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Digitalchaos
04-10-2003, 03:23 PM
Hello. My brake pedal seems to have significant travel when stopping the car. I had the system flushed, then rebled to check for air, as it was somewhat like this before. Essentially the car stops well but for a normal 40-0 stop the pedal will move with not much resistance to 3/4 way down. Also, when stopped, it feels like I can almost press it to the floor, although it doesn't quite get there. I noticed brake fluid splashed out onto the resevoir last night, enough to get 1 side wet & the sensor plug. There is no fluid loss otherwise.. and level is normal.

So what are your thoughts? Bad master? Bad caliper? What does a master cylinder cost 4 this year; and if its 1200 dollars, is there an alternative?

Digitalchaos
04-11-2003, 04:40 PM
^

Katoom
04-12-2003, 08:32 AM
You know, it's funny.....my car is like that too. I just replaced a caliper in the front drivers side and bled it well. I have the same soft pedal syndrome.
It seems like anytime I do brake work on this car its like that for a good long while......no explanation.
Is there some special bleeding procedure that we are missing? On the back you let the pump push the fluid through, but the front should be conventional bleeding to my knowledge.

Digitalchaos
04-16-2003, 05:25 AM
Strange. Myself and the mechanic found no leak, although the calipers were not checked for piston problems. The car does stop pretty well, just that soft pedal. They actually bled the system twice, over the course of maybe 2 weeks. The first time was flushed then bled, the second time bled. No air was found.

Did your pedal eventually become firmer w/o making any other changes? This would definatley imply air.

pastera
04-16-2003, 11:01 AM
I had the spongy pedal before I did my brakes. I flushed and bled the system before doing the brake job, just in case I had a fluid spill. It firmed up the brakes some, but not much. The problem was one of the guide pins on the passenger's side rear caliper was seized. After this was fixed, the pedal firmed up. If you look at the design of the system, that should not have been the case but it is what I experienced.

Aaron

Digitalchaos
04-16-2003, 05:26 PM
Excellent; this is very likely the case then. Any place where I might find more info about this? I could probably take the wheel off myself & find it, but I would need more knowledge to fix it confidently.

Katoom
04-16-2003, 06:58 PM
I grease my guide pins on the rear calipers every 6 months to prevent seizure. They are expensive. If you remove the wheel and then remove the two 13mm caliper retaining bolts the caliper should lift off. The guide pins can then be removed and greased.

Mike8675309
04-17-2003, 11:11 AM
Guide pins have little rubber boots around them. there is one on the top and one on the bottom. the lower one on the rear had a tendency to sieze up if not regularlly maintained. Below is a picture with the top one circled. I ended up having to replace the whole bracket on mine due to the lower pin siezing up.

One other item that can cause a pedal like that is a weak brake accumulator.

http://www.frontiernet.net/~miketoni/images/tbird/calipertogetherclose.jpg

pastera
04-17-2003, 04:31 PM
I picked up two new guide pins for about $10 at the local Autozone.

Mike - My accumulator is on it's way out so maybe that is my real problem.


Aaron

Katoom
04-17-2003, 05:09 PM
That explains my car then because I know that my accumulator is on it's way out too.

Digitalchaos
04-19-2003, 03:29 PM
Thanks for the info Mike! The caliper pin is probably my problem then as I've no accumulator.

Still Crusin
04-19-2003, 07:57 PM
How can you tell if accumulator is going bad, other than spongy brake pedal. Seems I'm having similar trouble. I recently had shop flush and bleed my system as well. Brakes seem to work ok, but pedal seems too spongy. I have a 94, with 95k miles

Mike8675309
04-19-2003, 08:40 PM
Accumulator Symptoms of failure are:
Brake pedal travel is too much, yet brake fluid level is fine.
Brake fluid level decreases dramatically, but no leak is visible.
ABS Pump runs during each brake application rather than only after about each 10 brake applications.

All of these are signs of excess travel or lack of pressure storage in the brake system. The accumulator is the only component in the system that can vary the space available to brake fluid, as well as store brake pressure. A spongy brake pedal sounds more like air in the system if none of the other symptoms are found.

markadeck
12-04-2004, 03:00 PM
How about I just add a question to a thread already about brakes? For years while sitting stopped in gear (AOD) with firm pressure on the brake pedal the pedal will go to the floor and the SC will creep forward til you release the pedal and step on it again. If you sit with just very light pressure it seems to hold just fine. I have put up with it all this time cuz the car usually sits for months at a time. But now my girl wants to drive it daily so she is complaining about it. Mine is a '90.

Mike8675309
12-04-2004, 07:18 PM
If you pump it up a few times, will it then hold? I.E., hold, to floor, lift, hold, to floor, lift, hold solid.

If so it may be your Accumulator is bad on the brake master cylinder. The pressure of your foot on the brake is overcoming the nitrogen charge in the accumulator allow it to fill with brake fluid. The more you pump, the more that fills up until it's full and then you can maintain pressure.

Now if that's not it, then you have a master cylinder that is allowing fluid to pass by it's seals. Time to get it rebuilt.

markadeck
12-06-2004, 09:25 AM
Thank you, I will look at and try the suggestions. Did not receive an e-mail notifying me of a reply to my question. Which explains the delay in getting back to you.

TbirdSCFan
12-06-2004, 01:02 PM
Thanks for the info Mike! Thats probably my problem then as I've no accumulator. Well there you go then :rolleyes: I've got an old worn out one sitting in my garage.. you're welcome to it. ;)

Anyways, did you ever find a TevesIV pump motor activator tool? If I were you, I'd bench bleed (not actually on a bench mind you) the master cylinder. I think you still have an air bubble in there somewhere. You pull the lines off the MC and run lots of fluid through it at a rate where the bubbles can't work back into the MC. Usually, you route the lines back into the reservoir with clear tubing and pump-pump-pump till happy or no bubbles are visible in the outgoing stream. But, you can also use a bucket and pause to refill the reservoir as needed with the overflow.

Then, you reattach the lines and bleed as normal using your Teves IV tool. :)

Mike8675309
12-06-2004, 03:57 PM
1989 through 1992 SC's have the Teves Mark II ABS system. These use an external accumulator to store hydraulic pressure easing the burden on the hydraulic pump. These systems are an all inclusive master cylinder and supply the assist for braking.

1993+ SC's have the Teves Mark IV ABS system. These don't use an external accumulator and are remote mounted. Instead these have a standard vacuum assisted master cylinder.

Someone posted in the member section being able to get the tool built for him by Thexton to bleed the Teves Mark IV system.

Sorry to the original poster of this thread as I didn't notice he had a 1993 car.

Digitalchaos
01-22-2005, 02:08 AM
Hellow again everyone. I haven't frequented the SCCOA in a while, aamof its almost time to update my membership so much time has passed :eek: .

As an update, I have not been able to attend to my brakes. They are essentially the same as always, and I now believe it is simply air trapped in the system. I am now waiting for the time when I can purchase the tools necessary to complete this.

Also, Mike, no apology is necessary! You have provided a wealth of very valuable information to our community, and also to me about a great many problems! I have personally failed to notice year related differences on more than one occasion, its easy to do. I was thankful for the information you provided about my rear calipers however, as this was indeed a problem and I fixed it near the end of '04. It made a nice difference, especially when my rotor stopped glowing orange :o .

Thanks for the wonderful threads and replies everyone, I think it would be very difficult to find another vehicle which had a community following like our SC!

Mark Ostasiuk
01-29-2005, 04:40 PM
Hey Mike,

I noticed on an old posting that you mentioned that you replaced the abs accumulator on your SC.. Where did you get your accumulator? The dealer says that it is discontinued... Also, did you have to take out the entire assembly to replace this part?

Thanx!!

Mark





1989 through 1992 SC's have the Teves Mark II ABS system. These use an external accumulator to store hydraulic pressure easing the burden on the hydraulic pump. These systems are an all inclusive master cylinder and supply the assist for braking.

1993+ SC's have the Teves Mark IV ABS system. These don't use an external accumulator and are remote mounted. Instead these have a standard vacuum assisted master cylinder.

Someone posted in the member section being able to get the tool built for him by Thexton to bleed the Teves Mark IV system.

Sorry to the original poster of this thread as I didn't notice he had a 1993 car.

darkstar_one
01-30-2005, 12:41 AM
you know what dudes... i had the same problem... and i replaced my accumulator and so forth and yet its still the same... im blaming my problem on my rear brakes... my rear rotors are warped beyond belief.. my dad says to just get new brake pads... but ima go for the new rotors as well... but anywho... what im worried about is the stop lights coming on... thats my real problem since i live here in the city and nothing but traffic... so im constantely watching my rear view mirror.. making sure my stop lights turn on completely... and on time...