jeeper31

My new (to me) '88 Turbo S's brakes seemed to be behaving inconsistently. Until a few days ago the pedal stayed high and the was rock solid when depressed. A few days ago I was driving in a residential area by work and made a quick left then right then left again. When I stepped on the brake pedal it seemed lower then it usually is. They seemed fine the rest of the day. Didn't drive the car again until today. This morning I went through the same set of turns and the pedal seemed lower again. Tonight I was driving it and the pedal felt as usual on some stops and seemed a bit lower on others. When I mean it seemed low it never seems too low, just lower than usual. Funny enough I started a thread previously on how to lower the brakes as they seemed too high to heel toe. So now, when I say the brake is low it is about even with the height of the gas pedal. I checked the fluid level and it is good.

AR10

This is usually caused by the brake pads being "knocked back" into the calipers by a loose
wheel bearing.

Dave951M

Check your front wheel bearings.

Lorax

Please describe this in more detail!

luckett

Does it stay low if you pump it or return to normal height/firmness? If it stays low, it's probably something hydraulic.

jeeper31

When I pump it it goes to the regular height. Actually I don't have to pump it it just goes back the next time I press the brake.

AR10

When the wheel bearings are loose the rotor moves in and out which pushes the pads
away from the rotor. The first time you push the brake pedal down it has to push the pads
out to the rotor before the brakes can work which causes the pedal to travel more than
usual. The pedal height will stay normal until you make a hard turn or hit big bumps.

jeeper31

That's what happens to me it seems. Seems to happen on right turns. What is a good wayt to check the wheel bearings?

Dave951M

Proper way-
Jack the car up, take out wheel bearings, inspect, if ok, repack, put wheel back on, set car on ground.

Another way-
Jack car up, place one hand on top of wheel and one on bottom and try to wiggle the wheel.

I prefer method 1 as it does two things, it insures visual inspection of the bearing and repacks it with grease till the next time.

shiners780

Here's a good write-up describing knockback:

http://www.stoptech.com/tech_info/wp_knockback.shtml

Lot's of other good stuff on that website as well.

jeeper31

I jacked car up and shook from 12 to 6. There was some play. I took off the dust cap to adjust and noticed I could not turn the thrush washer and the adjusting clamp was all the way tight. The grease looked fresh like they might have been repacked recently. I loosened it up to the point where I can move the thrush washer and the wheel seemed looser. Tightened it up again as tight as I could get it with my hand and there was still some play in the wheel. Still getting the knockback.

Now what?

Techno Duck

Ball joints and tie rods.

jeeper31

Would that cause the knockback of the brake pads? Could the bearings be bad without making a noise?

xsboost90

if they were adjusted too tightly initially it could kill the bearings causing that- you may also just need to rebleed your brakes if the fluid is old or boiled and temperature etc is making the level and pressures fluctuate.

jeeper31

What would you suggest first? The fluid level is good. It seems to happen only when I turn. If there is air in the system wouldn't it happen at other times too, not just when turning?