SPF brake firmness

[Mike Christian]

Those caps have the hole in the top. If the inner rubber gaskets are not solid across the inside of the cap, the hole allows fluid to spurt out hence creating issue. These caps were used on many British cars and hence the source of many issues. New caps with solid rubber seals inside would solve this problem. I do not believe the caps are bottoming out on the panel.

Not sure I completely understand "if the inner rubber gaskets are not solid across the inside of the cap". Please elucidate!

No evidence of spurting on top of the caps. Washer inside does not appear fully seated on one.

New caps and washers have been ordered. I will adapt one to use the pressure bleeder...if possible.

Leaving the area for a while though, so this will be a June project.

 

[Mike Christian]

Re: Cap installed above panel - That’s clearly an uncharacteristic misstep on the part of Superformance..

Luckily that panel is removable/replaceable. I have contemplated removing it and opening up the hole for better cap clearance. Or finding a thicker gasket to seat the cap a bit higher.

 

[Lee Patterson]

I saw some caps advertised with a full rubber inner-rubber seal with no hole. Can't find now. sorry

 

[Blas]

Pegasus has both caps and gaskets.
Hole is necessary for pressure equalization.
I'll guess your original gasket deformed hence symmetrical damage all around cap.
How is the reservoir mounted on the early cars. Perhaps a few photos if possible? I'll document this in the SUPERFORMANCE GT40 Owners Manual or perhaps the Addendum Document. You get your name on the document
Blas

 

[Lee Patterson]

Here's the seal you need from Moss Motors. Click on the PDF they have which expands on the issue and how their seal works.

SEAL, filler cap

SEAL, filler cap

mossmotors.com

OBTW, the Wilwood reservoirs do not have a hole in the cap. They must vent inside the cap within the rubber seal.

Wilwood Disc Brakes

MasterCylinder No: 260-12696, master cylinders, aluminum tandem, combination remote, compact master cylinder, go-kart master cylinder, handle-bar master cylinder, rebuild kits, high volume, hvm master cylinder, tandem, bleeding kits

www.wilwood.com

 

[Mike Christian]

Dang, I had already ordered the caps from Moss...wonder if I can add these gaskets before shipping.

The answer is "no, too late". Looks like another order from Moss as this newer seal looks like it will help solving the issue. Thanks Lee.

Blas, if I end up taking the cover off, then I will take and post photos. There is a good chance once I get into it.

 

[Blas]

Thanks, you will be immortalized in the SPF GT40 Owners Manual for generations to come.
Blas

 

[Mark H.]

I moved the reserviors from the front A/C cover to the cowl. Made doors in the front clam for access. Was a bit nervous cutting without having to repaint. Raised the reservoirs some and used thin orings to the seal reservior can to cowl sheet metal plate.