dshulik

Did a search and found a few folks had this problem but I didn't find the answer.
This always happens to me just when its running great!

1980 Model, all new rotors, pads and fluid replacement within the past 18-24mos. Original Master Cylinder.

I'm getting a "Brake Press." and the usual flashing "!". The brake lights are functioning fine, fluid level has not dropped and brake response feels unchanged in both hard and easy braking situations.

At the advice of my mechanic, who was pretty busy working on a 993 at the time to get it done for his other client this evening, I've already pulled the black cable that attaches to the chassis inside the rear tool compartment for a minute or so but the flashing "!" and "Brake Press." lights still-a-flashin'. I'm assuming that WAS the proper cable since my radio presets all went to the Spanish and Easylistning stations....its usually set for Jazz, 91X, and some other station that plays Metallica every other song.

I almost forgot the problem as I was sitting in another one of his client's GTR3's or whatever model ya call it (Same model as the powder blue Rennlist racecar that's graced the Rennlist homepage).....problem not quite forgotten...but almost!

Now where was I? Oh yes, --Any suggestions on what to check next? If its just a couple of sensors, how much are those little buggers for a 1980 model and are they difficult to put in? I know, I know....still don't have a set of shop manuals. But I have you guys which is even better! <img border="0" alt="[blabla]" title="" src="graemlins/a_smil17.gif" /> <img border="0" alt="[byebye]" title="" src="graemlins/wave.gif" /> <img border="0" alt="[crying]" title="" src="graemlins/crying.gif" />

ViribusUnits

I just fixed this problem. It wasn't too bad.

There are two pressure operated switches on the bottem of the master cylinder.

If one goes out, the brake lights will continue working fine, but the warning will come up.

To check, pull the plug off the sensor. If the warning doesn't go out, put the plug back on, and pull the other one. The warning should disapere. Do the "clear memory" ground strap thing to see if the warning goes out.

If the warning goes bye bye, replace that sensor. It would be better if you replaced both sensors.

They can be replaced with a cressent wrench (Also called a monkey wrench where I live.) They come out with only a little effort. You will need to remove the air filter cover, and the 4 way connecter for the a/c to get to them. It's tight, but do able.

The 928 intl has them for about $25 a peice. performancemotorcars.com had them for $4.00 or so. preformancemotorcars.com is not a rennlist sponcer, so buy what you wish. My experences with 928 intl are great. I can't realy justify to spending the $40 or so diffrence, so I bought them from performancemotorcars.com They arrived when they said they would, for the cost they said it was, and it was the right part. Can't complain. It's the only bussness I've ever done with them.

One of the easyer repairs out there.

dshulik

Thanks for the tip. Least expensive repair I can remember on my car was a lightbulb. I think it was twice the cost for both sensors you describe. BTW, can the sensor wires be temporarilly disconnected without causing any problems? I have black electrical tape covering the "!" on the dash and in the pod as well as covering the "brake press" light.....the blinking is driving me blinking-insane!

SteveG

"Black Tape Indicator Repair" = Click & Clack or were you first?

ViribusUnits

Just pull the plastic connecter off the switch, and the warning should go off, eighter instantly, or when you reset the brain.

If it's not that switch, do the other one. However, rember to have at least one on one switch. If you don't, the brake lights won't work.

I drove around like this for about 4-5 months.

I only finaly got around to replaceing them because one started leaking through the body. As it turns out it was the bad one. Try to avoid that. It's not cool!

dshulik

What do you mean by "started leaking through the body"? What was leaking through? Brake fluid through where the sensor is????? This afternoon's project is to get that flashing to stop...

ViribusUnits

It was leaking out of where the plugs where, NOT where the seam between the threads and the master cylinder are.

Somehow or another, the seals inside the body of the switch came apart, and it started leaking fromt he inside. Realy weird if you ask me. Just so happened, it was the one that wasn't working. I don't know if thats linked or not. I kinda dought it, but...

It won't take you an afternoon to get it fixed.

John Struthers

dshulik,
A lot of the warnings seem to be voltage source related.
Weak batt = oddball warnings.
I don't know how the 'BOOKS' are set up but if you you find pg 90-36(or 38 -small print sorry-.)
Para. 9 Brake Circuit Failure, there is a test -JUMPER -, and the NOTE provided indicates a battery disconnect is necessary to clear the warning/fault.
A word here:
Mine clears with or without batt. disconnect - over time-. Sorry Guru's, "it just does!"
I had replaced brake fluid, pads, brake pad sensors - to include continuity check for shorts -, the brake press. and pad warns showed up and would not go away.
Replaced Forward pressure sensor on master cylinder . Still no joy!
Someone on the Renn, Dennis I think suggested changing both sensors and recommended I replace with BOTH from same Manufacturer.
Did so and still no Joy! Over time the warn just went away...
In the meantime brakes were excellent, no drag, pulling, squeal, loss of fluid, or lock-ups.
Units may be right on that leak, but the way I'm looking at it even if it leaks internally the leak is contained by the seal and threads on the external portion of the sensor. Keep in mind there is an enormous amount of pressure generated in the brake system when you apply the brakes.
So snug it down, - don't REEF on it - and check for leaks on the inner well underneath Master Cylinder occasionally.
Read my earlier posts in the archives for removal and installation.
Have fun.
John S.

WallyP

Your search should have found an answer:

<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=14;t=002281" target="_blank">http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic;f=14;t=002281</a>

John Struthers

Wally, and John P.
Thanks again.
John S.

dshulik

Hmmm, this is strange. Good news in fact. I went to go take a look to find out where the wires for the sensors hook in and in the process of doing so, I disconnected the battery again (in the tool-kit area in back). This time it was disconnected for about 10 minutes versus only about two minutes the first time round. Problem solved! No more flashing lights. I'm not exactly sure why it got set off in the first place but perhaps it is related to a possible altenator problem (lights go dim at night at stops and the volt meter reads really low unless I go into neutral - yeah, I know "off topic") I'm thinking for some reason this may have been related. I also have about 600 watts of stereo equipt. but the volt meter issue seems to only happen at night when the headlamps etc are switched on. The original warning was intitiated in the daytime with on a/c air on and only the stereo going. I also had my right foot into it most of the ride before it happened so I don't think the car was anywhere close to idle or lacking of any charge to the battery from the alt. I really appreciate your guys tips though. It made me take another look and save some bucks.

dshulik

Check that..... "without A/C on"

John Struthers

dshulik,
I mentioned this in an earlier reply and for some reason the whole 'reply' never got to your post.
Part of my problem with warning /caution lights is a charging problem.
Keep in mind our OEM alternators are only pushing a little over 90 amps.
When you do a lot of short trips there is no time to completely recharge the battery, particularly if the short run also involves wipers, heater,sunroof,adjusting the seats, windows, or
A/C, and a couple hundred stereo watts.
Throw in a few aging grounds, an older battery and there you have it...
I posted on one of my recent alternator glitches that for no reason when I hooked up my battery,
ALL of my warning lights were blinking.
I constantly have my battery on trickle charge due in the main because of the non-charging alt.
-new one due this tuesday-. Pattycakes is in a good state of tune so she'll start up with less than 12 volts. But, when undercharged, till the voltage comes up, or I trickle charge other issues such as open loop-rich condition, and hunting idle will occur. Most if not all will disappear/clear after voltage comes up or after a battery disconnect and charge.
Keep a mental recvord of what's happening, when and voltage in the battery.
John S.

dshulik

Thanks John,
Saw the notes on the charging issue. Its the first time the car has experienced any problems other than the dimming lights at a stop light. I definately should look into a new altenator sometime soon. If this kind of thing continues to happen it will expedite that process, but I'm hoping its only an isolated incident. Before spending on that, I need to hunt down a leak in my AC unit first to keep things cool before S.Cal starts getting toasty. Us banker-types have to wear long sleeves and ties most of the work week and the two-eight is my daily driver.

dshulik

Wouldn't you know it! Its blinking again....Just reset the computer once more but looks like its going to require some work. I'm sure it'll start blinking again once I drive the car. I'll have to get the ol' black electrical tape to cover the flashing lights again just in case.

Since it seems to me that a bad sensor would immediately have caused my warning indicator to go off again right after resetting the computer the first time, and since it didn't set off the warning for a day or so, is it likely at this point that I can rule out a bad sensor in favor of an altenator issue?