Where to cut the firewall for the master cylinder

[Buckster]

I have seen many ad trucks with firewall mounted master cylinders. I am planning on using one from a 2000 s10 .I just don't want to mess up the hole location when i go to do the set up. any one have this info.
Thanks,

[LOW A D]

If using a firewall mounted booster, it will bolt to your brake pedal inside the firewall. I usually put the pedal where it is comfortable, that will then determine where the booster goes. Make sure your pedal doesnt hit your column and the booster has room without hitting your inner fender etc. before making your hole in the firewall

[slammed57]

I just did this last week, first mock up your pedal assembly (make sure for pedal travel as well as it being comfortable for your feet). then take measurements of reference points of where the clevis/rod for the master cylinder will be, so you can refer to when you go outside to the engine bay and mark where that clevis/rod will be. if you are using a booster then measure out where you marked to see how much clearance to the valve covers to allow enough room to remove the valve cover , also allow clearance if you have the inner fender removed

[joedoh]

yes, what low ad and slammed said is right, you need your pedal assembly and column mocked up to find the position.

I use mostly 98-03 s10 parts and I use the firewall chunk from the s10, mock up the pedal and column mounts, and weld in the firewall chunk. usually the booster does not mount 90 degrees to the firewall, it has a slight tilt backwards that the firewall chunk captures for me.

[62 Barnfind]

Originally Posted by joedoh

yes, what low ad and slammed said is right, you need your pedal assembly and column mocked up to find the position.

I use mostly 98-03 s10 parts and I use the firewall chunk from the s10, mock up the pedal and column mounts, and weld in the firewall chunk. usually the booster does not mount 90 degrees to the firewall, it has a slight tilt backwards that the firewall chunk captures for me.

Exactly what they said. I installed the pedal then cut the hole.

[whitedog76]

I initially picked up a clutch and brake pedal assembly for a Jeep TJ and was planning on using it.

When I was crawling around at the U-pull yard one day, I came across a Hydroboost unit and assembly from a GM van. $30 later and I couldn't be more pleased on how it fits.

[whitedog76]

http://www.67-72chevytrucks.com/vboa...1&d=1542147179

http://www.67-72chevytrucks.com/vboa...1&d=1542407115

http://www.67-72chevytrucks.com/vboa...1&d=1542407253