DruDown720 Posted April 21, 2014 Report Share Posted April 21, 2014 So I have done a full disk upgrade to my 720 with dual piston front calipers to rear disk on my 620 axle off a pathfinder. Now what Proportioning block should I use the 720 or the one for the pathfinder? Quote Link to comment
DruDown720 Posted April 21, 2014 Author Report Share Posted April 21, 2014 Yep which Quote Link to comment
datzenmike Posted April 21, 2014 Report Share Posted April 21, 2014 I don't believe the Nissans use a proportioning valve. Instead the calipers are sized to the master cylinder. There's no way of knowing how a 720 master with D21 front and Pathfinder rears calipers will react. For one, the 720 had rear drum brakes and will have a drum brake residual valve in it. Brakes should all lock up at about the same time under hard stopping. Fronts have the most weight and weight transfer, so the most traction and can contribute maybe 80% of all the braking. If the fronts lock up first then the back ones aren't doing their share. If the rears lock first, this is extremely bad when hard braking on a corner as the back end will come around. Trust me, locking up the rears coming up to a stop light is very embarrassing too. If the rears lock too soon, an adjustable proportioning valve from Wilwood can be placed in line and dialed in. I did this on my 620 with 4 pot Toyota front calipers and 16" of lift. I dialed out about 60% of the brake pressure to the rears and they more or less locked up together now. I can brake fully with more confidence. It was about $50. Quote Link to comment
DruDown720 Posted April 21, 2014 Author Report Share Posted April 21, 2014 It has one on it I have the whole system out of the truck right now the only thing is the master cylinder is out of a 620 is that decent stoping power with a higher horse powered motor Quote Link to comment
datzenmike Posted April 21, 2014 Report Share Posted April 21, 2014 You should have a larger master (at least a 720) as the larger calipers will meed more fluid volume. The 620 master will have to travel further to move more fluid and will seem mushy. Quote Link to comment
DruDown720 Posted April 21, 2014 Author Report Share Posted April 21, 2014 With the 720 master I run in to my tire hitting it when the truck is laid out all the way, that's why I use the 620 master smaller size had not had a stoping issue with it before. Quote Link to comment
DruDown720 Posted April 21, 2014 Author Report Share Posted April 21, 2014 The only thing that I have really not messed with is the manifold that all my brake lines go to Quote Link to comment
ggzilla Posted April 21, 2014 Report Share Posted April 21, 2014 Some later Datsuns used a proportioning valve, called the NP Valve. Trucks used a load-sensing proportioning valve. Use the 720's Valve. There were seven different ones used by 720 depending on 2wd/4wd, load rating , and year. Quote Link to comment
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