Brake Master Cap cross reference

[m_w]

Is there a generic replacement available for the brake master Cylinder cap?
So far I've only found this: https://www.pegasusautoracing.com/productdetails.asp?RecID=1104

I'm concerned my original will probably leak.

[Mark D]

I don't think anyone has ever sourced an exact replacement that includes the built in low level switch but generic caps are readily available. I bought this one as part of the brake pressure bleeder I built... I originally got it for my 3 series BMW but it also fits the DeLorean brake reservoir.

http://www.ecstuning.com/ES61052/

http://dmctalk.org/attachment.php?attachmentid=32003&d=1418052385

There are also those generic "HELP!" brand caps available at Auto Zone. I had one of those at one point but they're not quite as well made. I tried searching for the PN but I didn't have any luck.

[PJ Grady Inc.]

Is there a generic replacement available for the brake master Cylinder cap?
So far I've only found this: https://www.pegasusautoracing.com/productdetails.asp?RecID=1104

I'm concerned my original will probably leak.

None that I'm aware of but I have some NOS BMC caps and also the fluid reseviours in stock.
Rob Grady

[m_w]

I don't think anyone has ever sourced an exact replacement that includes the built in low level switch but generic caps are readily available. I bought this one as part of the brake pressure bleeder I built... I originally got it for my 3 series BMW but it also fits the DeLorean brake reservoir.

http://www.ecstuning.com/ES61052/

http://dmctalk.org/attachment.php?attachmentid=32003&d=1418052385

There are also those generic "HELP!" brand caps available at Auto Zone. I had one of those at one point but they're not quite as well made. I tried searching for the PN but I didn't have any luck.


That would be perfect. I don't care if the low level switch works, so that cap you list would be nice. I checked at advanced and napa, and they didn't have anything for me. Do you know what model bmw that is from?

[Chris4099]

If you need a specific make/model/year, you can also check for a 2005 MINI Cooper S (uses a lot of BMW parts). I have this car and I use the same pressure bleeder as my D. I never actually tried to put it's cap on the D, but in theory it should work.

[David T]

That would be perfect. I don't care if the low level switch works, so that cap you list would be nice. I checked at advanced and napa, and they didn't have anything for me. Do you know what model bmw that is from?


Actually that low level switch is very important. It will be your only warning if you have a leak before you lose all of your service brakes. There is no proportioning valve which would seal off the leaky system and keep at least 2 wheel's brakes working. All you would have left is the emergency brake and you do not want to have to use it, it is not all that effective. Try to get another level switch and cap assembly. BTW, the center of that cap has a round rubber section. It is a test button to prove the wiring and bulb. To test the level you would remove the switch/cap assembly and turn on the ignition. The light should light up. The brake waring light also lights (or at least is supposed to) when you use the emergency (aka parking) brake.

[m_w]

If you need a specific make/model/year, you can also check for a 2005 MINI Cooper S (uses a lot of BMW parts). I have this car and I use the same pressure bleeder as my D. I never actually tried to put it's cap on the D, but in theory it should work.

I'll reference that and the above part - Thanks for the help!

[Mark D]

That would be perfect. I don't care if the low level switch works, so that cap you list would be nice. I checked at advanced and napa, and they didn't have anything for me. Do you know what model bmw that is from?

If you click on the ECS tuning link from my previous post you can buy it direct from the website for around $9. Otherwise if you want to try and find one at a local store it cross references to E46 (3 series) generation BMW 323, 325, 328, or 330 from 1998-2001 but will physically fit many models after that. They switched to a cap with integrated sensor in 2002.

I have a 2004 325i and it fits perfectly.

[m_w]

As a follow-up:
I purchased the brake master cap from that ECS Tuning site. It fits perfectly, appears to be good quality (has a good seal in it), and looks like it belongs.

I did this to eliminate a cap that probably (almost certainly) leaked, and doing that removed a system that I feel isn't important. Perhaps one day, the perfectionist in me will get that fluid sensor back in working order.

Thanks for the tips and the links :)

[Mark D]

Awesome, glad to hear it worked out for you! :thumbup: