929 Master cylinder upgrade?

[Stingray77]

Has anyone tried this on their car I know this is for an RX7 but would we see a diffrence? Perhaps the guys with the big brake upgrades might benifit from this?

http://robrobinette.com/mastercylinder929.htm

[Stingray77]

???

[Rafi]

Hey,

The thread you are reading is specific to RX7's. On the PGT, if you properly size the calipers there are no brake pedal travel issues.

-Rafi

[N/A Matt]

Todd posted a thread about this awhile ago, oddly enough I stumbled upon this thread because I was looking for his thread. I will ask Damon if he can salvage the info from the post for us.

[FuLcRuM]

When you upgrade to larger brake calipers your brake pedal movement may increase because more brake fluid has to be moved to power the bigger (or more) pistons. Upgrading to the Mazda 929's master cylinder (MC) can bring the pedal movement and feel back to stock (or better than stock). Our stock master cylinder is 15/16" in diameter, the 929's is 1" in diameter and about 1/4" longer. That 1/16 of an inch larger piston pushes quite a bit more fluid.

The only difficult part of this mod is moving the two feed lines to the oppisite side of the master cylinder.

What You Need:

A 93-95 Mazda 929 master cylinder part # HG31-43-400G (ABS version) - I got mine from Autozone for $95 + $55 core charge. They will take your MC as a core.
You also need a banjo to female flare adapter and metric bolt. The 929 MC comes with a banjo connection on the front outlet.
Loosen the two MC feed lines coming from the ABS unit and rotate them 180 degrees. Carefully bend the two line to line up with the 929 MC outlets. Connect the brake lines and torque the connectors to 113 to 190 inch pounds (10 to 15 foot pounds). Bleed the brake system.

http://www.supermotors.org/getfile/2..._upgrade_1.jpg
http://www.supermotors.org/getfile/2..._upgrade_2.jpg
http://www.supermotors.org/getfile/2..._upgrade_3.jpg


Added info from Gavin:

FYI there are two archetectures for 2nd gen 15/16" master cylinder. only one of these is compatable with the 929 MC (unless you remove both the stock MC and the brake booster and related materials)
http://www.supermotors.org/getfile/2..._upgrade_4.jpg
http://www.supermotors.org/getfile/2..._upgrade_5.jpg
http://www.supermotors.org/getfile/2..._upgrade_6.jpg

[drumer919]

So if you dont have ABS do you not need the ABS version?

[FuLcRuM]

I just copied the post from another forum.

I did just do this MOD myself this weekend though. I tried bleeding the brakes tonight and have had some problems. The pedal hits the floor so I'm gonna try and rebleed the system again tomorrow then maybe have some personal input as to the differance.

[FuLcRuM]

Ok, I have the 929 MC installed and working now. I had to rebleed the system properly to get all the air out.

I don't think you want an ABS MC from a 929 if your car was not equiped with ABS. I am not positive the non-ABS version will work but I would think so.

I've only had 2 days of driving and no serious braking but the pedal does seem to be a bit shorter and require less effort. It is not signifigantly changed but noticable.

I would suspect that if you have upgraded all 4 calipers then you would see more of a differance.