A few 94 Mazda repairs and then the power brake booster breaks

A couple weeks ago the front brakes were done on the Mazda. Then the wheel bearings needed to be done. I think the shop outsourced what I guess was the packing of the bearings. I paid for the work, and drove away, nearly, but didn’t because I had no brakes and there I was pulling out into 5:00 PM traffic. The emergency brake saved me. I walked back into the shop and they discovered the power brake booster had broken. I wonder, because if you drove the Mazda to park it in the shop lot where the customers pick up the vehicles after repairs are made, wouldn’t you notice that there is no braking action. The brake pedal was high and hard and there was literally no response when I depressed it. The shop keeper said, darn I guess I’ll have to replace this, meaning pay for it, since it (may have) happened when the bearings were being worked on. My question is, is there any reason why working on bearings might end up breaking the brake booster? Chances are, it was just coincidence, right? or? I don’t know. Because the car is old, he had to take several days to find the part. Anyway, he sent me off and told me to drive it carefully. The drive home was absolutely nervewracking and required continual tugging up on the emergency brake stick. I wonder if they despise my car so much now that they are sending me off to drive in it in such an unsafe condition. Anyway, hoping it will be fixed tomorrow. But my question still is … would working on bearings possibly be cause for breaking the brake booster?

I think the bigger question is why did you knowingly drive a car with no brakes?

The brake booster is on the firewall, basically right behind/under the brake pedal. It has a vacuum line that runs from the engine to the booster on the fire wall. That vacuum line will be toward the top of the engine. All of that is pretty far away from the wheels.

One question might be why you drove without your brakes working. Another is why the shop let you leave without working brakes. Another is what the shop did to actually diagnose the issue. A high hard pedal with low braking power is a sign of a booster problem. But the booster itself isn’t the only possible problem. Did they at least check to find out if vacuum is being supplied to booster? If the vacuum line is in good shape? The check valve? Here’s a good explanation of what the booster does: http://www.aa1car.com/library/pwrsteer.htm Every booster needs a good supply of vacuum, a reliable check valve to hold the vacuum in, and an unobstructed port for regular air to enter.

All of this stuff is pretty far from the wheel bearings. It is not, however, far from the master cylinder which would have been in play during the brake job.

Is the car running ok? Does it idle smoothly?

DO NOT GO BACK TO THIS SHOP. Take it to a good mechanic and have them undo the block in the vacuum line to the power brake booster. I think you are dealing with a shop that intentionally sabotages vehicles to get more money. At the very least, have someone else look at the vehicle for this type of damage.

The quick way to do this is to put a cork or plug in the vacuum line where the one way valve is located, on the booster side. This will allow the engine to run OK but keep the brake booster from working. Brake boosters typically last 20 to 30 years or more.

The booster and the front wheel bearings are not related in any way so it should not have been touched.

I’m with Keith. I also suspect that the problem may not be the booster.

First of all, while the booster makes braking considerably easier, a disabled booster does not render the brakes unusable. It just leaves them with a hard feel and requiring more pressure to apply. It is only an assist to your applied force.

Secondly, I cannot see any way whatsoever that one can affect the booster by replacing the bearings.

However, it is necessary to depress the caliper pistons and remove the calipers to replace the hub bearings. I’d bet lunch that the problem is in the calipers themselves. They could have somehow damaged them, they could have reinstalled them incorrectly, damaged the flexable lines, or done something such that the pistons are not able to function. It sounds like the pistons aren’t moving at all.

This car is dangerous to drive the way it is. Id recommend getting it towed to a different shop, tell them the story, and have them repair it properly.

the same mountainbike could be right, I did not think of possible caliper damage. One way or another, go to another shop.

Even if they somehow disabled the calipers, the rears would still work some, and the pedal should still move, albeit with greater difficulty.

It should never have been driven off their lot to start with, though. In efffect, they said “Take this deathtrap and go kill yourself or someone else, then come back.” in the hopes they’d never see you again. Sounds harsh, but that’s the only way I can interpret that. Any mechanic worth his salt would never knowingly put someone back in a car that had no brakes.

Point made about the rears, but if the calipers were somehow frozen on the front, the only way the pedal could be pushed down once the rears closed would be by compressing the hydraulic fluid…and that’s not going to happen. That’s what I’m thinking might be going on here.

I doubt that the OP would be able to tell you the difference between zero braking power and what it would actually feel like without vacuum assist. If you’ve never experienced a lack of power brakes before I think it would be easy to confuse “really hard to brake” with “zero brakes.”

Of course, that still doesn’t change the basic story - get it towed to a reputable shop for repair.

You might be right Cig. I’ve experienced the difference but just pressed harder. The OP may not have realized he/she could do that.

My money is still on the fronts having been somehow made inoperable. hopefully the OP will post back and let us know in the end. .