View Full Version : TR4/4A Brake Master Cylinder Cap Options

07-13-2013, 02:20 PM
I'm getting kind of tired of the cheap stamped tin master cylinder caps. Does anyone know of a plastic option which fit our brake master cylinder? I believe the diameter is 2.5" or 2.45"

Much appreciated


07-13-2013, 04:10 PM
You can get an original Girling cap from Pegasus Auto Racing. But it's the original metal embossed cap, not plastic, not cheap, not inexpensive either. Also, someone does a billet cap which covers the original plastic TR6 cap. Maybe you can check that our for fit. Not sure who sells it.

07-13-2013, 06:50 PM
I am one of these guys that does not throw much of anything away unless it is totally bad and destroyed. What I had to do to get a good fitting cap on the brake master cylinder was to go back to my junk stock and retrieve an old metal cap. I complained to TRF about the caps coming with the new master cylinders because I found that the cap would not snug down, would leak from under the cap and if you would just pull up on the cap after getting it down as snug as it looked like it was going it would pull right up and off. The old metal cap was the only thing that I found would seal and stay on. A non-sealing cap allows brake fluid to splash out during autocrossing--NOT NICE!!!!! Or at least the way that I drive it splashed out.

You might put out an inquiry for anybody who has an extra old metal cap if you want to go that route.


Geo Hahn
07-13-2013, 07:28 PM
...You might put out an inquiry for anybody who has an extra old metal cap if you want to go that route...

I agree - for looks as well as the functionality, the original caps are what appeal to me.


07-14-2013, 08:28 AM
I replaced my caps with these plastic ones, also from Pegasus. https://www.pegasusautoracing.com/productdetails.asp?RecID=1104

07-20-2013, 09:18 AM
Too bad Pegasus doesn't have a 2.5" dia cap to fit the brake master
My search continues.


07-20-2013, 06:37 PM
They did. I got one last year or so. You could always call them and ask since it is listed in their catalog.

12-28-2016, 12:20 PM
OK, for those who even care, I strive to close open threads like this with some kind of resolution. So...three years later I finally purchased the plastic brake master cylinder cap from Pegasus Racing. It is a 2.5" plastic cap, Part No. 3573, and pleased to confirm it fits perfectly.

My whole reason for moving from the cheap metal to plastic (albeit not original) is b/c the metal caps would tend to rust really badly on the threads making a mess of the master cylinder -and occasionally making it hard to remove the cap. And I religiously bleed the brake and clutch fluid every 2 years.


12-30-2016, 09:04 PM
Thanks for the info.
I have been looking for an answer to the cheesy metal master cylinder cap problem.
Just placed an order for plastic brake and the clutch master cylinder caps.


01-01-2017, 12:06 PM
Bob - Thanks for the update on the plastic replacement caps. The metal replacement caps from Pegasus are aluminum and won't rust for anyone else interested.

Geo Hahn
01-01-2017, 03:02 PM
Deleted post (was the same photo and comment I made 4 years ago - at least I'm consistent).

01-04-2017, 06:00 PM
Received my plastic master cylinder caps yesterday and they fit perfectly.