Re: Brake pedal weirdness after getting bearings changed

[Mike Cripps <mikecripps@mediaone.net>]

The other possibility is that the vacuum booster has failed or the
vacuum line to it is disconnected.

Try this:

With the car parked safely,

Run the engine and step on the brakes a few times to get the feel
of the pedal response.  Turn OFF the engine. Now step on the pedal
a few times.  After one or two strokes, the pedal should feel 
significantly stiffer - you have no vacuum boost once the engine
isn't operating and you depress the pedal a few times.

If there isn't a difference - you've found the problem and can
duplicate the symptom for your mechanic.  At the moment, I can't
think of something that would cause the failure during a bearing 
change - but then again do you have ABS? I know the pump can
be a royal pain about how the brakes are repaired, etc.

>So is there a potential that when they pressed the new bearings in that 
>they did it wrong?
>
>The only difference between your associate's situation and mine is my 
>pedal is always really stiff,
>as though there were like a rock under the pad or something, not like it's 
>being set after the first
>time.
>
># Nathan
>
>----- Original Message -----
>From: "Mike Cripps" <mikecripps@mediaone.net>
>To: <jettaglx@igtc.com>
>Sent: Wednesday, January 09, 2002 11:45 AM
>Subject: Re: Brake pedal weirdness after getting bearings changed
>
>
>I don't know if this applies to your situation, but...
>
>An associate of mine had a terrible time getting his brakes to firm up.
>The first stroke was always very mushy, then the rest (at one stop)
>were rock solid. We went through his system with a fine tooth comb.
>*Nothing* out of spec,  replaced rotors, pads, calipers, etc.  just
>because
>he was a perfectionist.
>
>Turned out to be a bad wheel bearing. The bearing allowed (caused?)
>the rotor to wobble slightly, pushing the pads further apart.
>The first brake application would push them back in close and
>"unwobble" the rotor. The second stroke was as normal because
>the pads had been reset to normal clearance from the rotor.
>
>This drove four mechanical techs nuts until we found the bearing
>by sheer chance. It wasn't even that bad - just some extra play.
>If one guy hadn't pulled on the tire/wheel without removing the
>nuts, it might still be a mystery.
>
>
>
>>I'm having a really hard time rationalizing this one, and the very
>>competent mechanic who did the
>>job is a bit baffled as well. Hopefully one of you can shed some light on
>>what causes this.
>>
>>I just got both my front bearings replaced. The car runs absolutely dreamy
>>now; the alignment is
>>perfect, the noise is finally gone... but the brakes are much stiffer now.
>>How in the hell, I don't
>>know, I would think if anything they'd be a little looser. By stiffer, I
>>mean I used to have a
>>really nice, easy feel of increasing pressure pretty uniformly down to
>>maybe 3/4 of the way to the
>>floor, at which point you just can't push it any further and the car has
>>thrown you into the
>>steering wheel :-)
>>
>>Now, I can't get it more than 1/4 the way to the floor before it's rock
>>solid won't budge any
>>further. I talked to the mechanic and he doesn't understand how it could
>>be that way, that he didn't
>>adjust the braking system at all, but he did have to pull the calipers off
>>the rotor. He said he was
>>quite careful getting it back together and that nothing he did should have
>>caused the pedal to
>>respond in this fashion.
>>
>>Any ideas on what happened? I really liked the feel of the brakes before
>>he did this, and I'm kinda
>>worried about it, even though the brakes in a technical sense work great
>>still... My only thought
>>was that maybe he tightened the two hex-head bolts too much? Could this
>>possibly affect things that
>>dramatically?
>>
>>Thanks in advance!!!
>>
>># Nathan
>>1996 Jetta GLX