260DET Posted July 30, 2002 Share Posted July 30, 2002 Seeing the present 15/16" master cylinder is worn and brake pedal height has never been that good, has anyone tried a 1"? Any good? From what vehicle? My '77 has 4 spot calipers on the front and single sliding calipers on the disc converted rears. Quote Link to comment Share on other sites More sharing options...
Guest Aaron Posted July 30, 2002 Share Posted July 30, 2002 According to the research I have done (which is only a little). The early D21 "Hardbody" pickups had a 1" master cylinder that may bolt up to a Z. I think it was in 87-89 2WD V6 pickups not Heavy Duty and not Dual rear wheels. The research I have done has is pretty much looking at online parts places and checking the description and usage of various parts. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted July 30, 2002 Share Posted July 30, 2002 A 1" bore will provide about 30% greater piston area than the OEM bore (7/8"). It will definitely firm up the pedal feel, but you will need a pretty strong leg to go along with that. I'd like to see or hear the results of going to that large a bore. Has anyone actually measured the piston area (combined) of the 4 piston Toyota brake calipers vs the piston area of the 2 piston Datsun brake calipers. Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 30, 2002 Share Posted July 30, 2002 Terry, I've seen those numbers before on piston area between the 4x4 and OE Z caliper. I remember the difference was less thatn 10%, but I could be wrong. I bet Ross or scca-Mike knows... Quote Link to comment Share on other sites More sharing options...
Guest Aaron Posted July 30, 2002 Share Posted July 30, 2002 I was researching the 1" because I am planning a 280ZX and I assume that a significant upgrade to the calipers would also need a upgrade to the master. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted July 30, 2002 Share Posted July 30, 2002 That seems to ring a bell to me too (about 10% bigger). With the 15/16" master cylinder, the bore is an increase of about 14% over the stock Z master cylinder, and my 280ZX front caliper piston size vs the Z front caliper piston size was about an 11% increase. Quote Link to comment Share on other sites More sharing options...
260DET Posted July 31, 2002 Author Share Posted July 31, 2002 According to a good brake man I know, both the Nissan 280C sedan and the Nissan Patrol GQ '88 model have 1" master cylinders. The 280C is a very old Nissan product. But how they would match up is another question entirely of course. The above are Aussie model vehicles. Yep, the right leg is quite well developed, a bigger +2 booster helps too. Quote Link to comment Share on other sites More sharing options...
Guest scca Posted July 31, 2002 Share Posted July 31, 2002 james (240TT) put that in his car and he seems to think its OK.. there was a thread a while back abou it with a rebuilding of the booster Quote Link to comment Share on other sites More sharing options...
zcarnut Posted August 4, 2002 Share Posted August 4, 2002 I am using a one inch diameter master cylinder on my early 260Z. You can find a 1" master cylinder on the 1991 to '96 Nissan Hardbody 2WD truck. I have noticed that the later years have a smaller plastic fluid reservoir. This master cylinder does not have an internal proportioning valve. The Hardbody Truck also used a 15/16 inch diameter master cylinder during this time frame so you should identify the master cylinder it before removing it from a donor vehicle. I have also seen the same 1" master cylinder on early 1990's non-ABS Maxima's and also on an early ‘90's non-ABS Subaru Legacy. I have even seen an inch and 1/16 diameter(!) master on a Subaru SVX of the same vintage. All these master cylinders utilize the later “horizontal” mounting configuration. So, I also used the later ('82 and '83) 280ZX booster in conjunction as well. For three reasons: (1) The 1" master cylinder bolts up to this booster without any problems. The 1" master cylinder will not bolt to the '70-'78 Z car boosters without modifications. The bolt spacing is slightly different on the booster so you would have to slightly elongate the mounting holes on the master cylinder slightly to allow it to fit. (2) The 280ZX booster is larger in diameter than the '70-'78 boosters, and this helps to reduce the increased pedal effort you get with the larger diameter master cylinder. (3) The ZX booster fits the '74-'78 Z cars without any problem. You have to mount it upside down (but that does not affect its operation), and you will have to shorten it's mounting studs that go through the firewall. However, the ZX booster will not bolt into the '70-'73 Z cars (the 240Z's) because the firewall mounting bolt spacing is different. You might be able to use the '74-'78 pedal support bracket or perhaps be able to redrill the '70-'73 pedal support bracket for the ZX booster. In either case the firewall must be redrilled, and there still may be an interference problem with the clutch master cylinder. The brake line fittings on the one inch master cylinder exit from the side and the top of the master cylinder. The Z car's master cylinder brake lines all exit from the bottom of the master cylinder. So, you will need to fabricate some new brake lines from the master cylinder to the brake balance switch assembly. Use 3/16 inch stock brake line (it's less than .001" different than the Nissan 4.75mm lines) and double flare the ends. Why did I use a one inch master? Well, I had to! The earlier Toyota truck calipers that everyone uses have two 42.8mm and two 33.9mm diameter pistons, for a total area of 46.8cm sq. I am using a later Toyota four piston caliper (for a vented rotor) that has four 42.8mm diameter pistons. Total area being 57.6cm sq. A 23% increase. The 15/16 inch diameter master is only a 14.8% increase in area over the 7/8 inch diameter master. However, the one inch master has 30.6% more area. Result, firm pedal. Quote Link to comment Share on other sites More sharing options...
Mike C Posted August 4, 2002 Share Posted August 4, 2002 Good answer! I redrilled my 72 to use a 78 booster. The 73 is already the larger bolt pattern/booster than the 70-72. Quote Link to comment Share on other sites More sharing options...
260DET Posted August 5, 2002 Author Share Posted August 5, 2002 Thanks Steve. Now I have obtained a new iron bodied 1" (25.4mm) master cylinder from the local Z car specialist that bolts straight on to the 240/260 booster although I use the larger 2+2 booster. But the box it came in had no ID so I don't know what it was originally made for, sorry. However this mc had residual pressure valves in both outlets which resulted in the replacement front 4 spot Nissan Z32 calipers binding. So the valve for the fronts has been replaced with a non residual pressure valve from a 15/16" 280ZX mc. Which goes to show that if you can buy a proven brake upgrade kit you may save yourself a lot of stuffing around. Should be able to do a road test in a day or so. Quote Link to comment Share on other sites More sharing options...
260DET Posted August 10, 2002 Author Share Posted August 10, 2002 After doing a short road test the results so far are excellent. Nice high pedal with just right for me boost from the 2+2 booster. Ended up removing the residual pressure valve from the rear (disc) brake outlet port as well, because the back pads were dragging a bit. The real test will be in a few days. A fair drive to a racing circuit and a few laps there. Quote Link to comment Share on other sites More sharing options...
zcarnut Posted August 11, 2002 Share Posted August 11, 2002 According to “Aussie” Steve Lamb (of the main Z car list) the 1960's-70 vintage Nissan Patrol used a one inch diameter cast iron brake master that bolts up the early Z cars. This brake master seems to be unavailable in the USA. The Nissan Patrol had drum brakes at all four wheels, hence the residual pressure valves. BTW, the rear drum brakes found on the early Z cars do not need a residual pressure valve as the wheel cylinder seals are kept in contact with the wheel cylinder walls with a spiral spring. Hence, no need for the 3 to 4 psi developed by a residual pressure valve. Quote Link to comment Share on other sites More sharing options...
Guest Aaron Posted August 12, 2002 Share Posted August 12, 2002 ZCarNut, do you know if the pickup MC is specific to the king cab, 4cyl, or v6? Or is it random where you find the 1" MC? Quote Link to comment Share on other sites More sharing options...
zcarnut Posted August 13, 2002 Share Posted August 13, 2002 According to Nissan the D21 (Hardbody Truck) came with the following diameter master cylinders: 11/85-08/88--VG30---------------15/16 inch 11/85-07/87--Z24-----------------15/16 inch 11/85-07/87--4WD----------------15/16 inch 11/85-08/88--HD VG30------------15/16 inch 07/87-08/89--2WD VG30 SE--------1 inch 07/87-07/90--4WD----------------15/16 inch 07/87-08/89--2WD Z24------------15/16 inch 08/88-08/89--VG30----------------15/16 inch 08/89-01/92--2WD KA24E----------15/16 inch 08/89-01/92--2WD VG30E----------15/16 inch 07/90-01/92--4WD-----------------1 inch 01/92-07/93--2WD KA24E or VG30--1 inch 01/92-07/93--4WD KA24E or VG30--1 inch 07/93-07/98--2WD KA24E or VG30--1 inch 07/93-07/98--4WD KA24E or VG30--1 inch (My micro fiche is only good up until 12/98, but the last two entries may also apply to the later D21 trucks.) As you can see there is some overlap. So, the best way to be sure is to examine the master cylinder itself. Like on the Z cars, Nissan used two suppliers for this master cylinder: Tokico and Nabco. The Nabco one has a raised "1" cast it's side, indicating a one inch diameter, but the Tokico one does not. However, both supplier's one inch master cylinders have "BM50" on their castings, so use this marking to identify the one inch master cylinder. If you can not locate one a good used one, I have several available for sale. Please contact me off line. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted August 13, 2002 Share Posted August 13, 2002 Note here: My '92 KA24E had a 7/8", which I later changed to the '85 VG30 15/16" when I went with the larger calipers. Just an FYI. Quote Link to comment Share on other sites More sharing options...
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