OT: Carolla brake oddness

[almarconi]

To check and see if your master cylinder is the problem, simply disconnect the lines to the MC and plug the ports in the MC with some test plugs. When you step on the pedal if the MC is bad it will go to the floor if it is good it will be firm.

If you are capable of doing the work yourself, I find that www.rockauto.com has very reasonable prices on parts. Check them out to see what the parts will cost.

If it was me I would replace the rotors, calipers and brake lines. Then pressure bleed the system. If pressure bleeding will not work you can try injecting fluid through the caliper into the MC.

[Dogma]

To check and see if your master cylinder is the problem, simply disconnect the lines to the MC and plug the ports in the MC with some test plugs. When you step on the pedal if the MC is bad it will go to the floor if it is good it will be firm.

If you are capable of doing the work yourself, I find that www.rockauto.com has very reasonable prices on parts. Check them out to see what the parts will cost.

If it was me I would replace the rotors, calipers and brake lines. Then pressure bleed the system. If pressure bleeding will not work you can try injecting fluid through the caliper into the MC.

Hmm... I was basically able to do the master cylinder test when I did the bench bleed. I'll try it again if I still have the little plastic plugs. So, some sort of blockage really can produce these symptoms?

Thanks for the link. The prices there are MUCH more reasonable than what I've been finding. Much easier to swallow replacing the calipers at those rates. Is it not possible to rebuild them though?

[rusty boltz]

rockauto is great for parts and ship fast too. Yes you can rebuild the front calipers. They are no harder than a suzuki caliper just its not easy to find places that sell these kits to the public ( usaully only to companys that exclusively rebuild cores). Rebuilt calipers can be had for much less than new ones. Line replacement is also very cheap, the hoses should cost no more than 40 a piece (and thats high) and hard line is sold by the foot and is something like 1-2 bucks a foot. You shouldn't need more than 5 ft for a corolla. A tubing bender can be used to make factory like bends. With new rotors you should pay no more than 300 for parts (provided you do this yourself since ALL shops charge a markup on parts, just business). I worked at shops for 10 years and some places charge 2-3 times what the customer could have bought the same part for themselves. Try bleeding them again and again that air bubble has got to come out somehow!! Good luck!

[Dogma]

I was hoping the hoses would be cheap too.

So, you agree that it sounds like a trapped air bubble then. Of all the brakes I've ever worked on (not too many) I've never seen a case where air would completely prevent building up pressure.

Thanks for the encouragement, but I am SO sick of bleeding this thing.

[GQROD]

1- If it was the master cylinder that was bad the brake pedal would have felt spongy and firm but would not have put alot of pressure on the brakes.

2-Bleed the system very well front to back and in a alternating pattern between tires otherwise this spongy feeling will remain and brakes won't work. Sometimes a mighty vac may not pull out all the air. Have a friend sit in the car pump the brake pedal three or four times and hold the pedal down, then loosen the nut and you should see air and fluid come out, repeat this on each wheel until you do not see any more air coming out of each nipple, it should just be fluid. Sometimes the old school ways work better.

3-If the pedal went all the way to the floor with no resistance then the rear brake shoes need to be adjusted in order for the shoe to touch the drum fully! there should be a hole or slot on the backing plate behind the drum use a flat screwdriver fits into it to turn a wheel with notches may look like a gear, this step should make a big difference right away providing the front pads are good. Hope this helps.

[rustybronco]

I think at this point you should be looking at a shop manual for the recommended bleeding procedure.
as an example, if it has abs, do you have to energize the abs solenoids to bleed it?
do they require pressure bleeding?

[Dogma]

1- If it was the master cylinder that was bad the brake pedal would have felt spongy and firm but would not have put alot of pressure on the brakes.

2-Bleed the system very well front to back and in a alternating pattern between tires otherwise this spongy feeling will remain and brakes won't work. Sometimes a mighty vac may not pull out all the air. Have a friend sit in the car pump the brake pedal three or four times and hold the pedal down, then loosen the nut and you should see air and fluid come out, repeat this on each wheel until you do not see any more air coming out of each nipple, it should just be fluid. Sometimes the old school ways work better.

3-If the pedal went all the way to the floor with no resistance then the rear brake shoes need to be adjusted in order for the shoe to touch the drum fully! there should be a hole or slot on the backing plate behind the drum use a flat screwdriver fits into it to turn a wheel with nothes may look like a gear, this step should make a big difference right away providing the front pads are good. Hope this helps.

The pedal goes to the floor and only build some pressure. Pumping does not build pressure, so we went to one pump, bleed, one pump, bleed...

[Dogma]

I think at this point you should be looking at a shop manual for the recommended bleeding procedure.
as an example, if it has abs, do you have to energize the abs solenoids to bleed it?
do they require pressure bleeding?

I did track down the service manual, at the EBSCO link (library, library) that was posted a few weeks ago. No ABS. No mention of pressure bleeding. The procedure described was just old-school brake bleeding.

[rusty boltz]

there is no special procedure for bleeding those brakes. It's very rare to have to do anything other than the "old school" method. I've only seen it on older fords that have the abs,master and booster unitized but then again I haven't worked on everything. Anyway, the symptoms you describe don't seem like line blockage. Think about it if something was blocking fluid flow your pedal would be hard (no place to go) or if it was blocking it from returning to the m/c the caliper that had the blockage in the circuit would drag. If your rear brakes are in adjustment, the master is new and properly bled and all the air is bled out there is really only the hoses left. The hoses could be "ballooning" when you push the brakes which would absolutely cause the symtoms described. This may or may not be difficult to see when looking at them but if the hoses are ballooning the pressure from the m/c will be used to swell the hose rather than apply the brakes causing a low pedal and crappy stopping power. Another thing just to throw it out there is I have had to fix other shops boo-boos and switch the adjusters to the correct sides. The shoes adjust themselves most of the time but if the adjuster was put on the wrong side they will adjust in instead of out. Not likely your case but figured I'd throw that in.
Have someone push the brakes with the car running and closely inspect the hoses for swelling, you may not even be able to see it but if it's really bad you will. Good luck I'm sure you'll figure this out soon as there is not much left in the brake system to check. Your patience will pay off in saving money that you can spend on your GS!

[Dogma]

Talking it over with my dad last night, I'm just about convinced I screwed up the adjusters. I'll be picking the car up tonight, so we'll see how things are. If there is no change in the brakes, I'll check the adjusters. If that doesn't make things satisfactory, I'll have a close look at the hoses.

What you said about a blockage makes perfect sense to me. Since intuition can be wrong, I thought I'd ask for confirmation here. I've already decided based on cost that I'll have to do whatever work myself. At least taking it to the mechanic shook loose a discussion of drum adjusters, which finally made me realize I had bungled that. If the entire problem is adjusters, I'll be making sure to post negative reviews in the appropriate place on-line. I should look up the BBB too, I suppose.

[bakalorz]

Talking it over with my dad last night, I'm just about convinced I screwed up the adjusters. I'll be picking the car up tonight, so we'll see how things are. If there is no change in the brakes, I'll check the adjusters. If that doesn't make things satisfactory, I'll have a close look at the hoses.

What you said about a blockage makes perfect sense to me. Since intuition can be wrong, I thought I'd ask for confirmation here. I've already decided based on cost that I'll have to do whatever work myself. At least taking it to the mechanic shook loose a discussion of drum adjusters, which finally made me realize I had bungled that. If the entire problem is adjusters, I'll be making sure to post negative reviews in the appropriate place on-line. I should look up the BBB too, I suppose.

one way to tell if it it is the adjusters is:

Lift and pull both rear wheels and drums and manually (with a screwdriver) adjust the adjusters out enough that you cant put the drums back on.
Now, one click at a time, adjust the adjusters in, to where you can barely wiggle the drum back on.

Only put the drums 1/2 way on though. If the drum is somwhat worn, there may be a "ridge" at the outside (where it is not worn) and you want the shoes to temporarily rest on that

So now the shoes are in contact with the rear drums on both sides of the car. And the rear cylinders basically wont move at all.

After all that, step on the pedal. If your symptoms remain then its not the adjusters. If that cures it ... .

Now, before you put the wheels on, remove the drums again, loosen up the adjusters, and (with the drum off, watch while you have someone else pull on the emergency brake to make sure the adjusters work.

Sometimes they stick, and go back and forth; rather than ratcheting like they should. Check that they work right with the adjustment screw all the way in, all the way out, and in the middle. Mine worked properly in the middle, but not at one end of the travel once ... which meant I was pulling the cable for a bunch of times and not getting any adjustment.

before you put the drum back, manually adjust them to where the drum goes on fairly easily, but doesn't have a "bunch" of free play, so that you don't have to pull the cable a million times to get them to adjust. (each pull only turns the screw a like 1/20th of a rotation, it takes a LOT of pulls to move it much at all)

Now put your drums and wheels back on.

[Dogma]

....
Now put your drums and wheels back on.

We'll see. We'll also see if this teaches me not to hurry up and reassemble a mechanism I haven't taken the time to understand. I've done brake shoes a few times over the last 20 years, so I took it for granted that I knew what I was doing. I guess I never really knew in the first place. 1 hour of experience repeated over 20 years, not 20 years experience...

Assuming it's as simple as the adjusters. I don't want to get my hopes up too soon.

[Dogma]

OK, 5 points to everyone who told me to look at the adjusters. I just brought it home, and the brakes are much better after CARx adjusted the drums during their diagnosis (which they didn't charge for). I can still get the pedal to the floor when the engine is running, so there is some more checking to do. Even so, the car seems to be on the verge of locking up when I stand on the brake, so it's at least drivable. Still, it's not completely right, so I'll have a look at the hoses and make sure they're healthy, and make sure the drums are completely adjusted (not just good enough for diagnosis).

Bottom line: I'm outta there for free, and they wanted over $600 to replace the whole front brake system. I paid for a new master cylinder because I didn't know enough about drum adjustment.

Thanks everybody.

BTW, one of their techs rides a black 750E, looks like a 79 or 80 with a chrome 4->1.