CPP Brake Booster and Master Cylinder Kit Issues

[dz1087]

Bought the CPP Booster and master kit through LMC. Had a few questions since the instructions are extremely lacking.

Does this mounting orientation look correct? I’ve never seen a master cylinder that is tilted that far down. Can’t see another way to get the booster mounted though.




Second - should the rod coming out of the booster be that close to the firewall? It has no vacuum on it so I dot want it to dent the firewall or damage itself if that rod is going to come out or something once vacuum is applied.

[sick472]

It looks like mine too. I got my kit from GMC Pauls and thought it looked more slanted down than the originals. The black assembly below is original equipment and the gold anodized is the new kit. Sorry the pics are not at the perfect angles, but your install looks correctly assembled and my push rod was very close to the firewall too. Keep in mind that my truck has a bit of a raked stance which amplifies the angle.

[yysenhimer]

I got the same kit recently. The rod was the wrong length and the booster was bad right out of the box (didn't hold vacuum, hard pedal). Spent a lot of time troubleshooting and straightening out the issues. My setup doesn't angle down as much. Will post a photo later.

[dz1087]

Originally Posted by yysenhimer

I got the same kit recently. The rod was the wrong length and the booster was bad right out of the box (didn't hold vacuum, hard pedal). Spent a lot of time troubleshooting and straightening out the issues. My setup doesn't angle down as much. Will post a photo later.

Which rod was the wrong length? The booster already had the master rod in there. It also came with another one, I'm not sure why though as the current rod looked correct.

The other two rods (From the pedal to the lever and from the lever to the booster) appear adjustable.

[dz1087]

Originally Posted by sick472

It looks like mine too. I got my kit from GMC Pauls and thought it looked more slanted down than the originals. The black assembly below is original equipment and the gold anodized is the new kit. Sorry the pics are not at the perfect angles, but your install looks correctly assembled and my push rod was very close to the firewall too. Keep in mind that my truck has a bit of a raked stance which amplifies the angle.

Yeah, yours looks pretty slanted like mine.

[Sheepdip]

I realize yours is pointing downward but I think pedal geometry may be the reason as stated here.

https://www.hotrod.com/articles/old-...-upward-angle/

[dz1087]

Originally Posted by Sheepdip

I realize yours is pointing downward but I think pedal geometry may be the reason as stated here.

https://www.hotrod.com/articles/old-...-upward-angle/

Good read. Those angles are what I'm familiar with and why my current mounting location looked so off to me.

[sick472]

I have not dug into what the right and wrong rod lengths are, and hope no to have to, but I don't think the booster/master assembly can be mounted any other way...it's going to slant down. If you zoom in on my left photo...you can see that the brake "stuff" that was on the truck 25 years ago when I bought it slanted down too...about the same amount. I'll try to get some better pics.

[dz1087]

Oh, I meant which of the three rods was the one with the incorrect length. I was assuming it was the booster to master cylinder rod that was the wrong length, but there are three rods on the system.

[yysenhimer]

The rod between the booster and master cylinder was too long. The booster not holding vacuum was a separate issue.

The pedal geometry also had to be corrected because the truck was originally manual brakes. Additional hole was drilled to correct this.

Edit: I should also add that a Wilwood caliper/disc setup is used on the front. Rear brakes are still drum.

[dz1087]

Originally Posted by yysenhimer

The rod between the booster and master cylinder was too long. The booster not holding vacuum was a separate issue.

The pedal geometry also had to be corrected because the truck was originally manual brakes. Additional hole was drilled to correct this.

Edit: I should also add that a Wilwood caliper/disc setup is used on the front. Rear brakes are still drum.

So even with the kit you had to relocate the pedal rod hole? Looking at it, it seemed like the lever arm on the mount took care of that.

How far did you move the hole? Up or down?

[yysenhimer]

I was mistaken about the added hole in this setup. Setup from previous owner was pieced together, required ratio change and never really worked. The new Wilwood/CPP setup did not require the ratio to be changed in the existing pedal bracket.

Here are photos of the mounting

[dz1087]

Originally Posted by yysenhimer

I was mistaken about the added hole in this setup. Setup from previous owner was pieced together, required ratio change and never really worked. The new Wilwood/CPP setup did not require the ratio to be changed in the existing pedal bracket.

Here are photos of the mounting

For your pro-valve there -- Are the two lines in the front (the one on the top and the front bottom one) going to each side of the front axle without linking anywhere?

[sick472]

Here are some better pics from my archives of original brake components.

[dz1087]

Yeah, the prebent ones I got from LMC are bent.

What they are bent for, I have no idea.