Aussie Brake Booster
Thread Starter
Burning Brakes
Joined: Dec 2002
Posts: 1,199
Likes: 4
From: Cairns Australia
Aussie Brake Booster
The outer shell of my brake booster (1988) split and the local brake shop fitted a 2nd hand one from a Falcon (I'm in Australia).
I have some questions -
1. Does anyone know what model Falcon the outer shell was from ? and whether the entire Falcon brake booster would fit?
2.Is the metal replacement booster better or worse than the plastic one - picture here http://www.ecklers.com/product.asp?p...1&dept_id=1068
3. Is there a more powerful booster that I could use - ie dual diaphram or whatever?
I have some questions -
1. Does anyone know what model Falcon the outer shell was from ? and whether the entire Falcon brake booster would fit?
2.Is the metal replacement booster better or worse than the plastic one - picture here http://www.ecklers.com/product.asp?p...1&dept_id=1068
3. Is there a more powerful booster that I could use - ie dual diaphram or whatever?
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
Mate there is not much point to a more powerful booster unless youre changing the master cylinder as well i reckon, the ZR1 booster is a dual diaphramn and can be made to fit, but itll be ALOT of work on your RHD car. I dont reckon its worth the effort, cause the braking problem with Corvettes from 88-94 with the JL9 brakes is nothing whatso ever to do with the booster, its the same booster as used on the J55 fitted cars, and was used by the VR Commodore, no braking issues there, stopped same as the VP, and the Falcon using that booster stopped fine too.
I dont like the metal booster, and it will last no longer internally than the plastic one will.
Due to my hours of tafe attendance at the moment ill be unable to find out exactly which Falcon had the same booster for about 2 weeks, but there is a few ways to find that out.
I replied to your email earlier on with a fair bit of info for ya, any decent brake joint or Repco center should be able to tell you exactly which Falcon used that booster.
I dont like the metal booster, and it will last no longer internally than the plastic one will.
Due to my hours of tafe attendance at the moment ill be unable to find out exactly which Falcon had the same booster for about 2 weeks, but there is a few ways to find that out.
I replied to your email earlier on with a fair bit of info for ya, any decent brake joint or Repco center should be able to tell you exactly which Falcon used that booster.
Thread Starter
Burning Brakes
Joined: Dec 2002
Posts: 1,199
Likes: 4
From: Cairns Australia
Thanks Casey, just got your email - would be good to find out which Falcon Model and also whether the entire unit will fit.
Is the ZR1 booster wider? Is that why it would be hard to fit? and why wouldn't it make braking easier/better?
Is the ZR1 booster wider? Is that why it would be hard to fit? and why wouldn't it make braking easier/better?
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
It wont do anything for braking apart from make the effort easier, which is pointless, cause youll just hit the back of the master cylinder easier. Booster is not your braking problem.
The thing that will make it hard to fit is the fact it has 4 mounting studs and the standard booster has 2, so youll need to modify it for that, as well as anything else you may find an issue during the install.
At the end of it all, your brakes will still have the same friction co-efficients they had before you replaced the booster.
The thing that will make it hard to fit is the fact it has 4 mounting studs and the standard booster has 2, so youll need to modify it for that, as well as anything else you may find an issue during the install.
At the end of it all, your brakes will still have the same friction co-efficients they had before you replaced the booster.
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
Believe another reason to NOT use the metal ZR1 booster is the rods to/from the pedal/master are slightly different and would need to be adjusted/modified.
Suggest (like suggested above), just continue to use the OEM/plastic unit -- since it's all about the internal rubber diaphram anyway.
And if your trying to improve the brakes --- check to make sure your getting good idle vacume (15-20 psi) and that the check valve (where the vacume hose connects to the booster) is holding in the vacume, otherwise replace it (remember vacume varies, so the check-valve helps hold in the higher vacume for when vacume is lower, but braking is needed).
Suggest (like suggested above), just continue to use the OEM/plastic unit -- since it's all about the internal rubber diaphram anyway.
And if your trying to improve the brakes --- check to make sure your getting good idle vacume (15-20 psi) and that the check valve (where the vacume hose connects to the booster) is holding in the vacume, otherwise replace it (remember vacume varies, so the check-valve helps hold in the higher vacume for when vacume is lower, but braking is needed).
Thread Starter
Burning Brakes
Joined: Dec 2002
Posts: 1,199
Likes: 4
From: Cairns Australia
Case -
- that sounds great to me, it might bring the braking 'feel' up to the level of normal cars - my brakes work it's just that they need more pedal pressure than a modern car.
BUT if it means I have to modify the rod which is part of the valve assembly then I think I'll pass. I'm happy to tinker and modify things, but in this case I doubt it's worth the effort.
Thanks for the advice, looks like I'll stay with the plastic booster.
Now I just need to know whether there is an aussie equivalent, if not, then I'll get the Corvette one.
It wont do anything for braking apart from make the effort easier
BUT if it means I have to modify the rod which is part of the valve assembly then I think I'll pass. I'm happy to tinker and modify things, but in this case I doubt it's worth the effort.
Thanks for the advice, looks like I'll stay with the plastic booster.
Now I just need to know whether there is an aussie equivalent, if not, then I'll get the Corvette one.
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
Rob the reason you need more pedal pressure is the bore size in the master cylinder. If you change to a master cylinder with a smaller bore size, youll need less effort, but youll have to push further.
The booster fitted to your car now is a good piece, its the rest of the setup that lets it down, if you want to look at it that way. I was always quite happy with the extra effort required.
When you go changing things around like this, be prepared to have issues, or find that the way you thought would be better, is actually not as good as youd hoped.
Ive driven a ZR1, and i dont reckon the booster made the brakes any different to any other J55 fitted Corvette ive driven before.
Your engine should easily have plenty of vacuum, so your booster should have plenty of draw. If it does not, then i would think your reaction disc is not sealing the front half of the booster from the rear half properly when you push on the pedal.
Have a bit of a read of a piece i wrote a fair while ago:
From that, you may be able to gain some more knowledge on where you feel your system is leaving you short.
The booster fitted to your car now is a good piece, its the rest of the setup that lets it down, if you want to look at it that way. I was always quite happy with the extra effort required.
When you go changing things around like this, be prepared to have issues, or find that the way you thought would be better, is actually not as good as youd hoped.
Ive driven a ZR1, and i dont reckon the booster made the brakes any different to any other J55 fitted Corvette ive driven before.
Your engine should easily have plenty of vacuum, so your booster should have plenty of draw. If it does not, then i would think your reaction disc is not sealing the front half of the booster from the rear half properly when you push on the pedal.
Have a bit of a read of a piece i wrote a fair while ago:
They wont always hiss inside the car when they fail, this only occurs when the main diaphramn fails.
When your foot is off the pedal, both the front and rear of the booster is subject to vacuum, by pushing on the pedal, the reaction disc will seal off the front section from the rear, and the rear valve will open, which allows the rear to return to atmospheric pressure, which in turn will result in the vacuum piston being drawn toward the front of the booster.
In the case of a damaged shell (front or rear), the vacuum leak will be always present, foot on the pedal or not. You wont hear any hissing inside the car if this is the case.
If indeed the main diaphramn fails, you can bet the rear main seal wont be far behind it.
When your foot is off the pedal, both the front and rear of the booster is subject to vacuum, by pushing on the pedal, the reaction disc will seal off the front section from the rear, and the rear valve will open, which allows the rear to return to atmospheric pressure, which in turn will result in the vacuum piston being drawn toward the front of the booster.
In the case of a damaged shell (front or rear), the vacuum leak will be always present, foot on the pedal or not. You wont hear any hissing inside the car if this is the case.
If indeed the main diaphramn fails, you can bet the rear main seal wont be far behind it.
