Brake Booster Dimensions

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BAMBY
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Brake Booster Dimensions

Postby BAMBY » Sat Jun 10, 2017 11:51 am

Many of you probably have the answer to this question sitting in a pile of parts somewhere...
And probably all of you have heard this story before, but I've got a little twist to add.

So I have a turbo, and it's close to the brake stuff... The turbine and downpipe are less than 3/8" from the brake master cyl and the brake booster. Here's the twist, my platform is a 1999 D22 Frontier...
Now, I've done some digging and have found great tales of a S14 5spd NonABS Brake Booster, and how much smaller it is... which got me wondering.

Question: Does anyone have dimensions of the bolt pattern where the booster attaches to the firewall for the S14? Thread length of the studs coming off the booster would be appreciated as well.
My hope is that it would be able to bolt up to my firewall, giving me the clearance I need from my turbine and downpipe... and then I could experiment with the master cylinder bore to get my pedal feel back where it needs to be.

I've done some searching and can't seem to find actual dimensions, really hoping someone either can grab measurements for me, or connect me with another person who has one for sale, or knows somebody who might know how to get the measurements... There are no junkyards near me with one of these in stock to go measure, and my local auto parts store manager wasn't smiling when I asked if he could order me one just to measure it... lol.

Thanks for any help y'all can offer!


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AZhitman
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Car: 72 240Z RB25, 63 Bluebird RHD, 63 NL320, 67 WRL411, 67 SPL311, 68 510 SR, 73 240Z, 77 620 SR20, 89 Pao, 98 S14, 12 Titan CC 4x4.
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Re: Brake Booster Dimensions

Postby AZhitman » Sat Jun 10, 2017 9:41 pm

Could be a tough one. We have a S14 here, but I'd prefer not to drop the booster to check.

Give it a couple days, let's see if anyone pops in with an answer.

BAMBY
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Re: Brake Booster Dimensions

Postby BAMBY » Tue Jun 13, 2017 4:32 pm

Thanks AZhitman, definitely would appreciate the help.
In my D22 chassis, one can grab the meaurements from the interior side of the firewall, without removing the MC and booster, not sure how feasible that is on a 240 though...
Fwiw, I have contacted Chase Bays for dimensions as well, since they produce a BBE kit that is S14 compatible...
But I have yet to hear back from them...

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centralcoaster33
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Re: Brake Booster Dimensions

Postby centralcoaster33 » Wed Jun 14, 2017 12:56 pm

Well, I didn't take anything "off", but I did take a look at the inside of the firewall. My brake booster (S14) has a sort of rectangular bolt pattern approx. 3.25" left to right and approx. 2.5" top to bottom. All are bolts (well, studs I suppose) with 12mm nuts. I didn't get the thread pattern, but those nuts screw onto darn near any similar bolt in the area. That's the extent of the data I could get easily for you. Best of luck with the swap!

BAMBY
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Re: Brake Booster Dimensions

Postby BAMBY » Thu Jun 15, 2017 1:09 am

Centralcoaster33,
Thanks for the info!

Jonathon at ChaseBays also replied today with the following dims for S14:
"Its just a standard square bolt pattern. The pattern for the Nissan plate is 3.164 inches Wide and 2.414 inches tall."

That's nearly what you measured as well, so I feel confident we have good numbers from two good sources now.

So I'm reading the short message from Chase Bays, thinking to myself, "I wonder how STANDARD this bolt pattern really is"...

Here's the kicker- the booster from my D22 measured very close... originally I had used my dial calipers up in the footwell on the inside of the firewall to get some rough dims. Well I just pulled my booster and MC tonight, to get some accurate data for comparison... DEAD NUTS MATCH to the S14 dims!!
Thanks a ton for the help, if anyone's interested, I can update progress... though I know this is the S14 section...
Next I'm diving into some math to figure out how I really want to proceed... BBE kit would be optimal for freeing up space, but I'm surely concerned about the pedal requiring too much effort to brake safely. So if I determine via the math, that the BBE kit is a nogo, then I will be moving forward on the S14 booster, which likely will still require tweaking the master cylinder bore or something.
I've already got all my measurements done, master cyl bore, caliper piston diameters, brake pedal lever length and ratio, etc etc etc. And I spent the last hour building an excel spreadsheet to do the calculations with to figure out how changing up the variables will affect my pressure coming out of the master cyl and at the brake pads etc.
If anyone wants anymore info, just say so, be glad to give back a little help on this forum...
Thanks again y'all! :biggrin:

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centralcoaster33
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Re: Brake Booster Dimensions

Postby centralcoaster33 » Thu Jun 15, 2017 9:14 am

Stopping is just as important as anything else with a car. Maybe more. I think it's great you're geeking out on this a bit. Pedal feel and stopping power need to match the vehicle. Let us know how it goes. Others may be interested in this smaller booster configuration.

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AZhitman
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Car: 72 240Z RB25, 63 Bluebird RHD, 63 NL320, 67 WRL411, 67 SPL311, 68 510 SR, 73 240Z, 77 620 SR20, 89 Pao, 98 S14, 12 Titan CC 4x4.
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Re: Brake Booster Dimensions

Postby AZhitman » Sat Jun 17, 2017 12:39 am

This is cool - I'm thinking it'd make a great homepage article, if you keep documenting everything!

BAMBY
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Re: Brake Booster Dimensions

Postby BAMBY » Sun Jun 25, 2017 5:41 pm

Alright you guys seem to be curious, so I will leave an update or two along the way...

Here is the latest.

ChaseBays is very difficult to get good communication from in the past 17 emails I have sent. I keep telling Chase that I want to have a phone conversation about the numbers I am seeing in my spreadsheet. He has been acting evasive for some reason, with excuses every time. Only on the 19th email did he agree to setup a time with me this week to talk... We'll see how that pans out... Im actually not quite sure I would buy his BBE kit, even if we can get the numbers to make sense at this point, simply due to the poor communication, compounded by various other reports of same on the web.

In the mean time, I ordered a reman booster from my local auto store. For a 95 240SX/S14 5spd NONabs.
I sat down and compared it next to my D22 booster in order to see how it would fit etc etc. The D22 uses a 0.200" aluminum spacer between the booster and firewall. I noticed the threaded rod on the S14 booster is a bit shorter than on the D22, but if I subtract the thickness of the firewall spacer, it ends up being the same and the clevis position is unaffected. Then I checked to make sure the booster didn't interfere with the firewall if I avoided using the spacer... that mounted up flawlessly with about 1/4" clearance to a pinchweld where the firewall is mated to the cowl area that houses the wiper linkages at the base of the windshields. Booster diameters are the same, each close to 9" or so, so no change in interferences in a radial direction. Hmm... wonder if the mastercyl bolts up? Yup, sure does, exactly the same, even the pushrod stickout was the same. Only difference is the vacuum hose goes to the drivers side of this booster, where the D22 vacuum connection was on the psgr side of the booster, but putting a longer hose in is easy enough.

Long story short, it was truely a bolt in affair, with the exception of the brake lines between the MC and ABS block, which obviously required some adjusting to compensate for the MC that has now moved rearward a total of 2.200". But, that was no problem, I just gently adjusted the bends on those lines and put them right back where they go.

So that's the solution I am going with for now. I get to keep the stock master cyl, and therefore stock bias valve and calibration, and I have somewhat of a booster, but i get an extra 2.2" to work with, which is just on the edge of where I wanted to be.

I am still going to try to talk with Chase to see how the numbers work out, because I ultimately think I would like that setup better if I could make sure it was safe. My main concern is too much pedal effort required, which you could compensate for by lowering the mastercyl bore, but then you're also lowering the amount of brake fluid displaced, so the pedal would likely travel closer to the floor than normal to acheive the same braking pressure. Its a big darn balancing act basically with any of the variables.

Until I get the engine reassembled or built, I cant comment on the braking feel, but at least I know it would be the same if the booster failed, because in that case youre essentially deleting the booster, and only relying on the master cyl, which is a valid consideration when the OEM designs a braking system to ensure that minimal margin of ability to brake and slow the vehicle.

Any questions let me know, I'll check back in soon with another update.
And, i would like to upload a few pics to support, im doing all this from my android phone and cant see a way to just add pics to my post, unless im just missing something... anybody have advice for a guy without a photobucket account or the like?

Hope yall have enjoyed the weekend. :dblthumb:

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centralcoaster33
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Re: Brake Booster Dimensions

Postby centralcoaster33 » Mon Jun 26, 2017 12:08 pm

Cool stuff! Because we don't host pictures here, you can't directly upload them to us. So, you have to upload them to an image hosting site and then use the links they provide to embed the images into your post here. I'm pretty sure I use imgur.com (it's been a little while).

Anyway, I'm glad it all has been bolted up. Hopefully, you'll be testing your braking abilities soon. Good luck with all the engine work!


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