Stiff Brake Pedal and Burning Smell on 87 5ktq

[Brett Dikeman]

At 7:55 PM -0400 10/11/01, Bill Rowe wrote:
>I just ordered a recharged bomb from Russ cuz I suspect mine is 
>going or has gone bad.

Never "suspect"...do the pedal test, because it's so easy.  Run the 
car for a few seconds to guarantee the bomb is fully charged(bring it 
up above idle a little bit.)  Now, engine off, pump the brake pedal. 
You should get a LOT of pumps... I think at least 15-20.  If you get 
under 10, your bomb is on the way out.

>   Anyway I noticed the brake pedal got real stiff after a few hard 
>braking in an attempt to cure a front end shimmy due to potentially 
>warped rotors.

Yup, that's probably the bomb's charge going.  However, it is NOT a 
conclusive test.  Yes, you ran out of reserve, but, -why-?  Maybe 
your PS pump is tired, and not supplying full volume+pressure, so the 
bomb wasn't fully charged?  The Bently has a complete procedure on 
hydraulic system testing/repairing.  Do read it, it's good material 
even if you don't have all the tools(it gives you a good 
understanding of how the system works etc.)

You can at least partially tell a little more by then running the 
car(parking brake off) and watching to see when the brake warning 
light goes out.  Should be a few seconds, no more than 10. If you 
have to wait any longer, the pump might be going and you should have 
an audi mech take a look and test the pump.  They are easily rebuilt, 
the rebuild procedure is even in the Bently, and a complete seal kit 
available from a dealer parts source.

>   When I parked the car I could smell the brakes.
>   An hour later I drove off and the brake pedal was fine.  Any idea 
>what's going on?

Hmm.  Well, using up the bomb's charge transfers fluid that was in 
the bomb into the system.  I've noticed that after a bomb discharge, 
often the system will feel "better" because of all the fluid that is 
relatively fresh(since it doesn't circulate) is now in the system. 
It certainly does feel a little different if your fluid is due to be 
changed etc.

>  The burning smell would indicate that the brakes are binding but 
>would that cause the pedal to be stiff?  TIA

Mmm, not quite.  It indicates that they were hot.  If you did several 
hard braking stops, then sure, I would expect them to be hot.  If 
they hadn't been used that hard in a while, sure, all sorts of things 
that are on the rotors/pads/calipers might heat up and smell a little.


Oh...one caution.  The reservoir should not be above the MAX line or 
you will overflow the reservoir with fluid if your bomb is in top 
shape.  The reservoir, like any other container on the car with 
max/min markings, should be half way between min+max(especially oil 
level, which should never be at the max line.  Many audis have a 
prominent warning label on the tbelt cover to similar effect, stating 
it shouldn't be OVER the max line, but at the train station when 
cautioned to stay behind the yellow line, do you put your toes up to 
the edge? :-)

Hope this helps!

B
-- 
----
Brett Dikeman
brett at cloud9.[nospam]net
http://www.users.cloud9.net/~brett/
(vm/fax)212-894-3749x5271