brakes will not develope any hydraulic pressure

[Petros]

I need some ideas, I am supposed to be driving this car home from southnern california and right now there is a major problem with the brakes.

The brakes worked okay, a little soft but working, before we started. the car has sat for several years but was occationally drive, and the brakes worked a few days ago.

We replaced the rear wheel cylinders, and the front flex hoses (olds ones were scary bad), and we tried to bleed the system. We pump new fluid though the whole system, getting the left rear and right front bleeder to run clear and free of bubbles. But the right rear and the left from ran freash fluid but was continuous stream of airbubbles, no matter how long we pumped. I though the right rear cylincer might be bad (even if new) so I put on the old one, that was not leaking before we took it out. same thing, continous stream of bubbles.

I bought a new master cylinder this morning, a remanufactured unit (all I could find), and bench bled it (seemed to work normal except it would suck the brake fluid back in the "out" lines when I released it, I used pliers on the lines to not allow it suck back in). got the air out of the master than way, installed it. and now I can not get any pressure at all anywhere in the system. even though it seemed to bleed normal at the lines at the master cylinder.

I need to get this car on the road today. any ideas! is the new master bad? should I take it apart and check if it has the one way valve?

[marlinh]

You didn't mention if you are getting fluid out of the fronts. What about that valve on the driver's fender well? Maybe it shifted and is causing problems. I don't know how rusty this car is but maybe you can crack a line there and see what is happening. The only other thing I can think of is pressure bleeding. Try applying air pressure through the cap (Remove the rubber seal) and leave the caliper bleeders open and see if anything comes out.

[Petros]

with the old master cylinder we got slight pressure it bled as normal from all four bleeders (front and rear), excet we were getting air bubbles in two of the bleeders (left front and right rear had bubbles). with the new master cylinder we got no pressure at all in any wheel bleeder. even when pumped, open or closed bleeder valve.

I took the remanufactured master apart and there are 4 seals, two on each of the two pistons. One of the seals was in facing backwards, the rear seal on the front piston.

I looked in the FSM and there is not enough detail to see if having one seal backwards in correct. I do not ever recall seeing this before when I have rebuilt them in the past.

[marlinh]

Sounds like the master is faulty.

[Petros]

that is what I am thinking; it has to be the master. Nothing else in the system changed. so I had to delay departure another day...they will have a replacement master for me in the morning. I returned the original one and got back my core. I put it on the bench vise and tried to bench bleed it. the front outlet will run clear, but the rear one keeps putting bubbles into the line just like I saw when we were bleeding it last night. Hopefully the replacement master will solve the problem and we will be on our way. If I could get a new one I would have, but they cost twice as much and were 2 to 5 days away!

I guess I will have to do a "home front end alignment" since I do not know if the alignment place is open in the morning.

[TURTCEL]

This is all exactly what I have been dealing with for the last week. My posting brought forward some great ideas for a fix, but none with any luck.

https://tercel4wd.com/forums/viewtopic.php?f=4&t=9521

Peter...is this ironic or what? Same problem...same time.

A very good mechanic friend of mine gave me a tip today that I have not checked yet but I will tomorrow. It is that there should be a small amount of space between the master cylinder piston and the booster push rod end. If they are touching the system will never bleed properly. You can take some white out or paint and put it on the tip of the push rod and do a dry install. Remove the master and see if there is paint on the master piston. If yes, adjust the push rod end to make space between the two. Clean the piston of paint and re-dry install the master until no paint is on the piston. Continue to bleed the system as normal to see if there is change.

My new master (not rebuilt) will be here tomorrow so I will see if that helps. I have tried 2 reman master cylinders in the last week with no luck. Other than the above tip, I have tried everything under the sun. I was going to call Toyota tomorrow and see if there is an older tech in the shop that might know about the system.

I considered changing the wheel cylinders too but they worked a week ago and now no such luck.

Peace

[c_j]

The left front and right rear are on one part of the master cyl, and the right front and left rear are on the other (criss-cross). You say clear fluid on both front and air bubbles on the back. Unless the lines have been switched around, I would wrap the bleeder screws with teflon tape so they make a tight seal on the threads and try again. In other words, I think your air could be coming in from the bleeder screw threads.

...but, if that is the case then your pedal would feel good. If the pedal feel is not good then disregard this suggestion (unless you are vacuum bleeding in which case you need those threads sealed).

Another thing: if your self-adjuster screw is backed way off then the wheel cylinders could be over-extending and popping the cups out and getting air from there, but you should see leakage from them if that is the case.

[Petros]

it is almost certainly the reman master. the store manager says that Cardone is usually reliable. But I told him that has not been my experiance with their other products and would perfer to not by reman from cardone, but I have no choice. looks like you had the same problem with the reman master. it is amazing since they are not that complicated an assembly, I used to rebuild them all the time from a kit and I have never had a problem. Kits are no longer available.

we will see how the replacement master works.

[Petros]

success! the replacement master pumped up fine. pedal is up and firm. Nice to know that solved the problem at last. what a PIA, if I had a choice I would not use remanufactured anything.

[Jarf]

Petros -
In all my years pulling wrenches, no other single component has caused more grief than rebuilt masters, I hate them with a passion.

That said, all the rubber cups should be oriented in the same direction, they are designed to build pressure in ONE direction only.
That rubber is most certainly in backwards, that is why you had so much trouble bench bleeding it, there should never be cause to pinch off the lines during a bench bleed,
They should only need to be submerged, that in itself indicates an internal problem with that master.
If it were me, I would be reassembling it with all the cups oriented the same way and retry the bench bleed.
If it bleeds up nicely, you should be back in business.

Clearly I type way too slow as you have sorted this out in the meantime

[Petros]

yes, I switched the seal around and tried to bench bleed it again, it still would not behave and I did not want to install it and try it in the car. The new one came the next morning and it worked.

Curious however, I took apart the old one and it too had the rear seal on the front piston in backwards (but it too could have been a reman). I remember rebuilding the stock tercel master some years ago in my daily driver and do not recall a reversed seal, I have never seen a reversed seal in a master cylinder or I would have remembered. I rebuilt my first master cylinder in 1973 in an auto shop class, and I have seen a lot of them since. I would likely still be rebuilding them if I could get a rebuild kit.

There is a check valve in the master in front of each of the piston seals, I suspect it was bad. I was temped to try switching this check valve, but it is a lot of trouble to bleed the master, install it and than bleed the system again to see if it works.

[TURTCEL]

If I am not mistaken I have seen master cylinder rebuild kits on RockAuto.com.

Peace

[rer233]

+1- saw 'em last night.

[Petros]

I could not wait that long, O'Reily's got me the master cylinder same day for $49, all other suppliers were 4 to 7 days away and cost more. they got me a replacement next morning and they could have done it same day had I called earlier in the day.

They did a great job for me, it was not their fault that the Cardone reman was junk. the store manage said they typically get a 2 percent return rate for all of the Cardone parts, they had trouble with their alternators in the past. I told him about the very bad luck with the cardone reman axles (about 50 percent rejection rate), no one on this forum will buy them for the Tercels if they have a choice.

[Petros]

Funny thing happened this morning back home. I usually listen to several Saturday morning radio programs about car repair in the Seattle area, one of them is hosted by the manager of a local chain of (overpriced) Japanese car repair shops (Greg's Japanese Auto).

A guy calls in this morning with a Tercel4wd wagon he got for free from a relative, it had been sitting for 7 years. He had owned them before and was very familiar with these cars. He got it running but the brakes were leaking all over the place. He replaced first the rear wheel cylinders, and than got a re-manufactured master cylinder but could not manage to build any pressure or get the air out of the system.

The somewhat arrogant chief mechanic said he should have bench bled it (which the Tercel owner had), than the mechanic claims he must not have done it correctly, than that he must have allowed air into the system by not filling it all the way, and he also suggested the propositioning valve is bad (I have never seen a bad one on a toytoa). But the caller had done everything the guy suggested, and could not get the air out of the system. No time did he suggest to the poor guy that his re-manufactured master could be the culprit.

This sounds like a familiar story here, but this just goes to show you that even at a shop that specializes in Japanese cars, their most experienced "expert" mechanics might not be familiar with cars as old as ours, nor the problem with the aftermarket parts we have to deal with.

That Tercel owner should join this list! If I could have gotten on the radio I would have suggest he return the master cylinder for another one. The brakes on these cars are simple compared to the computerized junk they sell today on the new cars, apparently too simple for modern mechanics to know how to fix.