Bleeding the Brakes and Alternator

[hpmaxim]

I got a P5 from my father a couple years ago, and to be honest, I just let it sit -- I know, naughty, naughty...

Anyway, I decided to try to get it on the road about a week ago and have run into a number of issues:

1) Battery was dead, replaced the battery.
2) Front left brake was seized. I literally could not spin the front left wheel no matter what I did. I removed the caliper, sanded the rotor, and then put everything back together. Spins fine now.
3) Went to go move the car and the brake hydraulics felt like they had air in them. Still driveable, but not comfortable. Brought the car into the garage, took the wheels off, attempted to crack each of the bleed screws open, but the front right bleed screw snapped off. Replaced both front calipers.
4) Brake pedal actually felt like I was moving some fluid immediately prior to bleeding (this might have been my imagination). After starting bleeding the brakes went to nothing, and then stiffened up to about where they were prior to me replacing the calipers. Then they went to nothing (this might have been me letting fluid get too low in the reservoir) then they went back to what it was like prior to replacing the calipers. I went through 1 liter of fluid and had a helper. Pretty sure we did everything right (other than the one accident in the middle). Fluid coming out was pretty clear. Still seems like there is air in the system.
5) The "battery" (alternator) light comes on after the car has been running for a few seconds. Battery voltage with the car running was I think around 12.2V -- so it appears the alternator isn't working.

So the questions are:

1) What the heck do I do to get the air out of the brakes? I'm wondering if air might be stuck in the ABS system. I keep wondering why there isn't some way I can use the OBD2 port to command the ABS system to turn on (i.e. pump comes on, valves open and then just open the bleed screw to effectively pressure bleed the system with no work on my end.
2) Is there anything I can try before replacing the alternator? Any common failures (other than the alternator which might cause this?)

 

[TheSwapnessMonster]

Did you start bleeding at the caliper furthest from the MC and work your way to the closest caliper?

 

[hpmaxim]

You know, I don't put that much credence into that, however, I generally obeyed it. I did FL, FR (to get the air out of the lines that were opened), and then RR, RL, FR, FL. I know how to bleed brakes. Other than the lines I opened, very little air came out.

There are some cars that I have found to be far more difficult to bleed than others though. I assume this is just because of the design of the brake system, more places for air bubbles to hide or get stuck on (like proportioning valves or local high spots.

Repeatedly pushing on the brake pedal seems to stiffen the pedal some... I'm pretty sure the car was fine before I let it sit (both the alternator and brakes).

 

[TheSwapnessMonster]

Sounds like you did it right. How bad are the brakes? And is the rotor ok after you sanded it? I've heard of resurfacing on a lathe but never sandpaper.


Sent from my iPhone using Tapatalk

 

[hpmaxim]

The brake rotors are rusty. One of the pads literally rusted onto the rotor. I was just trying to get the rotor to turn. I have no idea if the rotor is okay, and at this point don't care. The rotor is a hunk of cast iron. It is what it is, its not causing my hydraulic issue. That's what I care about. If I get the hydraulics working and I need to replace the rotor, I will, but until then, I don't see it as a serious issue.

I have been testing the brake feel with the car in the air on a lift and the wheels off. The wheels aren't turning so the condition of the rotor shouldn't affect anything, but it does feel similar to what things felt like while I test drove it after freeing the brake pad. That said, during the test drive, when I pushed on the brake pedal I felt a pulsating as if the ABS was engaging even though I don't think it was (ABS light didn't come on and I wasn't braking that hard). It's possible I was feeling the damaged rotor. But like I said, that shouldn't be contributing to the bad hydraulics.

 

[Keno1542]

If you let the fluid run out in the MC, you will have to bleed the MC, air will be stuck there.

 

[hpmaxim]

If you let the fluid run out in the MC, you will have to bleed the MC, air will be stuck there.

I've never found bleeding master cylinders to do all that much. I'm not clear what bleeding the MC does that bleeding the system as a whole doesn't, bleeding a master cylinder basically just pushes the fluid through the master cylinder and back into the reservoir whereas bleeding the system pushes the fluid out to the calipers. In theory it may make things a bit easier if you bleed the MC first, but that's only in theory. But, here's the deal... Brakes felt bad. I replaced the calipers and bled the system. After bleeding it, the brakes felt about the same as before replacing the calipers. I continued to bleed the system. I may have let fluid get to low, I refilled and bled some more. Brakes feel the same as before I let the fluid get to low and as before I replaced the caliper. I'm quite confident that I properly bled the brakes using the standard 2 man bleeding sequence.

The question is: Could a faulty master cylinder, caliper (rear), or proportioning valve cause it to either feel like there is air in the system or keep air in the system without it ever coming out a caliper bleed screw. If not, what else can I do? Is pressure bleeding effective on these cars? Is there any trick to get the computer to turn on the ABS pump and let it pressure bleed for me?

As for the alternator --- do they often go bad just sitting there? Is there anything I can do other than checking the connections and wiring (i'm always worried that a mouse might have done some teeth sharpening on my wires).

 

[hpmaxim]

So literally everything below the top alternator bolt is seized. I spent several hours and finally dislodged the alternator from the the bottom bracket. Tried to remove the top bracket/tensioner per https://www.youtube.com/watch?v=7ofq2DhQZlg
but the bolt head stripped and I have no idea how to get it or the alternator off at this point. I swear, I feel like my father scammed me when he gave me this car.

 

[pcb]

...but the bolt head stripped and I have no idea how to get it or the alternator off at this point....

U-tube won't let me watch your video but this (or something similar) might help.

... I swear, I feel like my father scammed me when he gave me this car.

.

Your dad is evil...

 

[hpmaxim]

I've never had much luck with those tools, and besides there just isn't room to get it in there. However, I was able to get the alternator out. When I tried today, it only took about 10 minutes of fidgeting with it, wasn't as hard as I had been led to believe. I just systematically tried to get it over the power steering hoses and then push it back as far as I could, lifted it up a bit, rotated, and then it just came out.

However, much to my dismay, I took it to Autozone, and they tested the alternator and claimed it was working (they tested it twice). The power connection (from the stud to the battery) appears to be good, not sure how to easily test the other two wires, it's always possible a mouse got to it. Looking at the wiring diagram, the only fuse I can find is the 100A main fuse which is obviously still good or the car wouldn't start. It's possible that maybe I knocked some rust loose that was blocking a good electrical connection I guess, but does anyone have any better ideas before I try to reinstall this godforsaken thing?

The guy at Autozone thought the seal on the master cylinder might have gone bad from sitting there and that could be my brake problem...

 

[TheSwapnessMonster]

Sounds like you're really having a tough time with this car. My p5 sat for two years and I had some upstate NY rust. I can tell you that once you get all the rusted parts freed up, it'll be a lot better. Every time removing something has driven me crazy, it's made working on that part of the car way easier.

 

[pcb]

... not sure how to easily test the other two wires, it's always possible a mouse got to it....
... does anyone have any better ideas before I try to reinstall this godforsaken thing?
..

The alternator on our car is controlled by the ECU. If the control wire is broken (or eaten by mice) the alternator effectively shuts off.

Check this wire specifically... light green with a white stripe. Make sure you have continuity from the alt. to the ECU.

 

[hpmaxim]

Apparently the ECU has all sorts of diagnostic goodies which I should have read about prior to disassembly. So I decided to put everything back together, and according to my friend, magic happened at some point and everything is working fine. Not sure what the magic was, or why... My guess it was either unseating/seating an electrical connector (also pulled the engine block ground and cleaned it, or bashing the alternator trying to get it out may have gotten better contact with the brushes. But it appears to be working fine now.

So this leaves me with what to do about the brakes? Replace the master cylinder, the rear calipers, both, or try to bleed again using a different method.

 

[MrGiggles]

A bad master cylinder usually results in no brake pressure at all, either all the time or intermittently.

Air pockets in the master can be tough to work out, since the piston doesn't fully displace everything in the bore. Cracking the lines there and bleeding may get the air out.

Make sure you close the bleeder before letting the pedal return, or air can sneak past the bleeder threads. You might also open all the bleeders and let them gravity bleed for awhile, or pressure bleed if you have the equipment.

The rear calipers may need adjustment as well.

 

[hpmaxim]

A bad master cylinder usually results in no brake pressure at all, either all the time or intermittently.

Air pockets in the master can be tough to work out, since the piston doesn't fully displace everything in the bore. Cracking the lines there and bleeding may get the air out.

Make sure you close the bleeder before letting the pedal return, or air can sneak past the bleeder threads. You might also open all the bleeders and let them gravity bleed for awhile, or pressure bleed if you have the equipment.

The rear calipers may need adjustment as well.

1) A very bad master cylinder would result in no brake pressure, but what if there was just a tiny gap in the seal which allowed some fluid to penetrate past the piston. Then I can imagine it would lessen pedal effectiveness. Multiple people have pointed toward a bad master, admittedly I'd think bad rear calipers could also cause the problem -- not sure how to distinguish without shot gunning the system which I hate to do.

2) Why would there be air pockets in the master? The master never came off the car. No lines were opened. I bled the crap out of it, felt the same as before I started bleeding, then let the fluid level get too low and repeated the process and it went back to where it was. Seems highly unlikely to me there are "air pockets" in the master. How did they get there in the first place?

3) I know how to bleed the brakes. I pushed the brake pedal down, yelled "open", and then the pedal would go lower, and he'd yell "closed" and i'd pull my foot back and we'd repeat. I never allowed the brake pedal to move upward with the bleed screws open. Before we stopped at each wheel, we would do at least 5 pumps with just fluid and no air coming out. If I had been sucking air back in, it would have come out on the next pump cycle.

I have a pressure bleeder. I have had limited success with it. Some systems it works great, other systems it works poorly. My A2 VWs for instance never properly bled with a pressure bleeder, I suspect it was the rear proportioning valve. My MR2 clutch on the other hand bled great, just pressurize to 8 psi, open the bleed screw for 30 seconds, close and you're done. I have no idea if the Mazda proportioning valve has the same problem.

I have also never understood the point of "gravity" bleeding. Perhaps you could explain it to me. Since the calipers are nearly the lowest point on the car, fluid will come out, but air will go up, which is the opposite direction of the calipers. Might get a little air out at the caliper, but I can't see how it would get much of any air that wasn't in the calipers themselves. It is conceivable if you ran the tube up above the master cylinder it would eventually allow air to collect up there, particularly if you pumped the pedal or bang on the brake system with a rubber mallet -- sort of like a reverse siphon. It seems so.... crude.

4) Adjustment to the rear calipers? The only adjustment I'm aware of is screwing in the rear caliper piston so you can install new pads. What other adjustment is there?

Again, please remember, the brakes were normal the last time I drove the car. This problem developed by just sitting there, but it did not leak any fluid out, so the system should have been pretty tight.

 

[pcb]

... It's possible I was feeling the damaged rotor. But like I said, that shouldn't be contributing to the bad hydraulics.

I think you're feeling four damaged rotors... The rotors don't rust the same where the pads were sitting on them causing a pulsation.

I figure that can make the pistons sorta float and need more travel to grab.

The brake pedal height is adjusted with the parking brake. There should be 5-7 notches to engage the p-brakes...

If you lost a lot of rear rotor thickness due to rust the adjusters need to adjust. Applying the parking brake is what turns the adjusters automatically... If they're working... Our rear calipers are notorious for having rear caliper adjuster screw issues.

You can try this....

(some guys say you can push the brake pedal hard then pull the p-brake handle a bunch of times till it tightens up.)

 

[MrGiggles]

1) A very bad master cylinder would result in no brake pressure, but what if there was just a tiny gap in the seal which allowed some fluid to penetrate past the piston. Then I can imagine it would lessen pedal effectiveness. Multiple people have pointed toward a bad master, admittedly I'd think bad rear calipers could also cause the problem -- not sure how to distinguish without shot gunning the system which I hate to do.

2) Why would there be air pockets in the master? The master never came off the car. No lines were opened. I bled the crap out of it, felt the same as before I started bleeding, then let the fluid level get too low and repeated the process and it went back to where it was. Seems highly unlikely to me there are "air pockets" in the master. How did they get there in the first place?

3) I know how to bleed the brakes. I pushed the brake pedal down, yelled "open", and then the pedal would go lower, and he'd yell "closed" and i'd pull my foot back and we'd repeat. I never allowed the brake pedal to move upward with the bleed screws open. Before we stopped at each wheel, we would do at least 5 pumps with just fluid and no air coming out. If I had been sucking air back in, it would have come out on the next pump cycle.

I have a pressure bleeder. I have had limited success with it. Some systems it works great, other systems it works poorly. My A2 VWs for instance never properly bled with a pressure bleeder, I suspect it was the rear proportioning valve. My MR2 clutch on the other hand bled great, just pressurize to 8 psi, open the bleed screw for 30 seconds, close and you're done. I have no idea if the Mazda proportioning valve has the same problem.

I have also never understood the point of "gravity" bleeding. Perhaps you could explain it to me. Since the calipers are nearly the lowest point on the car, fluid will come out, but air will go up, which is the opposite direction of the calipers. Might get a little air out at the caliper, but I can't see how it would get much of any air that wasn't in the calipers themselves. It is conceivable if you ran the tube up above the master cylinder it would eventually allow air to collect up there, particularly if you pumped the pedal or bang on the brake system with a rubber mallet -- sort of like a reverse siphon. It seems so.... crude.

4) Adjustment to the rear calipers? The only adjustment I'm aware of is screwing in the rear caliper piston so you can install new pads. What other adjustment is there?

Again, please remember, the brakes were normal the last time I drove the car. This problem developed by just sitting there, but it did not leak any fluid out, so the system should have been pretty tight.

Master cylinders can fail in that manner, but it's not as common. If you hold the pedal down, does it slowly sink to the floor? If so, that's probably your issue, if there are no other leaks. Sediment can build up in the MC bore (especially after sitting) and compromise the seal.

If you ran the reservoir empty like you said, there is or was probably air in the master. Since the piston doesn't fully displace everything in the bore, air pockets can stay trapped until you open a path of less resistance, like loosening the lines at the master.

Any air in the calipers will be at the top near the bleeder. Fluid is pulled by gravity to the lowest point, which displaces the air in the caliper. Some cars have too many bends in the tubing for it to work though.

 

[hpmaxim]

I think you're feeling four damaged rotors... The rotors don't rust the same where the pads were sitting on them causing a pulsation.

I don't disagree. I'm sure the pulsation I felt had to do with the rotors. I'm prepared to replace them if that's the issue. However, the mushiness I've felt occurs both with the wheels turning and not turning. So I don't think rust is the cause of the mushiness (at least not directly).

I figure that can make the pistons sorta float and need more travel to grab.

I might be able to see this if the problem occurred only while the wheel is spinning, but by definition, hydraulic brakes should be self-adjusting, so when the wheel is not spinning, I'd think after hitting the brakes a few times, this would be self-corrected.

The brake pedal height is adjusted with the parking brake. There should be 5-7 notches to engage the p-brakes...

If you lost a lot of rear rotor thickness due to rust the adjusters need to adjust. Applying the parking brake is what turns the adjusters automatically... If they're working... Our rear calipers are notorious for having rear caliper adjuster screw issues.

You can try this....

Will give this a shot.

MrGiggles, it feels like there is air in the lines. You press on the brake and the brake pedal sinks further than it reasonably should and then gets stiff, but only toward the end of the travel. While driving, it seems like if you pump the pedal it gets a bit stiffer. But to answer the question, if you press on the brake pedal and start feeling pressure it's pretty static. The pedal doesn't sink further over time once you start applying real pressure.

I'd also like to point out the pedal felt mushy. I replaced the calipers and it felt incredibly soft (for obvious reasons). I bled it, and it felt EXACTLY like before I replaced the calipers. I accidentally let the reservoir go lower than I should (I assume too low), it got very soft again. I bled it more and it got to exactly where it was twice before. With the exception of letting the fluid go too low, I really think I did a good job of bleeding before and after and it didn't correct the problem.
(some guys say you can push the brake pedal hard then pull the p-brake handle a bunch of times till it tightens up.)

 

[pcb]

I think you just need to seat your brakes...

Push your brake pedal hard.... Hold in your P-brake button... Pull the handle about fifty times.... Then drive hard on the brakes to resurface them.

If that doesn't work then look at your master cylinder.

If that doesn't work then give the car back to your dad.

 

[pcb]

Did you ever get your car figured out ???

How are your brakes ???

What did you do to fix them ???