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Discussion Starter · #1 ·
I just installed the stealth bolt and the metering bolt, I took the car down the road and hit the brakes...... Holy Cow!!! What a difference. I have never spent $50 and got this much of an improvment with anything I have put on the car yet.It feels so good to have the car stop the way I want it to and the way it should have from the factory.I wish I would have done a 60-0 before and after because the results would have been dramatic.As a matter of fact I am now curious how long my rear brakes will last because I know they are doing so much more work. I guess we'll see. I figure even if I have to replace them once a year it will be worth it. I have read some things about the way the car acts during a panic stop with this mod. I will be on the look out for any negative effects and I will post my findings. However for now I am very pleased.
 

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agreed! the steath and metering bolt are the best braking upgrade you could do. my rear brakes are actualy lasting longer now, before my rear rotors would rust/rot/pit badly cuase they weren't doing anything. now no issues. i used ceramic pads and cross drilled rotors, i'm super happy with the brakes....
 

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I haven't done a burnout in 5 years since I did this mod. I really need to get that line-lock installed...

My rear pads seem to be wearing a bit faster than the fronts now. Be aware that there are a number of front pad variations that may help equalize wear on the pads. Not all B-body brake pads are the same in size and profile.
 

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It's pretty much 'common knowledge' for most that both the steath and metering bolt mods are intended only for disc rears.

Just not intended to be used on drum rears. Bears repeating occasionally.
 

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Discussion Starter · #5 ·
Doing a burn out is something I forgot to consider but that is a good point. I guess I will be looking for a line lock too. I only go to the track a few times a year so I guess its not the end of the world
 

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I believe the panic stop issue was only if you didn't install the metering bolt (front brakes would apply slightly later than the rears). I only did the proportioning bolt and haven't noticed it, but I haven't really been in any super panicky braking situations

as for burnouts, I can still do them, but that's most likely because my posi hasn't worked in years :-(
 

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$50!!!! Holy piss...did they include a 5 gallon vat of vaseline?
 

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Why have you found them cheaper? Because I've only seen one dealer for these and thats how mucher they've been selling them for.
Just did mine too and paid that much! Plus I decided to pay NTB to bleed/change the the brake fluid too. Then decided to have them change the oil while it was in there. Got expensive quick.:(
 

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Why have you found them cheaper? .
He might be referring to the fact that you can simply mod the original bolt for just the cost of maybe a threadtap if you don't already have the right size.
 

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Discussion Starter · #12 ·
The stock bolt can be tapped, however on the stock bolt there is a void space where the spring and shuttle used to go.I am not sure how this empty space will effect things.As for the metering bolt they are the same over all length. It looks as if you could cut a 45* chamfer on your stock bolt. How much and how far? Thats anyones guess.$50 seems like alot but there is nowhere that sells them cheaper and it is one of the best bang for the buck mods you can do
 

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IIRC red loctite after tapping seals the hole when installing the smaller bolt insert. Simpling grinding a chamfer of the shoulder does the other bolt.

There's write-ups out there on the process. Scott's manual or Qalo's book might have it. Check the Stickies, otherwise F-body.com or the like.
 

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The stock bolt can be tapped, however on the stock bolt there is a void space where the spring and shuttle used to go.I am not sure how this empty space will effect things.As for the metering bolt they are the same over all length. It looks as if you could cut a 45* chamfer on your stock bolt. How much and how far? Thats anyones guess.$50 seems like alot but there is nowhere that sells them cheaper and it is one of the best bang for the buck mods you can do
Well then that one shop (and no I don't care if it's a vendor or not) is RAPING everyone.

Thats a $4 (if that) part...especially for a shop who clearly has their lathe already making it...even a local machinist with a lathe and a scrap pile can make one for you in about 10 minutes having never made one before...it's just a straight thread, nothing fancy about it...and the "mod" to the rear bolt...takes about 4 seconds in a lathe as well.

And...there is NO "neck of the woods" without a machine shop nearby.

Or you could just do it the original way...go to the junk yard, take the rear bolt out of a car...now that combined with the one in your car already gives you 2 solid bolts...mod one to make it what the front bolt needs to be (just needs to end at the threads) and mod the other to be what the rear bolt needs to be (just needs that chamfer)...put them both in the proportioning valve, bleed your brakes.

Anyone who ONLY does the stealth bolt without the metering mod...should really go out in a parking lot, at about 10 mph, and pretend a pedestrian just walked out in front of their car and smash the brake pedal to the floor as abruptly as you can...watch how poorly the car reacts (it will be very very very ****ty)...now go back home and do it right.
 

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All I know is for years it was "stealth bolt" you just gotta do it! We all wanted to fix that "90/10" factory action and the "stealth bolt" was the fix. So....a bunch of us ran out and did the "stealth bolt" which is the proportioning mod and never bothered about the metering end of things, in fact in the early days you could not find a thing about the metering at all, at least I could'nt. Nobody whispered a thing about the metering.

Now....I bet alot of cars are currently driving around this country with just the front proportioning "stealth bolt" installed and I will bet that their owners have been more than happy with the results. I gueSS they have not had to do a panic stop yet. Who knows.

I will say that with all the knowledge now posted (in detail) about the "rear bolt" there is no reason why folks should be running just the proportioning mod in 2010, definately go back in there and do the metering end of things too. It does make a difference.
 

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All I know is for years it was "stealth bolt" you just gotta do it! We all wanted to fix that "90/10" factory action and the "stealth bolt" was the fix. So....a bunch of us ran out and did the "stealth bolt" which is the proportioning mod and never bothered about the metering end of things, in fact in the early days you could not find a thing about the metering at all, at least I could'nt. Nobody whispered a thing about the metering.

Now....I bet alot of cars are currently driving around this country with just the front proportioning "stealth bolt" installed and I will bet that their owners have been more than happy with the results. I gueSS they have not had to do a panic stop yet. Who knows.

I will say that with all the knowledge now posted (in detail) about the "rear bolt" there is no reason why folks should be running just the proportioning mod in 2010, definately go back in there and do the metering end of things too. It does make a difference.
Well...I've been on the forum for 10 years now (the early days for me were 2000 when I was 18)...and I remember reading in extreme detail way back then, about why I should do both at the same time. It was posted by Ken Rolt way way way back in the day, it was in "The IGBA Tech Archives" and a few other places that are all now gone...it was there in the days when you could ask a question and not have the first 14 responses be "do a search"...
 

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The reason people are saying that it costs $50 is because we sell the stealth bolt and the metering bolt as a package for $49.99. The stealth bolt alone is around $29.

Here is a copy of the writeup we did on these mods a while back:


We lost a lot of great info on the Brake Bolt Upgrades in the crash of '09. I'll do my best to do a brief overview of the problem and solutions with information I've collected over the years. Much credit due to the people who pioneered these solutions - I'm just passing along the info.

The Stealth Brake Bolt and "Bolt II" Metering Bolt are two of the easiest, cheapest, and most beneficial mods that you can perform on your B-body. Read on to find out why!

Cliff's notes for those of you who don't want to read: the Stealth Brake Bolt and "Bolt II" Metering Bolt take about a half hour to install, cost less than $50, and significantly improve your braking. They are available on our website - www.powerperformancemotorsports.com

Background


Source - carphotos.cardomain.com/ride_images/1/3438/3541/8594270003_large.jpg

The combination valve in the Impala SS / Caprice (pictured above) performs the following functions:

1. Front/rear brake bias (also called proportioning)
2. Metering (delay) of front brakes
3. Shuttle switch for hydraulic failure of front or rear brakes.

Because the Impala was made in such small numbers, GM didn't bother to design a specific combi valve for the SS. The bean counters at GM installed the exact same brake proportioning valve in the 1991-93 Caprice (drum rear brakes) as the 1994-96 Impala SS/Caprice 9C1 (4 wheel disc brakes). This causes two problems:

1. Proportioning. Disc brakes have much greater braking power than drum brakes, so cars with rear drum brakes use a mechanism to reduce the pressure to the rear drums - this way, the front brakes do most of the work. Factory brake proportioning is 95% front and 5% rear, which is ideal for cars with drum rear brakes. In a 4-wheel disc car, however, you want the rear brakes to do more than 5% of the work (because the brakes are much more capable). The result of the 95% front / 5% rear proportioning in a 4-wheel disc car is accelerated front pad wear and excessive brake dive under heavy braking. The rear pads are just along for the ride and last practically forever. The brake proportioning is controlled by a 19mm hex bolt on the front of the combi valve (see photo below).

2. Metering. Drum brakes take time to "energize." Cars with rear drum brakes use a mechanism to delay the onset of the front brakes so that all 4 brakes engage simultaneously. This "metering function" allows the return springs in the rear drums to be stretched to the point of drum/brake-lining contact before engaging the front brakes. In a 4-wheel disc car - like the Impala SS and Caprice 9C1 - this delay is unnecessary and hurts the reaction speed of your brakes, ultimately resulting in longer stopping distances. In a hard stop, the front brakes will not engage at the same time as the rear brakes. The brake metering is controlled by a 19mm hex bolt on the rear of the combi valve (see photo below).


Source - gofasst.us

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Solutions

Fortunately for all of us Impala SS / Caprice 9C1 owners, there are solutions for these two problems. The Proportioning problem (problem #1 above) is solved by replacing the stock 19mm hex bolt on the front of the combi valve with a nifty little piece called the Stealth Brake Bolt. The stock bolt is vented and holds a spring and red aluminum plunger in place (see below). The Stealth Brake Bolt replaces the stock vented bolt and the spring and red aluminum plunger are discarded. It's that simple - after that is done, your brakes are now proportioned at approximately 65% front and 35% rear!


Source - gofasst.us

The Metering problem (problem #2 above) is solved by replacing the 19mm hex bolt on the rear of the combi valve with a different bolt, commonly referred to as the "Bolt II" Metering Bolt. The stock metering bolt is aluminum and is comprised of an integral hex nut, rubber o-ring, and a male threaded section. It is a solid bolt and is machined to have two stepped, concentric metal solid cylinders. The innermost metal cylinder is the longest part and it serves as a mechanical stop for the brake safety shuttle switch (should it engage due to a hydraulic failure), as well as serving to reduce the brake fluid volume in the front-brake section of the combination valve. The outermost cylinder also serves to reduce the brake fluid volume in the front-brake section of the combination valve, but its main purpose is an inexpensive metering valve. When the bolt is screwed into the combi valve assembly, the outermost cylinder covers 50% of the orifice used to feed the front brake line with brake fluid pressure. This can be a bit of a confusing description - the main point is that part of the stock metering bolt covers a hole, causing a brake fluid flow restriction and causing the delay in engagement of the front brakes.

To solve this metering problem, the stock bolt is removed and discarded, and replaced with a new bolt that is modified to remove the flow restriction. Alternatively, the stock bolt can be modified to remove the flow restriction, but I won't cover this here for liability reasons.

Both the Stealth Brake Bolt and the "Bolt II" Metering Bolt are available from Power Performance Motorsports. The Stealth Bolt is $26.99, the "Bolt II" is available for $28.99, and they are available as a package for $49.99. All prices include free shipping.

Our website is www.powerperformancemotorsports.com

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Instructions

Stealth Brake Bolt Instructions

Tools needed:

Ratchet
19m hex socket
Adjustable wrench
Needle nose pliers
Paper towels

Procedure

1. Place some paper towel or a shop rag underneath the combi valve.

2. Remove the rubber vented cap and paper tag from the stock bolt (located on the front of the combi valve).

3. Use the adjustable wrench to hold the combi valve body. Loosen the stock bolt (located at the front of the combi valve) with the ratchet. Be careful not to bend the brake lines.

4. Remove the bolt by hand and use the needle nose pliers to extract the spring and red aluminum valve. Be sure that the red aluminum valve has a black plastic "doughnut" at one end. If not, you will have to remove it from the combi valve with a paper clip or other suitable tool. Discard the spring and red valve.

5. Hold the combi valve body with the adjustable wrench and install the new Stealth Brake Bolt.

6. Reinstall the rubber vent cap and paper tag (to retain stock appearance).

7. BLEED THE BRAKES (procedure not covered here) and check for leaks, especially around the Stealth Brake Bolt.

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"Bolt II" Metering Bolt Instructions

Tools needed:

Ratchet
Shallow 19mm socket
Adjustable wrench
Brake fluid
Plastic bags
Paper towels
Shop rag
Turkey baster (found in utensil aisle at grocery store or Walmart)

Procedure

1. Place paper towels inside plastic bags. Place plastic bags underneath back of combi valve to catch brake fluid.

2. Use the adjustable wrench to hold the combi valve body. Loosen the stock bolt (located at the rear of the combi valve) with the ratchet. Be careful not to bend the brake lines.

3. Remove the bolt by hand and discard. Replace it with the new "Bolt II" Metering Bolt.

4. Remove the cover of the master cylinder reservoir and remove the old brake fluid using the turkey baster, down to almost to the bottom of the front and rear reservoir. Wipe the remaining "sludge" from the bottom of the reservoirs.

5. Refill each reservoir halfway, and bleed the brakes (procedure not covered here).

6. Check for leaks, paying close attention to the new bolt that you just installed.

7. Replace the master cylinder reservoir cover.

8. Start the car and press the brake pedal. The pedal should be hard and feel tight.

9. Re-check for leaks.
 

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So other than the idea of making money...is there anyway this mod can be done utilizing the stock bolts. If it says that a bolt is too long and covers one of the orifices, why can't it be shaved down?
has anyone done this?
Granted, I don't have a complete machine shop in my garage but it's not short of having a few specialty tools.
 

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So other than the idea of making money...is there anyway this mod can be done utilizing the stock bolts. If it says that a bolt is too long and covers one of the orifices, why can't it be shaved down?
has anyone done this?
Granted, I don't have a complete machine shop in my garage but it's not short of having a few specialty tools.
Yes, it can be done. Search around and there are procedures on how to do it.

For those not comfortable with grinding/modifying the components in their brake system, they can order the correct, new, bolt-in stuff from us.

Hope this helps!
 
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