Datsun Roadster Forum-311s.org

Hello Swappers,

I was out test driving. I started leaning on the throttle pretty good, and pretty often so I'm sure the turbo got nice and toasty. Then, gradually all 4 brakes started getting tight. By the time I got back home, I had all 4 calipers smoking hot. I checked the MC temp and it was hot but not crazy bad (I could just barely keep my hand on it so it was probably 190 deg or so. I opened the 2 bleed ports on the MC and it puked out some fluid and everything freed up. So now a few questions:

Is the brake hydraulics be check valved such that it can't handle expansion of the brake fluid in the lines?

Anybody else have this happen to them?

Anybody successfully running a SR20DET top mount without a MC heat shield?

Thanks
Steve

The building of pressure is most likely from the MC piston not returning to its "Rest" position.....the return holes open.

Usually that is because the pedal doesn't have the "play" necessary......might be because the heat cause more drag than normal.

I would install a heat shield either way.

I installed a turbo blanket and wrap for the down pipe, and am making an aluminum shield for the brake master.
Have not wrapped the pipe yet or installed the shield, but the blanket made a big difference.

Thanks guys,

So, if I understand the hydraulics, The MC spool is spring return, and when it returns to the home position, it should open up ports back to the MC reservoir so that there is no way fluid pressure can build up.

If that's the case then my MC spool was stuck in some. But my pedal was hard as a rock and there was almost no freeplay which doesn't make sense to me. I would have thought I would have freeplay.

Also,
I will be ceramic coating my downpipe and turbo once I disassemble everything for final paint. I know Michael S has photos of a SS MC heat shield he did on one of his turbo swaps as well.


Regards,
Steve

I agree with Phil that it sounds like your brake master cylinder is not fully releasing-- that being said, if you have a top mount turbo, I would highly recommend adding a heat shield to cut down on the reflective heat next to the master cylinder.

Michael

Thanks Michael,

Ever see a roadster with tastfully done hood louvers over the turbo?

My project is still plodding along. The car runs great. Probably will swap MC down from 7/8 bore to 3/4 bore to get a little more brake response. Almost everything is bolted on the exterior now. Getting some latches and stuff re plated. Then it's on to the interior. I have miata seats and I'm thinking of having seats, door panels, package tray etc done in leather with some white stitching accents to match the stering wheel. Maybe a bit over the top.

Regards,
Steve

Accents arent over the top. Garth and Garm have applied stitch accents to their upholstery and IMO look great.