Brake booster motor groan

[mhuppertz]

I pulled a Teves brake setup out of the boneyard and replaced the part that had the ball and electronics. Now when I tap the brakes the motor groans. 

I din't bleed the brakes after, could this just be air in the lines? Sounds a little like when a power steering pump is low on fluid.

Thanks,

Mark

[Barney Eaton]

It could be a lot of things.....I would do some brake flushing.   You do not know the overall condition of the unit you installed and may just be crying (groaning) for some fresh fluid.

Another thought........when I tap the brakes the motor groans.... the pump motor should NOT come on everytime you tap the brakes.   The accumulator should have enough reserve to allow one or two pumps before the pump turns on.

I suspect you need a new or better accumulator.

[mhuppertz]

It didn't groan with the original unit, but I changed it to try to get a better accumulator and pressure switch. Guess I got a worse one than I had!

[2seater]

22 minutes ago, mhuppertz said:

It didn't groan with the original unit, but I changed it to try to get a better accumulator and pressure switch. Guess I got a worse one than I had!

Did you have symptoms of poor brake performance before this change?? Any salvage yard part will require testing to determine the quality level, so that is an unknown at this point.

 

From the many pumps, switches and accumulators Daves89 and I have tested, the switches rarely fail unless they leak into the electrical connection, the pumps are generally pretty robust as well as long as they get clean fluid. The one item that is the most common failure point is the accumulator, which if left in a defective state, will shorten the life of the pump and possibly the switch due to constant cycling. 

Edited March 4, 2019 by 2seater (see edit history)

[DAVES89]

When I swapped out the pump/motor on the Red last fall due to motor failure, I did it too quickly and missed getting the rubber insulator set right. The pump made a noise every time it came on [which as Barney says is correct] about every second or third brake pedal push. I thought too that I had air in the system, but that was not the case. It wasn't mounted correctly. It was surprising to me just how often the motor runs. The pump/motors are really well built.

 Nothing wrong with having an extra pump/motor. I have 5 right now in inventory.  

[mhuppertz]

Found the issue. The rubber bushing was missing from the firewall mount, so the metal cup was contacting the pin and transmitting the motor vibration into the cabin. I put a spare bushing in and it is super quiet now.

[Barney Eaton]

Just because it is working.........don't forget to flush the brakes.

Old, moisture containing fluid will corrode parts and that corrosion will damage things like the pump motor, seals, ABS solenoids.  

Depending on where you live (high or low humidity) all vehicles with ABA brakes should be flushed and fresh fluid added every 2 to 5 years.

2% moisture lowers the boiling point of brake fluid 100 deg F which is also important if you live in hilly or mountainous country..... you can boil the brake fluid and it will feel like brake fade.

In most areas,  fresh fluid can contain 2% moisture in about 18 months.