Brake Failure Again!

[Double M]

Same as the last time. I am driving along for about 30 minutes or so with no problems, sat at a light, no problem, then I go to make a right... my pedal sinks to the floor, vibrating like it is ABS-ing, acting like there is no fluid perhaps and then i notice my ABS light is on, (it goes off at first start and comes back on and stays on all the time) my Red Brake light is on (it goes off at start and stays off). I am able to stop, but with a pedal sunk to the floor and greatly dimminished braking going on.

This happened once before a few months ago. Then, I carefully slowly drove home, parked it for a few hours, started it up and all was well... When I did the brake test, the next day, it did not indicate any problems.

...until this incident that just happened 20 minutes ago.

Now my car is a t work and I am hoping that it comes back later today, because it is a 30 mile drive back home.

I have a 1990 with a NOS Accumulator (from Amazon), a new right side sensor and new front calipers. Any advice or assistance would be greatly apprciated.

[Mc_Reatta]

How is the fluid level?

Have you jumpered the ALDL connector to pull the ABS trouble codes? Not that they are necessarily gong to point to the problem.

Yellow light is on all the time when driving and this time the red came on also, or both lights came on at the same time?

[Double M]

No, no diagnosis ability, as I am at work...

...nor do I know what an ALDL connector is or the meaning of ABS codes of how to even view them. Sorry, I am old school and I get in trouble around here for not being as tech savvy as some others here.

So I am hoping to get some advice to pass on to my mechanic if I can get the car home tonite, otherwise I am looking at a $200 towing charge, which will wipe me out finacially until next week.

The Yellow light is on all the time when driving as the norm, but the red light came on when this happened and stayed on.

[Double M]

UPDATE: I just went out to check the fluid and I started it up.


The Fluid is fine, the lights went out as always, but the yellow comes back on after moving - and now I have brakes! What is up?

It is literally 110 degrees out there acording to the Reatta.

[padgett]

Red light means a problem with the boost circuit and consistant with pedal going to floor. Yellow will be on any time red is on but will go out if red light goes out. No code will set in EBCM but may get a BCM B482 code (ABS pressure) but low pressure needs to be present for 50 seconds before it will set.

Yellow alone means an ABS problem and should set an EBCM code (ground ABS pin in ALDL and count ABS flashes)/not go out until ignition is cycled. If happens over 18 mph I would suspect a failing sensor.

[Mc_Reatta]

I'd pull the electrical connector to the pressure switch on unit below the accumulator and see if there is any hint of brake fluid in the socket or on the connector.

Assuming the accumulator hasn't failed again prematurely, it might be the pressure switch is becoming intermittent. An internal fluid leak is one indication of a problem.

Could also be the contacts in the relay on the firewall are going as well. Both the relay and switch are used to turn the pump on. You could try swapping them and see it any changes are noticed.

[Double M]

I will try the switch and the relay when I get it home. I wish I understood Padgett's reply, but its greek to me and please dont chastize me, but..

Could a failing sensor cause the brakes to loose pressure? I had 1 sensor replaced last year, my mechanic found it disconected with wires hanging out.

The ABS does work for a few seconds before the yellow light comes back on, BTW. Once the yellow light didnt come back on for a few minutes and I had fully functional ABS for about a mile or so.

The Red light now goes out as it always did and there ia no indication of a problem except for the Yellow ABS light being on, but is always on, so that is nothing new.

This happens so infrequently, twice in 3 months, that a leak should have shown itself by now, but I will check it all tonite or this weekend as soon as it cools off around here!

Thanx a lot and wish me luck.

[wws944]

ALDL - Look under your dash. Just under the hood release handle, there is a gray box that says "DIAGNOSTIC CONNECTOR DO NOT REMOVE". Remove it. You will then see the connector.

To get diagnostic information, you must take a bent paper clip and jumper pins A (top rightmost) and H (bottom, 2nd from left.) Turn key on, but don't start engine. Watch the ANTI-LOCK light and count flashes for a two-digit code. (E.g., 3 flashes, then 4 flashes would mean code 34.)

Without turning the key off, disconnect the jumper and reconnect it. Record additional code, if present. Repeat as needed. Then report back here.

This is all described in the on-line factory service manual near the beginning of file 90Reatta-05D-Brakes.pdf.

[padgett]

OK will try to keep simple.

It sounds like you have two issues that could be related. I am wondering if an ABS issue is opening a dump valve (pedal goes to floor, does not become hard) which depletes the accumulator pressure faster than the pump can restore, turning the red light on (normally if the pump fails to maintain pressure, the pedal will get hard but still stop.

Need to know if there are any codes, stored either BCM or EBCM

The real issue here is that what you describe is just plain dangerous both to you and anyone else on the public road. Testing really needs to be done only under controlled conditions.

[Double M]

Awesome and thank you for the awesome and simple explanations. Thanx to wws944 and Padgett for splainin' it to me, that I understood...

I know its dangerous, I dont have a death wish and I am not a thrill seeker... but at this point I'm 30 miles away from home and my mechanic.

Getting it towed would use up all my cash and then I couldnt bring it in to the mechanic. It has always been time vrs money vrs reatta since day one, and as poor as I am, sometimes safety, electricity, food and my health becomes a luxury I cannot afford. Dont worry, I understand is you all dont.

The Brakes seem to working now, so I will carefully drive home tonite and drop it off at my mechanic in the morning.

My issues with my Reatta have not been a priority because I havent been driving it all that much. My new project is that Silver Vespa in my signature picture and I have put 3000 miles on it in the past 2 months.

The Brakes have been working fine, the headlights dont come up at all, but Kingley said he had an idea about that, but I just havent been driving at night or much at all in the past few months. Which explaind why you all have gotten a reprieve from my sometimes annoying posts.

Anyways I thank you for the advice and concern and wish me luck. I have no internet, TV or phone at home, so I will update you on Monday!

[padgett]

All I'll say is the symptoms sound more like a failure in the ABS system and pulling the firewall relay (one for ABS, not one for pump) so yellow light is on steady should disable the ABS.

[Barney Eaton]

I must go along with the others. With a new accumulator, it is either a relay or pressure switch that is causing the problem.

A wheel sensor has NOTHING to do with the pedal being hard or going to the floor.
The wheel sensor is part of the ABS and you are having BOOST problems.

[padgett]

While we think of the Teves as a normal system it really is different. For instance there is no direct connection from the pedal to the rear brakes, it is all through linkages. One of those linkages operates the control valve which releases boost prssure into the system.

Barney, you are right, the control valve is part of the boost system and is hydraulic. It shuts when braking is not needed to keep the accumulator pressurized. If grit is in the system (why periodic flushing is required) I believe the control valve could stick and the system would never become pressurized. From here the diagrams become confusing since even without boost the pedal should not go to the floor unless air is in the system.

We have suspected that under certain conditions the main valve could do odd things but not what you are experiencing.

More I think about it, the more I suspect the control valve is involved and could happen at any time but every time I look at the diagrams there is something that I just do not follow. I would not drive it on a public road without knowing what is going on.

I have enclosed a diagram from the training manual (rest are on reatta.net in the docs section toward the bottom).

[Double M]

Well, I made it home with no problems on Friday. I dropped it off with my mechanic on Saturday. Saturday is also Race Day at the local track in Riverhead, so they could not get to it. I was away most of the weekend and could touch it either. Now I'm at work again, with my Scooter. I will print all this out and bring to my mechanic this evening.

[Double M]

So far, no diagnosis. I just spoke with my mechanic and he told me what I already know, that "this car has a f---ed up brake system and it has been designed this way" The basic design w/o an emergancy brake is an accident waiting to happen, in any case. So far he tells me that if I need a new master cylinder that new ones cost $1500.

It has not duplicated the problem at all. I told him to check for a problem with the relay and the pressure switch. he said the only real cure is to replace the whole system with another different one. Of course as we know, this is no easy job requiring parts from some other car, that I dont have or can afford to get. I am letting him hold onto the car for a few more days, so he can really go through it. I cant afford anything near $1500 bucks, so my hopes are now with the relay and pressure switch theory. Wish me luck.

[NCReatta]

You can get a used Master Cylinder for much less. I think I can get my hands on one in a couple weeks. Send me a PM.

[Mc_Reatta]

When was the last time you know all the brake fluid was changed out and replaced and all the calipers bled?

If you had a caliper replaced and only that line was bled it doesn't count. All the fluid needs to be removed from the reservoir and the rest flushed out of each line. As mentioned, any foreign matter in the fluid can catch in a seal or valve and cause havoc. Believe it is recommended every couple of years.

I would think if you have an electrical boost problem that it would occur more frequently, and not cause the pedal to sink to the floor.

[63viking]

Double M, You need a new mechanic.......

[padgett]

Does anything change if you pump the brake after it goes to the floor ? This is the first time I have heard of that problem - hard pedal or no power assist I have but this is different.

Have had normal brakes & hydraulic clutches do that if air gets in lines but usually comes up if you pump. However Teves is "different".

[Double M]

You can get a used Master Cylinder for much less. I think I can get my hands on one in a couple weeks. Send me a PM.

Are you talking about a new or rebuilt or just a used old one?

He was quoting me a price from the only place he says he has found that supplies them.

[NCReatta]

Are you talking about a new or rebuilt or just a used old one?

He was quoting me a price from the only place he says he has found that supplies them.

Just a used one. But I agree with Jon.. You need a new mechanic.

[NEMO]

You should FLUSH the whole brake system. Use a turkey baster to suck out the master cylinder, use new fresh brake fluid,starting in the passanger side rear caliper.then the rear drivers side bleed the system. The rears are done by. Key on, holding the foot brake down,then open the bleeder,the fluid will pump out on its own. Keep the master cylinder toped off with fresh brake fluid.The fronts key OFF,you pump foot brake slowly then open bleeder,fluid will squirt out .DO this into a jar with brake fluid to keep the bleeder hose under the fluid level as to keep air from sucking in . You will be able to see what is in the brake system,if orange that is RUST.

[padgett]

Keep thinking about it and the only way I have been able to come up for the pedal to go to the floor if something is not sucking air with is if both an inlet and an outlet valve on the same wheel were open at the same time. Conceptually a sticking outlet valve could do that but only if ABS was commanded.

The point of a dual master cyl is that even if one side fails catastrophically, the other still works sortof - that is why there are two diaphrams in series.

If both valves were open at the same time it would just dump all pressure back to the resovoir and trigger the red light Does the steering feel at all funny when it happens ? Afterwards is the fluid in the resovoir up to the full mark ? If so the open valve depleated the accumulator faster than the pump could restore.

If this is the case, what you need is a valve block, not a master cyl. (though a replacement might have everything.

Perhaps someone with a breakout box (I do not have one) could test what happens if both an inlet and outlet valve are open at the same time. Since it has had a code 22, I'd use the Left Front. The EBCM for the LF outlet valve (inlet is normally open) shows B+ (12v?) power on pin16 to close, B+ power comes from pin 3 or 20 when the ABS relay is closed.

[63viking]

There is absolutely nothing wrong with the brake system on the Reatta, as long as you take care of it. Even with my oversized calipers and rotors the system works perfectly ever time, even in a panic stop. I bled the system as described below but with the rear brakes you only need slight pressure on the pedal to cause the pump to run and flush the system. I used a length of wooden dowel 1/2" between the pedal and the seat and moved the seat up until the pump started. Works great if you don't have a helper.

[Double M]

Pumping doesnt do anything when this occured, the only braking power there is, is at the floor, the bottom of travel and pressing that harder is what stops me. Again this has only happened at very low speed, thankfully. It truly feels like there is no brake fluid. I have felt a similar feeling with a non power antique car when the single cell master cylinder went.

I truly do apprciate your efforts, everyone and am trying my best to pass this info on. We have...

a pressure Switch
a relay (on the Firewall?)
and a complete brake Flush on the table right now,

if I get it all right. And I also want to thank you all again foe expressing this in simpler terms, as I have been able to follow all of this without my usual difficulties.

Getting a new mechanic, sure, find me one... Find me one, on Long Island, near Levittown, NY, that specializes in Reattas, installs used parts, doesnt charge a fortune and can get things done in a timely manner.

I also wont comment on wheather or not the Brake System Design is safe or not, any further, that is not what this thread is about. I am seeking and thankfully getting help (THANK YOU) with a brake problem, not looking to start a debate.

Please start a new thread perhaps for that and I will chime in!