Volvo Repair: 2001 volvo s 40, volvo s 40, volvo repair

Question
I have 2 questions.
1.  My coolant was low so someone at a volvo repair "topped if
off". They over filled it.  Shortly after it began to run really
rough, loud shaking at a stop. Now the check engine light is on.  
Could overfilling cause this problem?

2. The reason I went in to the shop was the brakes wouldn't
engage all the way.  Brake fluid fine, they said car had a re-call
on a brake booster part. To let the car warm up and then it
would be ok.  True, brakes work when it's warm.  One dealer
said no such re-call on my car.  Would this problem cause the
shaking and rough sound and the check engine light to go on?

Is the car safe to drive, at least to a repair shop?

Answer
Robbie, the answer to both questions is No. Purely a coincidence.  As far as the brakes go, be careful.  I've never heard of that recall, but you may be dealing with a Master cylinder issue.  If you have AAA use it, if not drive very carefully.  ROger