I give up with brake bleeding

[Hydratech®]

Note that the brake pedal rod MUST enter the master cylinder dead on straight in a manual brake scenario. Discussions of drilling different holes in the brake pedal in efforts to alter brake pedal ratios are not valid because the brake pedal rod will then enter the backside of the MC at an inappropriate angle causing linkage bind, MC failure from extreme side loading of the pistons, and even possible complete failure of the brake pedal rod linkage entirely.

Summary? You MUST keep your brake rod connection in the factory manual brake top hole - no if's, and's, or but's about it.

[GregWeld]

Funny.... when you buy a 1969 Camaro Brake pedal assembly - it has two holes from the factory -- Manual -- and Power....

It's only about a 1 inch difference and the angle of the pushrod is hardly an issue. The pushrod swings thru an arc regardless - it doesn't go straight in and out. The pedal pivots thru an arc....

The difference between a power booster and a manual is taken up in the ANGLE of the mounting at the other side of the firewall.... the power booster is usually tilted back (at the top) slightly due to the LOWER hole in the brake pedal being used (less ratio).... and the manual is usually mounted flat - and uses the "upper" hole (more pedal ratio).

Originally Posted by Hydratech

Note that the brake pedal rod MUST enter the master cylinder dead on straight in a manual brake scenario. Discussions of drilling different holes in the brake pedal in efforts to alter brake pedal ratios are not valid because the brake pedal rod will then enter the backside of the MC at an inappropriate angle causing linkage bind, MC failure from extreme side loading of the pistons, and even possible complete failure of the brake pedal rod linkage entirely.

Summary? You MUST keep your brake rod connection in the factory manual brake top hole - no if's, and's, or but's about it.

[Hydratech®]

"It's only about a 1 inch difference and the angle of the pushrod is hardly an issue."

The 1st gen F car factory vacuum booster is angled upward at whopping 17 degrees. Go crawl under the dash of a 1st gen F body and try to force the manual brake rod into the lower power brake pedal hole and see how that goes for you - it flat out isn't going to happen. If you somehow do actually manage to force it to happen, you are definitely going to get into linkage bind and extreme MC piston side loading leading to direct failure. Sooooo..... unless you angle your manual brake MC upwards by whatever means imaginable (to accommodate a 17 degree angle as bolted to the firewall), you are causing trouble talking about moving the brake pedal rod connection point from the upper manual brake pedal point to the lower power brake point in a manual brake equipped 1st gen F car.

[vstol]

Originally Posted by Hydratech

Note that the brake pedal rod MUST enter the master cylinder dead on straight in a manual brake scenario. Discussions of drilling different holes in the brake pedal in efforts to alter brake pedal ratios are not valid because the brake pedal rod will then enter the backside of the MC at an inappropriate angle causing linkage bind, MC failure from extreme side loading of the pistons, and even possible complete failure of the brake pedal rod linkage entirely.

Summary? You MUST keep your brake rod connection in the factory manual brake top hole - no if's, and's, or but's about it.

Thanks it is in the manual position now but switching to power and like Greg said the power location is about an inch lower. Thanks for the comments to both of you.

[GregWeld]

Originally Posted by Hydratech

Note that the brake pedal rod MUST enter the master cylinder dead on straight in a manual brake scenario. Discussions of drilling different holes in the brake pedal in efforts to alter brake pedal ratios are not valid because the brake pedal rod will then enter the backside of the MC at an inappropriate angle causing linkage bind, MC failure from extreme side loading of the pistons, and even possible complete failure of the brake pedal rod linkage entirely.

Summary? You MUST keep your brake rod connection in the factory manual brake top hole - no if's, and's, or but's about it.

I'm not sure you're tracking here. There are two holes in the pedal -- changing ratio - depending on if you have power or manual....

If the cars pedal only has the power brake hole -- but is being used as a manual car... then of course the ratio is messed up (4:1 vs 6:1) and the pushrod position and angle would be in the wrong location.

What I stated is that the MANUAL hole - if missing - needs to be added to the pedal to correct the ratio. When corrected - the pushrod would then be in the proper position for the manual master cylinder - and the ratio would also be corrected.

You're trying to inject a different issue -- which is to try to use the wrong position. The lower hole (closer to the floor) is there for POWER brakes - and the booster is at an angle so the rod and arc etc work correctly. The Manual brake position is about 1 inch higher -- making it a straighter "angle" -- and the factory manual master is mounted as such -- flat to the firewall.

[vstol]

I will use the lower hole in the 71 corvette pedal for the power brake setup thanks

[Hydratech®]

You're trying to inject a different issue -- which is to try to use the wrong position. The lower hole (closer to the floor) is there for POWER brakes - and the booster is at an angle so the rod and arc etc work correctly. The Manual brake position is about 1 inch higher -- making it a straighter "angle" -- and the factory manual master is mounted as such -- flat to the firewall.

Rest assured that I am certainly not trying to cause any trouble. In fact, I'm only making it certain that "under discussed" issues are crystal clear for some of our members / readers.

[vstol]

No issues here thanks for all your help guys. Once it is set up I will get back and close this out.

[dontlifttoshift]

So you are going to power brakes?

[vstol]

YES, booster came today