Should brake fluid go up in master when brake pedal is pushed?
11-30-2015, 01:51 AM
#1
Instructor
Thread Starter
Should brake fluid go up in master when brake pedal is pushed?
Hey guys,
I recently gravity bled my brakes and after taking the car out for a spin I noticed the brakes felt like crap with very little stopping power. I have had the car for about three weeks and only drove the car for maybe 1-2 miles before I bled them so I'm not sure if they were this way when I bought the car.
Anyways, since I am partially redoing my front end suspension I decided to rebleed the front two brakes and I had a question about something I observed.
On previous cars, when I open up the master cylinder and press on the brake pedal I can see the fluid rise as I do so. I tried this on the Vette but didn't see any movement of the fluid.
Should the fluid move as I press the pedal?
Also, I did hear some noise on the passenger side near the brake, but I'm thinking it might just be the normal operation of the brake pistons, however it did seem louder than the left side.
My fluid is clear and I didn't see much, if any air come out when I rebled the front two lines.
Thanks in advance!
I recently gravity bled my brakes and after taking the car out for a spin I noticed the brakes felt like crap with very little stopping power. I have had the car for about three weeks and only drove the car for maybe 1-2 miles before I bled them so I'm not sure if they were this way when I bought the car.
Anyways, since I am partially redoing my front end suspension I decided to rebleed the front two brakes and I had a question about something I observed.
On previous cars, when I open up the master cylinder and press on the brake pedal I can see the fluid rise as I do so. I tried this on the Vette but didn't see any movement of the fluid.
Should the fluid move as I press the pedal?
Also, I did hear some noise on the passenger side near the brake, but I'm thinking it might just be the normal operation of the brake pistons, however it did seem louder than the left side.
My fluid is clear and I didn't see much, if any air come out when I rebled the front two lines.
Thanks in advance!
11-30-2015, 10:29 AM
#2
Le Mans Master
Did you bleed rear? Does parking brake work? If not rear pistons may not be adjusted out causing a low pedal. Fluid will move some, but not like vehicle with rear drum brakes. Did you have a strong stream of fluid while bleeding front? Did it have good brakes when got it?
11-30-2015, 11:25 AM
#3
Team Owner
Pro Mechanic
Elaborate. Did the brakes fail to stop you fast? Or was the pedal soft? If the pedal was soft, you have more bleeding to to.
The fluid level in the reservoir shouldn't rise noticeably when you press the pedal down.
The fluid level in the reservoir shouldn't rise noticeably when you press the pedal down.
11-30-2015, 01:16 PM
#5
Instructor
Thread Starter
Kevova,
I bled all the brakes and the parking brake works. I had a decent stream but I was gravity bleeding so it wasn't fast. I don't think the car had great brakes when I got it, but I don't think they were bad either.
Tom,
I guess it feels spongy which probably means I have more air in the lines, but I bled them like I've done them in the past and have never had any issues before. The fluid in the system was very nasty before I bled them, but now it's clear.
Ok, good to know about the fluid rising, I thought it was supposed to rise when I pressed the pedal.
I may have to convince my wife to do the pedal/bleed procedure, but that might be like pulling teeth. :P
I bled all the brakes and the parking brake works. I had a decent stream but I was gravity bleeding so it wasn't fast. I don't think the car had great brakes when I got it, but I don't think they were bad either.
Tom,
I guess it feels spongy which probably means I have more air in the lines, but I bled them like I've done them in the past and have never had any issues before. The fluid in the system was very nasty before I bled them, but now it's clear.
Ok, good to know about the fluid rising, I thought it was supposed to rise when I pressed the pedal.
I may have to convince my wife to do the pedal/bleed procedure, but that might be like pulling teeth. :P
11-30-2015, 01:30 PM
#6
Le Mans Master
I installed speed bleeders on both my 85 and 95 which makes bleeding the brakes much easier.
$7.25 per pair from Rockauto...below...
https://www.rockauto.com/catalog/mor...nid=499&jpid=4
My I make a suggestion. I push a 3 foot section of clear plastic tubing over the nipple with the other end in a glass jar with a small amount of fluid in the jar with the end of the tube submerged in the fluid. This way, you can see any air bubbles come out and if for some reason there is a back flow of fluid....it only draws fluid from the far. I pump the brake peddle very slowly and check the reservoir often to be sure it is always full. You do not want to suck air into the lines and push this past the ABS unit...so be sure the reservoir is always full.
I would bleed them again, starting at the rear passenger side (farthest from the master cyclinder) the drivers side. Then move to the front passenger side then driver's.
$7.25 per pair from Rockauto...below...
https://www.rockauto.com/catalog/mor...nid=499&jpid=4
My I make a suggestion. I push a 3 foot section of clear plastic tubing over the nipple with the other end in a glass jar with a small amount of fluid in the jar with the end of the tube submerged in the fluid. This way, you can see any air bubbles come out and if for some reason there is a back flow of fluid....it only draws fluid from the far. I pump the brake peddle very slowly and check the reservoir often to be sure it is always full. You do not want to suck air into the lines and push this past the ABS unit...so be sure the reservoir is always full.
I would bleed them again, starting at the rear passenger side (farthest from the master cyclinder) the drivers side. Then move to the front passenger side then driver's.
Last edited by John A. Marker; 11-30-2015 at 01:37 PM.
11-30-2015, 01:44 PM
#7
Le Mans Master
Did you have brake lines apart or were you just trying to change fluid? Did master cylinder run out of fluid while you were gravity bleeding? Will brake pedal "pump up"? This is a 96 Vette? If so, the J55 Heavy Duty brakes were standard equipment so it should stop.
11-30-2015, 05:06 PM
#8
Instructor
Thread Starter
John Marker,
I will try the jar idea when I do them again. I did them RR, LR, RF, LF.
Kevova,
I did not have the brake lines apart, I was just trying to flush the old crappy fluid out. I'm pretty sure the master did not go empty. The brake pedal doesn't feel like it's pumping up. And it's a 1996.
I will try the jar idea when I do them again. I did them RR, LR, RF, LF.
Kevova,
I did not have the brake lines apart, I was just trying to flush the old crappy fluid out. I'm pretty sure the master did not go empty. The brake pedal doesn't feel like it's pumping up. And it's a 1996.
11-30-2015, 05:32 PM
#9
might need a new master.
11-30-2015, 08:51 PM
#10
hi Punk. just did 4 cars brakes so i know what u r going through.
i bought a vacuum pump. admittadly it was 40 bucks but it was worth it over the 2person pump and bleeder screw adjust. wife was annoyed. even though she wants safe brakes. tool makes this a manageable one man job.
IF THE PEDAL is hard like a rovk and u just arnt getting much stopping power, your booster (big black thing) is either toast or the vac line is unplugged! (u would notice the running maniaclly in that last case though. )
IF THE PEDAL goes to the floor with a steady 3/4 pedal pressure, then as ant said, you probably need a new master cyl, (fluid going around the seals in the mc plunger piston instead of getting pressurized and transmutting that pressure down the lines to the calipers to squeeze the pads. assuming u dont have a leak, which i assume u ruled out already.
even if u have some air in the system, u should be able to pump the brake and have it get harder. but even if you pump it and it gets harder, but then sags with your foot on the pedal, then u have pressure getting past the mc plunger.
IF YOU HAVE ABS then after bleeding #1, go to gravel , of if u live like me in a snow zone, activate the abs brakes. it cycles the abs pump and makes a huge difference. then bleed one more time.
now, if u go with the vacuum gauge sucker tool,.... another thing. if your bleeder screws are like mine, they will allow air to suck into the vac line, past the threads, and it will look like u have a whoooole lot of air in thd line.
i took all my bleeders out one at a time which allowed fluid to drain out uncontrollable. used a rag to soak it up.
wrapped the bleed screw threads in pipe fitters tape. reinstalled, all good.
highly recommend a tool.
i bought a vacuum pump. admittadly it was 40 bucks but it was worth it over the 2person pump and bleeder screw adjust. wife was annoyed. even though she wants safe brakes. tool makes this a manageable one man job.
IF THE PEDAL is hard like a rovk and u just arnt getting much stopping power, your booster (big black thing) is either toast or the vac line is unplugged! (u would notice the running maniaclly in that last case though. )
IF THE PEDAL goes to the floor with a steady 3/4 pedal pressure, then as ant said, you probably need a new master cyl, (fluid going around the seals in the mc plunger piston instead of getting pressurized and transmutting that pressure down the lines to the calipers to squeeze the pads. assuming u dont have a leak, which i assume u ruled out already.
even if u have some air in the system, u should be able to pump the brake and have it get harder. but even if you pump it and it gets harder, but then sags with your foot on the pedal, then u have pressure getting past the mc plunger.
IF YOU HAVE ABS then after bleeding #1, go to gravel , of if u live like me in a snow zone, activate the abs brakes. it cycles the abs pump and makes a huge difference. then bleed one more time.
now, if u go with the vacuum gauge sucker tool,.... another thing. if your bleeder screws are like mine, they will allow air to suck into the vac line, past the threads, and it will look like u have a whoooole lot of air in thd line.
i took all my bleeders out one at a time which allowed fluid to drain out uncontrollable. used a rag to soak it up.
wrapped the bleed screw threads in pipe fitters tape. reinstalled, all good.
highly recommend a tool.
11-30-2015, 09:12 PM
#11
Instructor
Thread Starter
I think I'll try the bottle idea first (I got a good sized one from work) and see how that goes. I really want my wife to push on the pedal so I can see if any air comes out.
11-30-2015, 09:31 PM
#12
with VT I like the vacumme pump saves the wife from getting upset when pumps instead of holds. 
and very easy to see the bubbles in the clear tube. 
12-03-2015, 11:09 AM
#13
i tried the "rope method" on my valve stem seals and it was a cluster ****. got the spark plug air hose adapter and i did 7 cylinders as fast as i did one with the rope method.
the right tool for the job. in canadian dollars it was 40$. so what in american that is 30$.
as a noob, there are just so many brand new things to learn and deal with. a crappy tool makes it that much worse@!
Last edited by VikingTrad3r; 12-03-2015 at 11:09 AM.
12-03-2015, 12:08 PM
#14
12-04-2015, 06:31 PM
#15
I'm not a huge fan of the vacuum bleeder method. I've used it, and it seems that enough air leaks in through the brake bleed screw threads that you ALWAYS see air bubbles in the line.
I much prefer the systems that pressurize the master cylinder reservoir and push fluid through the system. There are several systems out there - or if you're cheap (like me) - just get a spare Master Cylinder cap (the screw on kind) - drill and tap it for a 1/4 NPT fitting - screw a male quick connect fitting on there, and connect it to an air tank that is inflated to about 10 - 15 psi. You NEED to keep a close eye on the master cylinder fluid levels!!! When the fluid looks nice and clean coming through the hose attached to the bleeder, close the bleeder - remove the air line - refill the master cylinder and repeat for the next wheel.
So - anyway - after your next bleed - if you still feel your car isn't stopping the way it should (and IMHO the 13" brakes on the C4's are under rated by most - I've pounded the heck out of mine on the track - and while I certainly can't outbrake a 911 - I can haul that thing down pretty darn fast) - you need to do some diagnostic work. Since the car is new (to you) jack up the front and pull the front wheels. Do the rotors look good ??? How much pad is left ??? Put the tire back on - Maybe you can get someone to very gently apply the brakes while you try to spin the wheel - a pound or so of pressure on the brake pedal (with vacuum in the brake booster) should make it very difficult to turn the front wheels. If you're not happy with the feel - pull the front calipers off, and check that the moving surfaces that allow the calipers to move in the brackets are not rusted solid. If the pads are not in great shape - this would be a wonderful time to replace them (good brake pads aren't that expensive). Once you finish with the fronts - then check the rears.
You want to be able to trust your brakes - so take a couple of hours to make sure that they're in good shape.
And most importantly - ENJOY THE CAR !!!!
I much prefer the systems that pressurize the master cylinder reservoir and push fluid through the system. There are several systems out there - or if you're cheap (like me) - just get a spare Master Cylinder cap (the screw on kind) - drill and tap it for a 1/4 NPT fitting - screw a male quick connect fitting on there, and connect it to an air tank that is inflated to about 10 - 15 psi. You NEED to keep a close eye on the master cylinder fluid levels!!! When the fluid looks nice and clean coming through the hose attached to the bleeder, close the bleeder - remove the air line - refill the master cylinder and repeat for the next wheel.
So - anyway - after your next bleed - if you still feel your car isn't stopping the way it should (and IMHO the 13" brakes on the C4's are under rated by most - I've pounded the heck out of mine on the track - and while I certainly can't outbrake a 911 - I can haul that thing down pretty darn fast) - you need to do some diagnostic work. Since the car is new (to you) jack up the front and pull the front wheels. Do the rotors look good ??? How much pad is left ??? Put the tire back on - Maybe you can get someone to very gently apply the brakes while you try to spin the wheel - a pound or so of pressure on the brake pedal (with vacuum in the brake booster) should make it very difficult to turn the front wheels. If you're not happy with the feel - pull the front calipers off, and check that the moving surfaces that allow the calipers to move in the brackets are not rusted solid. If the pads are not in great shape - this would be a wonderful time to replace them (good brake pads aren't that expensive). Once you finish with the fronts - then check the rears.
You want to be able to trust your brakes - so take a couple of hours to make sure that they're in good shape.
And most importantly - ENJOY THE CAR !!!!
12-04-2015, 08:27 PM
#16
i echo all of this. fwiw with the vacuum tool method, if you want, you can use a tiny but of teflon tape (dont let tape go over the ond of the threaded nipple on the bleeder). that solved my drawing air past the threads. the problem with this method is that if you have 4 cars that is alot of pita to get the tape on each screw. i did it to my tacoma, 2 c4's, and a yukon xl. super pita but it works. i do like the vacuum method because i can pull a 15 vac and leave it there (it doesnt gush out super fast) and walk over to ensure the master cyl has fluid in it. it would run dry if you let it and suck air into the lines.
i cannot beleive how incredible crappy my fluid was. i could have stained my deck with it to a cherry red color.
on the pads, we had one pad that was having a hard time getting full comtact with the disc. i pulled it off, sanded the disc back and forth face down on a table over a sheet of sandpaper, it was 120 i think, and boom problem solved. turns out the po had installed the pads wrong and we got this one pd that was wonky. sanding it flat worked perfect with the right re install and now the contact pattern on the disc is across the whole disc. (was like , 2mm offor about an 1/8th).
the car went from having scary brakes, to having beakes better than my newer cars.
as the pp said, take the time in your brakes and dont leave any stones unturned. the stock c4 brakes are awesome if they are simy installed as intended from factory with a good set of pads (for me, agressive street pads that yes produce dust but stop amazingly well and i just rinse!
good luck and enjoy the learning!
QUOTE=Purple92;1591043532]I'm not a huge fan of the vacuum bleeder method. I've used it, and it seems that enough air leaks in through the brake bleed screw threads that you ALWAYS see air bubbles in the line.
I much prefer the systems that pressurize the master cylinder reservoir and push fluid through the system. There are several systems out there - or if you're cheap (like me) - just get a spare Master Cylinder cap (the screw on kind) - drill and tap it for a 1/4 NPT fitting - screw a male quick connect fitting on there, and connect it to an air tank that is inflated to about 10 - 15 psi. You NEED to keep a close eye on the master cylinder fluid levels!!! When the fluid looks nice and clean coming through the hose attached to the bleeder, close the bleeder - remove the air line - refill the master cylinder and repeat for the next wheel.
So - anyway - after your next bleed - if you still feel your car isn't stopping the way it should (and IMHO the 13" brakes on the C4's are under rated by most - I've pounded the heck out of mine on the track - and while I certainly can't outbrake a 911 - I can haul that thing down pretty darn fast) - you need to do some diagnostic work. Since the car is new (to you) jack up the front and pull the front wheels. Do the rotors look good ??? How much pad is left ??? Put the tire back on - Maybe you can get someone to very gently apply the brakes while you try to spin the wheel - a pound or so of pressure on the brake pedal (with vacuum in the brake booster) should make it very difficult to turn the front wheels. If you're not happy with the feel - pull the front calipers off, and check that the moving surfaces that allow the calipers to move in the brackets are not rusted solid. If the pads are not in great shape - this would be a wonderful time to replace them (good brake pads aren't that expensive). Once you finish with the fronts - then check the rears.
You want to be able to trust your brakes - so take a couple of hours to make sure that they're in good shape.
And most importantly - ENJOY THE CAR !!!![/QUOTE]
i cannot beleive how incredible crappy my fluid was. i could have stained my deck with it to a cherry red color.
on the pads, we had one pad that was having a hard time getting full comtact with the disc. i pulled it off, sanded the disc back and forth face down on a table over a sheet of sandpaper, it was 120 i think, and boom problem solved. turns out the po had installed the pads wrong and we got this one pd that was wonky. sanding it flat worked perfect with the right re install and now the contact pattern on the disc is across the whole disc. (was like , 2mm offor about an 1/8th).
the car went from having scary brakes, to having beakes better than my newer cars.
as the pp said, take the time in your brakes and dont leave any stones unturned. the stock c4 brakes are awesome if they are simy installed as intended from factory with a good set of pads (for me, agressive street pads that yes produce dust but stop amazingly well and i just rinse!
good luck and enjoy the learning!
QUOTE=Purple92;1591043532]I'm not a huge fan of the vacuum bleeder method. I've used it, and it seems that enough air leaks in through the brake bleed screw threads that you ALWAYS see air bubbles in the line.
I much prefer the systems that pressurize the master cylinder reservoir and push fluid through the system. There are several systems out there - or if you're cheap (like me) - just get a spare Master Cylinder cap (the screw on kind) - drill and tap it for a 1/4 NPT fitting - screw a male quick connect fitting on there, and connect it to an air tank that is inflated to about 10 - 15 psi. You NEED to keep a close eye on the master cylinder fluid levels!!! When the fluid looks nice and clean coming through the hose attached to the bleeder, close the bleeder - remove the air line - refill the master cylinder and repeat for the next wheel.
So - anyway - after your next bleed - if you still feel your car isn't stopping the way it should (and IMHO the 13" brakes on the C4's are under rated by most - I've pounded the heck out of mine on the track - and while I certainly can't outbrake a 911 - I can haul that thing down pretty darn fast) - you need to do some diagnostic work. Since the car is new (to you) jack up the front and pull the front wheels. Do the rotors look good ??? How much pad is left ??? Put the tire back on - Maybe you can get someone to very gently apply the brakes while you try to spin the wheel - a pound or so of pressure on the brake pedal (with vacuum in the brake booster) should make it very difficult to turn the front wheels. If you're not happy with the feel - pull the front calipers off, and check that the moving surfaces that allow the calipers to move in the brackets are not rusted solid. If the pads are not in great shape - this would be a wonderful time to replace them (good brake pads aren't that expensive). Once you finish with the fronts - then check the rears.
You want to be able to trust your brakes - so take a couple of hours to make sure that they're in good shape.
And most importantly - ENJOY THE CAR !!!![/QUOTE]