This is a 'how to' for rebuilding the vacuum clutch booster found in the Z32 TT as pictured, I'm not sure if there were different versions. So far it's a bit of a draft and probably needs proofing and some better formatting just putting it up now to get some feedback on what could be clearer or things I missed/did wrong. I've got more photos Here for further reference I used a genuine Nissan rebuild kit for a GQ patrol from ATOC, all of the parts were a perfect fit except for the control rod/valve assembly which you either need to cut down or reuse you old one. I know rod300zx has done this recently, not sure how many others have dealt with it but at ~$80 posted its much cheaper than a new unit. First thing is to remove the seal and push rod from the front shell of the booster (faces the master cylinder). Simply lift the retaining star washer with a screwdriver then pull out the push rod and seal Next you need to open up the booster; it's a simple twist-lock mechanism but it very tight so you'll need a vice and a breaker bar. Be careful doing this as it's easy to damage the stud thread or bend their seat in the housing and not easy to replace them. The best way I found was to install the nuts winding them down until they sat flush with the housing on all six studs (two front, four rear), then back them off until they line up giving a square edge to put in the vice or lever with the breaker bar. Fix the four studs of the rear shell in the vice, just use as much force as needed, you don't want to go breaking stuff. With the unit clamped I used a star picket as my breaker bar, make sure you line it up square on the nuts (do not apply pressure to the vacuum inlet, it's soft) and they're flush with the housing so you don't bend anything then apply a constant pressure twisting the unit anti-clockwise, watch that everything is secure and the studs aren't bending as you go. You'll be able to see when the locking tabs reach the end of their travel and you're ready to open the booster. You'll need to pry open the booster by working around it with a screwdriver. Caution! This part of the assembly is sprung so don't lean over it looking at the locking mechanism while you're opening it, the force isn't going to break fingers or anything but would give you a nice blood nose or black eye. I just hold my hand on top of it so bits don't go bouncing onto the floor. Now we disassemble the rear shell and valve body. Remove the dust boot from around the control, mine had fallen apart but it's just held on by a push-fit retainer, turn the boot inside out to access the retainer and pry it off with a screwdriver. Remove the valve body (big plastic bit with the diaphragm) from the shell then pull off the diaphragm. Pry the reaction disc (black rubber disc, sits between control rod and push rod. Master of camouflage.) out with a screw driver. To remove the control rod and valve assembly place the valve body flat on the table and push down a bit on the control rod then use your favourite needle nose pliers to pull the locking plate out, if it doesn't come easily move the control rod up and down until you can feel it free up, it's only held in by a bit of grease and tension from the rod. Then you can pull the control rod out. Remove the seal from the rear shell, same as the front shell only on the inside pry the star washer out with a screwdriver. Now everything is in pieces, yay! Clean everything up, I believe metho is the preferred solvent to avoid damaging rubber and paint, then we can begin assembly. Now the problem with the patrol rebuild kit is that the control rod is a bit longer, this effects pedal position and it needs to be cut down to fit a 300zx pedal . I cut about 1.5cm off mine progressively test fitting it half assembled until I could get the correct adjustment of the clevis and then didn't have room for the lock nut and ended up using loctite to lock the clevis once reinstalled in the car (Caution! Wear safety glasses if using loctite above eye height). If your original valve assembly still looks healthy you would probably be well off re-using it, a cut down patrol control rod has reduced adjustment in pedal height and you may not be able to fit the lock nut on. To assemble, apply a smear of the supplied rubber grease to the valve assembly and install it in the valve body pressing down on the control rod insert the locking plate. Cover the new reaction disc with rubber grease and install. Clean and dry your hands and install the new diaphragm onto the valve body, it should be installed dry as it is covered with a mica powder (like talc). Cover the new seal and retaining disc for the rear shell with rubber grease and install (seal, then disc, then washer). Install the valve body with diaphragm into the rear shell then put the rear shell back in the vice same as before. Assemble the front and rear shells, I pushed the front shell on until it stuck then tapped it down with a rubber mallet (don't tap on the studs). Once the shells are sitting flush, twist the top clockwise with your breaker bar. Install the new filters (felt and rubber discs) onto the control rod and install the new dust boot with the retainer. Grease the base of the push rod and install it. Assemble the front seal and disc and grease them, install in the front shell with the new star washer. You're done! I found it easiest to assemble the booster and pedal assembly then install them in the car together. Make sure you set your pedal stops correctly after installation.
What tools do you need to do that? Would a good die set work or have to take it to a machining shop? I considered looking into that but figured if I could make it work without I'd save the effort. Other than that no problems with how I did it? I did want to ask which way around the filters go, I ended up putting the foam to the outside since the previous one had it scattered around the inside of the housing
Nice write-up. 1. How difficult is it to remove the clutch booster to rebuild it? 2. Did you have to remove the whole clutch peddle assembly? 3. Is the part number for the complete GQ rebuild kit that is in your pics - 30684-01J25? 4. Is there no oem rebuild kit for the Z32 clutch booster?
1. It's easier than a dash-in heater core pull (what I was doing when I pulled the clutch pedal out), I didn't have too much trouble. 2. Yes, you have to pull the clutch pedal assembly, this takes a bit of force to get past a bit of loom under the instrument cluster (I pried the loom out of the way with a large screwdriver). If you have collected a good variety of sockets, extension bars, uni's and spanners it's just a matter of pulling everything out (under-dash trim and climate control ducting are the main things). I think I could pull it out just by undoing the two nuts beside the master cylinder in the engine bay and then the one bolt hiding up above the loom at the end of the bracket closest to the steering wheel, if you can't jiggle it out in one piece you can undo the four nuts holding the booster on the bracket and try to take them out separately. 3. Based on the photo from the product I linked on ATOC I would say yes, didn't pay much attention to it myself and don't have FAST. 4. I'm not sure, there probably is but finding genuine Z parts in Australia is difficult/costly while Patrols are everywhere. It may be worth while for you to ask around your local Z parts dealers to see if they have them.
Is it safe to say you restored your clutch booster to full oem operation? It's been a few months since you did this rebuild and I was wondering how much actual road use you've had to confirm it's effectiveness. *EDIT* I forgot to ask if it makes a difference with that GQ Patrol kit between your 91TT and my 90TT?
All Z32 clutch boosters are the same and unique to the Z32, part number 30630-45P00. There is no OEM Z32 clutch booster rebuild kit. Kudos Motorsport has them cheaper in Australia then the USA. http://www.kudosmotorsports.com/cat...genuine-nissan-300zx-z32-vg30dett-p-1254.html
The booster had actually never worked while I owned the car so I can't say for sure that its the same but I can't imagine how it would be different to a brand new unit. At worst you'll need to get the control cut down and threaded depending on what other mods you have that affect pedal travel. It definitely does work now, quite nice to have a soft clutch pedal
Many thanks for this write-up. It was extremely helpful. I had the clutch booster rebuilt yesterday and I re-used the original control rod and didn't use those two fluffy fabric-type donuts either. I didn't read if they were supposed to be used when using the original control rod. At any rate, it feels so much nicer having the vacuum assist back with my 6 puck clutch. Now I want to rebuild my (RHD) JDM clutch MC. Will the rebuild kits from the LHD 1990 from Z1 or CZP work? Or is there actually a RHD kit with an oem part number?
No worries, I think the foam bits are filters so that you don't get bits of dirt on the control rod rubbing on the seal, if you still had the ones on the original rod they should be ok. I'm not sure about the master cylinders, they're all fairly similar in that they have the same bore/stroke but I'm not sure what internal differences there are. LHD/RHD shouldn't be important but I'm not 100% on that
Almost a year since the rebuild of my clutch booster using the Nissan GQ Patrol rebuild kit. I installed a new clutch master cylinder and the 1pc UAS SS braided clutch line at the same type as well. All is working just fine. Many thanks to all !!
Yes, thanks for the links you shared on Facebook and to the OP for doing the write up. I am definitely long overdue for this fix!
Reposting with image uploads and some editing, more photos are available here https://photos.app.goo.gl/YXAuukNnAx9g97mZA This is a 'how to' for rebuilding the vacuum clutch booster found in the Z32 TT as pictured, I'm not sure if there were different versions. I used a genuine Nissan rebuild kit for a GQ patrol from ATOC , all of the parts were a perfect fit except for the control rod/valve assembly which you either need to cut down or reuse you old one. I know rod300zx has done this recently, not sure how many others have dealt with it but at ~$80 posted its much cheaper than a new unit. First thing is to remove the seal and push rod from the front shell of the booster (faces the master cylinder). Simply lift the retaining star washer with a screwdriver then pull out the push rod and seal Next you need to open up the booster; it's a simple twist-lock mechanism but it very tight so you'll need a vice and a breaker bar. Be careful doing this as it's easy to damage the stud thread or bend their seat in the housing and not easy to replace them. The best way I found was to install the nuts winding them down until they sat flush with the housing on all six studs (two front, four rear), then back them off until they line up giving a square edge to put in the vice or lever with the breaker bar. Fix the four studs of the rear shell in the vice, just use as much force as needed, you don't want to go breaking stuff. With the unit clamped I used a star picket as my breaker bar, make sure you line it up square on the nuts (do not apply pressure to the vacuum inlet, it's soft) and they're flush with the housing so you don't bend anything then apply a constant pressure twisting the unit anti-clockwise, watch that everything is secure and the studs aren't bending as you go. You'll be able to see when the locking tabs reach the end of their travel and you're ready to open the booster. You'll need to pry open the booster by working around it with a screwdriver. Caution! This part of the assembly is sprung so don't lean over it looking at the locking mechanism while you're opening it, the force isn't going to break fingers or anything but would give you a nice blood nose or black eye. I just hold my hand on top of it so bits don't go bouncing onto the floor. Now we disassemble the rear shell and valve body. Remove the dust boot from around the control rod, mine had fallen apart but it's just held on by a push-fit retainer at the pedal end, turn the boot inside out to access the retainer and pry it off with a screwdriver. Remove the valve body (big plastic bit with the diaphragm) from the shell then pull off the diaphragm. Pry the reaction disc (black rubber disc, sits between control rod and push rod. Master of camouflage.) out with a screw driver. To remove the control rod and valve assembly place the valve body flat on the table and push down a bit on the control rod then use your favourite needle nose pliers to pull the locking plate out, if it doesn't come easily move the control rod up and down until you can feel it free up, it's only held in by a bit of grease and tension from the rod. Then you can pull the control rod out. Remove the seal from the rear shell, same as the front shell only on the inside pry the star washer out with a screwdriver. Now everything is in pieces, yay! Clean everything up, I believe metho is the preferred solvent to avoid damaging rubber and paint, then we can begin assembly. Now the problem with the patrol rebuild kit is that the control rod is a bit longer, this effects pedal position and it needs to be cut down to fit a 300zx pedal. I cut about 1.5cm off mine progressively test fitting it half assembled until I could get the correct adjustment of the clevis and then didn't have room for the lock nut and ended up using loctite to lock the clevis once reinstalled in the car (Caution! Wear safety glasses if using loctite above eye height). If your original valve assembly still looks healthy you would probably be well off re-using it, a cut down patrol control rod has reduced adjustment in pedal height and you may not be able to fit the lock nut on. Exploded view, left to right: Clevis, locking nut, rear shell with seal still installed, diaphragm, valve body with control rod/valve assembly installed, spring, front shell, action rod, front seal and star washer. To assemble, apply a smear of the supplied rubber grease to the valve assembly and install it in the valve body pressing down on the control rod insert the locking plate. Cover the new reaction disc with rubber grease and install. Clean and dry your hands and install the new diaphragm onto the valve body, it should be installed dry as it is covered with a mica powder (like talc). Cover the new seal and retaining disc for the rear shell with rubber grease and install (seal, then disc, then washer). Install the valve body with diaphragm into the rear shell then put the rear shell back in the vice same as before. Assemble the front and rear shells, I pushed the front shell on until it stuck then tapped it down with a rubber mallet (don't tap on the studs). Once the shells are sitting flush, twist the top clockwise with your breaker bar. Install the new filters (felt and foam discs, pretty sure my photo above has them in the wrong order, the coarser foam disc should be to the outside) onto the control rod and install the new dust boot with the retainer. Grease the base of the push rod and install it. Assemble the front seal and disc and grease them, install in the front shell with the new star washer. You're done! I found it easiest to assemble the booster and pedal assembly then install them in the car together. Make sure you set your pedal stops correctly after installation.
