Brake fluid leak

tom4342 · Post by **tom4342** » 14 May 2017, 19:43

: brake.jpg (12.75 KiB) Viewed 2313 times

I noticed fluid leaking around the plug at the bottom of the fluid reservoir is there a gasket that can be replaced or am I looking at replacing the module?The plugin on top leaking around that pretty good

Post by **cn90** » 14 May 2017, 20:17

Search for the thread that someone wrote on Master Cylinder DIY recently.

Post by **abscate** » 15 May 2017, 04:50

Probably best to get that from a junkyard if you can find at the usual suspects...

Post by **theWIFES_S70** » 15 May 2017, 08:24

tom4342 wrote: ↑14 May 2017, 19:43 brake.jpgI noticed fluid leaking around the plug at the bottom of the fluid reservoir is there a gasket that can be replaced or am I looking at replacing the module?The plugin on top leaking around that pretty good

Hi, are you talking about the brake pressure sensor? If so, yes, there's an o-ring there. I don't believe that sensor is available new anymore. So you would have to get one from a junkyard if you want to replace it. I'm sure just the o-ring goes bad on that. Make sure you have a bunch of sizes on hand because you don't want your brake master cylinder to dry out because you took that switch off and drove around for hours (days...) looking for a suitable o-ring!

Robert Spinner has a video on taking that thing out https://www.youtube.com/watch?v=rhDAgSJmjAc

There are also o-rings around the base of the brake fluid reservoir.

What I'd do to try to isolate your drip is to really stick your finger with a napkin on it and try and touch where exactly you're leaking from. Touch different parts throughout and see what you find.

I don't know how to fix that cap... I don't think mine has ever been dry on the outside...

tom4342 · Post by **tom4342** » 15 May 2017, 16:03

https://www.myswedishparts.com/oem-part ... NS1nYXM%3D

tom4342 · Post by **tom4342** » 15 May 2017, 16:05

the switch is wet and dripping with fluid that sucks it's no longer available hopefully that's all it is the O ring.

Post by **theWIFES_S70** » 15 May 2017, 16:21

Make sure you aren't leaking from above. It's really hard to accurately pinpoint these leaks (hence using paper to see what's wet and what isn't). I have come to believe most of these leaks are probably master cylinder leaks... And man, is that a doozy... Good luck.

tom4342 · Post by **tom4342** » 15 May 2017, 16:24

At least I can get the master cylinder

tom4342 · Post by **tom4342** » 16 May 2017, 18:48

Definitely the switch leaking go figure I wonder if this is why the check engine light is staying on? I ran my scanner and showed no codes and the brake light is staying on even though I filled the reservoir.

Post by **theWIFES_S70** » 16 May 2017, 19:04

It's definitely connected to something so I would imagine it could trip a check engine light.

I might try to pick up some o-rings, take it out the sensor and clean the electrodes with electric parts cleaner and put on a new o-ring on it and hope it doesn't leak...

Seems like the used MCs on eBay come with the sensor. So maybe you want to go that route...
http://www.ebay.com/itm/99-00-98-volvo- ... IA&vxp=mtr

Make sure you find some o-rings that are compatible with brake fluid...
http://forums.mtbr.com/downhill-freerid ... 13710.html
The again, Harbor Freight says these nitrile o-rings are compatible with hydraulic fluid... https://www.harborfreight.com/225-piece ... 67677.html
You're looking for something you could roll onto something smaller than a pencil.

Good luck!