Any pro tips for replacing the brake booster?
 

I'm going to try to tackle the brake booster and master cylinder tomorrow and it looks like swapping out the brake booster is going to be a pain in the ass.

If you have any suggestions, I'd love to hear them.

Long extension, 14" should do. that way you don't need to swing a ratchet in tight confines.

I didn't find it to be that much if a pain IMO. It may help to have a friend though.

Pro tip: Put fluid back in and bleed the system before testing.

It's not that hard.

As others have said, easy peasy. A swivel adapter is your friend to get the two two bolts under the dash, iirc.

I don't think you understand how bad at cars I am.

Thanks for all of the advice!

Take the seat out, obviously. I dropped the lower panel below the steering wheel as well.

It's not difficult, I just get frustrated messing with stuff like that.

Taking out the seat is probably a 2 hour affair since I was in a rush to complete the car last year. I need to fix it, but I don't have the time flexibility until next month unfortunately.

I'm hoping that the seat won't bruise me too badly.

It's 4 bolts....

What are you doing that it takes 2 hours?

Interesting, don't know how everyone else contorted their bodies, but I just removed my seat and laid with my back on the floor and did it upside down.

Can't imagine trying to do it with the seat in.

Not a problem, either put you legs up on the cage and work fast (before your head gets too red) or place a bench in height with the sill and poke you head/arms in there from the side (not possible with door bars).

But I have a 12" steering wheel, that gives me more room. Big torso and long arms does not help...

Side mounts, didn't cut out the rear humps.

Steel stock to mount to the floor goes in first. Seat with side mounts goes in second and gets bolted completely blind to the steel stock. Basically, Momo side mounts don't fit in the Miata and they're pretty awful.

It's on my bucket list of stuff to fix, but time is of the essence.

That wasn't too bad, but the MC is leaking at one of the seals so Amazon Prime is 1-day shipping a new MC.

Now my booster is being held on by 4 nuts versus 3!

Getting the 4 nuts *out* is easy (long extension, might need a U-joint socket), no need to take the seat out.

Getting the nuts started so that you can put the new one back in is something else entirely. You want small hands.

I also found the little locking clip for the brake pedal clevis to be a major PITA.

--Ian

The brake one was easy. I've decided my clutch master one is impossible and will require me to pull the pedal assembly, its like it was installed with the pedal assembly out and whoever did it didnt think about how you'd get it off with it in the car. If they'd have just put the pin in the other way around...

What maes you think the booster needs replaced?

It's part of a conversion to the NB2 5/16 master.

You can't mix NB1 and NB2 boosters and masters.

--Ian

You cant mix masters between thick and thin boosters.

You mean in addition to the NB1 vs NB2?

(my original 99 NB1 booster and ABS NB2 2003 booster are the same thickness. They're visually identical except for the angle of the vacuum fitting and the length of the pushrod)

--Ian

No, you can mix nb1 and nb2 as long as they have the same thickness booster, because if they have the same thickness booster they'll have the same thickness pushrod. Not all nb2s have the thick booster.

I haven't seen enough of the booster and master combinations in person but my understanding is that the thick/thin booster on NB2s is an ABS vs non ABS car difference and that the masters are interchangeable between all NB2 cars. The thread is super off topic now- andrew swapped his NA booster/master combo for a non ABS NB2 booster and master in order to improve brake feel.

NB2 Sport Booster/Master.

Sport brakes were standard 2003-2005.

Except they don't. As I said, my NB1 booster has a different length pushrod in it than my NB2 one, and yet the two boosters are the same thickness.

--Ian

I put a 1" 929 MC in my ABS 94 and did not need to change the booster. Based on this mt.net thread I was led to believe that I would, but the 929 MC bolted right up to the NA8 ABS booster. I'm guessing the NB2 15/16" MC would as well.

It's possible (likely?) that the appropriate booster has a higher boost ratio for lower pedal effort, but I actually prefer the higher effort, especially with Carbotech XP8/XP10.

FWIW, I have two NB2 boosters that are should work with the 15/16" and 1" masters, though I have not tested either of them. I'd be willing to let them go for shipping + $10.

Edit- moved to PM

If the issue is the pushrod length, just make sure you get the pushrod with the booster. Derp!

Are you 100% certain on the thickness? The booster ratio between NB1 and NB2 is different.

I didn't break out the digital calipers, so it's possible they differ by a few mm, but neither of them is the double-thickness booster that is discussed in the miata.net thread. I had them sitting side-by-side out of the car, and they are visually identical except for the length of the pushrod and the angle of the vacuum fitting.

I think the booster/MC combinations are significantly more complex than the ones that Keith looked up and posted in that thread.

--Ian