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Old style vs new style brake boosters


Dark Ride
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ive heard if you swap the booster to grab its brake pedal from the donor car. but not for the plunger rod, but more for the pedal feel it has. iirc people say its got a different angle to it making it  feel better. 

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The M/C pushrod is at least 2 inches longer, maybe closer to 3. I took some pictures comparing them just need to get them posted. The hole for the pedal looks bigger on the m/c rod too. The old master cylinder will bolt up just fine to the newer booster. The pushrod on the front side is the same as the 99 Lumina booster, which is a little different design from the 90, but I don't think it matters.

 

I hadn't heard that about the swapping the pedal, it would be a lot of work, and the stock pedal doesn't bother me that much in that regard.

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brake pedal is rather easy, a plug and pin with a clip and it falls in your hands.  its one of the more simple things under the dash to remove.  and if its makes the push rods length right its a win win .

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Ah, I see what you mean now. That's a thought. I'll have to look under there as there isn't a lot of room for the pedal to come back farther without hitting the mount where the cruise control vacuum release switch was.

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Alright, so here are the pushrods:  Top is 90 GP, Middle is 99 Lumina, Bottom is 02 Monte Carlo:

 

20171211_181141.jpg

 

Here are the two booster side by side, basically identical.  Don't tell my wife they were on the table.

 

20171211_174737.jpg

20171211_174723.jpg

The second picture makes it look like the newer one is shorter, however that's mostly an illusion caused by the angle and slightly different shape.  I do not think it is any shorter.

 

Finally, here is what it looks like underneath.  Even if I swapped pedals I think the longer pushrod would cause problems.  This is where the pedal would be if I made a new slot on the old pushrod.

20171211_204809.jpg

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This is very interesting.

 

This post might turn into an odd mess, but bear with me...

 

First thing first, I don't mean to be rude in any form but what is being referred to a "push rod" in the picture post is actually the "pedal rod". The "push rod" is the one that makes contact with the master cylinder. I had to point that out because RockAuto lists all pushrods at 4.62 long but the pedal rods have different "codes" with no real indication of their size or mounting point taking into account that the W4 pedal rod is 3 inches longer and has a bigger hole compared the C7 from your 90 GP and the unknown code pedal rod from the 99 Lumina booster.

 

So a couple posts back, I had mentioned the 95-01 Lumina specifically had different pedal rods and each re-man company lists different pedal rod codes. What Dark Ride confirms is that the pedal rod codes do mean something to a degree BUT now it opens up the question....

 

Since every 3 years give or take got a new booster, would it be possible that there's a car that has a pedal rod that will work with the 2000-2005 Monte Carlo and Impala booster or is there more to be researched?

 

I mentioned in a post back that Prior had a reman booster on Rock Auto (PN: 7700568) that lists the 94-96 Regal, Grand Prix, Cutlass Supreme (but not 97) as cars that use this booster ALONG with the 2000-2004 Impala, the 1995-2005 Monte Carlo, and the 1995-2001 Lumina (but not the 1994 Lumina). I went back on Rock Auto to see what pedal rod it has, and it lists "W2" as the pedal rod code. Random thought, but could W2 use the same mounting point as W4?

 

I tried searching the pedal rod on google to see if they can be bought separately, but nothing shows up. 

 

Also, 2 things before I forget...

 

How did you turn the brake booster without the "special tool" that's supposed to go where the master cylinder goes?

 

How is the pedal attached to the rod? (I haven't gone down to look in my Z34, but I want to start preparing for that job)

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Hey Nas, yes calling it a pedal rod is more accurate and helps keep things clear. As far as turning the booster, I just use a claw hammer. One with a long claw so the head is basically a "T". Figure out which way you need to turn it (clockwise to lock, counter clockwise to unlock) and just go gentle. It's not something that takes a lot of force. In my last picture you can see where the pedal attaches to the rod. There is a shaft on the pedal that the rod and brake switch attaches to. There should be a clip on as well to keep the rod from coming off, but I hadn't installed it for that picture.

 

Also I just confirmed the 99 Lumina pedal rod IS the W2 rod, it was stamped on the other side.

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Just a silly question but, that lenght isn't necessary because the new booster has more throw right? Like a short rod isn't going to move the booster all the way? I imagine you verified that early on but still.

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With the short rod in, if I depress the brake pedal all the way it pushes the pushrod (going into the master cylinder) out at least an inch or more so it seems the rod length probably has to do more with the car design.

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  • 2 months later...

Been doing some more thinking on this and if anyone happens to have a brake booster out with the W3 pedal rod, I would be interested to know how long it is and where the slots in the rod are.  I'm guessing I'll end up using my stock rod with the new booster but would be curious to see the W3.

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  • 5 months later...

So I wanted to add some final notes to this thread.  I finally got back to this and the new 02 Monte Carlo Brake Booster is installed.  One other issue I ran into was when I went to put the master cylinder in place.  The 90 GP master cylinder is recessed into the brake booster farther than the 2nd gen master cylinder is.  This is the part I'm talking about.  The length it goes into the brake booster is longer.

20180810_151227.jpg

So what was happening was that when I tightened the bolts holding the master cylinder to the booster, the push rod was making contact with the cylinder and engaging the brakes.  When I took the master cylinder back off, it was pretty obvious what the problem was and at first I was unsure how to fix it.  I pulled the pushrod out and compared them.  Then I noticed a flat plastic washer/spacer on the end of the pushrod.

20180810_151032.jpg

I removed that and reinserted the rest of the pushrod, but still had a little bit of engagement.  I ended up putting two very small washers on the bolts between the master cylinder and booster and that solved my problem.  Now it's worth noting that this probably would not be an issue with a 2nd gen Master cylinder, but it was with mine.  I haven't driven it yet and won't be able to for a while, but hopefully it ends up being worth it.

Edited by Dark Ride
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So this is: 

Second Gen HD booster (Monte/Impala 9c1)

First Gen non-ABS MC

First Gen pedal rod

Second Gen push rod with the little bitzel removed from the end

Right?

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7 hours ago, Imp558 said:

So this is: 

Second Gen HD booster (Monte/Impala 9c1)

First Gen non-ABS MC

First Gen pedal rod

Second Gen push rod with the little bitzel removed from the end

Right?

Yes, that is the setup I'm planning to use.  What's interesting is that except for a small difference in the metal insert on the end of the pushrod, I didn't see any real difference.  I should've grabbed a picture.

Edited by Dark Ride
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