[Roadsters] Rx7 rear end issues ...edited

[Joseph Berkenbile]

Also check the rubber brake hose going to the wheel. Take the hose off and
blow through it both ways. I had a hose that delaminated inside,
effectively turning it into a one way valve.

On Tue, Sep 23, 2025, 7:26 AM Tim . via Datsun-roadsters <
datsun-roadsters at autox.team.net> wrote:

> If this was actually too much pressure in the line not being released,
> wouldn't one expect both rear brakes to be affected?
>
> In my case, only the RR is rubbing. Also, I ran the caliper piston all the
> way back in and have not touched the brake pedal at all.
>
> tim
> ------------------------------
> *From:* futofab <futofab at gsinet.net>
> *Sent:* Wednesday, September 17, 2025 7:04 AM
> *To:* Tim . <tims_datsun_stuff at outlook.com>; Datsun Roadster List <
> datsun-roadsters at autox.team.net>
> *Subject:* Re: [Roadsters] Rx7 rear end issues ...edited
>
> Check your master cylinder. The large nut on the underside of the duplex
> brake master, where the brake line attaches, houses a pressure releif
> valve.
>
> If you have a pressure relief valve for the drum rear brakes, they will
> maintain about 10psi line pressure when the brakes are released. This may
> be causing the pads to stay in contact with the rotor.
>
> This is something the 510 owners deal with when converting to rear disc
> brakes. Typically they remove it or swap in one from the front disc brake
> circuit which is 2psi.
>
> On 510 disc brake swaps, the brake master from a 79-80? 280ZX is typically
> used as it is for 4 wheel disc brakes.
>
> Dave Patten
> Futofab LLC
>
>
>
> Sent from my U.S.Cellular© Smartphone
>
>
> -------- Original message --------
> From: "Tim . via Datsun-roadsters" <datsun-roadsters at autox.team.net>
> Date: 9/16/25 6:55 PM (GMT-05:00)
> To: Datsun Roadster List <datsun-roadsters at autox.team.net>, "Tim ." <
> tims_datsun_stuff at outlook.com>
> Subject: Re: [Roadsters] Rx7 rear end issues ...edited
>
>
> I believe I have the rear end from an 82-83 Rx7 with disc brakes and LSD.
>
> I re-built my drive shaft and got rid of the noise I heard with no wheels
> or brakes mounted (and the car running in gear). Third member bearings and
> axle bearings spin nice and smooth. I've been told that the axle bearings
> were replaced by the person who customized this rear end for the Roadster.
>
> With the car on jack stands, I re-assembled the brakes, hung the wheels
> and ran the car (still on jack stands). I immediately heard a rubbing noise
> coming from the RR. The noise went away at higher RPMs but there was still
> something rubbing that caused the rotor to get so hot I could smell it.
>
> Pulled the wheel back off. Brake pads have a little play as does the part
> of the assembly that holds the piston. Nothing appears to be binding and
> nothing is sloppy loose.
>
> Parking brake assembly is (basically hanging) loose and does not appear to
> be applying pressure to the pads.
>
> WTF am I missing?
>
> Thanks
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