Brake Reservoir Cap for Motive Power Bleeder

[thehackmechanic]

Has anyone identified a source for a brake reservoir cap that can be used with a Motive power bleeder?  I've read all three forums and learned that the Motive "1110 Classic British Adapter" doesn't fit, and all I can find is a single reference from someone who said he modified the original cap. I can't even find a part number for the cap so I can order one and modify it. Does anyone have a solution to this? Using the Motive on my other cars has spoiled me.

Thanks.

--Rob

[Grumblebuns]

When I built my home made brake power bleeder I needed a spare plastic reservoir cap not wanting to drill a hole in the original Girling cap. I found that Pegasus sold a cap for Girling master cylinders so I ordered one. When I tried to screw on the new cap I found out that it would screw on about half way and then start to bind. It appears that the new Girling master cylinders have slightly different reservoir thread designs from the "classic" period. If you add additional rubber gaskets under the cap, it may seal sufficiently to maintain pressure. This is the cap I used.

https://www.pegasusautoracing.com/productdetails.asp?RecID=1104

[BDA]

Been there and done that! They spent a couple of weeks trying to find the right cap and we finally decided they didn't have it. I happened to have an old M/C cap and made my own. I think you'll be able to find just the caps. This looks like the right one but you'll have to measure the diameter and thread pitch and get with the seller to make sure (https://www.ebay.com/itm/Master-Cylinder-Cap-for-Girling-Cylinders-with-Small-Reservoir-Clutch-or-Brake/251784695568?hash=item3a9f898f10:g:PxYAAOSw1ZBUrXkK&vxp=mtr).

If I remember, I used the hose that came with one of the caps they sent me that didn't fit - I think they just gave me the last one I tried. The end is 1/4 NPT. I think all I did was drill a hole that was slightly smaller than the inside of the threads, put some silicone seal on the threads and screwed it on. I'm confident you'll figure it out. Here are some pictures.

[Grumblebuns]

Looking at the adapters that Motive offers for their products, found an adapter for "classic British cars". Again with the possible change in thread design, it's a pretty expensive gamble betting that it will fit the old Girling brake reservoirs.

https://www.motiveproducts.com/collections/adapters/products/1124-girling-2-5-id-adapter

In order to use a power bleeder for the Lotus, I would try to find a spare cap from a Spitfire master cylinder and use that. I'll call British Masters tomorrow and see if they a collection of spare master cylinder caps.

[BDA]

The M/C cap for my car is not as big as the one there. After working with the Motive folks and doing some searches, it seems there are a lot of different "standard" Girling M/C caps!

[surfguitar58]

Sounds like a job for a 3D printer to me.
t

[Grumblebuns]

I called British Masters this morning pricing out Spitfire master cylinder reservoir caps, they were asking $10/cap, plus $7.00 shipping; I passed. I did ask about pricing on Spitfire steering racks. Their price is $65 plus shipping. That sounds a bit more reasonable.

I dug up an old Spitfire master cylinder I remembered I had for the Spitfire M/C conversion article and found that the cap will thread on to the Europa M/Cs with no problem. For those needing a sacrificial cap for a power bleeder a Spitfire M/C small cap will work. The original OEM Girling Spitfire M/C is interchangeable with the Europa M/C. The later aftermarket Spitfire M/Cs will also work but the threads seem to a bit on the loose side but will tighten down without slipping.