Hls30-24140

[LeonV]

Also, Leon: I purchased the "wrong" 15/16" master cylinder, the 82-83 model. I of course had to trim it to get it to work, but afterwards it bolted on fine. Other than the fitment issues, are there other reasons this was "wrong" as an upgrade? Does the reservoir layout negatively impact performance somehow?

The master is fine, it'll give you less travel at the cost of higher pedal force. However, it should have nothing to do with actual braking capability.

What happens is, the combined piston area of the front pistons in the 4-piston caliper is greater than stock which biases the brakes further to the front. Thus, the rear brakes aren't allowed to do as much work as they could with the stock system and don't transfer as much weight to the fronts. That all equates to longer stopping distances. Proportioning is different depending on which exact front calipers you went with, as piston sizes differ.

Here's a great HBZ thread to reference, I consider it a must-read for anyone thinking about playing with brakes: Toyota Truck Calipers, Ventilated Brake Rotors, MM rear Disc Brakes - Brakes, Wheels, Suspension and Chassis - HybridZ

Edited October 10, 2013 by LeonV

[Sean240Z]

You wouldn't happen to recall what the width of the seat tracks, on the Honda seat - would you? That is, the outside of the Left track to the outside of the Right track.

thanks,

Carl B.

Carl - 18 3/4" is the seat track width (i.e. distance between outer edges of the inner and outer seat tracks). I will update my S2000 seat swap post with this info.

[30 Ounce]

Thanks Guaro,

Leon, long stopping distance, yep. I was hoping these 4-pots would grab more, but with such a hodgepodge of parts, its hard to say which element I goofed with.

Try adjusting the rod between the brake booster and MC. It made a huge difference on mine.

[pbarcher]

Bill,

Last year Eiji installed the Toyota four piston, non-vented, calipers on my 73 along with Stoptech slotted rotors and Posi-Quiet ceramic pads. All new rears too, with OEM shoes and a 15/16ths master.

As others have written, this combo upsets the front/rear brake balance and the rears don't do much at all. Switching to rears discs with an adjustable proportioning valve is the theoretical solution but tricky to achieve in practice.

I really like my 14" wheels, and rear discs won't fit so I'm stuck at this point. Under normal driving the car brakes well, but spirited driving overheats the fronts and the rear drums are still cool.

I suggest that you stay with stock until you decide on a comprehensive (expensive) upgrade.

Peter

[ksbeta]

Thanks Peter,

Does the setup he built for you work well? Aside from the Rotors and Pads, I'm running the same gear. Curious if you're pleased, or consider the 'upgrades' inadequate as well.

Leon/Guy/Carl/Sean, thanks (as always) for the help.

Edited October 14, 2013 by ksbeta

[pbarcher]

Bill,

Are you referring to the close ratio 5-speed and 3.90 diff? If so, then yes it's a great combination.

Peter

[ksbeta]

Thanks Peter,

Sorry, no, I meant the brake setup he installed for you. I believe you made note that I might want to revert to stock, and was unsure whether you were happy with the 'new' brake setup you'd installed as mentioned.

[pbarcher]

Yes, for my needs the Toyota four piston is an improvement but it's far from ideal and not up to modern standards. If it wasn't for my beloved 14" wheels I'd seek another solution.

[HS30-H]

Last year Eiji installed the Toyota four piston, non-vented, calipers on my 73 along with Stoptech slotted rotors and Posi-Quiet ceramic pads. All new rears too, with OEM shoes and a 15/16ths master.

As others have written, this combo upsets the front/rear brake balance and the rears don't do much at all.

Nissan's factory 'Sports Option' lists and race prep manuals always recommended switching to 13/16" rear wheel cylinders and competition linings when using 4-pots ( Sumitomo MK63 ) on the front.

[ksbeta]

Thanks Both, and sorry for the delayed response. After losing all braking on the last drive of the season (fortunately without any of the hairy stuff that normally follows such a loss), I'll be really trying to figure this thing out. For now, if anyone is curious, here's what doesn't work:

280zx 15/16" MC

240z Booster

Stock 240z Proportioning Valves

4-Pot Toyota Disc's up front (Stock pads/ Rotors for said application)

Stock 240z Drum brakes in the rear

Unless I'm missing something, that combination stops about as well as a good rumor about a Senator and a Mistress.

[ksbeta]

Quick update:

Swapped in Subaru STi 3.90 LSD with Beta Motorsport shafts from Wolf Creek. Such an improvement in driveability over the 4.11

Tidewater Z helped sort out the brakes and other details.

[240260280z]

Nice to hear!

What are the improvements?

Better cornering or the 4.11 reved too high... or both?

Did you loose much of the torque push when starting in first?