buzzing under hood

[roverman]

'99 rover 4.0
There is an electric motor pressure pump type unit connected to the brake fluid reservoir. It runs and hums (quite loud, can hear it inside the car) about 50-60% of the time. Often it will stop running after being stopped and taking my foot of the brake. Is this normal? If not, does it sound like a bad motor or a problem somewhere else in the system?

Thanks in Advance.

 

[joey]

Sounds like an ABS motor or modulator. Not sure it is an issue or not, but my be a good idea to flush the brake system.

 

[roverman]

thanks joey, it looks to me like some sort of pressure building unit. the motor is a cylinder about 6-7 inches long and there is a spherical dome like unit attached that looks like it's there to build pressure. Now I know NOTHING about brakes, someone once told me that it was an interesting system because it didn't use vacuum pressure like most cars, but was more like what they had in big trucks. Does that sound right or ring any bells?

 

[joey]

Wish I had more experience with the RR.... or at least had my newer repair manual... On its way, but still waiting.


I am thinking this is the ABS pump/motor....

 

[roverman]

Ok, thanks much Joey, I'll check into it more.

 

[healey1006]

You may find some useful info here:

http://www.rangerovers.net/repairdetails/abs.html