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81.5 720D Brake upgrade


SLO720

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Hello all, doing front suspension and brake work on my 81.5 Diesel. Knocked out strut rods and added sway bar and end links (truck not equipped). 

I've updated the spindles to '86 720 spindles and attempting to add D21 V6 rotors and calipers (83+ spindles will accept later brake setups). It looks like the bracket to mount the caliper is too thick. I may see about clearancing the bracket to make it fit? I'm just mot sure if it'll work like I need it doing that. I can only assume the brackets that came with the calipers are for a 4x4 truck. Also have to get another set of pads as I believe I ordered 4cyl pads

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I have an 82 4x4. The biggest brake improvement I made was swapping in a dual diaphragm brake booster. The early 720s had a single diaphragm booster. I adapted one from a frontier but I think 83 and up had them and that would be easier.

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Posted (edited)

@bottomwatcher I'm almost certain the boosters are specific to the diesel trucks but not entirely sure (may just be the check valve). I've considered going the chase bays route and going to mechanical brakes and deleting the vacuum pump on the alternator. I've had this stuff kicking around for a couple years and finally got a chance to add it. It should all bolt on but ran into issues. I just don't like the early style calipers. 

Edited by SLO720
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@bottomwatcher that's an eventual thing, I want to turbo, if it's in the engine bay it may be pretty tight. It also opens up the opportunity to higher amp alternator. Currently have this truck swapped to a Hitachi off an Isuzu box truck (110a vs 40a). I've driven manual brakes and manual steering it's alright. I only brought it up as the booster was mentioned. I do have factory power steering to add to this diesel eventually also. I'm just wanting to add modern brakes at this point. Anything is an improvement to what was on it. 

 

Your 4x4 looks great! Wish my bug was that clean lol. 

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That caliper in the last photo does not look like a 1986 720 caliper, this is what my 1986 caliper looks like.

 

DSC00402.JPG.912f4575f24722b461e9b64f31ba41cc.JPG

 

DSC00404.JPG.ecd375ee507cf16f2d3348d203e30c13.JPG

 

I would not be deleting the power brakes, any other pump than the existing vacuum pump is complicated, you can pipe the turbocharger up front/ahead of the brake system to avoid conflicts, that makes room for the down pipe to get it away from the starter, and you do not want that down pipe anywhere near that starter as I would know, if you think a 720 engine compartment is tight, just look at my 521 engine compartment.

 

DSC00405.JPG.f679ea3beb042f8242e04530eda5e313.JPG

 

Here is the 720 engine compartment, you just need to mount the turbocharger in the right spot.

 

DSC00407.JPG.d5e9fe0f8bf7b4ef5b878598940138b1.JPG

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@wayno it's not, it's a v6 d21 caliper, planned on doing a dual piston caliper swap. However, the spindles and hubs are from an 86 720 to give me the correct bolt hole spacing for caliper to mount. I used the write up below to gather my parts. The Hitachi from an Isuzu comes with vacuum pump mounted already and are 110a. I had run a Ford v-belt vacuum pump on this truck for awhile with a 120a maxima alternator. 

 

http://www.infamousnissan.com/forum/showthread.php?t=26447

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OK, it also does not look like my 1990 V6 D21 dual piston calipers that I have that bolted right in with my 1986 720 spindles, but I cannot see the back side of that caliper, what makes me think they are early is the hardline connection, early stuff had that metal line when all the late stuff I have has the rubber line that connects directly to the caliper.

 

DSC00409.JPG.a67e4e75ef48925b15372de911d8a812.JPG

 

Edited by wayno
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@wayno the caliper hanging in the background is the original, left it on to prevent air in the system until I had the new caliper mounted. The picture I showed was from me trying to mock up the new caliper but it's as if the caliper mount is too thick to fit between the rotor and the spindle. Both brackets (for each side) were too thick to fit

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The booster on the 720 aids the driver by applying about 4 X more pressure on the master.  It's removal basically increases the driver effort to stop at the exact same rate. Anything that reduces driver fatigue is a good idea.

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@wayno @datzenmike, yeah I realize that, what I'm hoping for is advice on the thickness of this set of caliper brackets.

 

Might seem silly, if I snagged the wheel bearings too tight to the spindle would it cause the spacing between the too to not allow the bracket to mount? I have the nut rather snug that holds the rotor to the spindle. The old one I removed after removing the cotter pin I was able to unscrew the nut with my finger. 

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Tighten wheel bearing nut to 25 ft lbs., spin tire in both directions, check and/or adjust to 25 ft. lbs., loosen nut 45 degrees. Install adjusting cap and  turn in the tightening direction till any of the holes aligns with the hole in the spindle. Use a new cotter pin.

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OK I did not understand everything, 1983 thru early 1986 rotors have a different offset than the late 1986 720 rotors, as far as I know the dual piston calipers are not compatible with the early vented rotor rotors.

 

Here is a photo of a set of parts I bought to change over to dual piston calipers using the vented rotor type spindles, I bought them long enough ago to forget the specifics, calipers on the bottom(L/R), rotors upper left, brake pads(MX333), and clips for the brake pads(HW13173), this works, it is the best I can do for you, except for my 1980 Datsun 720 kingcab turbodiesel that has the dual piston calipers all my trucks at this time have the late 1986 single piston calipers as they work good enough for me, but I bought the ones in the photo for the future.

 

DSC00410.JPG.68acceec0619b60ead676b89545c8f61.JPG

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Posted (edited)

@wayno @datzenmike, thank you both! So I also ordered centric calipers (online) I ended up with a different part number set though. I ended up with 141.42050/141.42049 as 2wd calipers and the ones you showed were listed as 4wd calipers. 

 

I actually bought all of mine brake hardware to go on my one ton. This truck happen to be close to inspectable and decided to upgrade for modern calipers and had this stuff laying around. I also used the larger v6 rotor doing this swap. 

Edited by SLO720
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I thought I heard someone mention that a Toyota 4x4 caliper (79-95) may work on the Datsun. 79-85 used a solid rotor, and a thinner caliper. 56-95 used a vented rotor and a thicker caliper. They are all 4 piston, but the 86-95 V6 caliper has larger pistons, and is slightly larger due to cooling fins cast into the caliper (which can be ground down a bit for fit).

Edited by Stoffregen Motorsports
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The '79-'85 Toyota 4X4 calipers bolt directly to the 240/260/280z cars and use their solid rotors. Thank-you Fuji Heavy Industries and part owners Nissan, Subaru, Mazda and Toyota. (at the time) This is why the Subaru R-165 fits the 510.

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@Stoffregen Motorsports I know they will fit a 4x4 truck but I believe the offset is wrong for a 2wd truck as beebani used to make a kit that utilized 4x4 rotors to fit them on a 2wd truck iirc. I have a set of 4 piston 300zx caliper I can try at a friend's house if I remember to pick them up (pretty sure offset is also wrong). 

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Well the caliper bolt spacing on the zx strut is 89mm center to center. This will tell only if it might bolt on.

 

I suspect that if it did, someone would already have done it. The Toyota caliper for solid rotor is heavy, the one for the vented rotor is insanely heavy.

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14 hours ago, SLO720 said:

@wayno @datzenmike, thank you both! So I also ordered centric calipers (online) I ended up with a different part number set though. I ended up with 141.42050/141.42049 as 2wd calipers and the ones you showed were listed as 4wd calipers. 

 

I actually bought all of mine brake hardware to go on my one ton. This truck happen to be close to inspectable and decided to upgrade for modern calipers and had this stuff laying around. I also used the larger v6 rotor doing this swap. 

 

Well I am going to be unhappy if they are the wrong parts as they were bought quite a while back and they cannot be returned anymore.

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14 hours ago, datzenmike said:

Well the caliper bolt spacing on the zx strut is 89mm center to center. This will tell only if it might bolt on.

 

I suspect that if it did, someone would already have done it. The Toyota caliper for solid rotor is heavy, the one for the vented rotor is insanely heavy.

Yeah, unsprung weight is a problem.

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Hello, I found this thread while researching front calipers for my '82 720 4x4. I'm wondering if any of you can confirm that the '79-'85 Toyota calipers mentioned by @datzenmikeabove will fit my truck? I'm having a very hard time finding OEM replacement calipers. Also it looks as if maybe the Centric calipers in the pic posted by @wayno are correct part numbers?? Any help much appreciated, this is the final step toward getting my new friend on the road;) 

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56 minutes ago, Finspop said:

Hello, I found this thread while researching front calipers for my '82 720 4x4. I'm wondering if any of you can confirm that the '79-'85 Toyota calipers mentioned by @datzenmikeabove will fit my truck? I'm having a very hard time finding OEM replacement calipers. Also it looks as if maybe the Centric calipers in the pic posted by @wayno are correct part numbers?? Any help much appreciated, this is the final step toward getting my new friend on the road;) 

Does your truck have vented rotors? If so, the 79-85 calipers definitely won't work, but the 86-95 calipers might.

 

79-85 calipers use thin non-vented rotors

86-95 calipers use vented rotors

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