brake fluid resevoir cap
 

We lost the brake fluid resevoir cap to our 1986 RX7. I thought this would be easy to replace but turns out that is incorrect. The caps that I have purchased are screwed on type while the cap I need has three "ears". The caps I have found look like the cap for the clutch fluid resevoir and are a bit larger than 4cm while the cap I need should be a bit bigger than 3cm. Can somebody point me to a source that will have the correct part?

If you have a local pick & pull wrecker yard, look for just about any Mazda of late '80s/'90s vintage. Brake & clutch caps seem pretty common across Mazda's of that era. I needed a spare brake cap for my '89T2 to fabricate an adapter for my pressure bleeder kit that I pulled from a mid-90's Protege

If you don't want to hunt the wrecker yards, here's a Dorman part that looks like it's supposed to fit... (Google is your friend)

https://www.dormanproducts.com/p-702...Cap&origin=YMM

re: Pete_89T2
 

The cap you linked appears to be threaded to me as the caps I have found via google appear to be. I have purchase one Dorman part via the web that was threaded. I know that the car we have was in an accident soon after it was purchased. There was a lot of front end damage. I wonder if the resevoir was replaced with a part that was not OEM? Thanks for the reply

what does your cap look like
 

Perhaps a better question would be..... For those of you that own a 80's RX7 would you please look at your cap on the brake fluid reservoir and let me know if you have one that is not threaded. Am I the only one that has a non-threaded cap? Thanks

They are threaded on all first gens. Can you post a pic of your master and cap?

https://cimg6.ibsrv.net/gimg/www.rx7...eaf5fb13e2.jpg

Maybe you have this style which on found on RockAuto under 1986 RX-7
https://cimg1.ibsrv.net/gimg/www.rx7...f276abd06d.jpg

reservoir picture
 

https://cimg9.ibsrv.net/gimg/www.rx7...f42688d57e.jpg
This is what the reservoir looks like in our 1986 non turbo 2nd gen RX7. The caps I get when I order online are like the cap for the clutch fluid reservoir, threaded and larger than the brake fluid reservoir. My apologies for the blurry photo

My cap is threaded, like the Dorman caps. It's on an '89 T2 that was equipped with ABS, and as far as I know, the reservoir is original. As an FYI, when I did purchase a new master cylinder from Mazda, it didn't come with the reservoir & cap - I had to re-use those from my old master cylinder. So it's possible that if your MC was replaced at some point, they might have used an OEM replacement part that included the reservoir & cap with it, but with the different cap design.