2007 XC90. Strange interior noise after brake job

RiverMck · Post by **RiverMck** » 16 Apr 2014, 19:55

So I replaced the front pads and rotors on my wife's XC90 last night. Didn't have time to wrap it up, last night so I put the wheels back on tonight after work. I started it up in the garage and pumped the brakes to re-establish brake pedal pressure. No problems there, after four or five pumps the pedal firmed up nicely, but I then started to hear a strange noise coming from under the dashboard.

The only way I can describe it is a flapping noise, and it sounds like its coming from behind/underneath the glove box. Every time I release the brake pedal the flapping noise happens. I have not road tested it yet to set in the new pads to the rotors and I kinda don't want to drive it until I know what this noise is. Has anyone else experience this issue as well or have any suggestions?

Thanks for your help in advance....

Post by **jimmy57** » 16 Apr 2014, 21:21

Listen around the vacuum pump on the back end of the exhaust cam.

RiverMck · Post by **RiverMck** » 17 Apr 2014, 06:10

Thanks for the reply Jimmy. I'm still learning the ins-and-outs of the Volvo mechanical world. Prior to this vehicle, we owned two jeep grand cherokees which I did a lot of work on personally. Volvo is on a completely different level than Chrysler when it comes to mechanical technologies. Could you please direct me to where the exhaust cam is located in the engine compartment?

Also, let me add another point of information that might help in the diagnosis of my problem. When I pressed in the passenger side caliper piston, I did not have the cap to the brake fluid reservoir open for fear that fluid would spill out onto the engine compartment. There was not any abnormal resistence when I pressed in the passenger side caliper piston. I did however open it when I pressed in the driver side caliper piston. Could this have caused an issue such as a blown seal, check valve, vacuum line, etc.?

Thanks again

RiverMck · Post by **RiverMck** » 17 Apr 2014, 06:16

This link demonstrates the noise I'm hearing when pressing and releasing the brake pedal while the car is running and in Park. Unfortunately, there were no comments posted for this video, but at least you can hear the "flapping" or "popping" noise I'm experiencing...

Post by **jimmy57** » 17 Apr 2014, 08:33

The noise in the video is the shiftlock solenoid. If you have vehicle in P then every brake pedal depress and release causes that solenoid that blocks you from getting it out of Park to operate.
If your noise is that noise and doesn't occur in D then you have no problem.
Opening bleeder screw or pushing caliper pistons back in calipers has no effect on vacuum check valves or anything on brake booster.

IF you open bleeder screws when you push caliper pistons back into their bores you will need to bleed brakes on any caliper you do that to. Air easily enters through open bleeder screw when you do that.

RiverMck · Post by **RiverMck** » 17 Apr 2014, 09:02

Okay, thanks for the heads up Jimmy. I'll check to see if it makes the noise in Drive as well. It's my wife's vehicle, but I've driven it enough to know that I've never heard that noise before. Although, now that I think about it, prior to doing this brake job I've never just sat in her car and pumped the brakes while it was running in Park either...

As for the caliper bleeder valve, I did not open those up, only the brake fluid reservoir in the engine compartment. I read several brake job posts on MVS that mentioned the need to bleed the brake system if those valves were open, which is why I didn't touch them. Someone did mention that pushing the caliper in with the valves closed and the reservoir cap closed could damaged the master cylinder. That was my concern in my intitial post about that.

Hopefully the noise is just the shiftlock solenoid, me hearing it for the first time, and not something I damaged while doing the brake job. My wife would not be pleased. I'll follow up when I get home from work.

Thanks again!

RiverMck · Post by **RiverMck** » 18 Apr 2014, 06:12

Update: Drove the car yesterday after work and the noise was not replicated when in D and pumping the brakes. Good news! Thanks Jimmy57 for your insight. I've learned a great deal about the shift interlock solenoid after searching this forum . I've been lurking on this sight for a while and think it's by far the best Volvo forum out there!

Thanks again

Post by **abscate** » 18 Apr 2014, 15:52

RiverMck wrote:Okay, thanks for the heads up Jimmy. I'll check to see if it makes the noise in Drive as well. It's my wife's vehicle, but I've driven it enough to know that I've never heard that noise before. Although, now that I think about it, prior to doing this brake job I've never just sat in her car and pumped the brakes while it was running in Park either...

As for the caliper bleeder valve, I did not open those up, only the brake fluid reservoir in the engine compartment. I read several brake job posts on MVS that mentioned the need to bleed the brake system if those valves were open, which is why I didn't touch them. Someone did mention that pushing the caliper in with the valves closed and the reservoir cap closed could damaged the master cylinder. That was my concern in my intitial post about that.

Hopefully the noise is just the shiftlock solenoid, me hearing it for the first time, and not something I damaged while doing the brake job. My wife would not be pleased. I'll follow up when I get home from work.

Thanks again!

I would not worry about damaging anything by pushing in the pistons. Whenever I do brake work, though, I push new brake fluid through the system. This stops corrosion and rust in the calipers and master cylinder. I have, in my younger days, cracked the bleeder and pushed the piston back in and not bled the system afterwards. My lawyer advises me to state YMMV.