Wilwood master cylinder help

[cbolt]

Just installed a Wilwood system and having trouble keeping the master from leaking. The dual reservoir master has a fluid transfer hole between the front and rear reservoir and due to the angle of the master connected to the brake booster the fluid leaks from the rear of the master cover as gravity forces the fluid to level itself between the reservoirs. The solution seems to be either plugging the fluid transfer hole or installing an adaptor that makes the Wilwood master sit level, thus eliminating the problem. 

Has anyone run into this issue before and if so, what did you do to fix it? I'm leaning towards the adaptor route, but that is a bit more expensive than using JB weld and plugging the hole, which is certainly not out of the question at this point. 

If someone used an adaptor, can you point me in the right direction? All the adaptors I have found so far are used to marry a GM booster to a Chrysler master cylinder. 

There is sketchy info on the internet about this, but enough chatter to know I am not the first one to experience this problem with the Wilwood dual reservoir master cylinder. 

[Dtret]

I think Joe plugged his. He wrote about it in a post somewhere but it was just in a general conversation In a brake topic. 

[Marks71]

It seems to me that having a hole between the 2 reservoirs defeats the purpose of having 2 reservoirs. How close to the top of the divider is the hole? Even if you could prevent the cover from leaking, every time you check the levels you’re going to have a splash of fluid when you remove it. I think I’d plug it. What does Wilwood say?

[cbolt]

Wilwood says either plug it or buy the master with the separate reservoirs. Naturally, the first recommendation from Wilwood is buy the other one lol

[Scott S.]

I believe the related discussion concluded that the plug (or J.B. weld) could blow out during braking pressure.

If I remember right, it was suggested that a small nut & bolt through the hole with plastic/rubber washers would solve the problem.

But I'm just going from memory here............. 

[jft69z]

I put a small brass machine screw and nut in the hole, also used a small 'captured O-ring' washer to seal it up. No issues at all. (no pics either, apparently)

[Scott S.]

Not enough room in your phone's memory....... Too many photos of the kids and all.  

[cbolt]

50 minutes ago, Scott S. said:

I believe the related discussion concluded that the plug (or J.B. weld) could blow out during braking pressure.

If I remember right, it was suggested that a small nut & bolt through the hole with plastic/rubber washers would solve the problem.

But I'm just going from memory here............. 

problem with rubber/plastic washers is they won't hold up to brake fluid. I considered that too. 

[cbolt]

44 minutes ago, jft69z said:

I put a small brass machine screw and nut in the hole, also used a small 'captured O-ring' washer to seal it up. No issues at all. (no pics either, apparently)

That may be the route I take as well, sans washer. I could make a small washer from a master cylinder gasket. That material should hold up to the brake fluid without issues. Joe, you don't happen to recall the size of the machine screw you used off the top of your head, do you? 

[jft69z]

16 hours ago, cbolt said:

 Joe, you don't happen to recall the size of the machine screw you used off the top of your head, do you? 

Not sure Jim, something small enough to fit with the existing hole. Maybe an 8-32 or something similar.

I just trimmed it to length with the screw cutters on a set of wire strippers.

[BobW]

FYI, Google search: For automotive brake systems, Ethylene Propylene Diene Monomer (EPDM) O-rings are the most commonly recommended and compatible material for use with glycol-based brake fluids (DOT 3, DOT 4, and DOT 5.1). EPDM O-rings are also known for their resistance to sunlight and weathering. While other materials like Viton (FKM) are also used in brake systems, EPDM is generally preferred for its compatibility with the common glycol-based fluids.