924Board.org

[B]

hi everyone

I guess this is kind of an extension of an earlier thread/problem I was having with the brakes

I have managed to get the brake pedal height to come up and to have much better firmness in the pedal.

When the car is started the pedal falls drastically (to me) - to probably less than 1/2 or maybe 1/2 pedal.

After a short time - 1 minute or less - the pedal returns to its original height before the car was started and appears firm again.

these things are started to drive me crazy - more than before

Does this sound normal for these brakes ?

thanks

Sean
_________________
1979 924 n/a
BAE turbo
5-speed snailshell

[!tom]

Is the problem you are describing caused by a different amount of brake assist due to changing vacuum during warmup? How well are the brakes stopping your car?

It doesn't sound right to me, but I know that it can be very difficult to accurately assess brake pedal feel without actually driving the car.
_________________
78 924 NA
5-lug

[B]

that was what I was not sure about - I had not driven the car for fear that they may fail I will do a small test in the drive to see how well they stop.

when I had the front on stands I spun the wheel and had someone apply the brakes and they seemed to work as did the rears

this just seemed really strange

thanks
Sean
_________________
1979 924 n/a
BAE turbo
5-speed snailshell

[B]

driveway test seemed ok - I know it is not much of a test, but at least at 10 mph I know I can stop pretty well -

I will try to get it on the road today or tomorrow for a better test

thanks again
Sean
_________________
1979 924 n/a
BAE turbo
5-speed snailshell

[B]

well after numerous speed bumps along the way - frozen adjuster and broken bleed screw being the last two, I finally put the car on the road for a short sputtering and chugging road test.

The pedal still feels somewhat soft and I am not sure I could lock them up - I hope I do not have to - The brakes do stop the car in a reasonable distance

There appear to be no leaks, the rears are adjusted to drag at 2-3 clicks and completely stop at 4-5 clicks and at least 2 qts of fluid have been bled through the system. Hopefully I am not missing anything. If the softness or mushy feel seems to become bothersome, perhaps I will need to look into master cylinder . ? .

Does this sound like I have done this somewhat correctly? Or does the pedal for your cars seem more rock hard - similar to a disc brake set up?

Thanks again

Sean B
_________________
1979 924 n/a
BAE turbo
5-speed snailshell

[!tom]

Large brake pedal travel can be caused by what's known as "knock back," which is when the brake rotor opens a brake caliper. This can be cuased by loose wheel bearings, but in a properly maintained car, can come from flexure of the spindle.

Long travel could be from this.

Or, there could be a stubborn bubble somewhere in your car.

Or, you could have a flexy rubber brake line that is causing your spongyness.

Or, another possibility is that your brake shoes aren't bedded in to the diameter of your brake drum, and what you are feeling is flexing of the brake shoe.

Could be lots of things.

Normally, a mastery cylinder needs replacing/rebuilding when the seals leak. This manifests itself by having a certain pedal pressure (fairly light) where you can push the pedal to the floor. Push harder and the seals stop leaking and the pedal gets hard. The pressure is usually around what you would use to stop rolling when at a stop light, so the brakes are doing something at that point.
_________________
78 924 NA
5-lug

[B]

thanks again

when I begin to apply the brake, I feel them begin to work - so they are working to a certain degree, I do not feel the hardness, after a point that I guess I expected to feel.

I checked the rotor after I put it back together for any movement side to side and did not have any - unless I was not pushing hard enough ?

I did replace the rubber hoses with stainless

I think i cleaned all of the grease off of the rotor when installing

I suppose it could be another bubble - they sure seemed to come pretty clean of those

Is there a time for new shoes and pads to bed (?) or seat themselves?

thanks again
Sean
_________________
1979 924 n/a
BAE turbo
5-speed snailshell