BRAKES

I didn't realize how important brakes were until I put a blower on my T.

 

And a parachute! LOL

Do you know how much boost you are running?

 

Brakes and steering are two very important items for a T-bucket. Even a mildly tuned engine can provide enough power to get you in real trouble if not careful. Most of these cars tip the scales below 2,000 pounds, and if you have added power via blowers, multiple carbs etc. you are driving a rocket sled! Fun, but potentially hazardous to your health!

 

Speed never hurt anybody. It’s suddenly becoming stationary that gives you problems!

 

What Breaks ?

 

What Breaks ?

 

Yes they are, I am having a vacuum issue. No power. Thinking I need new booster.

 

Buck. What size bore master cylinder are you using? For example, if you are using a 1 inch or great with a manual setup, you might not have enough fluid pressure for stopping. Generally, the smaller the diameter, the greater the pressure is produced with the same amount of force. There is a limit on how small you can go. That's why Wilwood uses 7/8" cylinder bores on many of their pedal setups. You might just need to replace the master cylinder with a smaller bore version if you are running a one inch or larger cylinder bore. Also, the pedal ratio is important for pressure too. If equal force is applied to a pedal with a 5 to 1 ratio as to a 7 to 1, the 7 to 1 will apply more force to the master cylinder do to leverage. This increases fluid pressure, better stopping. Make sure you pedal ratio is at least 6 to1 or higher with manual brakes so you don't need to stand on the pedal to stop. One last note, when was the last time you bled the brakes and or replaced the brake fluid. Brake fluid does not last forever.

 

Spirit uses 1” bore and 7:1 pedal and they have built a bunch of buckets.

 

Here is part of a Wilwood master cylinder bore to pedal ratio chart. With 100 pounds of force, a 1" bore with a 7 to 1 pedal produces 886 psi. With a 5 to 1 pedal, 633 psi. Swapping to a 7/8" bore with the same 7 to 1 pedal increases psi to 1167, nearly 281 more psi. This is why matching bore and pedal ratio is important. Next is fluid volume then front and rear bias.

 

When I built my wrecker I tried to build the best brakes I could using stock parts. One of the things I did was use a larger bore mc as well as the largest vacuum booster available. I have very little pedal travel and it will put you through the wind shield if not cognizant. Prior to the upgrades, it had more travel and much less aggressive stopping power. I’m also using non metallic, organic pads.

 

Does anybody use the silicone type brake fluid rather than the traditional DOT 3 fluid?

 

Not me. I did use it for motorcycles when I had my shop.

 

Nope only use Dot 3 or 4..............

 

Unfortunately Dot 5 Silicone Fluid creates lots of issues on a street vehicle. Most seals in everyday use are not compatable with the fluid.

 

I've used DOT 5.0 since the 80's and have not noticed any problems. Sure is nice not having to worry about the paint !

 

I wasn’t aware that silicone would negatively affect rubber parts.

 

Here's just one article on Silicone fluid, plenty more out there.
Brakes - silicone brake fluid
Regards,

 

Interesting article on silicone brake fluid. If it acts as the article says it does, seems there’s not much advantage to using it!