thisismatt Posted January 30 Report Share Posted January 30 My question about residual valves was to make sure he even had one in the rear circuit, just in case his pads were pulling away too much and causing excess pedal, but it sounds like he has very little pedal if any, so I'd go back to something not bled fully, something leaking, or faulty master. Even with a much undersized master I would think it could be pumped up to hard with residual valves 1 Quote Link to comment
Crashtd420 Posted January 30 Report Share Posted January 30 They also sell inline residual valves.... Remove old from master cylinder and place the new one inline.... could go anywhere.... I did mine in the engine bay but could have easily placed in along the frame rail out of sight.... 1 Quote Link to comment
Stoffregen Motorsports Posted January 30 Report Share Posted January 30 2 psi valves are good for disc brakes 10 psi valves are for drums 2 Quote Link to comment
Biggs Posted January 31 Report Share Posted January 31 Willwood 2 psi inline residual valves are on order though I did see a video with a Willwood tech stating residual valves on disc brakes should only be needed if the m/c is located at a lower elevation than the calipers. I figure it’s better to be safe than sorry and I like experimenting, anyway. 2 Quote Link to comment
datzenmike Posted January 31 Report Share Posted January 31 If using the inline valve make sure the one in the master is removed. 1 Quote Link to comment
Stoffregen Motorsports Posted January 31 Report Share Posted January 31 2 hours ago, Biggs said: Willwood 2 psi inline residual valves are on order though I did see a video with a Willwood tech stating residual valves on disc brakes should only be needed if the m/c is located at a lower elevation than the calipers. I figure it’s better to be safe than sorry and I like experimenting, anyway. It's kind of trial and error. Technically, yes, the valve should only be needed if the master is floor mounted and lower than the calipers. But, some people like a quick response to their pedal action. The deciding factor is drag. If the brakes drag after installation, then it should be removed. 2 Quote Link to comment
mklotz70 Posted February 3 Report Share Posted February 3 If you put a dual reservoir m/c in, make sure the circuits match up correctly. Datsun changed the front and rear circuits back and forth for some reason, so if you connected the rear circuit to the front circuit of the m/c, you could end up with the issue you're having. The front/rear biasing is built into the m/c via the spring rates. Typically, the rear should get fluid first to help engage the brakes before the front to help the vehicle "squat". A lot of the Datsun m/c's have an F and R on the outputs to mark which is the front and rear circuit. Volume isn't much of an issue. I know guys that have run disc/drum and disc/disc on the stock, single reservoir m/c....which is a huge no no in my book. Here's the two I would recommend with my front disc setup.... http://www.bluehandsvideo.com/master-cylinder.html ...and if you haven't seen the inside of an m/c, this will help....despite the poor quality. http://www.bluehandsvideo.com/brake-master-cylinder-anatomy.html 2 1 Quote Link to comment
datzenmike Posted February 4 Report Share Posted February 4 Mike you are confirming my observations on Datsun dual circuit braking. There are no brake bias valving in the rear line and it's all in the design of the master and possibly the size of the rear wheel cylinders. This may be why the fronts are at the rear of the master and are the first to move mechanically. 2 Quote Link to comment
Stoffregen Motorsports Posted February 4 Report Share Posted February 4 Yes, good point. I have seen guys get the front and rear connections backwards. 1 Quote Link to comment
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