OK thanks everyone. I'll take it that it'* not quite how it'* supposed to be but it'* quite normal for Teves systems to go spongy. I'll leave it alone - it doesn't seem to be affecting its ability to stop.

Agreed if its not affecting your ability to stop and you can live with the spongy pedal leave it alone.
Its possible that there were revisions to the system for the final (90) model year.

Doubtful, your car was probably better taken care of, or just survived the testament of time.

Yo guys taken any apart? It seems to me this could be caused by low accumulator pressure or crud in the valve block.

Well, I'm on my 2nd Teves master cylinder/abs unit... my first had the spongy pedal, along with a delay before the brakes would cut it properly, and a pedal that wouldn't move at all when the brakes were slammed on... (almost cost me 2 rear-enders..).. my current MC/ABS module is a junkyard pull, and has the spongy pedal, and the delayed braking, but you can slam the brakes, and she will lock up well enough for the ABS to cut in on hot, dry asphault...

Maybe one of these days I'll pull apart my old MC to see whats going on in there... I knew I was a packrat for a reason...

http://reatta.net/brakes/brakes_troubleshooting.html

You may want to check out the Teves brake test above. I know it pretty well from my Reatta work. You may have a bad accumulator so the system isn't storing pressure like it should. Also, this means the pump runs a lot more than it needs to. This results in a greater chance of it failing, and if it does, you won't have much reserve pressure...

That'* food for thought... Is the accumulator available seperately and is it an expensive part?

Accumulators are around $114 total from GMpartsdirect.com

Guys, if your Teves system is spongy, just because it'* normal between most other Teves systems doesn't mean its right. It'* probably spongy because the accumulator is shot and not holding pressure.

If you guys have a house with a well, imagine if the well tank was bad. Whenever you turn a faucet on (touch the brake) the pump would have to run. Pressure isn't consistent, nor very high. Place more demand on the system (two faucets, or a panic stop) and you won't have as much pressure. Also, the pump is going to have to run a lot more, wearing it out.

If the pump fails and you have a bad accumulator, you will not have boost. You're gonna have to stand on the pedal and will only get a little bit of braking effect.

So please, make sure your accumulator is good using the brake tests, and change the fluid in the resevoir and bleed the lines like every other year.

yes i have a 1988 sse with 76,023 original miles and as the second owner and my uncle the first, we both can tell you the brakes do feel very spongy but they work real good and still continue to stop on a dime with out any problems.. try putting some degreaser lubricant spay on the pedals my uncle said. but yeah spongy is normal

Guys, spongy is NOT normal. It means something is wrong with your Teves system