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Another brake scenario


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Just had the 89 serviced by a local mechanic which included changing the front and rear brakes. They were in pretty bad shape. Now the red light has come on and stays on but I had no problem driving the car home or braking. (The ABS light goes off a few minutes after starting the car).<P>With the car running in my driveway (sloping down) the brakes work just fine if I put the car in neutral and let it start rolling down. I was also trying to get a feel for whether the emergency brakes might be sticking. <P>The service manual hasn't arrived yet so I haven't tried reading any codes. After the reading the post here I'll take it in to a local dealer but I'm interesting in any comments or suggestions anyone would like to offer. Is there anything I can try?<P>(From the old receipts in the glove box it looks like this car had a new accumulator and pump installed in 2000). confused.gif" border="0

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Guest wally888

Unusual but the Pressure Sensor has 3 circuits. Not sure if one of these circits malfunctioning could be the culprit.<BR> You won't find anything related at the ASDL as it is for Antilock problems. A bad Main Relay will cause a Yellow light and if the relays are switched ( just takes a moment) you can get a Red light also. I'd switch relays while I was waiting on Manual.<BR> However everything you report does point to the Emergency Brake.

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Guest Brolliar

About the parking brake possibly being the cause - on an 89 Reatta if the parking brake is on - then as you shift into drive you will get a diagnostic in the CRT screen. The diagnostic says "Parking brake on - release before driving". The service manual says this would happen and I just checked it on my Reatta and I got the diagnostic when with the key on I left the parking brake on slightly and shifted to drive.

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Guest Brolliar

My 89 Reatta Service Manual says the brake light can be on for two other critical reasons but for these the Anti-Lock light should also be on. They are:<P>1. The pressure measured by the presure switch goes below 1500 psi (pounds per square inch). The light should go off if the pump raises the pressure above 1900 psi. Depending on how far it is below 1500 psi would determine how much power brakes you have (some or none). This condition could make stopping much harder (much more pedal pressure required and much longer stopping distances). Back in 2000 Wally 888 ran a brake test, quoted below.<P>"To confirm stopping distance of Reatta and other cars: Not very scientific but I picked a nice level stretch, accelerated to 50mph, stomped the pedal and kept the car (89 R.) in Antilock engaged mode till it stopped. <BR>Results 83 feet( repeated 2nd tme, no significant difference) Note: I also repeated the test w/ no Hydraulic assist( zero pressure, as I removed the Pump Relay and pumped the pedal until it was high and hard. Results- almost 300 feet!"<P> <BR>If the brake light is on and the pump is not running at all to add pressure to the accumulator, you can have a few stops with some power assist until the accumulator pressure is used up. Then you have no power assist and should get un-assisted braking like Wally 888 described above, if you have a strong leg. It could take someone with less leg strength quite a bit longer to stop.<P><BR>2. If the low fluid level switch in the brake fluid reservoir is actuated it will also turn on the brake light. One should carefully read the WARNING message on the front of the reservoir before adding any fluid. My fluid level is at the line after I, with the key off, apply the brakes 25 times to empty the accumulator. The level normally is about 1/2 inch below the line when the accumulator is full. <P>The manual says the Graphic Control Center should display a warning message, if the key is on and the car is shifted to drive, when either the pressure in the accumulator is low or the fluid level is low. <P>The manual also says if just the brake light is on while the Anti-lock light is off the condition is usually a short in the pressure sensor or the liquid level sensor or their wiring.<P>If my Reatta had just the red brake light on as you described, with the Anti-lock light off and if the power brakes seeming to work, having read the Service Manual if I was driving the car to the dealer I would still drive slow and allow alot of stopping distance so that I could bring the car to a safe stop even if the power brakes suddenly disappeared.

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Thanks for the reply. One thing I noticed. I tried pumping the brakes 25 times with the key off and the pedal got real hard after only 15 pumps. I tried it again today and it only took 8 pumps with the key off before I couldn't pump it any more. I don't know if that suggests anything -maybe you guys know. <P>In any event I'm not trying to drive the car.

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Guest Brolliar

This page describes the brake tests<BR><A HREF="http://www.reatta.net/brakes/brakes_troubleshooting.html" TARGET=_blank>http://www.reatta.net/brakes/brakes_troubleshooting.html</A> It would be a good idea to read it.<P>This page (below) has alot of excellent pictures and descriptions of the brake system.<BR><A HREF="http://www.reatta.net/brakes/brakes_pictures.html" TARGET=_blank>http://www.reatta.net/brakes/brakes_pictures.html</A><P>The first page above gives more details on the brake tests. If you turn the key on the pump should start running and pressurize the accumulator to above 1900 psi. After the accumulator is pressurized the pump stops. You can hear the pump running if the radio is off. Can you hear it run and then stop? Easier to hear if the hood is open. The pump should run over 1/2 minute if the accumulator pressure is all the way down. <P>Then if you turn the key off and pump the brakes until the accumulator is empty it should take more than 15 pumps. If it is only 15 after the accumulator has just been pressurized you probably wont have as much pressurized fluid in the accumulator as you should have. If there was some time between having the key on and the pump running until it stopped and when you depressurized the accumulator then it might be just 15 pumps. This is because the pressure in the accumulator would have leaked down some over time.<P>When you turn the key on wait one minute and then shift to drive does the screen show any diagnostics. If the pressure in the accumulator is low you should get a diagnostic. Do you get a diagnostic? The brake light and the Anti-lock light should also be on. Are they?<P>After you get your manual you can sort things out. If you enjoy working on cars you may be able to run the tests in the manual and tell what is keeping the brake light on and fix it. My email address is dick@brolliar.com. Email me if you want to talk on the phone some.

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Now that I've got a replacement CRT screen, and the manual I can give you guys some feedback. The car does in fact think the emergency brakes are on - they might be. They're certainly released under the dash. <P>Maybe when the mechanic changed the pads, etc. something got stuck. Thanks to everyone for all the help. It's a neat car. I'm trying to make it a keeper.

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The CRT kept going out so I couldn't check the diagnostics. All I could see was the red brake light on. Once I fixed the CRT I was able to press the dianostics for the brakes and it displayed a message stating that the emergency brakes were on. The most likely suspect is probably the switch attached to the emergency brake. Make sense?

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