Wilwood Brake pedal travel question

[95050JohnR]

Hello All. I've never had a car with manual brakes so I'm looking for some reassurance that my brake system is correct. Finally got the system bled and noticed the brake pedal travels about 1" before becoming rock hard. I'm still on a chassis dolly, but all 4 corners appear to lock up when the brakes are applied. I'm using Wilwood brakes/pedal box and preemptively swapped to Tilton 76 series MCs (13/16" front and rear). The MC sizes were spec'd for me by a fellow local builder, but unfortunately, he passed away before I got to the point I'm at today. I have the balance bar set (I think) evenly at the moment. I just want to make sure I'm in the ballpark for expected pedal travel and the sizing of the MCs aren't an issue before I start buttoning up the engine bay aluminum in case changes are needed.

John

[michael everson]

Sounds perfect. It should be rock hard.
Mike

[rponfick]

I am at the same point on my MK5. I am using Wilwood MC, 3/4", and have at maximum of the 1-inch travel you mention. Not sure how 13/16" bore would affect travel. I thought the 75 series Tilton MC fit easily, not the 76's. I understand there is a lot of discussion on Wilwood vs. Tilton, but not the issue here.
My brakes were easy to bleed and get solid, but not there yet on hyd TOB clutch.
Ralph

[95050JohnR]

Thanks Mike and Ralph. The mention of the bore size was just another datapoint to give a complete picture of my setup. FWIW, the Tilton 76's fit fine in my MKIV, but it was kind of a pain sourcing barbs, hoses and fittings.
John

[Jeff Kleiner]

...Not sure how 13/16" bore would affect travel. I thought the 75 series Tilton MC fit easily, not the 76's....
Ralph

Ralph,
FYA a 13/16" master will require less travel 3/4" to move the same volume of fluid. The Tilton 76 fit all 3 positions of the pedal box on a Mk5; the 75s do not. The 75 will fit all 3 positions in a Mk4.

[Mike.Bray]

I have Wilwood brakes all around and Tilton 76 master cylinders with a Tilton HRB. I ended up with a 3/4" on the front brakes, a 1" on the rear brakes, and a 13/16" on the clutch. 13/16" all around sounds a bit odd, you might want to double check that. Give Tilton a call, they can help.

[95050JohnR]

Thanks Mike. Yeah, that's what I'm worried about. I'll call Tilton on Monday. Do you happen to know what info they'll need (i.e. just caliper part numbers or do I need to add total piston area myself, etc...). Since I have 13/16 front and rear, and 1" for clutch (planning to go external slave route), swapping some MC's around may be in my future.

[Mike.Bray]

They'll have you fill out a form like this.

224022

[Aleinsteingenius]

I have Tilton 3/4" Series 75 and 13/16" Tilton Series 75 in my Mark V. They do fit...barely.224026

[95050JohnR]

They'll have you fill out a form like this.

224022

Thanks Mike.

[rponfick]

Ralph,
FYA a 13/16" master will require less travel 3/4" to move the same volume of fluid. The Tilton 76 fit all 3 positions of the pedal box on a Mk5; the 75s do not. The 75 will fit all 3 positions in a Mk4.

Jeff, thanks good to know if I use a Tilton.
Did they change something in the pedal box area of the MK5 to not allow the 75 to fit, but will fit in the MK4? Is the 76 smaller than the 75? Just curious, as I can order whichever fits best.
Thanks, Ralph

[M22_COBRA]

I just submitted my sheet and they came back 13/16 for both front and rear on 45/55 and 40/60 distribution.
224434

[95050JohnR]

Just heard back from Tilton....they recommended 7/8" front and rear. Question for those with more experience on this than me: Would there be a noticeable difference between 7/8" vs. 13/16"?
224482

[M22_COBRA]

Looks like you have 6 piston fronts and 4 rears. It will be more travel on the pedal if you use the 13/16 vs 7/8 (CORRECTED). My setup above requires less due to less required volume to move the pistons X distance, thus 13/16 Tilton recommendation. You could call them to see how close you are to threshold on a 7/8 but that sounds like where you should be based on what they told me.

[95050JohnR]

M22_COBRA - yeah, I inquired with Tilton. They said I could try the 13/16" and see how they work since they're already installed. They mentioned that if the pedal is near the end of travel (or the car just doesn't stop well), I'll need more volume. I don't think I'm near full travel as there's only about 1" of pedal travel and even less than that of actual MC plunger travel.

[Jeff Kleiner]

... Question for those with more experience on this than me: Would there be a noticeable difference between 7/8" vs. 13/16"?




...It will be more effort and potentially more travel on the pedal if you use the 13/16 as you need to move more fluid to move the piston volume. ...

M22, this is incorrect. A smaller master will require more travel but take less effort to displace the same volume of fluid,

Jeff