!
Maybe.....just maybe...you aren't mechanically inclined enough to tackle this job.
I had to replace the rear calipers, rotors, brake pads, complete parking brake assemblies, and both the steel and rubber hoses on both rears, as well as GRAVITY bled them BY MYSELF....I took several times reading & watching videos on others that did this, and found out, even though the 'Vette IS a bit different than others I've worked on, it was not that hard, and I STILL have a nice firm brake pedal, with NO leaks! FWIW, I also had the original brass radiator fixed (new core, but kept the tanks, etc) & replaced the fan clutch, belts, & fixed the tach & clock MYSELF.....Suspension grommets/cushions are next......I'm looking forward to all of it....cuz, after all, it IS a VETTE....MY 1st VETTE!
Maybe.....just maybe...you aren't mechanically inclined enough to tackle this job.
07-08-2015, 07:16 PM
#6
Race Director
you do not need to open hydraulic system (brake fluid) to change caliper pads)
you have created a big can of worms...
Proper pad replacement:
leave system closed. remove caliper, remove old pads, use clamp to open the caliper pad opening, install new pads, put caliper and wheel back on, done. no bleeding required.
Corvettes require specific bleeding procedures not the same as regular car, plus some tricks to get a firm pedal.
you now must locate the bleeders on all calipers, and use the correct top bleed valve, and with correct procedure.
good luck.
you have created a big can of worms...
Proper pad replacement:
leave system closed. remove caliper, remove old pads, use clamp to open the caliper pad opening, install new pads, put caliper and wheel back on, done. no bleeding required.
Corvettes require specific bleeding procedures not the same as regular car, plus some tricks to get a firm pedal.
you now must locate the bleeders on all calipers, and use the correct top bleed valve, and with correct procedure.
good luck.
WHY??? Simple physics ( you can not compress liquids)....because...WHEN you go and attempt to push the pistons back into the caliper....the FLUID has to go somewhere. Either is goes back into the master cylinder.....which if the lid is TIGHT on it...you are building up unneeded pressure in the system and can blow out a seal in the master cylinder...when if the lid is loose...the AIR that is in the master cylinder reservoir can ESCAPE...allowing the brake fluid to fill back into the reservoir.....OR....when you begin to push the pistons back in with a spreader tool....open up the bleeder screw and the fluid NOW has a place to escape and NOT cause a problem.
In a 'perfect world'......YES...if the pistons are pushed back SLOWLY and the lid of the master cylinder was released...in theory...if NO AIR is in the system ...then no air will just magically appear...so...no bleeding is required...in theory. BUT....coming from a professional point of view and it is not that big of a deal for me...I pressure bleed the calipers to just make sure. And KNOWING that when I pressure bleed the system at or around 15 PSI....it is in no way the same as when I apply the brakes and see fit the pistons are leaking.....due to the brake pressure when the pedal is applied is very high...800 psi easily.
And YES...I care less if it is a lipped seal brake caliper or an 'O' ring design.....they can leak...regardless if the calipers are stainless steel sleeved or not....it DOES NOT MATTER. I have seen and encountered BOTH styles or design of sealed calipers that leak. AND...the main culprit....DIRTY /NEGLECTED DOT 3 brake fluid.
The sludge that builds up in a DOT 3 brake system DOES REQUIRE maintenance. Because you can have brake pads that are worn down and need replacing....and when they are worn down...the position of the seal on the piston is in a set location on the sleeve or bore.,,,,and when you PUSH BACK the piston INTO A BORE that has been contaminated over the years due to DIRTY FLUID...do not be surprised if when you put new pads in the caliper pistons can leak. BUT if you put the OLD PADS back in the same location...the leak stops.
DUB
07-08-2015, 07:22 PM
#7
Race Director
Actually we only replaced the front pads, then lost the pedal, took it to my local vette guru..He bled the whole system and said that only the left front and right rear calipers had air....Pedal has been restored...
Glad to read it is repaired and working.
Perhaps I am not sure what you mean by gravity bleed????
Gravity bleeding is a process that some people use....and it is simply opening up a bleeder fitting on a caliper and letting the brake fluid drip out...and constantly keeping an eye on the master cylinder reservoir and making sure it does not run DRY and out of FLUID which is BAD. I do not have the time to gravity bleed due to having a pressure bleeder which is an approved method.
Are you saying that the rear calipers have no bleeder screw??? Maybe you can expand on that procedure???
The rear caliper each have TWO bleeders...at the top of each half of teh caliper assembly.
Mike
Glad to read it is repaired and working.
Perhaps I am not sure what you mean by gravity bleed????
Gravity bleeding is a process that some people use....and it is simply opening up a bleeder fitting on a caliper and letting the brake fluid drip out...and constantly keeping an eye on the master cylinder reservoir and making sure it does not run DRY and out of FLUID which is BAD. I do not have the time to gravity bleed due to having a pressure bleeder which is an approved method.
Are you saying that the rear calipers have no bleeder screw??? Maybe you can expand on that procedure???
The rear caliper each have TWO bleeders...at the top of each half of teh caliper assembly.
Mike
DUB
07-08-2015, 10:40 PM
#8
Burning Brakes
Usually when I just change pads it doesn't require bleeding, but I do it anyway - just to change out the fluid. It gains water over time and really is one of the most neglected fluids. I have been known to change fluid after a couple of years even though the brakes are OK.
07-09-2015, 07:21 AM
#9
Racer
Thread Starter
Hello DUB.......
Actually I think you left out something VERY IMPORTANT ...removing the master cylinder cap does no harm....or setting the lid back on and NOT clamping it is required when you are getting the piston to go into the caliper.
WHY??? Simple physics ( you can not compress liquids)....because...WHEN you go and attempt to push the pistons back into the caliper....the FLUID has to go somewhere. Either is goes back into the master cylinder.....which if the lid is TIGHT on it...you are building up unneeded pressure in the system and can blow out a seal in the master cylinder...when if the lid is loose...the AIR that is in the master cylinder reservoir can ESCAPE...allowing the brake fluid to fill back into the reservoir.....OR....when you begin to push the pistons back in with a spreader tool....open up the bleeder screw and the fluid NOW has a place to escape and NOT cause a problem.
In a 'perfect world'......YES...if the pistons are pushed back SLOWLY and the lid of the master cylinder was released...in theory...if NO AIR is in the system ...then no air will just magically appear...so...no bleeding is required...in theory. BUT....coming from a professional point of view and it is not that big of a deal for me...I pressure bleed the calipers to just make sure. And KNOWING that when I pressure bleed the system at or around 15 PSI....it is in no way the same as when I apply the brakes and see fit the pistons are leaking.....due to the brake pressure when the pedal is applied is very high...800 psi easily.
And YES...I care less if it is a lipped seal brake caliper or an 'O' ring design.....they can leak...regardless if the calipers are stainless steel sleeved or not....it DOES NOT MATTER. I have seen and encountered BOTH styles or design of sealed calipers that leak. AND...the main culprit....DIRTY /NEGLECTED DOT 3 brake fluid.
The sludge that builds up in a DOT 3 brake system DOES REQUIRE maintenance. Because you can have brake pads that are worn down and need replacing....and when they are worn down...the position of the seal on the piston is in a set location on the sleeve or bore.,,,,and when you PUSH BACK the piston INTO A BORE that has been contaminated over the years due to DIRTY FLUID...do not be surprised if when you put new pads in the caliper pistons can leak. BUT if you put the OLD PADS back in the same location...the leak stops.
DUB
WHY??? Simple physics ( you can not compress liquids)....because...WHEN you go and attempt to push the pistons back into the caliper....the FLUID has to go somewhere. Either is goes back into the master cylinder.....which if the lid is TIGHT on it...you are building up unneeded pressure in the system and can blow out a seal in the master cylinder...when if the lid is loose...the AIR that is in the master cylinder reservoir can ESCAPE...allowing the brake fluid to fill back into the reservoir.....OR....when you begin to push the pistons back in with a spreader tool....open up the bleeder screw and the fluid NOW has a place to escape and NOT cause a problem.
In a 'perfect world'......YES...if the pistons are pushed back SLOWLY and the lid of the master cylinder was released...in theory...if NO AIR is in the system ...then no air will just magically appear...so...no bleeding is required...in theory. BUT....coming from a professional point of view and it is not that big of a deal for me...I pressure bleed the calipers to just make sure. And KNOWING that when I pressure bleed the system at or around 15 PSI....it is in no way the same as when I apply the brakes and see fit the pistons are leaking.....due to the brake pressure when the pedal is applied is very high...800 psi easily.
And YES...I care less if it is a lipped seal brake caliper or an 'O' ring design.....they can leak...regardless if the calipers are stainless steel sleeved or not....it DOES NOT MATTER. I have seen and encountered BOTH styles or design of sealed calipers that leak. AND...the main culprit....DIRTY /NEGLECTED DOT 3 brake fluid.
The sludge that builds up in a DOT 3 brake system DOES REQUIRE maintenance. Because you can have brake pads that are worn down and need replacing....and when they are worn down...the position of the seal on the piston is in a set location on the sleeve or bore.,,,,and when you PUSH BACK the piston INTO A BORE that has been contaminated over the years due to DIRTY FLUID...do not be surprised if when you put new pads in the caliper pistons can leak. BUT if you put the OLD PADS back in the same location...the leak stops.
DUB
I am assuming that our response was directed to "69vette"???
Your perspective does make a lot of sense, especially because I am not overly experienced for a caliper/pad etc job....
My son and I did manage to replace the front pads with MC lip open using a 4" stiff bladed putty knife......It test drove fine but then the pedal went to the floor...The dummy I am was in not being able to locate the bleeders..We looked all over the caliper and only could find a hose at the top which we decided to not loosen....My local vette guru was able to bleed the system and add some brake fluid....He did say that most all C3 calipers leak eventually but what made me stop and scratch my head was only the left front and right rear calipers had air....with that I paid him for what he did and immediately got on CF and shared my experience....
So DUB please send me in the right direction as is how do I find the bleeder screws???? I am not sure about the calipers as in make model or manufacturer..only that all the calipers and rotors have been replaced at least once since I have had my 78....
If you feel like corresponding with me outside the forum please do...my email address is mkane25@verizon.net and I'd be very interested to hear from you directly.....
Mike
07-09-2015, 07:50 AM
#10
Race Director
left side are rears, gold things are bleeders they point forward (although bubba might have installed a third instead of a plug, don`t touch the third bleeder), right side are fronts, silver thing is bleeder it is near the top and points toward center of car, two bleeders in the rear, one in the front...on each side.
Last edited by redvetracr; 07-09-2015 at 07:54 AM.
07-09-2015, 11:46 AM
#11
Order of bleeding has always been the caliper farthest way from the brake reservoir on any car first, next farthest second and so on.. So right rear, left rear, front right, front left.
07-09-2015, 06:00 PM
#12
Race Director
I am assuming that our response was directed to "69vette"???
NO...I was replying to what was written...and the information is for anyone who reads it and cares to use it as another information source.
Your perspective does make a lot of sense, especially because I am not overly experienced for a caliper/pad etc job....
I am glad I wrote it in a way that you and possibly others can hopefully understand the dynamics of the brake system...even though the full operation dynamic was not written out....but WHY I had to respond the way I did.
My son and I did manage to replace the front pads with MC lip open using a 4" stiff bladed putty knife......It test drove fine but then the pedal went to the floor...The dummy I am was in not being able to locate the bleeders..We looked all over the caliper and only could find a hose at the top which we decided to not loosen....My local vette guru was able to bleed the system and add some brake fluid....He did say that most all C3 calipers leak eventually but what made me stop and scratch my head was only the left front and right rear calipers had air....with that I paid him for what he did and immediately got on CF and shared my experience....
YES....your Vette guru is correct. The calipers are know to either leak fluid or draw in air...and I have seen it many times....so it is not just my imagination.
So DUB please send me in the right direction as is how do I find the bleeder screws???? I am not sure about the calipers as in make model or manufacturer..only that all the calipers and rotors have been replaced at least once since I have had my 78....
'redvetracr' posted photos that clearly show teh bleeder locations.
If you feel like corresponding with me outside the forum please do...my email address is mkane25@verizon.net and I'd be very interested to hear from you directly.....
Mike
I will 'say' this. WRITE DOWN you mileage. Keep it handy. If you notice your brake pedal begins to go down....and eventually the BRAKE light comes on...notice the mileage.
WHY do this....because the mileage from the pedal being good and solid to where it begins to go down and cause the light to come on can be an aid in what to check and look for and what is causing this problem.
So...having air in the rear caliper where you did not do anything to the caliper or pads....it can be an issue in the bearings or rotor.
DUB