@asemaster is correct about the master cylinder being your original problem. Buy 2 new hoses, 2 new calipers and a new master cylinder. Bench bleed the master cylinder before installing it. Then bleed the system and you’ll be good for another 10 years.
Caddyman:
I’m OK. Hope the same with you. I know - you miss me because you had so much fun guessing the make and model of that “Mystery Vehicle” my exhaustive new car search unearthed a few years back ('09, I think it was). Remember? It was a brand new vehicle (untitled) but 2.5 years with 7 miles on it (turned out to actually be 700 miles). Sticker was ~$32,000, I offered $15,000 and they countered $15,500. After my GM dollars it was going to cost me $11,000 out of pocket. Deal fell apart when GM dollars could not be verified on a Saturday (unbeknownst to me, Redemption Center had changed their hours since my '02 Impala purchase), and I didn’t trust the dealer’s offer to give me $2,000 up-front then the rest later “if I was telling the truth”. Didn’t believe they could give me the rest once the deal was done. Anyway, bought a 2011 Equinox two years later and glad I did. Uplander would’ve been overkill at this point and current generation Equinox is a much nicer vehicle.
But I digress …
When I was trying to push the piston in with the C-Clamp, the caliper was off the car and completely open. I’m not sure what happened there. Maybe it was just too dry? The car had been sitting for several weeks while I casually changed the oil pan and front cover gaskets … and then the water pump after that. And the O-rings came out pristine, so it wasn’t like that was jamming it up inside. The piston must’ve just been sticking to the rubber O-ring, I guess? Right now, with all the rubber removed, I can push the piston in by hand on the passenger-side caliper. I scored the driver-side piston and it won’t drop all the way in now, but the passenger piston will drop into the driver caliper, so hence the new piston for the driver side.
FYI: I just watched a YouTube video yesterday of a guy rebuilding his calipers and I had to laugh because it could’ve easily have been a video of me! The guy lubes the O-ring and drops it into the groove in the bore - that part looks easy. Then he tries pushing the piston in with his thumbs and cannot do it, so out comes the C-clamp and old brake pad for more leverage, but unlike me - he’s able to push it all the way in. Then he (fairly easily) pops on the dust boot cover, then taps it all the way around with the rounded handle of a screwdriver, and <voila’ !> he’s done!
BustedKnuckles:
It’s only costing me $10 (delivered) for the new piston and the (2) seals. I would’ve bought the flexible brake lines anyway. So if this doesn’t work out, I’ll just order the remans and have the experience to relate to someone else some day down the road.
asemaster:
Thanks for your support. I know this doesn’t make a lot of sense to a professional (it really doesn’t make a lot of sense, period!), but it’s a one-time thing for someone who’s changed pads several times over the past 25 years, but never taken calipers apart. Just hope I don’t kill myself in the process! (LBNOL
keith:
So I’m putting the O-ring in first, then slipping the top of the dust boot onto the bottom of the piston, then putting the bottom of the dust boot into the cylinder bore groove, then pushing the piston all the way in? That’s not what the guy in the YouTube video did, but maybe it was a different application? Check this out (no audio for some reason). The guy tries to push the piston in with his thumbs and fails, then appears to try to pull the piston back out, but cannot, then finally reaches for the C-clamp to brute force it into the bore. But watch how he attaches the dust cover. Makes it look real easy … but then again, one of the comments says ‘not the best way to install the dust seal’. Always get a kick out of the comments people post online. Some people are so funny!
knfenimore:
But how did the Master Cylinder fail? Did just sitting dormant for a few weeks somehow do it? Did I pour in the wrong DOT-X fluid (I used DOT-3) and that somehow did it (by damaging the seals)? Or did just a little bit of air somehow get into the lines because I had the car sitting cockeyed for several weeks on ONE jackstand on the passenger side while I pulled off the exhaust, balancer and crank pulley to replace the front cover and oil pan gaskets. The brakes worked fine before I started that project. Was shocked to discover the pedal went to the floor after the car finally sat flat on the ground.
Forgot the link:
One More time:
youtube.com/watch?v=6HdFdmueLsA
The guy’s name is Nathan of ProTec garage? He’s wearing a knitted cap. Can’t hear the audio for some reason…
You have to turn the audio up using the little speaker symbol on the bar at the bottom of the picture. Sometimes someone posts one like this with zero volume. Adjusting your computers volume control will not help until you adjust this one up first.
I guess I have been unlucky with the calipers that I have rebuilt. His had a rabbit for the dust seal, the ones I have done had a groove and you could not get the bead to go into the groove if the piston was in the way. But if yours is like this then it should be a lot easier.
If the pedal goes to the floor, which is what you said was the original problem, then the master cylinder gave up the ghost. The seals go bad inside it and allow fluid to bypass. Then the pedal goes to the floor.
Master Cylinder by Raybestos or Wagner? Or does it matter?
http://www.rockauto.com/catalog/moreinfo.php?pk=309449&cc=1139037
http://www.rockauto.com/catalog/moreinfo.php?pk=908557&cc=1139037
And how hard to replace?
I don’t think it matters but I tend to go with Wagner just because they have worked for me. Not hard to replace, just be sure to bench bleed, a bench bleed kit usually comes with them and match the power booster rod to the new master cylinder. You will need a service manual to get the procedures for that.
If you don’t have access to the procedures, try this. Get some modeling clay. Pull the old MC, put a pea sized piece of clay in the end of the MC and then remount it and bolt down. Remove, carefully peal out the clay and measure its thickness. Then put another pea sized piece of clay in the end of the new MC and mount it and bolt down. Remove, peal out the clay and measure its thickness. Adjust the push rod in the booster and repeat until the thickness is a match to step one.
Note: some cars don’t require an adjustment.
Hey Keith!
Looks like there’s not need to adjust the booster push rod on this car. The shop manual makes no mention of it. Appears to be just a ‘drop-it-in-and-bolt-it-up’ arrangement.
But here’s what I’m going to do tomorrow: Like asemaster suggested - I’m just going to put it all back together first (seals and piston into driver’s caliper, then both calipers and new flex lines installed). Then I’m going to see if I can prove the master cylinder is, in fact, bad. If it is, then I guess this will go another weekend, as the part won’t arrive until mid next week.
But what if just bleeding the brakes fixes it? Would that mean that air got into the lines somehow (while the car was sitting dormant for several weeks) through the parts I just replaced (caliper seals and flex lines)? Doesn’t seem plausible. But neither does the Master Cylinder failing after sitting dormant (unless stagnant fluid can destroy the cylinder’s internal seals).
Well, I got the original calipers cleaned up with fine sandpaper, installed new O-Rings, and fitted a new piston to replace the one that was scored and refused to go in (must’ve gotten distorted out-of-round, or something). Then added the new dust boots and pushed the pistons in with my hands this time. Went very easy. Only used the C-clamp for the last 1/4" of travel to get it all the way in, but that was very easy, too. Don’t know what happened before. Maybe the bore was dirty? I dunno. Anyway, got the calipers on with the new flex lines, but now I’m going to replace the master cylinder because I’m convinced that was my original problem.
Questions:
1.) Bench bleeding: I don’t have a vice, so I thought I’d just install the MC right in the the car and just pre-bleed it right there. I saw one video where the guy pumps the piston on a bench and the air bubbles travel up the tube back toward the reservoir, but then he releases the piston and the bubbles travel back down! He keeps doing this again and again … doesn’t seem to be accomplishing anything! Is this the correct method? Aren’t you supposed to pinch the tubes before releasing the piston to prevent the air bubbles from being sucked back into the cylinder?
2.) Do I really need flare wrenches? I installed the new flex lines at the wheels without them. It’s just a typical hex nut, isn’t it? What’s the deal with the flare wrenches? Are they supposed to prevent you from stripping the nut??? But can’t you just be careful with a standard open-end wrench? I mean - it’s not like there’s a lot of torque on these small nuts, right? I guess if I have to buy a set I can get one at Harbor Fake relatively cheap?
3.) Is 32 oz of DOT-3 (plus maybe another 1 or 2 oz left in another small bottle) enough to do the bleeding? How much fluid does the entire system hold?
You gotta bench bleed the master. There really is no substitute. Buy your neighbor a case of beer in exchange for using his vise
You gotta use flare wrenches. Open end wrenches WILL round off the fittings. And if you’re the next guy to service the master, you’ll be cursing yourself
For putting the lines on, you can use an open ended wrench, but after they have been in place for a few years and you need to loosen them, you really need the flair wrenches.
It is better to bleed the MC on a bench with a vise, but I have been known to just push the MC into a corner and bench bleed it that way.
Push the piston in and let any air bubbles rise to the top of the curve in the tubing, then slowly let the piston return, slow enough that the bubbles can rise back up to the top of the tubing. On the next push, those bubbles should go into the reservoir. Repeat until the bubbles stop coming out of the MC. Then work the piston quickly a few time to make sure there are no more bubbles.
Well, didn’t need the flare wrenches. Got everything off and back on without any problems. Southern car, so the nuts were pristine. Installed the new flex hoses at the front wheels, installed the new Raybestos master cylinder, and just bled all four brakes (starting at the right rear, then front left, then the other diagonal), but I still have the same pedal problem - it goes right to the floor with a very audible WHOOOSH sound and very minimal resistance. Really no difference from when I was shocked to discover I had lost my brakes during the oil pan/front cover project.
Did I do the bleeding incorrectly? I pumped the brake (with the car off) a half dozen times to kill any residual vacuum (according to the manual). Then, starting at the right rear, I had my wife hold the pedal all the way down while I opened the bleeder nut (with the clear flexible 1/4" I.D. tubing fit tightly over the mushroom head of the valve). Then, with the pedal still fully depressed, I closed the bleeder nut.
Was I supposed to have the valve open before she depressed the pedal? Could that be what I did wrong?
I also had a 4’ length of clear tubing (really, too long) such that it had two coils in it (like a spring on a shock) flowing down to a clear glass (Gherkin pickle) jar filled halfway with brake fluid. At no time did the tubing come out of the fluid. But what I noticed was - I really only got noticeable fluid out of the back wheels - and even then it wasn’t much … the fluid never traveled all the way down the tubing to the jar. For the front wheels, I really couldn’t see any fluid coming out, but it turned out there was some in the line, just not very much and hard to notice without straightening out the tubing.
So I don’t know what to do now. The whole brake failure thing (with the car never moving during the oil pan/front cover project) was a mystery to begin with. Now I’ve replaced the front flex lines, the master cylinder, and the seals and piston boots on the front calipers only to see nothing improve. It’s as if I’d done nothing to fix the problem!
Don’t see any leaks anywhere, either. And, oh - the fluid level in the master cylinder may have dropped a hair below the “FULL” line during the bleeding, but I was checking it after each wheel and adding fluid as necessary.
One other thing that was weird … probably unrelated … there was a clicking noise (2 Hz?) coming from underneath the dash … sounded like a relay. And in the very rear of the car I could hear the same clicking noise. Appeared to be another relay box near the spare/jack area that was clicking in tandem with the one up front.
Oh, I did “bench bleed” the master cylinder before installing it. I used a 1/4" metal dowel to push the plunger in by hand. I must have push the plunger at least 100 times! I had the plastic plugs in the ports and it did seem to build up pressure and become harder and harder to plunge as I did it.
Glad to hear you bench bled the master
As far as the line wrenches and the fittings go . . .
You don’t use line wrenches because the fittings are corroded
You use line wrenches because they DON’T round off the fittings, unlike open end wrenches
Rebuilding calipers and master cylinders is like climbing Mt Everest. Expensive bragging rights.
@ColtHero, if the master is bench bleed and tested as you point out, you must still have a lot of air in the lines. The air will compress and decompress, taking away all of your pedal effort. Too much air, and the pump-bleed method can be fruitless.
I recommend starting at the rear, passenger brake cylinder, cracking open the bleeder, and letting it gravity bleed until fluid begins to consistently trickle out. Then, do the same with the drivers side rear, passenger front, then drivers side front in that order. It could take upwards of 30 mins or more for each wheel. But, it will evacuate a lot of that air.
Next, do the pump-pump-pump-bleed procedure on the exact same rotation starting at passenger side rear. You should see a firm pedal by the time you get to the passenger side front.
db4690:
Yeah, I realize that you use the flare wrenches to avoid damaging the nuts - because once those nuts are ruined you have to replace the line … and you don’t want to do that. However, I took the chance because the nuts were pristine, had never been touched since the factory, the open box wrench fit tight, and the first nut came loose with very little effort. Next time I’ll use the flare wrenches, though … don’t want to press my luck too much!
Rod Knox:
Expensive in terms of time (for a first-timer), but not money. The master cylinder was $39 delivered, the piston, seals and boots $15 delivered. I’m doing this for the experience, however painful it is.
BustedKnuckles:
Yes, it appears that I have no fluid at the calipers right now. I’ll try the gravity bleed, thanks! Could I do all four wheels in parallel to save time?
I have done all four at the same time but it really keeps you busy. You have to keep running around all four wheels to check that the brake fluid is flowing and still keep the master cylinder full. Two at a time is a lot easier, rears first, then fronts. Be sure to open the bleed valves quite a bit so that you can get a good flow. If you really open up the bleed valve, they gravity bleed quite quickly.
If you don’t open the valve at least a turn or two, then you can git a situation where the bubble stays in the line because the flow of the brake fluid isn’t fast enough to move it.
To help things along, the tube should come off the bleeder valve and loop up an inch or two, no more than two, then down to the ground into the container. Cut the tube to length, excess tubing creates drag which slows down the process, but bringing the tube as close to the ground as possible increases the drop distance and that increases the head pressure at the master cylinder.
BTW, I get my clear tubing in the aquarium section at my local wally world. Its cheap and you can get either 8’ or 25’ lengths. I get the 25’ because its like a buck more than the 8’ length. It has been awhile since I bought any though, 25’ lasts a long time.
If your wife is willing to man the master cylinder and keep it full, then doing two lines at a time is pretty easy to do, and it will only take a few minutes for each end of the car, probably about one minute for the front and three or four for the rear.
If you don’t get a steady stream with the bleed valve open two turns, you have another problem and most likely it is air in the master cylinder. You should be able to get a bench bleed kit of the master cylinder at AZ for just a couple of bucks. It consists of two plastic thread in hose barbs and a couple feet of plastic tubing. You can bench bleed the MC in place. Wife in car manning the brake pedal, point the plastic tubes back into the reservoir. Brake pedal to the floor, finger over each end of the tube, brake pedal up, repeat a few times until the air is gone. The stick the ends of the tubes into the reservoir and pump the brake pedal rapidly a few (dozen) times checking for air bubbles.
If you don’t mind making a mess, you can just remove the brake lines from the MC, brake pedal down, fingers over the hole tightly, brake pedal up, repeat until solid squirts of brake fluid is achieved, then as brake fluid flows from the MC, hook up the brake lines. Lots of old towels come in handy for this, brake fluid will remove paint.
Just gravity bled the two rear wheels. Seemed to work pretty well. I had the rear end sitting on two capstones (8" off ground), got a bubble about every two seconds for a couple of minutes at least…
But I cannot get any fluid to come out the front passenger right (and probably the driver front). This is where I replaced the flexible lines. There is a screw on the brass junction that sits up in the wheel well. Do I need to open this screw??? Is this a valve??? There were no instructions with these new lines that said I had to do anything with this screw, but I’m beside myself as to why I’m not seeing any fluid at the wheels!! My calipers are sitting there limp right now (can slide 'em in and out by hand), unable to pressure up.
Here’s the part I bought (installed on both sides of the front)
http://www.rockauto.com/catalog/moreinfo.php?pk=304956&cc=1139037
Look at the closer view and notice the screw on the bracket end. Is that stopping the fluid from coming through to the caliper???