sdsurf Posted February 2, 2008 Report Share Posted February 2, 2008 WHat dual master cylinder is a direct bolt up on a 521? I havn't seen a thread on this Quote Link to comment
pl521sss Posted February 2, 2008 Report Share Posted February 2, 2008 Yeah, me too Can anyone share their conversion to dual circuit on a 521. Getting ready to install front disc to go with it. Almost read to go. Quote Link to comment
Pacific coast Datsun Posted February 2, 2008 Report Share Posted February 2, 2008 The 620 unit MAY work but dont quote me. PM Mklotz i believe he's done a similar swap. Dont worry Mike...4 wheel drums are loads of fun :D Quote Link to comment
mnementh666 Posted February 2, 2008 Report Share Posted February 2, 2008 Wish I could help more, but my 521 came to me with the disks up front. But the entire front end is '79, so that makes a bit of difference. I can get pics of the master cylinder and the distribution block (right term?) that was run. :blink: Quote Link to comment
sdsurf Posted February 2, 2008 Author Report Share Posted February 2, 2008 The 620 unit MAY work but dont quote me. PM Mklotz i believe he's done a similar swap. Dont worry Mike...4 wheel drums are loads of fun :D Oh i remember!! Quote Link to comment
datzenmike Posted February 2, 2008 Report Share Posted February 2, 2008 You would want the '78 or '79 as it is made for front disc brake use and has the larger 13/16" m/c. Pedal effort might be a bit high so keep the booster as well. The 620 also had a load sensing device to help limit rear wheel lock up under no load conditions. It's located on the inside of the pass frame under the pass seat. Technically illegal, an in line adjustable brake pressure valve could be used to limit rear pressure for light loads and turned up for heavy. Quote Link to comment
sdsurf Posted February 2, 2008 Author Report Share Posted February 2, 2008 Would I need to relocate the clutch M/C or does it fit with the booster? Quote Link to comment
pl521sss Posted February 2, 2008 Report Share Posted February 2, 2008 Would I need to relocate the clutch M/C or does it fit with the booster? Mine is different It's a 620 spindle with a front disc conversion to use Z32 calipers. It would be easier to use a single circuit. But I need dual circuit for safety reasons. Quote Link to comment
datzenmike Posted February 2, 2008 Report Share Posted February 2, 2008 Good question, don't know, but the 620 booster isn't that big and sits on a small pedestal away from the fire wall. The clutch m/c is tucked in beside it. I could measure mine? C/L to C/L Quote Link to comment
sdsurf Posted March 7, 2008 Author Report Share Posted March 7, 2008 I pulled a M/C out of a z and it doesn't line up bolt to hole. Also what about the pedal connection? With stock M/O there is a pin at the pedal holding it all together... Quote Link to comment
datzenmike Posted March 7, 2008 Report Share Posted March 7, 2008 The Z car m/c might be made to work, but the booster is huge in diameter and would croud out the break m/c. Quote Link to comment
pl521sss Posted March 7, 2008 Report Share Posted March 7, 2008 There's got to be someone in this list that has done this swap on a 521. Anyone? Quote Link to comment
BEEBANI Posted March 7, 2008 Report Share Posted March 7, 2008 O.k., before we continue with a redundant thread, check out the "disc brakes on a kingpin truck" thread on NWDE. Mike Klotz did a 2-3 page section about making a dual res m/c work on a 521. For disc brakes, the 280zx '85+ works best from what I've been told. I'm running the '85 720 m/c and booster (15/16" bore) so I couldn't tell you for sure. Quote Link to comment
slodat Posted March 7, 2008 Report Share Posted March 7, 2008 There was no 280ZX after 1983. The one that fits is 79-81. Early 81 as far as I can tell. The later one will work, but the mounting bolts are a horizontal arrangement instead of vertical like the stock 521 M/C. Quote Link to comment
BEEBANI Posted March 7, 2008 Report Share Posted March 7, 2008 I stand corrected, wasn't sure on the year. Quote Link to comment
521Lvr Posted March 8, 2008 Report Share Posted March 8, 2008 well I have done it. 620 booster, 280z car mc. not an easy task. First I moved the clutch master over and up. No biggie.. drill 3 holes, hog out the center till the mc fits and bolt it up. Now how do I attach it to the pedal? I made a 2 piece bracket and welded it to the pedal arm. drilled a hole in it and hooked it up. Pedal travel is decreased. Takes alot of positioning and clamping to get it rite. Next. Mounting the booster. Made a templet of the mounting surface. Not enough room to mount it in line with the brake pedal. And with some measuring and drilling it still won't bolt up. Hits the fender well. No worries.. Where's my 2lb hammer? AHHH Now it fits. So the pedal connection is off just enough to put a long bolt thru the oe holes. add a spacer in the booster rod and works great. Now for the lines. well once I got it all figured out. I have very efective but Very touchy brakes. "Hello Windshield!" Trying to find a stiffer spring should fix it. I could prolly post a couple pics tomorrow. peace tc Quote Link to comment
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