240Z (manual only) Upgrade to Skyline/Silvia Booster and 15/16th Master Cylinder

[KatoKid]

I'm going to run R33 GTS-T front calipers and R31 rears on my car so I need to go to a bigger brake MC and it seems that 15/16 inch is the way to go. Ive looked at the old style patrol 15/16 MC's etc but my original 240Z booster looks pretty bad so I was in the market for another booster as well. Additionally the engineers like to see matching brake components where ever possible, plus the 240Z booster is pretty small so may not give the desired amount of assistance.

 

I had done some preliminary research and when Jamo posted his R33 GTS-T booster/MC for sale so I jumped on it. You can pick these up for $100 on evilbay easily, so they are a good alternative to the Patrol set up and you get a much newer booster as well.

 

Now a few disclaimers: This master cylinder is called a BM44, search ebay and you will see it is used across R33 skylines in ABS and non ABS versions as well as S13/14/15 Silvia's. There seems to be a few different versions of the basic BM44 MC so you will need to ensure you get the right one (see pic's of mine), I'm pretty sure mine would be the ABS version as I would guess only the lower spec R33's would be non ABS. I cant vouch for the stud pattern on the back of the booster for the Silvia's but I reckon they will be the same. I also don't know if this will work for a 260.

 

The width of the stud spacing on the R33 booster is the same as the Z but the height is different, also the stud pattern on the Z booster is not centered whereas they are on the R33 booster...see pics. This means that you can use the original lower holes in the firewall but need to drill new holes for the top studs. The booster came with a paper gasket which is a handy template for the new holes, a few minutes with a drill and you can slide the booster in, the nuts are really easy to get to under the dash so its very straight forward.

[KatoKid]

Before you bolt the booster in theres one more thing to do.....

 

The clevis pin on the R33 pushrod is 8mm and the hole in the Z brake pedal is 10mm so you need to either fill and redrill the Z pedal to accept the smaller pin....or drill out the R33 clevis to take the larger 10mm pin from the Z. Needless to say its much easier to drill out the R33 clevis! The R33 clevis is also a little wider (only about 1-2mm) meaning the clip wont fit on the Z pin so a bit of a squeeze in the vice and its all good.

 

After bolting the booster in I only had to adjust the pushrod about 3mm to match up with the hole in the Z pedal.

 

I wont be able to actually test this on the road for many many months but I don't see any issues that would stop (ha ha) it being a good alternative.

[C.A.R.]

Excellent!

 

This needs to be stickied!

[KatoKid]

Meant to add.......

 

The R33 booster is about 215mm wide so this will put it very close to the clutch master cylinder, I cant get in there to measure definitively so suggest you do some checking if you plan to do the same. Isn't an issue for me because my clutch MC is now under the dash as Ive got a cylinder head in the way!

 

Also a shot from the inside.

[KatoKid]

I cant get a good shot of my MC so Ive grabbed images of the web.

 

1st one is the same as mine, which I think is ABS.

 

2nd one is also R33 but non ABS, I think.

 

Either way just buy the correct one.

 

One other thing.... the rear outlet is for the front brakes and front outlet for the rear. They are clear stamped but take note this is the opposite to the standard Z arrangement.

[PeterAllen]

Meant to add.......

 

The R33 booster is about 215mm wide so this will put it very close to the clutch master cylinder, I cant get in there to measure definitively so suggest you do some checking if you plan to do the same. ...

 

With the LS1 install I opted for the Holden brake booster and the interference with the clutch master cylinder was a real PITA to rectify. The strengthening/backing plate needs to be extended for one thing and the pushrod locating point on the pedal arm needs to moved accordingly. Also, the GM clutch master cylinder will over-stroke with the standard Datsun travel so the pedal ratio needs to be changed.

 

Just a warning to anyone thinking of following David that you may need to address other issues unless you house the M/C internally like David.

 

Great work David, you're kinda encouraging me to have another go.

[KatoKid]

Thanks Pete, I will keep it up providing you have another go!

 

By the look of it Ive got more room than what you had for the clutch MC. When I pull the engine next time I will throw the original clutch MC in to confirm.

 

Cheers.

[garvice]

I've had an R32 gtr booster in my shed from the half cut for a couple of years with the intention of doing this very thing. Only thing I had never checked was whether the travel was the same on both boosters? Not sure if they change the travel length or not or whether every booster is the same length etc. Worth a check as it might mean changing the pivot point on the pedal or putting a stop on the brake (or bending the brake lever so it bottoms out quicker) etc.

[Zedman240®]

Should we sticky after confirmation there are no issues with installation and use? Just in case...

 

Brilliant write up David; might have to do it when all the zed boosters are dead and buried.

[NZeder]

FYI the zed has 2 type of boost bolt patterns. One aka early 240z is usually 80mm bolt spacing unless a factory auto. The later is 100mm spacing aka 240z auto + all 260z and late 240z shells.

 

David did you not try the z clevis on the e33 rod? My guess it would have gone on fine both would be metric and I assume m8.

[KatoKid]

I've had an R32 gtr booster in my shed from the half cut for a couple of years with the intention of doing this very thing. Only thing I had never checked was whether the travel was the same on both boosters? Not sure if they change the travel length or not or whether every booster is the same length etc. Worth a check as it might mean changing the pivot point on the pedal or putting a stop on the brake (or bending the brake lever so it bottoms out quicker) etc.

 

I don't think pedal stroke is really relevant, if it was a clutch system yes but if you're using all your pedal stroke with a brake system you've got big problems!

[KatoKid]

Should we sticky after confirmation there are no issues with installation and use? Just in case...

 

Brilliant write up David; might have to do it when all the zed boosters are dead and buried.

 

Thanks Dimitri.

 

Yep fair call, lets confirm clutch MC fitment and a road test before sticky.

[KatoKid]

FYI the zed has 2 type of boost bolt patterns. One aka early 240z is usually 80mm bolt spacing unless a factory auto. The later is 100mm spacing aka 240z auto + all 260z and late 240z shells.

 

David did you not try the z clevis on the e33 rod? My guess it would have gone on fine both would be metric and I assume m8.

 

Thanks Mike, I will measure up the pattern and confirm.

 

Yep, did look at swapping the clevis on the rod but the R33 is 10mm rod vs 8mm for the Z.

[KatoKid]

Confirm stud spacings are 80mm wide for both 240 and R33 boosters.

 

240 studs are 70mm height.

 

R33 studs are 60mm height.

[sexual_sushi]

Thanks for the writeup, good to see the details as I've been looking into master cylinder upgrades lately.

 

You mention wanting to pair parts to keep the engineer happy, but aren't there issues with drilling into the firewall? Would like to hear peoples thoughts on this.

[d3c0y]

You can use a Z32 MC aswell they are bigger than 15/16"s too 1" or maybe a bit bigger. I have all teh measurements in a G-Works magazine for various booster M/C combinations if anyone wants me to post it up.

[NZeder]

Confirm stud spacings are 80mm wide for both 240 and R33 boosters.

 

240 studs are 70mm height.

 

R33 studs are 60mm height.

Cool - so that confirm's it this will not work on a 260z without drilling 4 holes or the 240z with the 100mm spacing aka Auto 240z.

[KatoKid]

You mention wanting to pair parts to keep the engineer happy, but aren't there issues with drilling into the firewall?

 

I would doubt it Scoota, there are two layers on the firewall plus the pedal box behind that which is also braced to the plenum area . So you have 3 layers that are pretty well supported, I doubt that foot pressure would ever stress it with a couple of extra holes drilled.

 

Engineers "like" to see matching components as it gives them some reassurance around braking capability and front to rear balance.

[KatoKid]

Cool - so that confirm's it this will not work on a 260z without drilling 4 holes or the 240z with the 100mm spacing aka Auto 240z.

 

Bugger! Ive changed the thread name to reflect 240Z manual only.

 

Thanks Mike.

[sexual_sushi]

I would doubt it Scoota, there are two layers on the firewall plus the pedal box behind that which is also braced to the plenum area . So you have 3 layers that are pretty well supported, I doubt that foot pressure would ever stress it with a couple of extra holes drilled.

 

Engineers "like" to see matching components as it gives them some reassurance around braking capability and front to rear balance.

 

I'm sure there is more than enough support but I had a feeling that there was a regulation that you couldn't modify the firewall at all, even putting in a small hole to run wires etc. Perhaps this is a Qld rule? Either way, I'm sure most of us would do it without thinking twice but it might be good to clarify for the more fastidious types.

[PZG302]

You can use a Z32 MC aswell they are bigger than 15/16"s too 1" or maybe a bit bigger. I have all teh measurements in a G-Works magazine for various booster M/C combinations if anyone wants me to post it up.

 

Z32 is 1" and also has holes opposite to 240 (horizontal as opposed to vert IIRC), so not sure how this affects you if using a booster. Unboosted you will have to redrill holes in firewall to suit.

[Missinglink]

Thread resurrection time! Please excuse the hijak.

 

I have just installed an R33 MC and Booster (ABS) along with the std 240z clutch master cylinder. I had to drill two new holes for the R33 booster, file off a couple of the raised numbers on the side of the clutch master and roll the edge of the booster a couple of mm (not sure if this is even needed). As you can see from the pictures below it all fits.....just (with a few mm to spare), please ignore the hard lines, this was a test to see if it would all fit so the hard lines are a little random....(disclaimer done!)

 

I am running the AZC big brake kit (6 and 4 spot calipers front and rear) and was running the std booster with a 15/16 MC previously. This worked fine and felt ok, although the booster assistance was a little lacking at times. With the new system bled there is a big difference (as you would imagine), much more positive feel and a lot more assistance. I have not run this on the track yet so time will tell how much i need to adjust the balance for front to rear. My car is also running a 302 Windsor in case there are any differences in engine location etc.

 

For a quick drive around the block the brake pedal now feels a lot like the pedal in my brothers AMG C63, if that helps anyone. Its the only car that i have driven with big brakes and similar pedal feel....other than the fact it weighs A LOT! but i digress.....

 

Thats all for now.

 

Cheers

Edited April 8, 2016 by Missinglink

[KatoKid]

Hey, thats great news! Good to hear it all works and is an improvement over the traditional set up.

[Sirpent]

Excellent info and upgrade

[OZZ240]

I've just done the R33 M/C and Booster (ABS) upgrade to my 71 240Z.

My brake setup was 1" bore M/C on a std 240Z brake booster running Z32TT front and rear brake calipers, it was ok but in the back of my mind I knew it could of been better.

Now with the upgrade to the R33 M/C and booster the brakes have come alive and are phenomenal.

Brake peddle is sensitive compared to the old setup but easy to adapt to the new brake peddle feel.

 

I followed the information/installation notes from the above post from Missinglink and the install went well.

 

General info:

Took me approx day to do the install.

The M/C and std distribution block (underneath the M/C) both have a M10 x 1 Pitch thread for tube nuts.

The M/C and std distribution block both use a double flare.